2013-05-18T10:32:58Zhttp://scholar.sun.ac.za/oai/request

oai:scholar.sun.ac.za:10019.1/15652013-03-22T14:54:17Zhdl_10019.1_532

The effect of different vineyard management systems on the epigaeic arthropod assemblages in the Cape Floristic Region, South AfricaGaigher, ReneVineyard management StellenboschBiodiversity conservation StellenboschEpigaeic anthropodsDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyIn the Cape Floristic Region of South Africa, where wine grape production and biodiversity conservation are of major importance, innovative management of the landscape is necessary to integrate the two activities. Alternative farming, such as organic and biodynamic farming, focuses on the preservation of biological processes in agroecosystems with the aim of increasing the sustainability of these sytems. It has been demonstrated in other regions that alternative farming can enhance biodiversity. This study assessed the potential of alternative vineyard management to conserve biodiversity, in particular epigaeic arthropod diversity, relative to the more widespread integrated vineyard management in the CFR. A hierarchical design was used, consisting of three localities, with three land-uses nested within each locality. The land-uses were alternative vineyards, integrated vineyards and natural vegetation sites as reference habitats. Sampling was done in June and October 2006 using pitfall traps. Nested ANOVAs were used to test for differences in abundance and species richness of the total assemblages, functional feeding guilds and selected generalized predatory taxa. Assemblage patterns were assessed using hierarchical agglomerative clustering and non-metric multidimensional scaling. Canonical correspondence analyses were used to evaluate the effects of environmental variables, management practices and landscape variables on community composition. Alternative vineyards supported a significantly higher overall arthropod abundance and species richness, more diverse predatory, saprophagous, phytophagous and omnivorous guilds, as well as more abundant and speciose spider and rove beetle assemblages than the integrated vineyards. Integrated vineyards harboured a greater abundance of predators, whereas results for nectarivores, wood borers, parasitoids and carabid beetles were variable. The differences could be explained in part by higher non-crop vegetation complexity and reduced management intensity of the alternative vineyards. Community composition was influenced by a combination of management practices, the surrounding landscape and geographic locality, which highlighted the interdependence of the cultivated land and its surroundings.Thesis (MScConsEcol (Conservation Ecology and Entomology)--Stellenbosch University, 2008.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Samways, M. J.2008-09-11T10:24:15Z2010-06-01T08:27:30Z2008-09-11T10:24:15Z2010-06-01T08:27:30Z2008-12Thesishttp://hdl.handle.net/10019.1/1565enStellenbosch University

oai:scholar.sun.ac.za:10019.1/15902013-05-11T22:02:58Zhdl_10019.1_532

Use and conservation status of medicinal plants in the Cape Peninsula, Western Cape Province of South AfricaMintsa Mi Nzue, Agnan PierreDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyMedicinal plants -- South Africa -- Cape PeninsulaMedicinal plants -- Conservation -- South Africa -- Cape PeninsulaThesis (MScConsEcol(Conservation Ecology and Entomology)--University of Stellenbosch, 2009.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Watts, Scotney2009-02-27T12:56:10Z2010-06-01T08:28:05Z2009-02-27T12:56:10Z2010-06-01T08:28:05Z2009-03Thesishttp://hdl.handle.net/10019.1/1590enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/16272011-06-23T11:45:48Zhdl_10019.1_532

Comparative impacts of fragmentation on birds in two bioregions in a biodiversity hotspot, the Cape Floristic RegionKieck, Marius BurgerRenosterveldTheses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyBird populations -- South Africa -- Western CapeFragmented landscapes -- Environmental aspects --South Africa -- Western CapeBiodiversity -- South Africa -- Western CapeHabitat conservation -- South Africa -- Western CapeConservation Ecology and EntomologyHabitat loss and fragmentation are two of the most pressing threats to biodiversity. Avifaunal diversity and integrity is under immense pressure from these two processes. We have made major advances in our understanding of avifaunal responses to habitat fragmentation, but mostly focus on either fragment scale and/or landscape scale influences of fragmentation on birds. A more comprehensive approach to assessing the impacts of fragmentation was used in this study. The avifaunas of two different geographical regions and bioregions were surveyed and a multiscale analysis of avifaunal responses to fragmentation was attempted. The study sites include the West Coast and East Coast Renosterveld Bioregions in the Cape Floristic Region, South Africa. Assemblage shifts, feeding guild compositional changes, species abundance variation and species persistence were examined at the three spatial scales. Time- and distance-restricted point counts were used to document birds that were directly dependent on the habitat fragments. Forty fragments were selected in each bioregion and a once-off snapshot of the avifaunal richness and diversity was obtained. Results indicate that the avifauna of the two bioregions responded differently to habitat fragmentation. In the East Coast Renosterveld Bioregion, the assemblages, guild composition and species abundances were most accurately predicted by landscape configuration. An assemblage shift occurred at 20 ha fragment area, compared to the 50 ha fragment area threshold of the West Coast Renosterveld Bioregion’s avifauna composition. In the West Coast Renosterveld Bioregion, fragment area was the better predictor of assemblage, guild composition and species abundances. However in both bioregions, the persistence of common species was equally sensitive to area and landscape scale effects.Thesis (MScConsEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2009.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Krug, Cornelia B.Lloyd, PennSamways, Michael J.2009-03-03T08:42:25Z2010-06-01T08:29:00Z2009-03-03T08:42:25Z2010-06-01T08:29:00Z2009-03Thesishttp://hdl.handle.net/10019.1/1627enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/16552013-01-21T08:27:47Zhdl_10019.1_532

Management of Acacia species seed banks in the Table Mountain National Park, Cape Peninsula, South AfricaJasson, ReneAlien plant management techniquesFireFynbosRiparian systemsSoil seed banksDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyWithin the Table Mountain National Park (TMNP), Western Cape, South Africa, various management practices have been undertaken in the removal of alien vegetation. While considerable success in the control of alien plants is evident from the removal of standing plants, it is not known if this effort has actually made any long-term difference in the effort to eliminate alien vegetation from the TMNP. This is because no coordinated effort has been made to assess the extent of the alien seed bank, nor the effect that clearing (including the use of fire) has on this seed store. This study investigates the extent of pre- and post-fire Acacia saligna seed banks under differing stand ages, differing clearing techniques and different habitats in the Cape Peninsula National Park. Firstly, the focus is on two alien plant management techniques: The first technique involves clearing and stacking of biomass for burning during winter (stack burn technique), the second technique involves burning of standing alien plants (standing/block burn technique) to decrease heat release at the surface. Secondly, the extent of Acacia species seed banks along the Silvermine River is also investigated with the aim of determining the extent of alien seed stores in this habitat and therefore the long-term restoration potential of the riparian corridor. The primary question addressed in the first study is: “Under what clearing technique will most of the alien seed bank be reduced?” The secondary question reads: “Is seed bank density and distribution directly related to age of dense infestation of the alien vegetation stand and habitat?” The primary question addressed in the second study is: “What is the vertical, lateral and longitudinal distribution and density of Acacia species seed banks along the Silvermine River?” The secondary question reads: “Is seed density and distribution influenced by above ground density of alien vegetation?” In both riparian and terrestrial systems, alien soil seed banks accumulate in high densities where aboveground alien Acacia vegetation is dense. Most of the seed occurs in the upper soil layer, but seed density decreases with depth with an exception of a high seed density at a low depth in one of the samples in the riparian system. Intense fires are most effective in reducing seed stores and removing aboveground alien vegetation in both riparian and terrestrial fynbos systems. After burns, both stack and stand burns have shown a significant decrease in seed density especially in the upper layers but there is still much seed that remained in the matrix area between stacks. The cooler winter burns resulted in less destructive, lower temperatures that aided higher seedling recruitment. Mature stands of Acacia saligna tend to have greater seed stores than immature stands and habitats with deep colluvial soils have a greater density and also greater vertical distribution of seeds. The vertical distribution of the riparian system differed from the fynbos terrestrial system in that seeds were found down to lower depths. Along the river, seed density also increased laterally with more seeds occurring in the terrrestrial sections than in the channel. Seed density increased with longitudinal distribution with more seeds occurring at the sites in the lower catchment than upper catchment. Managers should be aware that fire is needed to reduce the seed bank in both riparian and terrestrial fynbos systems. The cooler winter stack burns is the best option as it results in less destructive, lower temperatures that aids higher seedling recruitment. It is important to know the site history as age of dense infestation, number of fires and geology of site could influence seed bank density. In riparian systems the vertical distribution of seed is deeper than in the fynbos area. In order for clearing to be effective it is imperative that follow-up takes place and should be done prior to flowering to stop reseeding.Thesis (MScAgric (Conservation Ecology and Entomology)--University of Stellenbosch, 2005.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Esler, K. J.Holmes, P.2008-07-15T12:11:53Z2010-06-01T08:29:52Z2008-07-15T12:11:53Z2010-06-01T08:29:52Z2005-12Thesishttp://hdl.handle.net/10019.1/1655enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/17102013-03-22T16:10:48Zhdl_10019.1_532

Conservation biogeography of South African dragonflies (Odonata)Simaika, John P.DragonfliesFreshwater managementFreshwater conservationHabitat quality indicatorsFreshwater invertebrate distribution mappingRed ListingBiodiversity indicesTheses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyDragonflies -- South AfricaDragonflies -- South Africa -- Geographic distributionWater quality biological assessmentn -- South AfricaHabitat (Ecology) -- South AfricaIndicators (Biology) -- South AfricaConservation Ecology and EntomologyThe great pressures on freshwaters require their conservationists and managers to develop methods to rapidly and accurately assess their condition. Dragonflies are excellent indicators of habitat integrity and are effective organisms for this purpose. However, assessment must be done at the correct spatial scale. My aim here is to optimize the spatial resolution at which species are mapped, using three different concepts and methods in freshwater invertebrate distribution mapping, with special emphasis on IUCN Red Listing. The first is the extent of occurrence (EOO) concept, using the minimum convex polygon, and the second, the area of occupancy (AOO) concept, using IUCN and quaternary catchments. The third approach uses a river layer to compare the suitability of grids as opposed to catchments in mapping. In this study I found that area estimation based on minimum convex polygons should not be encouraged for aquatic organisms. This study also suggests that the IUCN concept of area of occupancy (AOO) should be redefined simply as occurrence, referring to known point-locality presences only and, if future data allow, to known absences. The IUCN extent of occurrence (EOO), for aquatic species, should be defined as ‘the sum of the smallest hydrological units identified of presently known, inferred or projected occurrences of a taxon, excluding cases of vagrancy, that are used to estimate the threat to a taxon’. A single hydrological unit is also the conservation or management unit. Currently, that unit is the quaternary catchment. Dragonflies have excellent potential as indicators of habitat integrity. For this purpose, my aim was to develop the Dragonfly Biotic Index (DBI) for South Africa and compare the DBI to another index, the Average Taxonomic Distinctness Index (AvTD), which was believed to have potential in assessments. The DBI and AvTD are correlated, which suggests that they could be used on a complementary basis to prioritize sites. The DBI is a low-cost, easy-to-use method and is already used for measuring habitat recovery. It has great potential for environmental assessment and monitoring freshwater biodiversity, especially as a complement to freshwater quality assessments that use macroinvertebrate scores. I thus recommend its integration into freshwater management and conservation schemes.Thesis (MScConsEcol (Conservation Ecology and Entomology))--Stellenbosch University, 2008.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Samways, Michael J.2008-11-12T09:19:46Z2010-06-01T08:31:15Z2008-11-12T09:19:46Z2010-06-01T08:31:15Z2008-12Thesishttp://hdl.handle.net/10019.1/1710enStellenbosch University

oai:scholar.sun.ac.za:10019.1/17592011-06-23T11:27:32Zhdl_10019.1_532

Assessment of quantitative and genetic molecular variation of Acacia karroo in two extreme populationsBayonne Mboumba, GeorgesTheses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyPhenotypic plasticity -- South AfricaAdaptation (Biology) -- South AfricaAcacia -- Adaptation -- South AfricaConservation Ecology and EntomologyAcacia karroo is widespread in southern Africa and displays remarkable phenotypic plasticity over its geographical range. However, it is currently unknown whether this phenomenon is merely phenotypic variation due to environmental variance or whether such plasticity represents adaptation to different habitats (known as adaptive phenotypic plasticity). Adaptive phenotypic plasticity implies that genotypes differ and that there is local adaptation to the local environment. To shed light on this phenomenon, we used a common-garden experiment to investigate among-population variation in plastic responses to simulated rainfall and browsing in two populations originating from contrasting environments, namely arid Karoo (Leeu Gamka) and subtropical coastal forest (Richards Bay). We also studied genetic variation among populations by means of allozyme markers. The results suggest that the populations investigated are both genetically distinct and phenotypically plastic. In addition, there were high levels of polymorphism within populations and great differences in their range of plastic responses to treatments. Of the two populations investigated, the slow-growing one (Leeu Gamka) was phenotypically more plastic with regard to defence-related traits (longer spines, more tannin) while the fast-growing one (Richards Bay) was phenotypically more plastic regarding growth-related traits (taller, with longer leaves). Patterns of performance revealed that the populations have pure strategies of either growth (forest) or defence (arid). The interactions between populations and environments in some traits indicated genetic differentiation in plastic responses between populations and, consequently, that phenotypic plasticity is locally adaptive and not merely due to environmental differences. The two populations appear to have pure strategies; when environmental conditions were improved by addition of water, the forest population increased investment in growth but not defence, while the arid populations increased defence production but not growth.Thesis (MScConsEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2006.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Ward, David2008-01-22T10:52:26Z2010-06-01T08:32:37Z2008-01-22T10:52:26Z2010-06-01T08:32:37Z2006-03Thesis1116864 bytesapplication/pdfhttp://hdl.handle.net/10019.1/1759enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/18002013-01-21T09:08:17Zhdl_10019.1_532

Effect of invasion and clearing of alien riparian vegetation on benthic macroinvertebrate and adult odonata assemblages in Soutpansberg riversMagoba, Rembuluwani Norman NicholasBenthic macroinvertebratesOdonataAlien vegetationDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyPlant invasions -- South Africa -- Soutpansberg AreaFreshwater invertebrates -- Effect of habitat modification on -- South Africa -- Soutpansberg AreaBenthic animals -- Effect of habitat modification on -- South Africa -- Soutpansberg AreaOdonata -- Effect of habitat modification on -- South Africa -- Soutpansberg AreaBenthic macroinvertebrates (sampled using South African Scoring System, SASS5) and adult male Odonata (sampled with close-focus binoculars) were recorded on two streams and a river of Soutpansberg, with the aim of determining the effect of invasion and removal of alien riparian vegetation on their assemblages. A secondary aim was to establish the importance of dragonflies as indicators of degree of disturbance in rivers. Forty two aquatic macroinvertebrate families and 33 adult Odonata species were recorded at a total of 71 sampling units. Three distinct riparian vegetation types were selected (natural, alien and cleared). Cleared vegetation refers to clearing of invasive alien trees, allowing regrowth of natural vegetation. Natural and cleared vegetation supported more benthic macroinvertebrate families compared to alien vegetation. Certain families that were lost to alien vegetation were recorded from natural vegetation. The highest SASS5 score was recorded from natural vegetation, followed by cleared vegetation, and the lowest was from alien vegetation. The highest number of adult Odonata was recorded at cleared vegetation, with alien and natural vegetation supporting the least number of Odonata species. Vegetation type, stream flow and microhabitats were statistically identified as the most influential variables for benthic macroinvertebrate assemblages. For adult Odonata assemblages, vegetation type, shade and temperature were the most important environmental variables. Species assemblages of adult Odonata can be used as indicators of environmental condition of rivers. The clearing of alien riparian vegetation clearly benefits the indigenous benthic macroinvertebrates as conditions are restored to their natural state. It also benefits dragonfly species richness, but if natural succession proceeds to a shaded tree canopy, the effect becomes similar to that of habitat shaded by alien vegetation. The impact of alien vegetation is to reduce sun-loving invertebrate species, especially dragonflies, with lesser impact on shade-loving species.Thesis (MScAgric (Conservation Ecology and Entomology)--University of Stellenbosch, 2005.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Samways, M. J.2006-09-27T12:01:10Z2010-06-01T08:33:38Z2006-09-27T12:01:10Z2010-06-01T08:33:38Z2005-12Thesis4946903 bytesapplication/pdfhttp://hdl.handle.net/10019.1/1800en_ZAUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/18352011-06-23T11:25:35Zhdl_10019.1_532

Approaches towards a critical evaluation and update of the red list of South African ButterfliesBall, Johathan BradfordTheses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyRare butterflies -- South AfricaEndangered species -- South AfricaConservation Ecology and EntomologyUsing the World Conservation Union’s (formerly the International Union for the Conservation of Nature) IUCN 2001 categories and criteria, the conservation status of the South African butterfly fauna has been reassessed. This study includes an assessment of the 62 globally threatened South African taxa and 1 that has a marginal distribution in this region.Thesis (MScConsEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2006.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Geertsema, H.Samways, M. J.2006-11-02T09:17:52Z2010-06-01T08:34:27Z2006-11-02T09:17:52Z2010-06-01T08:34:27Z2006-03Thesis20160844 bytes225958 bytesapplication/pdfapplication/pdfhttp://hdl.handle.net/10019.1/1835University of Stellenbosch

oai:scholar.sun.ac.za:10019.1/18812013-03-23T12:07:35Zhdl_10019.1_532

The effect of spatial scale on the use of biodiversity surrogates and socio-economic criteria in systematic conservation assessmentsPayet, KarineBiodiversity conservationSystematic conservation planningBiodiversity surrogatesDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyA systematic conservation assessment is the first phase of a systematic conservation planning protocol; it uses spatial data and representation targets for the setting of priority areas and the assessment of risk to biodiversity. This thesis describes the findings of investigations on the use of data in systematic conservation assessments. Conservation planning can be done at different spatial scales (from global to local). Systematic Conservation planning can be done at different spatial scales (from global to local). Systematic conservation assessments rely on the use of surrogates for biodiversity and often, as well, socioeconomic criteria. Biodiversity surrogates can be classified as taxonomic, community and environmental. In Chapter 2, a literature review was performed (i) to quantify the use of biodiversity surrogates and socio-economic criteria in conservation assessments; and (ii) to test the hypothesis that surrogates are chosen in respect to the hierarchical organisation of biodiversity. In other words, fine scale conservation assessments are correlated with taxonomic surrogates, large scale conservation assessments are correlated with environmental surrogates, and assemblage surrogates are assessed at an intermediary scale. The literature review was based on a structured survey of 100 ISI journal publications. The analysis revealed that spatial scale had a weak effect on the use of biodiversity surrogates in conservation assessments. Taxonomic surrogates were the most used biodiversity surrogates at all scales. Socioeconomic criteria were used in many conservation assessments. I argue that it is crucial that assemblage and environmental data be more used at larger spatial scales. The allocation of conservation resources needs to be optimised because resources are scarce. A conservation assessment can be a lengthy and expensive process, especially when conducted at finescale. Therefore the need to undertake a fine-scale conservation assessment, as opposed to a more rapid and less expensive broader one, should be carefully considered. The study of Chapter 3 assessed the complementarity between regional- and local-scale assessments and the implications on the choice of biodiversity features at both scales. The study was undertaken in Réunion Island. A biodiversity assessment was performed at a regional scale and measured against a finer-scale assessment performed over a smaller planning domain. Two datasets composed of species distributions, habitat patterns and spatial components of ecological and evolutionary processes were compiled as biodiversity surrogates at each scale. Targets for local-scale processes were never met in regional assessments, while threatened species and fragmented habitats were also usually missed. The regional assessment targeting habitats represented a high proportion of local-scale species and habitats at target level (67%). On the contrary, the one targeting species was the least effective. The results highlighted that all three types of surrogates are necessary. They further suggested (i) that a spatial strategy based on a complementary set of coarse filters for regional-scale assessments and fine filters for local-scale ones can be an effective approach to systematic conservation assessments; and (ii) that information on habitat transformation should help identify where efforts should be focused for the fine-scale mapping of fine filters. Together with priority-area setting, the identification of threatened biodiversity features has helped to prioritise conservation resources. In recent years, this type of assessment has been applied more widely at ecosystem-level. Ecosystems can be categorised into critically endangered, endangered and vulnerable, following the terminology of the IUCN Red List of threatened species. Various criteria such as extent and rate of habitat loss, species diversity and habitat fragmentation can be used to identify threatened ecosystems. An approach based only on the criterion of the quantification of habitat loss was investigated in Chapter 4 for the Little Karoo, South Africa. Habitat loss within ecosystem type is quantified on land cover information. The study analysed the sensitivity of the categorisation process to ecosystem and land cover mapping, using different datasets of each. Three ecosystem classifications and three land cover maps, of different spatial resolutions, were used to produce nine assessments. The results of these assessments were inconsistent. The quantification of habitat loss varied across land cover databases due to differences in their mapping accuracy. It was reflected on the identification of threatened ecosystems of all three ecosystem classifications. Less than 14% of extant areas were classified threatened with the coarsest land cover maps, in comparison to 30% with the finest one; and less than 9% of ecosystem types were threatened with the coarsest land cover maps, but between 15 and 23% were threatened with the finest one. Furthermore, the results suggested that the identification of threatened ecosystems is more sensitive to the accuracy of habitat loss quantification than the resolution of the ecosystem classification. Detailed land cover mapping should be prioritised over detailed ecosystem maps for this exercise. This thesis highlighted the importance of ecosystems and processes as biodiversity surrogates in conservation assessments and suggested that results of conservation assessments based on these data, should be more widely presented in published articles. Finally, it also made apparent the important role of mapping habitat transformation for systematic conservation plans.Thesis (MSc (Conservation Ecology and Entomology)--Stellenbosch University, 2007.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Esler, K. J.Rouget, M.2008-06-25T10:21:55Z2010-06-01T08:35:33Z2008-06-25T10:21:55Z2010-06-01T08:35:33Z2007-12Thesishttp://hdl.handle.net/10019.1/1881enStellenbosch University

oai:scholar.sun.ac.za:10019.1/19282013-03-23T08:41:01Zhdl_10019.1_532

Initial investigation of Trichogrammatoidea lutea (Hymenoptera: Trichogrammatidae) as biological control agent of codling moth, Cydia pomonella (Lepidoptera: Tortricidae), in apple and pear orchards, under sterile insect technique (SIT)Wahner, NadineTrichogrammatoidea luteaBiological controlCodling mothParasitoidDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyCodling moth (CM), Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae), is the major pest of apples and pears in the South Western Cape, South Africa. Apart from conventional insecticide sprays, area-wide biologically intensive control methods, such as Sterile Insect Technique (SIT) and pheromone mediated mating disruption (MD) are currently in use on two farms in the Elgin valley. The indigenous parasitoid Trichogrammatoidea lutea Girault (Hymentoptera: Trichogrammatidae) attacks eggs of false codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), as well as CM and has been found to have considerable parasitism potential on both. Elevated host egg numbers, as achieved by SIT are thought to support establishment of populations of these natural enemies in the orchards. For rapid and secure Trichogrammatoidea species identification, the ITS2 sequences of Trichogrammatoidea lutea and T. cryptophlebiae Nagaraja (an indigenous FCM parasitoid on citrus) were determined and species specific primers were developed. Lifetable studies of T. lutea indicated an optimal temperature for reproduction at around 20 °C. Food was provided by the application of honey-solution soaked cotton wool, behind fine netting. The effect of food provision by this method was found to be dependent on temperature. The acceptance of CM eggs from sterilized vs. fertile parents and of radiation-sterilized eggs vs. fertile ones was assessed in choice trials. While no difference was observed between radiated and fertile eggs, sterile eggs from irradiated parents were significantly less attractive than eggs from fertile parents. In several field studies the dispersal capacity and population sustainability of released T. lutea were investigated. Trials took place in apple and pear orchards in the Elgin valley that formed part of an area-wide sterile CM SIT program. Most of the wasp releases were carried out within blocks of up to 1 ha. A square grid of up to 36 monitoring trees per block allowed spatial distribution analysis. Following single central point releases, parasitism of sentinel eggs was recorded until the end of all experiments, the longest of which lasted 37 weeks. T. lutea females were found to disperse up to 73 m, within one week. Studies concerning toxicity of four commonly used insecticides and one fungicide to immature and adult T. lutea indicated no to low susceptibility of wasps at egg- to first-instar-stage within host eggs. Contact toxicity of the tested materials to adults differed significantly, depending on the compound. All five pesticides caused significantly higher mortality among adults relative to the control. The overall aim of above studies was to determine the potential of T. lutea for broad-scale releases against CM, within a broader integrated pest management program in apple and pear orchards in the Western Cape.Thesis (MScAgric (Conservation Ecology and Entomology))--Stellenbosch University, 2008.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Addison, PiaAddison, Mathew2008-11-27T07:52:00Z2010-06-01T08:36:49Z2008-11-27T07:52:00Z2010-06-01T08:36:49Z2008-12Thesishttp://hdl.handle.net/10019.1/1928enStellenbosch University

oai:scholar.sun.ac.za:10019.1/19562013-03-23T08:43:09Zhdl_10019.1_532

Old field restoration : vegetation response to soil changes and restoration efforts in Western Cape LowlandsMemiaghe, Herve RolandOld field restoration -- Western CapeVegetation -- Western CapeSoil properties -- Western CapeDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyRangelands -- Revegetation -- South Africa -- Western CapePlant succession -- South Africa -- Western CapePlant-soil relationships -- South Africa -- Western CapeInvasive plants -- Control -- South Africa -- Western CapeAlien plants -- Control -- South Africa -- Western CapeIn the Mediterranean climate regions of the world, agricultural practices have caused considerable landscape transformation and lead to introduction of alien species that now dominate secondary succession on abandoned agricultural fields. Various restoration attempts have been made to reduce alien plant species cover, and to enhance the re-establishment and cover of native plant species. However, results and successes were mostly short-term due to re-growth and persistence of the weedy alien species, which has been suggested to be caused by land use history, especially the nutrient enrichment of soil, and particularly phosphorus and nitrogen. This study investigated different soil properties (pH, electrical conductivity (EC), soil moisture, as well as available phosphorus (P) and total nitrogen (N)) on 10 and 20 year old abandoned fields, as a function of depth in three habitats (ridge (old cultivated area), ditch (old drainage line) and slope (intermediate zone between ridge and ditch)) on the old fields. The relationship between these soil properties and the vegetation occurring on the two old fields was established. At the same time, restoration treatments (autumn burn, combination of autumn burn and herbicide, herbicide application alone, as well as spring burn) were conducted to reduce the cover and abundance of non-native plant species and Cynodon dactylon, and to enhance cover of native species. Results from the study show that levels of all investigated soil properties were higher on the younger field. The highest difference was observed in EC and pH. Seasonal differences in both soil properties could also be observed. A principal component analysis indicated that the dynamic of all soil properties shaped the vegetation type on old fields, with the main soil properties being dependent on land-use history and time since abandonment. This study suggests that EC and pH could be part of parameters that drive the persistence of undesirable species persistence on old fields and inhibit native plant species instead.Thesis (MScConsEcol (Conservation Ecology and Entomology))--Stellenbosch University, 2008.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Krug, Cornelia B.Rozanov, A.2008-11-25T16:09:36Z2010-06-01T08:37:25Z2008-11-25T16:09:36Z2010-06-01T08:37:25Z2008-12Thesishttp://hdl.handle.net/10019.1/1956enStellenbosch University

oai:scholar.sun.ac.za:10019.1/19992011-06-23T11:32:42Zhdl_10019.1_532

Assessment of veld utilisation practices and veld condition in the Little KarooCupido, Clement F.Theses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyGrazing -- South Africa -- Little Karoo -- ManagementGrazing -- Environmental aspects -- South Africa -- Little KarooVeld -- South africa -- Little Karoo -- ManagementRangelands -- Monitoring -- South Africa -- Little KarooConservation Ecology and EntomologyThe veld condition in the Little Karoo is in various states of degradation and grazing by domestic livestock is considered as the major anthropogenic force that changed the landscape. This region with its extremely rich plant species diversity and endemics, has supported small livestock for at least 2 000 years, and since colonization (250 years ago) been intensively used for the production of a variety of livestock. Ostrich production developed as the major source of income for this region. The first part of this study investigates the current veld management practices employed by livestock farmers in the Little Karoo region. Recommended veld management practices considered in this study are grazing rotation, moderate stocking rate control, moderate veld utilisation, separation of ecotopes, veld rehabilitation, controlling declared weeds and alien vegetation and regular assessment of veld condition. One hundred randomly selected farmers were personally interviewed by means of a structured questionnaire. Questions were grouped into the following categories: (a) demography of farmers, (b) ostrich farming, (c) perceptions and knowledge of farmers on farming practices, (d) grazing rotation, (e) stocking rate, (f) veld utilisation and veld assessment, (g) separation of ecotopes, (h) veld rehabilitation, (i) control of alien vegetation and (j) farmers’ knowledge on legislation. This was used to obtain information on the Little Karoo farming community, sizes of farms and camps, types of farming enterprises and on adoption of recommended veld management practices in the region. The main findings from this section are that relatively small farming units with few camps, poor separation of ecotopes and a low estimated grazing capacity, limit extensive livestock farming within the region. Perceptions of farmers on veld condition, grazing rotation, stocking rate, separation of ecotopes are fairly optimistic. As a result grazing capacities are overestimated and overstocking occurs within this region. The current stocking rate in ostrich camps (67.7% overstocked) and mammalian livestock camps (55.1% overstocked) is evidence that farmers overstock to compensate for these limiting factors in order to make a living from the land. The majority of farmers are well aware of the Articles in the Conservation of Agricultural Resources Act of 1983, which are applicable to veld management. Only more that 50% comply with this legislation by rehabilitating veld and 80% of them control invasive alien species on their farm. In the second part, veld assessments were done in randomly selected veld camps, using the multi-criterion, semi-subjective Quick Rangeland Health Assessment (QRHA) Method. Veld condition was significantly poorer closer to water or feeding points due to the piosphere effect caused by livestock. Veld condition in the Little Karoo can be related to altitude, vegetation types and land use. Therefore, the lowlying Little Succulent Karoo vegetation type is in a poorer condition compared to Spekboom Succulent Thicket and South and South-west Coast Renosterveld. Ostrich production on plains in the Little Succulent Karoo vegetation type is the main cause for the degradation of this vegetation type. It would seem as if historically high stocking rates cannot be ignored in explaining the current veld condition. A positive correlation between veld condition and the diversity of plant species (species density) were found, which highlights the importance of good veld management practices in sustainable agriculture. The third part tested whether all indicators in the QRHA method are equally sensitive and whether there is a positive correlation between the QRHA method and the Grazing Index Method. A significant positive linear correlation was found between the two methods. Cover was the least sensitive indicator of rangeland condition, and livestock induced disturbances (which include the indicators grazing intensity, disturbance indicators, soil health and species richness) were the most sensitive for Karoo veld assessment. A major benefit of the QRHA method is heuristic; therefore this method may have value in agricultural extension work.Thesis (MScConsEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2005.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Milton, S. J.Visser, N.2008-07-07T12:55:47Z2010-06-01T08:38:26Z2008-07-07T12:55:47Z2010-06-01T08:38:26Z2005-03Thesishttp://hdl.handle.net/10019.1/1999enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/20412013-01-21T07:29:06Zhdl_10019.1_532

Effects of gaseous emissions from the Namakwa Sands Mineral Separation Plant near Lutzville on the adjacent succulent Karoo vegetation : a pilot studyLukama, Beatice M. K.Dissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyNamakwa Sands Mineral Separation PlantSucculent plants -- Effect of acid deposition on -- South Africa -- LutzvilleSucculent plants -- Effect of gases on -- South Africa -- LutzvilleMineral industries -- Environmental aspects -- South Africa -- LutzvilleAcid-forming emissions -- Environmental aspects -- South Africa -- LutzvilleA pilot study was conducted at the Namakwa Sands Mineral Separation Plant, to investigate the effects of acidic gaseous emissions from the Mineral Separation Plant on the adjacent Succulent Karoo vegetation. Sulphuric acid fumes, a major gaseous emission of the mineral processing, was the subject of investigation of the present study, due to the potential high negative impact of elevated concentrations thereof on vegetation in the ecosystem. Permanent sample plots along three transects radiating from the Mineral Separation Plant were laid out in the eastern, south-eastern and southern directions following the prevailing wind directions and practical consideration of land accessibility. The ecological components assessed as indicators of possible pollution levels in the environment included percentage plant mortality, foliar sulphur content of selected plant species, chemical composition of solubles in mist and dust samples, and soil pH. In addition, the vegetation was screened for plant species suitable to be used as potential bioindicators. Potential bioindicator plant species were selected on the basis of their relatively wide distribution in the study area and apparent sensitivity to the ambient air pollutants. The percentage of dead plants of each species that occurred on the sample plots was used as a criterion of the possible sensitivity of the plant species towards air pollution. The bioindicator plant species selected for potential monitoring purposes were: Galenia fruticosa, Lampranthus suavissimus, Lycium ferocissimum and a Ruschia sp. (SP 9). Plant mortality was greater nearer the emission source, with 28 + 5 % dead plants at 400 m, 19 + 6 % at 800 m and only 10 + 4 % at 1,200 m from the Mineral Separation Plant. Data summed for all species recorded and pooled for all three transects per sampling distance. With the methods used in this study, in the case of all sample plots on the three transects, no significant difference was found between the mean pH values of soil samples collected from open spaces without plant cover (8.01 + 0.46) and those collected underneath shrubs (8.91 + 0.96). Subsequently only the pH values of soil samples collected on open spaces were used to investigate the variation in soil acidity with distance and direction from the emission source. The means represent total number of samples from open space versus those collected from underneath shrubs. The pH of soil samples increased with distance from the emission source along the transects to the south and south-east of the emission source. Eastward of the emission source, soil pH values remained relatively low at all sample distances. This pilot study could not determine whether the continuous acidity of the soil along the eastern transect in the direction of the prevailing wind, was caused by increased deposition of gaseous emissions on the higher lying hilly terrain in this area, or by the underlying geology. Ion chromatographic analysis of mist and dust samples collected on each sample plot indicated the presence of several chemicals that had probably originated from the gaseous emissions from the Mineral Separation Plant as well as wind blown constituents from the adjacent surroundings of the sample plots. Of these chemicals, only the sulphate concentrations of the mist and dust samples were further evaluated, since that could be related to the emission of sulphuric acid fumes by the Mineral Separation Plant. Results indicated that the mean sulphate concentration of mist and dust samples collected from sample plots relatively close to the Mineral Separation Plant, 118.8 + 31.6 mg/litre (400 m), were higher than further afield, decreasing to 57 + 30.1 mg/litre at 800 m and 43.1 + 19.6 mg/litre at 1,200 m. These values, representing the mean sulphate concentrations of mist and dust samples at each sampling distance (data of the three transects pooled), differ significantly at the 85 % confidence level. Statistical evaluation of the data of the mist and dust pH measurements, pooled for the three transects on the basis of distance, indicated a gradual increase of the mean values from 400 m (7.3 + 0.26), through 800 m (7.7 + 0.34), to 1,200 m (8.2 + 0.83), although these values were not significantly different. A decreasing trend in accordance with that in the case of the sulphate concentrations of mist and dust samples with distance from the mineral processing plant, was also observed in the sulphur content of the leaves of selected plant species, with mean sulphur content higher at 400 m sampling distance (0.29 + 0.091 %) than at 800 m (0.264 + 0.086 %) and a further decline at 1,200 m (0.232 + 0.079 %), data of the three transects pooled. However, these values were also not significantly different. Although not significantly so, the decreasing trend in the results of the sulphate concentration of mist and dust samples, the sulphur content of plant leaf samples as well as plant mortality observed, and increasing soil pH values with distance from the Mineral Separation Plant, suggest that the gaseous emissions from the Mineral Separation Plant could probably have had a detrimental effect on the adjacent Succulent Karoo vegetation. A more detailed study is necessary to confirm this trend. In addition it is recommended that in order to clarify the soil pH measurements outcome along the eastern transect that were contradicted by the results of the mist and dust pH measurements, a more intensive survey over a greater distance (at least further than 1.2 km from the Mineral Separation Plant), be conducted to quantify vegetation damage and acid deposition to the east of the emission source.Thesis (MSc (Conservation Ecology and Entomology)--University of Stellenbosch, 2006.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Milton, S. J.Boucher, C.Botha, A. T.2008-02-05T10:50:23Z2010-06-01T08:39:24Z2008-02-05T10:50:23Z2010-06-01T08:39:24Z2006-03Thesis3345322 bytesapplication/pdfhttp://hdl.handle.net/10019.1/2041en_ZAUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/21342013-03-23T08:39:17Zhdl_10019.1_532

Entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) for the control of codling moth, Cydia pomonella (L.) under South African conditionsDe Waal, Jeanne YvonneEntomopathogenic nematodesCodling mothCydia pomonellaBiological controlDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyThe codling moth, Cydia pomonella (L.), is a key pest in pome fruit orchards in South Africa. In the past, broad spectrum insecticides were predominantly used for the local control of this moth in orchards. Concerns over human safety, environmental impact, widespread dispersal of resistant populations of codling moth and sustainability of synthetic pesticide use have necessitated the development and use of alternative pest management technologies, products and programmes, such as the use of entomopathogenic nematodes (EPNs) for the control of codling moth. Entomopathogenic nematodes belonging to either Steinernematidae or Heterorhabditidae are ideal candidates for incorporation into the integrated pest management programme currently being developed for pome fruit orchards throughout South Africa with the ultimate aim of producing residuefree fruit. However, these lethal pathogens of insects are not exempted from governmental registration requirements and have therefore not yet been commercialized in South Africa. A nontarget survey was conducted to find suitable isolates of EPNs from local soils and to test their effectiveness as control agents against the codling moth. Soil samples were collected from several habitats and regions throughout South Africa and nematodes were recovered using the insect baiting technique. All EPN isolates obtained were identified to species level using a molecular taxonomic approach. Entomopathogenic nematodes were recovered from 20 of the 200 soil samples (10 %). Of these, eight (40 %) yielded Steinernema spp., identified as three isolates of S. khoisanae and five undescribed Steinernema spp. The other 12 (60 %) of the samples were positive for Heterorhabditis spp. and included six isolates of H. bacteriophora, five H. zealandica and one H. safricana. These isolates were then evaluated in laboratory bioassays for their potential as microbial agents of codling moth under varying conditions. A morphometric study indicated that all natural openings (mouth, anus and spiracles) of final instar codling moth were large enough for the infective juveniles (IJs) of all tested EPN species to gain entry into the larvae.Thesis (MScAgric (Conservation Ecology and Entomology))--Stellenbosch University, 2008.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Addison, P.Malan, A. P.Addison, M. F.2008-11-25T10:42:12Z2010-06-01T08:41:12Z2008-11-25T10:42:12Z2010-06-01T08:41:12Z2008-12Thesishttp://hdl.handle.net/10019.1/2134enStellenbosch University

oai:scholar.sun.ac.za:10019.1/21572013-01-21T08:36:06Zhdl_10019.1_532

Soil chemical and physical properties and their influence on the plant species richness of arid South-West AfricaMedinski, TanyaDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologySoils -- Africa, SouthwesternPlant species diversity -- Africa, SouthwesternPlant-soil relationships -- Africa, SouthwesternUnderstanding the drivers and mechanisms of changes in plant richness is a basis for making scientifically sound ecological predictions and land use decisions. Of the numerous factors affecting plant richness, soil has a particularly large influence on the composition and structure of terrestrial flora. Infiltrability is one of the most important factors determining soil moisture, and therefore is of particular interest in semi-arid ecosystems, where water is one of the most limiting resources. Other soil properties, such as clay + silt content, electrical conductivity (EC) and pH may also influence plants. Heterogeneity of these properties creates niches with specific conditions, which in turn affects spatial distribution of plants. An understanding of the relationships between plant richness and soil properties is, however, incomplete. The present study has two main foci. Firstly, relationships between plant richness and soil infiltrability, clay + silt, EC and pH (H2O) were investigated, and secondly, due to the strong influence of infiltrability on plant richness, further investigations were undertaken to improve the understanding of the role of particle size fractions, EC of the soil solution and exchangeable sodium percentage (ESP) on infiltrability. This study only concentrated on the surface 2 cm thick soil layer (known as pedoderm).Thesis (MScConsEcol (Conservation Ecology and Entomology)--University of Stellenbosch, 2007.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Esler, K. J.Mills. A. J.2007-11-22T10:06:41Z2010-06-01T08:41:48Z2007-11-22T10:06:41Z2010-06-01T08:41:48Z2007-11-22T10:06:41Z2007Thesis1198841 bytesapplication/pdfhttp://hdl.handle.net/10019.1/2157en_ZAUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/22062013-01-21T08:35:29Zhdl_10019.1_532

Impacts of cage aquaculture on the farm dam ecosystem and its use as a multipurpose resource : implications for irrigationDu Plessis, D.AquacultureWater qualityPhytoplanktonNutrientsEutrophicationDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyCage aquaculture -- South Africa -- Western CapeFish culture -- South Africa -- Western CapeCage aquaculture -- Environmental aspects -- South Africa -- Western CapeFish culture -- Environmental aspects -- South Africa -- Western CapeRainbow trout fisheries -- South Africa -- Western CapeDams -- South Africa -- Western CapeEutrophication -- South Africa -- Western CapeIrrigation farming -- Effect of water quality on -- South Africa -- Western CapeIrrigation water -- Quality -- South Africa -- Western CapeSmall farm dams (< 20 ha) in the Western Cape Province provide adequate water conditions for intensive cage production of rainbow trout (Oncorhynchus mykiss). A major environmental concern of cage aquaculture, however, is the high inputs of nutrients via commercial diets and the subsequent eutrophication of the water source. Eutrophication can result in the degradation of the general water quality (increasing pH levels, oxygen depletion, increased hydrogen sulphide and free ammonia) and shifts in the phytoplankton structure (increased biomass, single species dominance). Deterioration of water quality will affect the success of the fish farming enterprise as well as the performance of irrigation equipment by increasing the risk of clogging and corrosion. Water quality, phytoplankton and zooplankton compositions were monitored at four sites from June 2005 to November 2006 to determine the effects of cage culture on the farm dam environment, its associated biota as well as irrigation water quality. The distribution of nutrients, nitrogen and phosphorus, was mainly influenced by the stratification and mixing regime of the water bodies. Nutrient concentrations increased during the winter mixing period while in the summer months, they seem to settle to the lower part of the water column. Nutrient concentrations of production sites and reference sites were comparable except for the ammonia levels that were significantly higher at the production sites. Phytoplankton corresponded with nutrient availability resulting in high biomass during winter. In terms of biomass, phytoplankton was approximately two times more abundant in production sites compared to reference sites. Assemblage dominance by cyanophytes (Anabaena circinalis, Microcystis spp.) was found more often in production sites, while reference sites were dominated by dinophytes (Ceratium hirundinella, Peridinium spp.). Zooplankton biomass concurred with high phytoplankton biomass in winter. Zooplankton assemblages in production sites sustained much higher biomass. Effects of cage culture on irrigation water quality are evident from increased algal biomass and shifts in species composition. These results indicated that at its present production level, cage culture had impacts on the farm dam environment and irrigation water quality. The most significant evidence was given by increased plankton biomass and single species dominance in production sites. However, these findings can not solely be ascribed to the introduction of aquaculture as various other factors may also contribute to the water quality of these ecosystems.Thesis (MScAgric (Conservation Ecology and Entomology)--University of Stellenbosch, 2007.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Leslie, A.Salie, K.2008-10-30T09:32:04Z2010-06-01T08:43:21Z2008-10-30T09:32:04Z2010-06-01T08:43:21Z2007-12Thesishttp://hdl.handle.net/10019.1/2206enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/22282013-03-19T15:17:12Zhdl_10019.1_532

The impact of landuse on invertebrate assemblages in the Succulent Karoo, South AfricaNchai, Makebitsamang ConstanceInvertebratesLand useSucculent KarooConservationDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyThe Succulent Karoo biodiversity hotspot is threatened by pressure caused by increasing human populations and its associated land use types. Land use is primarily focussed on agriculture, with livestock grazing as a dominant land use in the region. Cultivation is also practiced along the major perennial rivers, and in drier areas, where this largely depends on rainfall. Only about seven percent of the biome is formally protected, and this area substantially under-represents the biodiversity of the Succulent Karoo and does not incorporate key ecological processes and biodiversity drivers. Therefore, there is urgent need for outside reserve conservation initiatives, whose success depend on understanding the ecosystem function of the Succulent Karoo. This study aimed to determine the impacts of heavy grazing, light grazing and cultivation (in a 30-year old fallow field) on assemblages of ground-dwelling and flying invertebrates. Seasonal assemblage changes were also determined. Vegetation structure and composition were determined using the line-intercept method to determine if vegetation patterns explain patterns in invertebrate assemblages. Abandoned fields harbour the lowest number of plant species, and these together with the heavily grazed sizes are dominated by a high cover of Galenia africana (Aizoaceae). Lightly grazed sites have the highest structural complexity, with a high cover of succulents and non-succulent perennials. After the winter rains, annual plants occupy most of the bare ground in heavily grazed and previously cultivated sites. Seasonal changes in assemblages of ground-dwelling and flying invertebrates were determined by sampling during the four seasons at the same localities. Results of pitfall traps sampling for ground-dwelling invertebrates and coloured pan traps for flying invertebrates showed that overall species richness and diversity peaked in spring for flying invertebrates while peaks in richness for ground-dwelling invertebrates were in summer, with no difference in overall diversity. Overall abundance for ground-dwelling invertebrates was highest in summer and lowest in winter. Ground-dwelling invertebrate fauna was dominated by Formicidae and Araneae. Grazing and cultivation lead to skewed community composition of ground-dwelling invertebrates which favours disturbance tolerant and generalist species such as Anoplolepis steingroeveri (Forel).Thesis (MScConsEcol(Conservation Ecology and Entomology)--Stellenbosch University, 2008.Imported from http://etd.sun.ac.za April 2010.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Krug, Cornelia B.Samways, M. J.2008-12-02T06:33:38Z2010-06-01T08:43:48Z2008-12-02T06:33:38Z2010-06-01T08:43:48Z2008-12Thesishttp://hdl.handle.net/10019.1/2228enStellenbosch University

oai:scholar.sun.ac.za:10019.1/22472013-01-21T08:30:35Zhdl_10019.1_532

Participatory governance for sustainable management of natural resources in the Great Limpopo Transfrontier Park: The case of Parque Nacional do Limpopo, MoçambiqueNhancale, Camilo CorreiaDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyGreat Limpopo Transfrontier ParkParque Nacional do Limpopo (Mozambique)National parks and reserves -- Mozambique -- Management -- Citizen participationConservation of natural resources -- Mozambique -- Citizen participationSustainable development -- MozambiqueNational parks and reserves -- Mozambique -- Public opinionThis study assessed (a) the inclusion of local communities in the process of the establishment and management of Parque Nacional do Limpopo (PNL); (b) local community resources use practices, livelihoods strategies, land resources use and ownership and institutional arrangements at the grassroots; and (c) attitudes and perceptions of local communities towards the park and its implications for the sustainability of the park. The study shows that local stakeholders were left out in the planning and implementation processes of the park, which was through top-down approach. There was a lack of involvement of local communities and co-ordination with local stakeholders concerning on-the-ground activities. Local community participation occurs through consultation, thereby depriving primary stakeholders of any decision-making power. However, the study notes that the ongoing interaction between the park management, community advocacy organisations and local communities in the park represents a positive step towards the evolving practice of participatory governance of the protected area. It is also shown that local communities have diverse livelihood strategies, including subsistence agriculture, livestock herding, forest products harvesting, small businesses, handicrafts and cash remittances by migrate labourers. It is worth noting that land and forest resources use constitutes the foundation of their livelihood strategies. Local communities considered land to belong to traditional land chiefs who head local socio-cultural and political organizations in rural areas. They allocate land and control access to natural resources. Other community members asserted that the land belongs to the respective families that inherited and use it. The legal framework in Mozambique authorises the establishment of new institutions at the grassroots. This overlaps with the pre-existing traditional institutions in the rural areas, resulting in power conflicts and in some cases disruption of local institutions for governance ...Thesis (MScAgric (Conservation Ecology and Entomology)--University of Stellenbosch, 2007.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Watts, Scotney2008-01-16T09:26:33Z2010-06-01T08:44:19Z2008-01-16T09:26:33Z2010-06-01T08:44:19Z2007-03Thesis2101388 bytesapplication/pdfhttp://hdl.handle.net/10019.1/2247enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/22762013-01-21T08:37:21Zhdl_10019.1_532

Source and identity of insect contaminants in export consignments of table grapesPryke, James StephenDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyTable grapes -- Diseases and pests -- ControlTable grapes -- South Africa -- Hex River ValleyTable grapes -- Postharvest diseases and injuriesInsect pests -- Control -- South Africa -- Hex River ValleyThe South African table grape industry exports approximately 60% of the table grapes produced. A major threat to the export of these grapes is the phytosanitary risk that insect pests pose. This study was conducted in the Hex River Valley, South Africa’s main table grape producing area. The aim of this study was to reduce the number of phytosanitary rejections from insects on table grapes from the Hex River Valley. Thus the main objectives of the study were to identify the most important phytosanitary pests in the Hex River Valley; the determination of their presence in the vineyards with possible means to control them; and to assess the possibility of using postharvest quarantine treatments in the Western Cape. Further aims were to determine the effect of different colour harvesting crates on the phytosanitary pests and whether the phytosanitary pests infested the grapes via packhouses. The most important phytosanitary pests of table grapes of the Hex River Valley are in order of importance: Phlyctinus callosus (Schonherr) (Coleoptera: Curculionidae), Epichoristodes acerbella Walker (Lepidoptera: Tortricidae), Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), Gonocephalum simplex Fabricius (Coleoptera: Tenebrionidae) and Dysdercus fasciatus Signoret (Hemiptera: Pyrrhocoridae). 12.71% of rejections were from species that were not identified, while a further 33% of the rejections were possibly identified incorrectly. Phytosanitary control of P. callosus appeared to be far more effective using Plantex® than pesticides. Weather conditions appeared to affect the abundance of P. callosus, especially warm weather, while bunches harboured less P. callosus later in the day. Control of E. acerbella with DiPel® (Bacillus thuringiensis var. kurstaki) appeared to at least reduce the population within the vineyards, and so its use is recommended. P. ficus is a non-actionable species for the USA market and is not listed as a phytosanitary pest for the Israeli market and so should not be causing any phytosanitary rejections. C. capitata appeared to be successfully controlled by the fruit fly sterile release program and the cold sterilisation it currently undergoes. G. simplex caused few rejections. It is still unclear where this pest infests the grapes, as it was found in both the field and in the packhouses. D. fasciatus occurrence on grapes was probably accidental. It was shown that picking during the early and late parts of the day, when this species was less active, reduced its occurrence in bunches. Gryllus bimaculatus (De Geer) (Orthoptera: Gryllidae), although not reported as a reason for rejections in table grapes for the past two years, was an actionable species that was present in large numbers in the Hex River Valley. There was a strong correlation between increasing quantities of pesticides and higher abundances of G. bimaculatus. It appeared to be an indicator of the overuse of pesticides. Results of this study showed that infestation by the phytosanitary pests came from neighbouring vineyards. The creation of barriers to prevent the movement of these pests between vineyards is suggested. Methyl bromide is the most commonly used postharvest quarantine treatment. Owing to the ozone-depleting properties of methyl bromide, it is scheduled to be outlawed in many countries from 2005. Alternative postharvest treatments are irradiation, extreme temperatures, forced air, vapour-heat treatments and the use of controlled atmospheres. Irradiation treatments appeared to control the pests at doses that do not damage the grapes. Controlled atmosphere treatments also have a high probability of success, although more research is required on this treatment. Low temperature treatments are relatively cheap as most exported fruit already undergoes cold storage, and appears to control species in the families Pseudococcidae and Tephritidae, although further research is required for the other pest. Colour or location of the harvesting crates in the vineyards appeared not to influence the number of phytosanitary pests collected, as they were not attracted to these crates.Thesis (MScAgric (Conservation Ecology and Entomology)--University of Stellenbosch, 2005.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Samways, M. J.Pringle, K. L.2008-07-24T11:58:48Z2010-06-01T08:44:54Z2008-07-24T11:58:48Z2010-06-01T08:44:54Z2005-03Thesishttp://hdl.handle.net/10019.1/2276enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/23102013-01-21T08:29:11Zhdl_10019.1_532

Monitoring rehabilitation success on Namakwa Sands heavy minerals mining operations, Namaqualand, South AfricaBlood, Jeremy RussellDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyAbandoned mined lands reclamation -- South Africa -- NamaqualandStrip mining -- Environmental aspects -- South Africa -- NamaqualandHeavy minerals -- Prospecting -- Environmental aspects -- South Africa -- NamaqualandRestoration ecology -- South Africa -- NamaqualandRevegetation -- South Africa -- NamaqualandPlant conservation -- South Africa -- NamaqualandAnglo American Corporation’s Namakwa Sands heavy minerals mining and beneficiation operation has been strip-mining a heavy mineral deposit, rich in the commercially valuable minerals ilmenite, rutile and zircon, since September 1994. The mine is located in the vicinity of Brand-se-Baai on the west coast of South Africa, approximately 385 km north of Cape Town. Strip-mining causes total destruction of natural ecosystems through the removal of vegetation and soil in the area where mining is being undertaken. Namakwa Sands has been rehabilitating mined out areas as the mining front moves forward. Due to the difficulty of rehabilitating mined out areas as a result of harsh environmental factors, Namakwa Sands has initiated various research projects to gain an understanding of the baseline conditions and ecosystem function in order to increase plant cover and biodiversity on post-mined areas. This on-going research and the development of rehabilitation and mining techniques have resulted in the implementation of four rehabilitation techniques varying in investment of topsoil replacement, seeding and plant translocation. This study assesses the success and effectiveness of these techniques in terms of various vegetation and soil parameters. In addition, those parameters that are considered useful for monitoring are identified. This study indicated that topsoil replacement and plant translocation facilitate the return of similarity, species richness, species diversity and vegetation cover to post-mined areas. The rehabilitation site that had the greatest amount of biological input (topsoil replacement and plant translocation) appeared to be the most successful technique in facilitating vegetation recovery similar to reference sites. In comparison, the site that had the least amount of biological input performed the worst and requires adaptive management, e.g. reseeding and / or plant translocation. Namakwa Sands should continue to replace topsoil in all future rehabilitation efforts and, when possible (e.g. after sufficient winter rain), continue to translocate species in multi-species clumps. In terms of species selected for translocation, Othonna cylindrica, Ruschia versicolor and Lampranthus suavissimus should be considered for future large-scale translocation projects. Zygophyllum morgsana appears to be more difficult to re-establish under the current climatic conditions (below average rainfall). The long-term viability of rehabilitated Z. morgsana populations needs to be determined before considering this species for any future large-scale translocation purposes. No translocated Asparagus spp. individuals survived and should therefore not be considered for any further translocation purposes. The grass Ehrharta calycina, which is dominant in the site seeded, should continue to be considered for future seeding. Species and functional diversity appear to be the most limiting factors within all the rehabilitation sites and Namakwa Sands will not be able to meet their long-term objective of small-stock farming if diversity and the number of palatable species do not increase significantly. Adaptive management should seriously be considered in order to speed up this process. Alternatively, an appropriate grazing strategy, which is related to the Tetragonia fruticosa dominated vegetation within rehabilitation sites, would need to be determined and adopted.More time is needed to ameliorate the rehabilitated soil profiles to the same level as in reference sites, especially with regard to carbon, pH and sodium levels. In order to increase organic matter within rehabilitation areas, Namakwa Sands should consider creating clumps with cleared vegetation from the mining front. Since the long-term rehabilitation goal has not been achieved, Namakwa Sands will need to continue to monitor plant and soil changes until it has been achieved. The objectives of the current rehabilitation programme are limited and Namakwa Sands should develop additional objectives relating to the structure and function of the natural vegetation. This will give a better indication of whether rehabilitation sites are progressing towards the desired end point and if adaptive management is required. In addition, the current monitoring programme (vegetation survey) implemented at Namakwa Sands could be improved by increasing the vegetation parameters to be monitored. It is recommended that the following vegetation parameters be monitored as part of the long-term monitoring programme: species composition and similarity, species richness, species diversity, vegetation cover, species dominance, vertical structure and functional diversity of the vegetation (clumps and inter-clumps). It is also recommended that carbon, pH and sodium of soil profiles be monitored as part of the long-term monitoring programme. These parameters should not be seen as exhaustive as this study only considered various vegetation parameters and soil chemistry between rehabilitation and reference sites. The results of other studies on the fauna, mycorrhiza, insects, etc. should also be taken into consideration and the monitoring parameters expanded accordingly.Thesis (MScConsEcol(Conservation Ecology and Entomology)--University of Stellenbosch, 2006.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Esler, Karen J.Milton, Sue J.2008-01-23T08:14:54Z2010-06-01T08:45:46Z2008-01-23T08:14:54Z2010-06-01T08:45:46Z2006-12Thesis3709297 bytesapplication/pdfhttp://hdl.handle.net/10019.1/2310enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/23672013-03-18T19:09:50Zhdl_10019.1_532

Comparing small mammal assemblages between communal and commercial rangelands within a region of the Succulent Karoo, South AfricaHaveron, Sara ElizabethSmall mammalsLivestock grazingArid regionsSucculent KarooOvergrazingCommunal rangelandsCommercial rangelandsTheses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyConservation Ecology and EntomologyThe widespread ecological impacts of overgrazing by livestock within the Succulent Karoo have received considerable attention. Literature shows communal and commercial rangelands have been thoroughly studied, and vegetation responses have been investigated in an attempt to understand the effects of overgrazing. Regarding animal species, literature is in short supply. In a one-year study of small mammal assemblages, the effect of the rangelands, and subsequently vegetation, on small mammal assemblages was examined, as well as the effects on number of occupied, unoccupied and collapsed burrows. This study shows that vegetation composition differs between rangelands, with a greater perennial shrub cover on the communal rangelands and a greater perennial succulent cover on commercial rangelands, consequently creating different habitats for animal assemblages. This study supports the notion of small mammal composition relating to vegetation structure, with certain species being impacted by heavy grazing. Four small mammal species were found in greater abundances on commercial rangelands, with one being exclusive, while communal rangelands were exclusively occupied by three nocturnal species. Diet and habitat requirements are the most important factors regarding species occurrence. With small mammal species composition differing between rangelands, and species richness not being affected by rangeland type, this study illustrates that the disappearance of certain species may arise without these different rangelands. This could result in reduced species richness, and thus diversity being lost. Regarding species present on both rangelands, no differences were observed in body mass, body size or body condition. Despite no differences found in body condition, calculating a body condition index is a good method for investigating how a species is coping within an environment. The proportion and number of occupied and collapsed burrows can be seen as a measure of trampling effect. It was expected for grazing intensity, as well as vegetation changes, to affect the occurrence of such burrows. This study showed differences between the communal and commercial rangelands as negligible. As expected, numbers of burrowing small mammal species were negatively correlated with numbers of collapsed burrows. However, a lack of consistency deemed this result unimportant. Results show that the effects of overgrazing on small mammal populations are complex and require more attention if to be fully explained. This study provides insights into the effects of land use on small mammals and burrow numbers, which have implications for the conservation of these species within arid regions.Thesis (MScConsEcol (Conservation Ecology and Entomology))--Stellenbosch University, 2008.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Krug, Cornelia B.Matthee, Sonja2008-11-25T18:07:24Z2010-06-01T08:47:09Z2008-11-25T18:07:24Z2010-06-01T08:47:09Z2008-12Thesishttp://hdl.handle.net/10019.1/2367enStellenbosch University

oai:scholar.sun.ac.za:10019.1/24392011-06-23T08:50:58Zhdl_10019.1_532

The feeding ecology of yearling, juvenile and sub-adult Nile crocodiles, Crocodylus niloticus, in the Okavango Delta, BotswanaWallace, Kevin MichaelNile crocodileFeeding ecologyOkavango DeltaDigestionDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyThe stomachs of 286 crocodiles (17 cm to 166 cm snout to vent length) were lavaged over a two year period. Crocodylus niloticus has a similar ontogenetic shift in diet to that of other crocodilians. Yearlings predated primarily on aquatic insecta and arachnida, as crocodile size increased (juveniles) the diet became more diverse including crustacea, amphibia and fish. The largest size class (sub-adults) consumed primarily fish. Yearlings fed consistently throughout the year, however a higher proportion of empty stomachs occurred within the juvenile and sub-adult size classes during the winter months. A captive experiment with wild caught crocodiles (0.7 kg - 20 kg) indicated a decrease in satiation rate (maximum mass of food eaten as a percentage of crocodile body mass) from 11.3 % to 6.5 % with an increase in crocodile size. Wild yearlings consumed 0.48 % of their body mass in prey per day, and juveniles, 0.23 %. The wild food conversion rates of natural prey were low, 32 % and 40 % for yearlings and juveniles respectively. This was possibly due to a high percentage of indigestible (chitinous) invertebrate mass in the diet. The percentage of stomach stone mass to crocodile body mass increased with crocodile size. Seven species of nematodes were found within the stomachs, four of which represent new geographic records.Thesis (MSc(Conservation Ecology and Entomology)--University of Stellenbosch, 2006.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Leslie, Alison J.2008-08-07T09:50:46Z2010-06-01T08:48:46Z2008-08-07T09:50:46Z2010-06-01T08:48:46Z2006-12Thesishttp://hdl.handle.net/10019.1/2439enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/24632013-01-21T07:28:16Zhdl_10019.1_532

Entomopathogenic nematodes : characterization of a new species, long–term storage and control of obscure mealybug, Pseudococcus viburni (Hemiptera: Pseudococcidae) under laboratory conditionsStokwe, Nomakholwa FaithEntomopathogenic nematodesMealybugsCharacterizationCryopreservationDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyInsect nematodes -- South AfricaMealybugs -- Biological control -- South AfricaApples -- Diseases and pests -- Biological control -- South AfricaPear -- Diseases and pests -- Biological control -- South AfricaENGLISH ABSTRACT: The obscure mealybug, Pseudococcus viburni (Signoret) (Pseudococcidae), is one of the common and serious pests of apples and pears in South Africa. The management of this pest in South Africa is dominated by the use of insecticides, while research into using natural enemies for biological control of mealybugs is still ongoing. Increasing concern over the environmental impact, pesticide residues in fruits, resistance, and expense associated with frequent use of insecticides make it necessary to investigate alternative biological control methods, such as the use of entomopathogenic nematodes, for the control of mealybugs. Entomopathogenic nematodes have proven comparable or even superior to chemicals in controlling certain insect pests, without residue problems or a harmful effect on the environment. An important aspect of using endemic nematodes includes the identification of species of nematodes and their symbiotic bacterial cells. A study was carried out to describe a new species of Steinernema, which was recovered during a previous survey in citrus orchards in three provinces of South Africa. Morphometrics, morphology, crossbreeding, drawings, light microscopy and Scanning Electron Microscopy (SEM) photographs were used to describe the new species. A cryopreservation method has been simplified and optimised for the long-term storage of Steinernema khoisanae (SF87) and Heterorhabditis zealandica (J34). Different cryoprotectants used included 15% glycerol, 8% ethylene glycol and 8% dimethyl sulfoxide (DMSO), in which S. khoisanae was incubated at room temperature for periods of two, three, four and five days, followed by a methanol wash. An optimum survival rate of 69% was obtained for S. khoisanae after a four-day incubation period in 15% glycerol. This technique has been used for the cryopreservation of H. zealandica, with a 78% survival rate. The thawed nematodes of both species were able to infect Galleria mellonella larvae after 42 days of cryopreservation (-196ºC) and were able to complete their life cycles.AFRIKAANSE OPSOMMING: Die ligrooswitluis, Pseudococcus viburni (Signoret) (Pseudococcidae), is een van die algemene en ernstige peste van appels en pere in Suid-Afrika. Die bestuur van hierdie pes word tans in Suid-Afrika deur die gebruik van insekdoders gedomineer terwyl navorsing oor die gebruik van natuurlike vyande vir die beheer van P. viburni nog aan die gang is. Die verhoogde kommer oor die omgewing, residue in vrugte, weerstand, en die koste verbonde aan die gereelde gebruik van chemiese middels maak dit nodig om alternatiewe biologiese metodes van beheer, soos die gebruik van entomopatogeniese nematodes vir die beheer van witluis, te ondersoek. In ander lande is reeds aangetoon dat entomopatogeniese nematodes onder sekere omstandighede en vir sekere insekte gelykwaardige of selfs beter beheer kan gee as chemiese middels. ʼn Belangrike aspek van die gebruik van endemiese nematodes vir die beheer van insekte sluit die korrekte identifikasie van die spesies met hul geassosieerde bakteriese simbionte in. ʼn Nuwe spesie van Steinernema is uit ʼn vorige opname van entomopatogeniese nematodes in sitrusboorde in drie provinsies van Suid-Afrika geïsoleer. Morfometrie, morfologie, kruisteling, ligmikroskoop en SEM fotografie is gebruik om ʼn nuwe spesies te beskryf. ʼn Kriopreserveringsmetode is ontwikkel en ge-optimaliseer vir die langtermyn bewaring van Steinernema khoisanae (SF87) en Heterorhabditis zealandica (J34). Verskillende kriobeskermingsmiddels insluitend 15% gliserol, 8% dimetiel sulfokied (DMSO) en 8% etileen glikol, waarin S. khoisanae vir periodes van twee, drie, vier, en vyf dae geïnkubeer is, is teen kamertemperatuur, getoets, gevolg deur ʼn metanolbad. Optimum oorlewing van 69% is verkry vir S. khoisanae nadat die infektiewe larwes (IJ) vir vier dae in 15% gliserol gehou is. Hierdie tegniek is ook toegepas op H. zealandica, met 78% oorlewing van die IJ. Die ontvriesde nematodes van beide spesies was in staat om Galleria mellonella larwes suksesvol te infekteer en hulle lewensiklus te voltooi nadat hulle vir 45 dae onder kriopreservering gehou is teen -196ºC.Thesis (MScAgric (Conservation Ecology and Entomology)--University of Stellenbosch, 2009.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Malan, A. P.Addison, P.2009-11-25T11:01:33Z2010-06-01T08:49:22Z2009-11-25T11:01:33Z2010-06-01T08:49:22Z2009-12Thesishttp://hdl.handle.net/10019.1/2463en_ZAUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/24952013-03-23T08:45:00Zhdl_10019.1_532

Medicinal plant trade and opportunities for sustainable management in the Cape Peninsula, South AfricaLoundou, Paul-MarieMedicinal plantsHealthcare provisionIncome generationPerceptions on cultivationTraditional healthcare practitionersMedicinal plant tradeMedicinal plant conservationDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyMedicinal plants represent an important asset to the livelihoods of many people in developing countries. This is the case for South Africa where most of the rural and also urban communities rely on medicinal plants for their primary healthcare needs and income generation. Harvesting for domestic usage is not generally detrimental to the wild populations of medicinal plants. However, the shift from subsistence to commercial harvesting is posing unprecedented extinction threat to the wild populations of medicinal plants. The purpose of this investigation was to: (1) document the most traded/used species of medicinal plants in the Cape Peninsula, including parts used, sourcing regions, harvesting frequencies and seasons as well as the conservation status of these species; (2) to profile and investigate the rationales for the involvement of stakeholders in medicinal plants related-activities; and to (3) assess constraints and opportunities for sustainable management of medicinal plants in the Cape Peninsula. Triangulation techniques such as semi-structured questionnaires, formal and informal interactions with key informants from the Cape Peninsula and surroundings, personal observations and field visits were used to gather relevant data for this investigation. Accordingly, about 170 medicinal plant species were found to be actively traded or used in the study area. These species were mostly traded/used for their underground parts; shoot, barks and in many cases the whole plant is uprooted. The bulk of traded/used species were from the wild populations, harvested on monthly basis and the Western and Eastern Cape provinces acted as the main source regions. Some of the traded/used species are rare, vulnerable, endangered, critically endangered and are declining from the wild. Nonetheless, there are subtitutes for some of these medicinal plant species. Traders and collectors were mainly men in the Cape Peninsula. Cultural considerations, economic conditions and the burden imposed by the number of dependents were the factors influencing local communities to engage in medicinal plants related-activities. Despite the fact that the majority of the informants acknowledged the decline of medicinal plants from wild stocks, an overwhelming number of them expected an upsurge in the future demand for natural remedy due to its popularity among South Africans. Similarly, the majority of the respondents were aware of the conservation status of the plants that they were using, but this did not prevent them from trading/using some protected species. Encouragingly, an overwhelming number of the informants were willing to use cultivated species and cultivate some of the most used medicinal plant species if seeds and land were freely provided. It is noteworthy that these results were influenced by the gender, age, category and time of involvement in medicinal plants, ethnicity and residence status of the respondents as well as the source of supply of medicinal plants. It is recommended that species that have been identified of concern should be prevented from further commercial harvesting. Competent conservation organizations like CapeNature should focus on practical skills development of people who have expressed willingness to cultivate medicinal plants or are already doing so, especially in plant propagation and basic gardening techniques.Thesis (MScConsEcol (Conservation Ecology and Entomology))--Stellenbosch University, 2008.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Jacobs, S. M.Watts, Scotney2008-11-25T14:06:55Z2010-06-01T08:50:16Z2008-11-25T14:06:55Z2010-06-01T08:50:16Z2008-12Thesishttp://hdl.handle.net/10019.1/2495enStellenbosch University

oai:scholar.sun.ac.za:10019.1/25782011-06-23T08:36:15Zhdl_10019.1_532

The short term impact of a collection of commercial Cape honeybee (Apis mellifera capensis Esch.) colonies on invertebrate flower visitors within a near pristine fynbos habitat in the Cape Floristic RegionBrand, Mariette RieksApis mellifera capensisHoneybeesPollinationFynbosDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyApiculture in the Western Cape is a well-developed industry based on honey production and pollination services to agriculture. Apart from Eucalyptus trees, fynbos vegetation serves well as bee forage to managed honeybee colonies outside the agricultural pollination season. Eucalyptus trees are cleared as invasive plant species while fynbos are rigorously protected as one of the 34 Biodiversity Hotspots identified worldwide. Thus, bee forage is in short supply and is most probably the only limitation to the number of honeybee colonies that beekeepers can feasibly maintain. The impact of a collection of commercially managed honeybee colonies on other floral resource-dependent species in the Cape Floristic Region is unknown. This is one of the first studies on the topic in South Africa and specifically in the Western Cape. Managed hives were introduced to near pristine fynbos habitat in De Hoop Nature Reserve and Marine Protected Area during July. The aim was to induce stronger competition for floral resources through greater resource exploitation by managed honeybee colonies and record the change in foraging behaviour for several insect guilds on specific plant species. The results suggest that eight hives per site proved insufficient to increase honeybee density above the natural density of honeybees. Honeybee abundance did not increase during the presence of the managed hives, while honeybee visitation frequency was significantly greater during the presence of the managed hives. Neither the abundance nor the visitation frequency of non-Apis bees and wasps differed significantly between treatments. Honeybees were the most abundant foragers on the three focal plant species during all three treatments and also made the most visits to flowers. Honeybee abundance and visitation frequency increased with distance from the managed hives. The significant increase in honeybee visitation frequency during hive presence, coupled with a significant decrease in the time honeybees spent per flower extracting nectar, were an indication of a lower standing crop of nectar during that treatment. Nevertheless, no competition for floral resources was obvious, as the number of honeybees did not increase the abundance and visitation frequency of all other insect guilds (except for a significant decrease in Muscidae, which could be ascribed to changes in weather conditions).Thesis (MScConsEcol (Conservation Ecology and Entomology)--University of Stellenbosch, 2009.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Samways, Michael J.2009-02-27T12:08:02Z2010-06-01T08:52:46Z2009-02-27T12:08:02Z2010-06-01T08:52:46Z2009-03Thesishttp://hdl.handle.net/10019.1/2578enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/26202011-12-12T15:24:09Zhdl_10019.1_532

An investigation into the integrated pest management of the obscure mealybug, Pseudococcus viburni (Signoret) (Hemiptera: Pseudococcidae), in pome fruit orchards in the Western Cape Province, South AfricaMudavanhu, PridePseudococcus viburniIntegrated pest managementMealybugPome fruitTheses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyMealybugs -- Integrated control -- South Africa -- Western CapeAgricultural pests -- Integrated control -- South Africa -- Western CapeApples -- Diseases and pests -- Control -- South Africa -- Western CapePears -- Diseases and pests -- Control -- South Africa -- Western CapeConservation Ecology and EntomologyENGLISH ABSTRACT: Pseudococcus viburni (Signoret) (Hemiptera: Pseudococcidae) (obscure mealybug), is a common and serious pest of apples and pears in South Africa. Consumer and regulatory pressure to produce commodities under sustainable and ecologically compatible conditions has rendered chemical control options increasingly limited. Information on the seasonal occurrence of pests is but one of the vital components of an effective and sustainable integrated pest management system needed for planning the initiation of monitoring and determining when damage can be expected. It is also important to identify which orchards are at risk of developing mealybug infestations while development of effective and early monitoring tools for mealybug populations will help growers in making decisions with regards to pest management and crop suitability for various markets. It is also essential to determine the presence and efficacy of naturally occurring biological control agents in orchards so as to ascertain the potential of biological control as a viable alternative in orchards. However, under the current integrated pest management protocol, it has been difficult to determine this, due to the sporadic and relatively low incidence of mealybug infestations in some orchards, or by simply relying on naturally occurring field populations of biocontrol agents. Knowledge of the environmental conditions under which P. viburni population levels may become destructive is also essential for timing the release of insectary reared natural enemies as well as understanding the population ecology of this pest and its natural enemies. Information was gathered regarding the seasonal phenology of P. viburni and its natural enemies in pome fruit orchards in the Western Cape Province during the 2007/08 and 2008/09 growing seasons. Seasonal population studies showed that P. viburni has multiple overlapping generations with all life stages present throughout the year. The highest orchard infestations occurred during the summer period until early winter (January to early June). This was followed by a decrease in population from late June to November, before another increase in December. Presence-absence sampling of mealybugs on the host plant revealed that woody parts of the tree, such as the trunk and old stems were the most preferred sites for mealybug habitation, due to the availability of protected refuge sites. Migration of mealybug populations to newer growth and the upper sections of the tree crown, such as the new stems, leaves and eventually the fruit, was observed from December throughout the summer period until the early winter in June. Fruit colonization in both apples and pears commenced in January, when the fruit had developed a size sufficient for P. viburni to penetrate and occupy spaces such as the fruit core, calyx and stem end. There was no evidence of P. viburni occurring beneath the soil surface or on the roots of host trees. Two natural enemies of mealybugs, namely Pseudaphycus maculipennis (Mercet) and Coccidoxenoides perminutus (Girault), were found to be active in apple and pear orchards in the Western Cape. However, the status of C. perminutus as a parasite of P. viburni still needs to be verified despite evidence of emergence from P. viburni mummies, which was not sufficient enough to suggest that it is a useful biological control agent. Seasonal abundance trends of the two natural enemies revealed that their lifecycle is synchronized with that of the host. However, there was no evidence of P. maculipennis activity in Ceres. No predators were found during the course of this study. The rate of P. viburni parasitism at harvest was 46.52%, with P. maculipennis and C. perminutus constituting 98.966% and 1.034% of the parasitoids recovered from mealybug mummies, respectively. Studies on the use of pheromone traps as early monitoring tools for P. viburni showed that there was a positive and significant relationship between the fruit infestation and number of P. viburni adult males caught in pheromone-baited traps (r2 = 0.454). The action threshold level was estimated to be 2.5 male P. viburni caught per trap per fortnight at an economic threshold of 2% fruit infestation.AFRIKAANSE OPSOMMING: Pseudococcus viburni (Signoret) (Hemiptera: Pseudococcidae) (ligrooswitluis), is ‘n algemene en ernstige plaag van appels en pere in Suid-Afrika. Druk deur verbruikers en regulasies om kommoditeite onder volhoubare en ekologies verenigbare toestande te produseer het chemiese beheeropsies toenemend beperk. Inligting oor die seisoenale voorkoms van plae is een van die essensiële komponente van ‘n effektiewe en volhoubare geïntegreerde plaagbestuurprogram. Dit is in die aanvanklike beplanning van monitering en om te bepaal wanneer skade verwag kan word. Dit is ook belangrik om boorde vroegtydig te identifiseer wat die risiko het om witluisbesmettings te ontwikkel. Die ontwikkeling van effektiewe en vroeë moniteringstegnieke vir witluisbevolkings sal produsente help met besluitneming rakende plaagbestuur en die geskiktheid van gewasse vir verskeie markte. Dit is ook noodsaaklik om die teenwoordigheid en effektiwiteit van biologiese beheer agente wat natuurlik in boorde voorkom te bepaal ten einde die potensiaal van biologiese beheer as ‘n lewensvatbare alternatief vas te stel. Onder die huidige geïntegreerde plaagbestuurprotokol was dit egter moeilik om laasgenoemde te bepaal weens die sporadiese en relatiewe lae voorkoms van witluisbesmettings in sommige boorde of deur bloot staat te maak op die veldpopulasies van biologiese beheer agente wat natuurlik voorkom. Kennis van die omgewingstoestande waaronder P. viburni bevolkingsvlakke skadelik raak is ook noodsaaklik vir die beplanning van vrylating van biologiese beheer agente, asook om die bevolkingsekologie van hierdie plaag en sy natuurlike vyande te verstaan. Inligting oor die seisoenale fenologie van P. viburni en sy natuurlike vyande in sagtevrugte boorde in die Westelike Kaapprovinsie is gedurende die 2007/08 en 2008/09 groeiseisoene versamel. Seisoenale bevolkingstudies het getoon dat P. viburni verskeie oorvleuelende generasies het met alle stadia teenwoordig regdeur die jaar.Thesis (MScConsEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2009.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Addison, Pia2009-11-25T13:43:11Z2010-06-01T08:53:48Z2009-11-25T13:43:11Z2010-06-01T08:53:48Z2009-12Thesishttp://hdl.handle.net/10019.1/2620enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/26302013-01-21T07:29:52Zhdl_10019.1_532

Evaluation of macro-invertebrates as bio-indicators of water quality and the assessment of the impact of the Klein Plaas dam on the Eerste RiverBredenhand, EmileDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyReservoirs -- Environmental aspects -- South AfricaWater -- Pollution -- South Africa -- Eerste RiverWater quality biological assessment -- South Africa -- Eerste RiverBenthic animals -- Effect of habitat modification on -- South Africa -- Eerste RiverInvertebrates -- Effect of habitat modification on -- South Africa -- Eerste RiverIndicators (Biology) -- South Africa -- Eerste RiverStream ecology -- South Africa -- Eerste RiverA semi-arid country, like South Africa, with unpredictable seasonal rainfall, is subject to great scarcity in water and an ever-increasing demand from the rising human population. Therefore, efficient reservoirs as well as monitoring methods are needed to manage the South African water supply. This study was undertaken on the Eerste River in the Western Cape, South Africa, focusing on the impact of the Klein Plaas dam system on the benthic macroinvertebrates. The study also examined the use of benthic macroinvertebrates as bioindicators of water quality with special reference to the South African Scoring System Version 5(SASS5) that is currently being used nationally. The impoundment of the water, as well as the inter-basin transfer programme and the experimental cage-culture trout farm, all play a significant role in the disturbance impact of the dam on the Eerste River system. The disturbance is manifested as a drop in water quality that can be seen in the distribution of keystone species, changes in the riparian vegetation, as well as in physical-, chemical-, and biomonitoring evaluations. The study also indicated that the SASS5 is effective, but needs some adjustments, such as inclusion of a prediction phase, finer spatial-scale methodologies and greater consideration of the rarity of species.Thesis (MScAgric (Conservation Ecology and Entomology)--University of Stellenbosch, 2005.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Samways, M. J.2008-07-01T07:46:53Z2010-06-01T08:54:02Z2008-07-01T07:46:53Z2010-06-01T08:54:02Z2005-12Thesishttp://hdl.handle.net/10019.1/2630enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/26552011-06-23T08:22:05Zhdl_10019.1_532

The effects of fire and harvesting on Restionaceae SPP. (Thamnochortus insignis and T. erectus) with different life histories : a matrix modelling approachCampbell, Tessa AngelaDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyRestionaceae -- HarvestingRestionaceae -- Effect of fires onFynbos -- Effect of fires onThe Restionaceae is a dominant family in the Fynbos Biome, an area in which fire plays a role as an important disturbance, yet little is known about their population dynamics. Two species of the Restionaceae (Thamnochortus insignis and T. erectus) are economically important as thatching reed and differ in their life-histories. This study aims to determine the effects of variation in life history (sprouter vs. non-sprouter) on the population structure and dynamics of T. erectus (“wyfies riet”, sprouter) and T. insignis (“mannetjies riet”), a non-sprouting species. A matrix-modelling approach based on field data collected by Ball (1995) is used to determine population growth rates, stable stage distributions and stage sensitivity and elasticity for the two species with no disturbance present. The sprouter (T. erectus) shows a positive population growth rate (λ >1) and greater persistence within all stages. The non-sprouting species (T. insignis) shows a negative population growth rate (λ <1) between disturbances as well as greater seed production, germination and growth between stages. Based on the population dynamics of these two species, further research was done to understand the effect of disturbance (harvesting and fire) on these species. A matrix modelling approach was used to determine which disturbance frequency maximises population output and success. Harvesting as well as fire results in a decline in T. insignis populations. A five year frequency for harvesting results in the greatest output of adult plants with the lowest effect on the population, and a fire frequency of 50 to 65 years is recommended. Testing indicates that the model underestimates the number of adults in the population and thus the model is conservative. T. erectus populations grow despite fire or harvesting; thus any reasonable harvesting (3-5 year frequency) and fire (10+ years between fire) regime would ensure population persistence. As data were limited it was not possible to test the results although T. erectus appears resilient to disturbance and therefore a predetermined regime is not as important as in T. insignis. Recommendations to farmers are made based on these results.Thesis (MSc (Conservation Ecology and Entomology)--University of Stellenbosch, 2006.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Esler, K. J.Ward, D.2008-01-24T10:49:43Z2010-06-01T08:54:34Z2008-01-24T10:49:43Z2010-06-01T08:54:34Z2006-12Thesis2145618 bytesapplication/pdfhttp://hdl.handle.net/10019.1/2655enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/27082013-03-23T08:43:47Zhdl_10019.1_532

Small mammal communities in the transformed landscapes of the Western Cape lowlands and their role in alien invasion into fynbos remnantsMugabe, Chapangara JamesSmall mammalsHabitat transformationSeed predationAcacia salignaAlien invasionsFynbos systemsDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyThe fynbos eco-region in the Western Cape lowlands has been extensively transformed by anthropogenic activities such as agriculture and urban development, as well as invasive alien plants. Elandsberg Private Nature Reserve and Farms lies on Swartland Alluvium Fynbos and has been largely fragmented by agricultural crop production, whilst Riverlands Nature Reserve together with the Pella Research Site, which lie on Atlantis Sand Fynbos, are under severe threat from the invasive woody alien Port Jackson Willow (Acacia saligna) which forms dense stands in the lands adjacent the nature reserve. Habitat transformation has resulted in subsequent loss of habitat and a reduction in habitat value for small mammal communities by creating a mosaic of optimal and sub-optimal habitats. The success of A. saligna is, in part, attributed to its production of copious amounts of small hard-shelled seeds and well established soil seed banks. In the first part of this study we investigated the effect of habitat transformation on resident small mammal communities by comparing small mammal species richness, diversity and abundance between natural and transformed habitats as well as between the two vegetation types. We also investigated the population demographics of the striped mouse (Rhabdomys pumilio) in the different habitats. Our study shows that whilst fragments of natural habitats, especially at Riverlands and Pella, may be playing an important role in harbouring rare and possibly endangered species, transformed habitats are also important as secondary habitats providing both cover as well as seasonal food resources. Reproduction and body condition in R. pumilio were dependent on seasonal changes such as availability of water and food resources in the habitats. The second part of this study was carried out to investigate the effect of alien plant invasion on the resident small mammal communities at Riverlands Nature Reserve and to determine the role of small mammals in the removal and predation of A. saligna seeds. Rodent species richness, diversity and abundance were very low in the A. saligna stands compared to the adjacent fynbos vegetation. The interaction of rodents with seeds (removal or predation) was dependent upon seed size and seed abundance in the habitats. Whilst rodents may play an important role in predator limitation in the acacias, it is also possible that they may be playing a significant role in dispersing the seeds of acacias into the fynbos. More work is required to fully understand the role small mammals play in seed predation, dispersal and limitation in alien invaded fynbos systems.Thesis (MScConsEcol (Conservation Ecology and Entomology))--Stellenbosch University, 2008.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Krug, Cornelia B.Matthee, Sonja2008-11-26T12:43:34Z2010-06-01T08:56:19Z2008-11-26T12:43:34Z2010-06-01T08:56:19Z2008-12Thesishttp://hdl.handle.net/10019.1/2708enStellenbosch University

oai:scholar.sun.ac.za:10019.1/28062011-06-23T08:27:19Zhdl_10019.1_532

Vegetation patterns and dynamics of Renosterveld at Agter-Groeneberg Conservancy, Western Cape, South AfricaWalton, Benjamin AlanDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyVegetation management -- South Africa -- Western CapePlant succession -- South Africa -- Western CapePlant diversity -- South Africa -- Western CapePlants -- Effect of grazing on -- South Africa -- Western CapeGrazing -- Environmental aspects -- South Africa -- Western CapeVegetation -- Effect of agriculture on -- South Africa -- Western CapeRemnant vegetation management -- South Africa -- Western CapeOld fields -- Ecological aspects -- South Africa -- Western CapeSwartland Shale Renosterveld is restricted to fertile fine-grained soils in the winter rainfall region of the Western Cape. Between 91% and 97% of this vegetation type is transformed, mostly due to agriculture. Remaining fragments have an irreplaceable conservation value due to a high richness of endemic geophytes. Information on renosterveld vegetation composition and response to disturbance is sparse. Research occurred at three sites near Wellington: Voëlvlei Provincial Nature Reserve (CapeNature), Elandsberg Private Nature Reserve (Elandsberg Farms (Pty.) Ltd.), and Krantzkop munitions factory (Armscor/Somchem) forming a contiguous fragment in the Agter- Groeneberg Conservancy. The primary research aim was to identify or ascertain patterns of plant succession in Swartland Shale Renosterveld and associated different-aged old fields (previously ploughed), with the interaction of grazing. The key research questions are: (1) What are the plant communities of unploughed renosterveld and different-aged old fields which originated in habitats of ploughed renosterveld? (2) What are the most characteristic features of the floristic and ecological relationship between the described plant communities in terms of ecological factors operating within the studied system? (3) Does total species and life-form group richness differ between natural vegetation and old fields? (4) Is life-form richness influenced by ploughing and grazing or the interaction between these disturbances? (5) Is life-form cover-abundance influenced by ploughing and grazing or the interaction between these disturbances? (6) Does alien plant species richness differ amongst seres, and with different levels of grazing intensity? A comparison of life-form richness and cover-abundance of old field vegetation was made with adjacent natural unploughed “controls”. The effects of ploughing on community structure, with the inclusion of grazing was established. These life-form richness comparisons also occur across a gradient of increasing large mammalian herbivore grazing intensity. Sampling was conducted in winter and spring using nested 1000m2 relevés. A hierarchical classification, description and floristic interpretation of renosterveld and old field vegetation were made using TWINSPAN, SYN-TAX 2000 and CANOCO. The samples were classified with TWINSPAN and two communities were described at the association level, namely: Ursinia anthemoides–Cynodon dactylon Grassland Community (with two variants) and the Pterygodio catholici–Elytropappetum rhinocerotis Shrubland Community (with two subassociations), respectively. The vegetation data were further hierachically classified using SYNTAX 2000 which revealed similar clustering of sample objects to that resulting from classification and ordination. Following ordination of sample objects with CANOCO, select groups of species were used to depict their response curves in relation to seral development. Briefly it was found that the effects of grazing vs. non-grazing was more pronounced on old fields than in unploughed vegetation. Overall total species and life-form richness was reduced by ploughing with old fields requiring a recovery period of 30 years to resemble unploughed vegetation. Keywords: Swartland Shale Renosterveld, phytosociology, vegetation patterns, life-forms, succession, disturbance, ploughing, grazing, old fields.Thesis (MSc (Conservation Ecology and Entomology)--University of Stellenbosch, 2006.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Milton, Sue J.Le Roux, A.Mucina, L.2006-10-19T06:40:22Z2010-06-01T08:58:44Z2006-10-19T06:40:22Z2010-06-01T08:58:44Z2006-03Thesis2926212 bytesapplication/pdfhttp://hdl.handle.net/10019.1/2806enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/28232013-03-31T22:58:05Zhdl_10019.1_532

Biodiversity enhancement in Cape Flats urban habitatsFaul, Andre KarelBiodiversity enhancementBiodiversity conservationUrban biodiversityTheses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyBiodiversity conservation -- South Africa -- Cape TownUrbanization -- South Africa -- Cape TownConservation of natural resources -- South Africa -- Cape TownUrban ecology (Sociology) -- South Africa -- Cape TownConservation Ecology and EntomologyBiodiversity is under enormous pressure from an increasing human population. Urbanisation, agriculture, and mining are just some of the factors responsible for the continuous degradation of the natural environment. Of these, urbanisation is one of the leading factors of diversity loss. To address this problem, it is necessary to understand the relationship between biodiversity and urban areas, as well as the relationship between society and biodiversity. This study focuses on these relationships and suggest ways in which urban biodiversity can be maximised without compromising on development. In order to create an urban environment that successfully supports maximised biodiversity, new methods and ideas must be developed to promote the protection of urban ecosystems. The Cape Floristic Region in South Africa is a good example of an area that requires immediate action in order to prevent enormous losses in biodiversity. Data have shown drastic decreases in natural vegetation cover in this area, and with its close to 9000 species, of which approximately 60% occurs nowhere else in the world. This state of affairs should be regarded as a serious crisis. This study consists of three main parts, the first being a literature review on the current relationships between the urban environment, society, and biodiversity. The second and third parts report on two empirical investigations on the campus of the Faculty of Health Sciences at the University of Stellenbosch in the City of Cape Town. The first of these investigates the possibility of using spirituality connected to nature as a promotional tool for conservation through rehabilitation or restoration of damaged urban vegetation habitats. For this purpose students’ and staff members’ opinions of the urban nature at the campus were tested. In the second investigation the options of restoring biodiversity to the campus was considered by exploring the best options available for rehabilitation while taking the current biodiversity status on and around the premises into account. This was carried out through three smaller projects that included the physical reintroduction of plant species, vegetation analysis, and bird identification and attraction. The response of employees and students at the Faculty of Health Sciences was found to be in favour of restoring vegetation and animal life to the campus. This is supported by a belief that their attitude towards their work would improve with improved natural surroundings. Initial rehabilitation attempts highlighted the complexity of rehabilitation practices by bringing forward challenges and problems experienced with the reintroduction of plant species. Despite these problems, increased plant diversity in experimental areas showed the possibility of successfully completing the project. Biodiversity analysis showed that methods of controlling vegetation used by the university are doing more harm than good, as it results in indigenous vegetation being displaced by exotic vegetation. This study introduces a number of questions regarding the relationship between urbanisation and biodiversity and to what extent the two should be linked. Hopefully it is a step in the direction towards marrying the urban and natural environment, and to create a sustainable urban environment where society no longer sees nature as something outside the city boundaries.Thesis (MSc (Conservation Ecology and Entomology))--University of Stellenbosc, 2005.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Pepler, D.2006-09-27T12:44:24Z2010-06-01T08:59:16Z2006-09-27T12:44:24Z2010-06-01T08:59:16Z2005-12Thesis483985 bytesapplication/pdfhttp://hdl.handle.net/10019.1/2823University of Stellenbosch

oai:scholar.sun.ac.za:10019.1/29132011-06-23T09:05:25Zhdl_10019.1_532

Synergies between biodiversity conservation and sustainable rural development of adjacent communities: a case study of the Tsitsikamma National ParkFaasen, HelenaDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyNational parks and reserves -- South Africa -- Tsitsikamma Region -- Management -- Citizen participationRural development -- South Africa -- Tsitsikamma RegionBiodiversity conservation -- South Africa -- Tsitsikamma RegionSustainable development -- South Africa -- Tsitsikamma RegionTsitsikamma National Park (South Africa) -- Management -- Citizen participationThe Constitution of the Republic of South Africa promotes participatory, cooperative governance and environmental conservation. This constitutional directive is enhanced into the National Environmental Management Act and other conservation laws. These legal requirements for active community participation in natural resources management, including benefit sharing are sufficiently captured in the SANParks’ policy and strategy for the management of national parks.Thesis (MScConsEcol (Conservation Ecology and Entomology)--University of Stellenbosch, 2006.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Watts, Scotney2006-11-06T07:06:16Z2010-06-01T09:01:26Z2006-11-06T07:06:16Z2010-06-01T09:01:26Z2006-03Thesis1793990 bytes139308 bytesapplication/pdfapplication/pdfhttp://hdl.handle.net/10019.1/2913enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/29912013-03-19T19:25:59Zhdl_10019.1_532

Alien grass invasion of Renosterveld : influence of soil variable gradientsMuhl, Sara AnnAnnual alien grassEdge effectRenosterveldSoil physical and chemical characteristicsAlien invasionTheses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyConservation Ecology and EntomologyThis thesis examines the role of agricultural activity in the process of invasion of west coast renosterveld fragments by annual alien grass species. This highly endangered vegetation type has less than 5% remaining, it is vital to understand the mechanisms allowing invasion of annual alien grasses in order to effectively prevent the loss of the many rare and endemic species found in west coast renosterveld. This study was divided into three major components. Firstly the distribution of indigenous and alien plant species in relation to fence lines, separating active agricultural fields from untransformed vegetation, was described. Regression analysis was used to test for relationships between distances from agricultural fields and soil physical and chemical characteristics in natural vegetation. Cover by annual alien invasive grasses in untransformed vegetation decreased significantly with distance away from agricultural land. Secondly alien and indigenous grass seed banks were sampled along the transects, at the same sites, in order to establish whether the seed banks correlated with above ground cover. Results varied among sites and seed banks were correlated with the vegetation cover at only one site. It appears that there are a multitude of factors determining the distribution of annual alien grass cover. Thirdly a greenhouse experiment established the role that nitrogen plays in the success of the alien grass Avena fatua. This species was grown in competition with three indigenous species, an annual forb (Dimorphotheca pluvialis), a geophyte (Oxalis purpurea) and an indigenous perennial grass (Tribolium uniolae) at three levels of soil nitrogen. The geophyte was largely unaffected, while growth of the annual and indigenous perennial grasses was negatively affected by competition with A. fatua. Nitrogen did not seem to affect competitive interactions. Management of these renosterveld patches, in order to conserve them effectively, will require a multi-faceted approach, including prevention of further invasion and removal of invasive grasses already present.Thesis (MScConsEcol (Conservation Ecology and Entomology))--Stellenbosch University, 2008.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Esler, K. J.Milton, S. J.2008-11-26T20:26:35Z2010-06-01T09:03:17Z2008-11-26T20:26:35Z2010-06-01T09:03:17Z2008-12Thesishttp://hdl.handle.net/10019.1/2991Stellenbosch University

oai:scholar.sun.ac.za:10019.1/30492011-06-23T09:11:58Zhdl_10019.1_532

The restoration potential of fynbos riparian seed banks following alien clearingVosse, ShellyDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologySoil seed banks -- South Africa -- Western CapeRevegetation -- South Africa -- Western CapeFynbos -- Reintroduction -- South Africa -- Western CapeRiparian areas -- South Africa -- Western CapeRiparian areas are highly complex systems with varying levels of disturbance that are highly susceptible to invasion by alien plants. Once invaded, riparian areas play a major role in the dispersal and spread of invasive alien plants (IAPs) through the river system and, in some cases, to neighbouring landscapes. Riparian areas have therefore been prioritized by many alien clearing initiatives in South Africa. Current practice for the restoration of cleared areas is minimal and relies mainly on the un-aided recovery of native species from residual individuals and soil stored seed banks. Little research, however, has been done on the effectiveness of this approach or the extent to which riparian seed banks contribute towards community restoration. This study is part of a national research initiative (Targets for Ecosystem Repair in Riparian Ecosystems in Fynbos, Grassland and Savanna Biomes) funded by Department of Water Affairs and Forestry, in collaboration with Working for Water, The Centre for Invasion Biology and the Universities of Cape Town, Stellenbosch, Rhodes and Witwatersrand. The initiative undertook to investigate different restoration techniques on various invaded sites for their cost-effectiveness, efficiency, practicality and conservation integrity. This study has three aims. The first is to determine the composition of seed banks in un-invaded riparian areas within the fynbos biome to be used as a benchmark for future research, restoration grading and other management requirements. The second aim is to determine the composition of seed banks in heavily invaded riparian areas, and thus to assess the impact of invasion on the integrity of the seed banks. The third aim is to evaluate the restoration potential of riparian seed banks following the clearing of invasive alien plants (IAPs). Study sites were selected within four river systems in the south-western part of the Western Cape Province in South Africa: the Berg, Eerste, Molenaars and Wit Rivers. Plots were selected in both invaded (>75% IAP canopy cover; considered “closed” alien stands) and un-invaded (also termed reference, with <25% IAP canopy cover) sections of the river. Replicate plots were established along varying gradients of elevation (mountain stream and foothill) and moisture regimes (dry, wet and transitional bank zones). Soil samples were collected together with above-ground vegetation surveys and comparisons were made. Results from this study confirm those of previous studies that seed banks offer little reference to current aboveground vegetation, but rather offer insight into past vegetation history as well as future vegetation assemblages. Worldwide, many of the species that characteristically form seed banks are early successional species. A community study was done for the seed bank based on the species that germinated and were identifiable at termination of the project (6 months after initiation). Three clusters of species could be identified. One group comprised 32 generalist species that occurred in both reference and invaded sections of the rivers. A second group comprised 39 species associated with invaded sites, and a third group of 40 species that was associated with reference sites. A few sub-community groups were found within both the “reference” and “invaded” community groups which were assumed to be habitat specific. Most species were “pioneer” or relatively-short lived, early-successional species which play a vital role in the initial post-disturbance vegetation cover, and facilitate establishment of later successional species. Seed banks are notoriously variable over space and time, and floristic representation is often biased as a result of differences among species in seed production, dispersal and longevity in the soil. The general consensus is that seeds have an irregular, clustered spatial distribution that is dictated by both biological and environmental factors. Within river systems, the irregular clustering can be exceptionally skewed with the influence of pockets of high sediment deposition along the bank. Environmental factors that were found to significantly skew germination results were the presence of fire, as well as the extent and intensity of invasion (duration and cover). The high level of diversity and abundance in reference Berg River mountain stream seed banks was perceived to be a direct result of a moderate fire frequency (between 8-15 years) and the relatively natural state of the vegetation (i.e. very little invasion). Also, diversity and richness of indigenous species from the Wit and Molenaars Rivers were substantially higher in the invaded samples than the reference samples, probably because both river systems have a long history of invasion and other anthropogenic disturbances which would have an effect on the samples from “reference” sections (i.e. even a 25% presence of IAPs seems adequate enough to alter the composition of the seed bank). Correspondence analyses showed that species had clear affinities towards different levels of “key” riparian environmental variables (fire, invasion and anthropogenic disturbance). Most species were associated with moderate levels of fire frequency, invasion history, and anthropogenic disturbance. Comparisons of seed bank species assemblages between the lateral and longitudinal variables of the rivers offered insights into the habitat requirements of certain fynbos and riparian species. Most significant were the results from bank zone comparisons which showed distinct species groupings along the different moisture bands. As could be expected, riparian species were best represented within the wet bank zones and fynbos species within the dry bank zone, while species characteristic of both zones occurred in the transitional zone, making this seed bank zone the richest in species. Mountain stream sections were richer and more diverse than foothill sections over both invaded and reference samples. This is hypothesised to be linked to lower levels of anthropogenic disturbance experienced in the mountain stream sections. The impact of invasion on the riparian seed bank was most clearly shown through the correspondence analyses for the 20 most frequently occurring species. The seed bank assembly patterns were clearly defined by the state of the river (reference or invaded). Interestingly, this pattern was evident at all three spatial scales; landscape (rivers), reach (mountain stream and foothill sections) and habitat (dry, wet and transitional zones). The reference seed bank assemblage was more tightly grouped, implying that the species were more closely associated with each other and less variable than those of the invaded seed bank assemblages. The species groupings within the invaded seed banks were influenced by variables such as reach and zone, whereas the reference seed bank assemblages seem relatively unaffected by these variables. This implies that the presence of invasive alien plants creates additional variation within the seed bank which alters the natural groupings. At a broad scale, the invaded seed banks were less species rich. This means that not only will the resulting seedling community be harder to predict, but it will also have fewer species. However although generally lower in species richness, the seed banks from almost all invaded rivers interestingly showed a higher diversity of indigenous species than their reference counterparts. This is very promising in terms of rehabilitation of post-cleared riparian sites, but more information is needed to understand the seed bank composition and determine how sustainable the seed banks are for rehabilitation in the long-term. All invaded sections had fewer herbaceous perennial species but more herbaceous annual species. Graminoids made up 50% or more of the seed bank regardless of state (reference or invaded), while woody species (shrubs/shrublets) were generally more prevalent in the reference samples. These results imply that following the removal of invasive alien plants, the vegetation to regenerate from the seed bank is likely to comprise of short-lived, herbaceous species that are not necessarily an accurate reflection of the indigenous riparian community. It is however important to note that this study investigated only the species that were able to germinate over the study period (6 month germination period). Many riparian species may not have been represented because they are either late germinators or may not be present in the soil seed bank at all. In order to gain a holistic understanding of riparian community recruitment, it is recommended that seed bank studies such as this one be included in a more broad scale, long term investigation which takes into account various reproductive strategies used by riparian species. Research of this nature is in its infancy worldwide and there are many challenges involved in measuring diversity and change in these systems. However, within the scope of this study, I suggest that these results shed light on previously unanswered and important questions regarding the ecology of seed banks in the riparian ecosystems of the Western Cape.Thesis (MScConsEcol(Conservation Ecology and Entomology)--University of Stellenbosch, 2007.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Esler, K. J.Richardson, D. M.Holmes, P. M.2008-04-15T07:50:08Z2010-06-01T09:04:57Z2008-04-15T07:50:08Z2010-06-01T09:04:57Z2007-12Thesis3356676 bytesapplication/pdfhttp://hdl.handle.net/10019.1/3049enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/30772013-01-21T07:25:22Zhdl_10019.1_532

Spatial and temporal distribution of false codling moth across landscapes in the Citrusdal area (Western Cape Province, South Africa).Stotter, Robert L.False codling moth (FCM) -- CitrusdalFalse codling moth, Distribution ofCitrus pestsDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyThe false codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), is an indigenous pest of citrus fruit in southern Africa, and is a pest of high phytosanitary concern, impacting negatively on the export of fresh citrus fruit from South Africa to some international markets. FCM is a particularly serious pest in the Citrusdal area in the Western Cape Province of South Africa. FCM is known to infest most types of citrus, with navel oranges being particularly prone to attack, whereas lemons are not considered to be a favoured host. Conventional control strategies that rely on the use of insecticides are of limited use due to high levels of insecticide resistance in FCM populations. Mating disruption, the Sterile Insect Technique (SIT) and the integration of different control techniques are options that are currently being adopted. Little is known about FCM host preferences in this geographical area, or about its dispersal capacity. The ability of FCM to migrate between various host patches, including citrus orchards and indigenous fynbos vegetation, and its ability to maintain a viable population in alternative host plants when there is no fruit available for infestation in citrus orchards has not been well studied. Knowledge of these largely behavioural facets is important in planning an effective control strategy for FCM. Towards addressing this dearth of knowledge, FCM pheromone traps were set out in transects in the Citrusdal area. These transects included citrus orchards, and extended beyond citrus orchards, to include a range of habitat types and elevational gradients. This provided a grid to assess the spatial and temporal distribution of male FCM in the area. In addition, intensive sampling and inspection of potential host plant material was undertaken in the area in an attempt to identify any alternative host plants.Thesis (MScAgric (Conservation Ecology and Entomology)--University of Stellenbosch, 2009.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Samways, M. J.2009-03-03T11:44:32Z2010-06-01T09:05:39Z2009-03-03T11:44:32Z2010-06-01T09:05:39Z2009-03Thesishttp://hdl.handle.net/10019.1/3077enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/31222013-04-05T09:40:40Zhdl_10019.1_532

The conservation value of artificial ponds in the Western Cape Province for aquatic beetles and bugsApinda-Legnouo, Emelie ArletteConservationPondsInsectsTheses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyPonds -- South Africa -- Western CapeFreshwater insects -- South Africa -- Western CapeFreshwater insects -- South Africa -- Western CapeFreshwater insects -- Conservation -- South Africa -- Western CapeFreshwater insects -- Habitat -- Conservation -- South Africa -- Western CapeConservation ecologyFreshwater insect species and their host ecosystems are widely threatened, particularly within agricultural and urban landscapes of Mediterranean areas, including that of the Western Cape Province, South Africa. The study here determined the biodiversity value of nineteen artificial ponds (temporary and permanent) and two river margin sites in the Cape Floristic Region (CFR). The aim was to determine aquatic beetle and bug abundance and species richness in these ponds, a topic which has been hardly explored in South Africa. Sites were sampled from September 2005 to September 2006. A total of 18 677 aquatic beetle and bug individuals were sampled, representing 43 genera (28 beetle and 15 bug genera), 64 species (44 aquatic beetle and 20 bug species). Different pond types had distinct species assemblages. The associated physico-chemical characteristics of these sites were also investigated. The key environmental variable affecting aquatic beetle and bug distribution was naturalness (no human and environmental impact on waterbody). The results showed that the most important determinant of aquatic beetle and bug species richness across all sites was emergent macrophytes, such as Typha capensis and Persicaria decipiens. Artificial ponds in the CFR clearly increase the area of occupancy for insects, and therefore play a major role in conserving them. This is especially so when the ponds are at moderate temperatures (i.e. 19º C). Although all ponds contributed to the aquatic beetle and bug diversity in the region, they differed in relative value, depending on the combination of environmental variables affecting each pond.Thesis (MScConsEcol (Conservation Ecology and Entomology))--University of Stellenbosc, 2007.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Samways, M. J.2008-02-11T07:57:12Z2010-06-01T09:06:50Z2008-02-11T07:57:12Z2010-06-01T09:06:50Z2007-12Thesis3292422 bytesapplication/pdfhttp://hdl.handle.net/10019.1/3122enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/44812011-06-23T11:54:24Zhdl_10019.1_532

Monitoring the success of an old-field rehabilitation trial in the winter rainfall succulent Karoo : the effect of Oxalis pes-capraeGhebremariam, Ghirmai EmunEsler, Karen JoanDreyer, Leanne L.Field rehabilitation trialHuman interventionRevegetation -- South Africa -- Karoo.Soil remediation -- South Africa -- KarooTheses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyENGLISH ABSTRACT: The main aim of an old field rehabilitation trial initiated in 2000 was to find a solution to the rehabilitation process for approximately 90 000 ha of unutilised land in the Little Karoo, South Africa. Depending only on a natural succession process to restore unutilised old fields would mean that the period of recovery would be longer than the life span of an average farmer. The trial, initiated by Witbooi in 2000 aimed to see how human intervention can facilitate the process of rehabilitation of old-fields. Three years later, the trial was again monitored to evaluate the success of reseeded indigenous species and method of cultivation in the rehabilitation process. A second objective was based on a result of Witbooi (2002) who showed that there was a tendency of 0. pes-caprae to invade disturbed areas, and aimed to evaluate the effect of this species on the rehabilitation process. Seven indigenous species were reseeded in 2000, of which only four species germinated and survived to the present. These surviving species are Pteronia incana Burm Dc., Tripteris sinuata DC., Ehrharta calycina SM and Chaetobromus dregeanus Nees. The highest level of recruitment in 2001 was recorded for T sinuata followed by P. incana, E. calycina and C. dregeanus. In September 2003, three years after the trial was initiated, the highest number of surviving seedlings were of T sinuata followed by E. calycina, C. dregeanus and P. incana. Five different cultivation methods were used to enhance the germination rate and survival of seedlings. The number of seedlings that survived differs according to the cultivation methods and soil type. Tripteris sinuata had the highest number of surviving seedlings in all cultivation methods off-heuweltjies. Tripteris sinuata was therefore selected to analyse the effect of various cultivation methods. The second objective was to study the impact of Oxalis pes-caprae on species diversity in restored old fields by assessing its ability to disperse in old fields under different cultivation methods. The multivariate ANOVA results showed that there was a significant difference in the density of O. pes-caprae between on and off heuweltjies (sites) and treatments (cultivation methods). There was a significant difference in the density of O. pes-caprae between cultivation methods. A Post Hoc LSD test showed a significant difference in the density of aboveground O. pes-caprae plants between control sites (no disturbance) compared to those sites that underwent some sort of soil disturbance. There was, however, no significant difference in the abundance of O. pes-caprae on plots that underwent some sort of disturbance (i.e Cleared vs Tilled vs Disked vs Ploughed sites) on heuweltjies. There was a significant difference in the number of O. pes-caprae bulbs collected between blocks (on and off-heuweltjie) and significant differences between cultivation methods. There was also a significant difference in bulb diameter between cultivation methods when compared between on and off-heuweltjie sites. The bulbs were classified into four measurement classes. The highest number of small (2-5 mm diameter) and medium (5-8 mm diameter) sized bulbs were found in the Tilled cultivation method. In contrast the Control treatment (uncultivated) had the highest number of large sized bulbs (14-17 mm diameter) and medium bulbs size categories. In conclusion, T. sinuafa has the potential to be used for rehabilitation of old fields in combination with Tilled cultivation method. Attention should be paid to the effect of O. pes-caprae especially on heuweltjies where this species showed a complete dominance in the rehabilitation trial.AFRIKAANSE OPSOMMING: Die hoof doel van 'n ou veld rehabilitasie eksperiment wat in 2000 geinisieer is was om 'n oplossing te vind vir die rehabilitasie proses vir ongeveer 90 000 ha onbenutte land in die Klein Karoo, Suid-Afrika. Indien daar slegs op natuurlike suksessie prosesse staatgemaak word om die onbenutte ou lande te restoreer, sou dit beteken dat die periode van herstel langer sou wees as die lewensverwagting van die gemiddelde boer. Hierdie eksperiment, wat in 2000 deur Witbooi geinisieer is, het gepoog om te bepaal hoe menslike inmenging die proses van rehabilitasie van ou velde kan fasiliteer. Drie jaar later is die eksperiment weer gemonitor om die sukses van die teruggesaaide inheemse spesies en bewerkings-metodes in die rehabilitasie proses te evalueer. 'n Tweede doelwit is gebaseer op 'n resultaat van Witbooi (2002) wat aangetoon het dat daar 'n neiging was vir O. pes-caprae om versteurde areas binne te dring, en het dus gemik om die effek van hierdie spesie op die rehabilitasie proses te evalueer. Sewe inheemse spesies is in 2000 teruggesaai, waarvan slegs 4 spesies ontkiem en oorleef het tot die hede. Hierdie oorlewende spesies is Pteronia incana Burm Dc., Tripteris sinuata DC., Ehrharta calycina SM en Chaetobromus dregeanus Nees. Die hoogste vlak van werwing in 2001 is vir T sinuata aangeteken, gevolg deur P. incana, E. calycina en C. dregeanus. In September 2003, drie jaar na die aanvang van die eksperiment, was die hoogste getal oorlewende saailinge die van T sinuata, gevolg deur E. calycina, C. dregeanus en P. incana. Vyf verskillende bewerkings-metodes is gebruik om ontkiemingstempo en saailing oorlewing aan te help. Die aantal saailinge wat oorleef het varieer volgens die bewerkings-metode wat gevolge is en die grondtipe. Tripteris sinuata het die grootste aantal oorlewende saailinge gehad in al die bewerkings-metodes af van heuweltjies. Tripteris sinuata is daarom geselekteer om te analiseer vir die effek van verskillende bewerkings-metodes. Die tweede doelwit was om die inpak van Oxalis pes-caprae op spesie-diversiteit in die gerestoreerde ou land te bepaal deur die vermoë van hierdie spesie om in ou velde te versprei onder verskillende bewerkings-metodes te evalueer. Die multi-veranderlike ANOVA resultate het aangetoon dat daar 'n beduidende verskil in O. pes-caprae digtheid tussen heuweltjie en nie-heuweltjie (persele) en verskillende bewerkings-metodes was. Daar was 'n beduidende verskil in die digtheid van o. pes-caprae tussen verskillende bewerkingsmetodes. 'n Post Hoc LSD toets het 'n beduidende verkil in die digtheid van bogrondse O. pes-caprae plante tussen kontrole terreine (geen versteuring) vergeleke met persele wat een of ander vorm van grondversteuring ondergaan het aangedui. Daar was egter geen beduidende verskil in die volopheid van 0. pes-caprae op persele wat een of ander vorm van versteuring ondergaan het (i.e Skoongemaakte vs Getilde vs Geskottelde vs Geploegde persele) op heuweltjies nie. Daar was 'n beduidende verskil in die aantal O. pes-caprae bolle wat versamel is tussen blokke (op en af van heuweltjies) en beduidende verskille tussen die bewerkings-metodes. Daar was ook 'n beduidende verskil in bol-deursnitte tussen bewerkings-metodes wanneer dit tussen heuweltjie en nie-heuweltjie persele vergelyk is. Die bolle is in vier metingsklasse verdeel. Die grootste aantal klein (2-5 mm deursnit) en medium (5-8 mm deursnit) bolle is in die Getilde bewerkings-metode gevind. In kontras het die Kontrole behandeling (onbewerk) die grootste aantal groot (14-17 mm deursnit) en medium bolle gehad. Samevattend het T. sinuata die potensiaal om gebruik te word in die rehabilitasie van ou lande in kombinasie met die tilting bewerkings-metode. Aandag moet geskenk word aan die effek van 0. pes-caprae, veral op heuwetjies waar hierdie spesies 'n totale dominansie in die rehabilitasie eksperiment getoon het.Thesis (MSc (Conservation Ecology)--University of Stellenbosch, 2004.89 leaves single sided printed, preliminary pages i-xiv and numbered pages 1-89. Includes bibliography. List of tables, figures used.Scanned with a Hp Scanjet 8250 Scanner to pdf format (OCR).Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.2010-08-26T09:36:36Z2010-08-26T09:36:36Z2004-12Thesishttp://hdl.handle.net/10019.1/4481en_ZAUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/40372013-03-23T22:01:12Zhdl_10019.1_532

Habitat use and diet selection of reintroduced white rhinoceros (Ceratotherium simum) in Pafuri, Kruger National ParkPedersen, GayleRhinoceros -- South Africa -- Kruger National parkDietary compositionHabitat preferenceWildlife reintroductionDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyENGLISH ABSTRACT: In 2005, six white rhinoceros (Ceratotherium simum) were reintroduced into Pafuri, in the far northern section of Kruger National Park (KNP), South Africa, as part of a large mammal reintroduction project. All six individuals were fitted with horn radio transmitters. Rhinos have been absent from Pafuri for over a century, and this project aimed to establish a breeding nucleus in the area. The aim of this study was to monitor post-release movement and habitat use of these animals within the 203 km2 study area and assess the short term success of the re-introduction project as well as the suitability of the five landscape types in Pafuri as a habitat for white rhinoceros. Habitat suitability and selection was assessed at two ecological hierarchical scales: 1) landscape system, analysed further down to the spatial scale of range and territory establishment, and 2) feeding station for diet selection. Rhinos were tracked for 12 months and a database of 719 sighting records was compiled. These data were used to determine the utilisation of and preference between the Pafuri landscape types, using preference indices that compare utilisation versus availability. An a-LoCoH nonparametric kernel method was used to calculate home ranges and utilisation distributions of each rhino. Feeding surveys were attempted by backtracking along fresh rhino feeding paths and recording the grass species present and eaten in 0.7 m x 0.7 m quadrats. Faecal samples were collected and analysed using microhistological techniques and dietary composition was assessed for each rhino. Landscape preference analyses showed that the rhinos favoured Colophospermum mopane Shrubveld on calcrete in the dry season, and the Punda Maria Sandveld in the wet season. The territory establishment of the dominant bull was substantially larger (44.8 km²) than those of adult male rhinos in the rest of KNP. Ranging areas of the mature females (17 – 25.4 km²), were consistent with sizes of previous studies. The two sub-adults ranged far more extensively, establishing an 84.1 km² annual range during the study period. The annual diet consisted of mostly perennial grass species, with moderate grazing value species dominating for most of the year. Dietary analyses showed that Schmidtia pappophoroides, Eragrostis superba, Enneapogon cenchroides, Cenchrus ciliaris and Stipagrostis uniplumis were the primary grass species consumed. vii This study demonstrated that the Pafuri rhinos are behaving similarly to rhinos established in other areas, with movements around the landscapes being primarily influenced by rainfall and permanent water sources, and the high quality grazing that is more abundant in the wet season. Their range and territory sizes were inevitably large, for a low density area, but not uncommonly so. The most significant outcome of this study was the preference shown for the Colophospermum mopane Shrubveld on calcrete landscape that is classed as unique within South Africa, and was also ranked as ‘avoided’ by the earlier KNP studies into landscape preferences of rhinos. The grass cover in Pafuri, although sparse and very dry, contained a diversity of low to high grazing value grasses that the rhinos appeared to exploit to the best of their ability. The abundance of moderate grazing value species in their diets, and the low number of low grazing value species suggests that they are maximising the opportunities to graze on nutritious grasses when they are available. Our findings suggest that the Pafuri area is suitable for the establishment of a small breeding nucleus of white rhinos. The abundance of permanent water, in the form of springs, is a great advantage however, the potential for bush encroachment into grasslands in areas of such low rainfall needs to be considered if the population continues to grow at the current rate. The birth of two new calves in 2008 confirms that these rhinos have settled and adapted to their new habitat, and is a very promising sign for the future of this increasing subpopulation.AFRIKAANSE OPSOMMING: In 2005 is ses wit renosters (Ceratotherium simum) hervestig in Pafuri in die noordelike gedeelte van die Kruger Nasionale Park (KNP), Suid-Afrika, as deel van ‘n groot soogdier hervestigings projek. Al ses individue is gemerk met horing radioseintoestelle. Renosters kom vir al meer as ‘n honderd jaar nie meer in Pafuri voor nie en hierdie projek was daarop gemik om ‘n teel-nukleus in hierdie gesied te vestig. Die doel van hierdie studie was om die verspreiding van die renosters na loslating en habitat-gebruik binne die 203 km2 studie-omgewing te monitor, om die korttermyn sukses van die hervestigings program te evalueer en ook te kyk na die gepastheid van die vyf landskap-tipes in Pafuri as ‘n geskikte habitat vir die wit renosters. Habitatgepastheid en seleksie is geëvalueer volgens twee ekologiese hiërargiese skale: 1) landskapsisteem, wat in meer resolusie tot die ruimtelike skaal van reikwydte en omgewingsvestiging geanaliseer is, en 2) voedings-stasie vir dieet-seleksie. Renosters is vir 12 maande gevolg en ‘n databasis wat 719 waarneming-rekords bevat, is opgestel. Laasgenoemde data is gebruik om die gebruik en voorkeur vir die Pafuri landskap tipes te bepaal met behulp van voorkeur-indikators wat die gebruik met beskikbaarheid vergelyk het. ‘n a-LoCoH nie-parametriese kern metode is gebruik om die reikwydte en gebruiksverspreidings van elke renoster te bereken. Voedingsopnames is gedoen deurdat vars renoster voedings-paadjies terugwaarts gevolg is en die grasspesies teenwoordig en waarop gevoed is, in 0.7 m x 0.7 m kwadrante te bepaal. Mismonsters is versamel en geanaliseer deur gebruik te maak van mikro-histologiese tegnieke en voedingswaarde-samestellings is vasgestel vir elke renoster . Landskapsvoorkeur analises dui daarop dat die renosters in die droë seisoen Colophospermum mopane struikveld wat op kalkreet groei verkies en die Punda Maria Sandveld in die reën seisoen. Die terrein vestiging van die dominanate bul was aansienlik groter (44.8 km²) in vergelyking met die volwasse bul renosters in die res van die KNP. Reikwydte van die volwasse koeie (17 – 25.4 km²) was ooreenstemmend met dié van vorige studies. Die reikwydte van die twee subvolwassenes het baie meer gevarieer, deurdat ‘n 84.1 km² jaarlikse reikwydte gedek was binne die studie periode. Die jaarlikse dieet het meestal bestaan uit meerjarige ix grasspesies, met spesies met matige weidingswaarde wat oorheers vir meeste van die jaar. Voedingswaarde analises dui daarop dat Schmidtia pappophoroides, Eragrostis superba, Enneapogon cenchroides, Cenchrus ciliaris en Stipagrostis uniplumis die primêre gras spesies was waarop gewei word. Die studie het bewys dat die Pafuri renosters soortgelyke gedragspatrone vertoon het as renosters in ander gevestigde gebiede, deurdat bewegings binne die landskap hoofsaaklik beïnvloed word deur reënval en permanente waterbronne, asook die hoë gehalte weidingsbronne beskikbaar gedurende die reën seisoen. Hulle reikwydte- en terrein-groottes was uiteraardelik groot vir ‘n lae-digtheid areas, maar dit is nie buitengewoon nie. Die mees betekenisvolle gevolgtrekking van die studie was die voorkeur vir die Colophospermum mopane struikveld op kalkreet landskappe wat beskou word as uniek aan Suid-Afrika, en wat ook beskou was as ‘vermy’ deur vroër KNP studies tov. landskap voorkeure spesifiek vir renosters. Die grasbedekking in Pafuri, alhoewel yl en baie droog, het tog oor ‘n verskeidenheid grasse beskik wat van lae tot hoë weidings waarde het, en wat die renosters tot die beste van hulle vermoë benut het. Die oorvloedige teenwoordigheid van beide spesies met matige weidingswaarde in hulle dieët en die lae hoeveelheid van spesies met lae weidingswaarde, impliseer dat hulle die geleentheid om op voedingsryke grasse te voed ten volle benut wanneer dit beskikbaar is. Ons resultate dui daarop dat die Pafuri omgewing geskik is vir die vestiging van ‘n klein teel-nukleus van wit renosters. Die oorvloedige teenwoordigheid van permanente waterbronne in die vorm van fonteine is ‘n groot voordeel, maar die kans vir bosindringing in hierdie grasveld-gebiede met lae reënval moet oorweeg word sou die populasie aanhou toeneem teen die huidige tempo. Die geboorte van twee nuwe kalfies in 2008 staaf die moontlikheid dat die renosters gevestig en aangepas het in hulle nuwe habitat, wat ‘n baie belowende teken is vir die toekoms van die groeiende subpopulasie.Thesis (MSc (Conservation Ecology and Entomology))--Stellenbosch University, 2009.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Leslie, AlisonOwen-Smith, Norman2009-03-05T08:23:19Z2010-08-13T13:11:38Z2009-03-05T08:23:19Z2010-08-13T13:11:38Z2009-03Thesis107 p. : ill., mapshttp://hdl.handle.net/10019.1/4037enStellenbosch University

oai:scholar.sun.ac.za:10019.1/40432013-03-23T22:00:56Zhdl_10019.1_532

Large herbivore stocking rate effects on plant palatability, forage preference and soil properties in an Alluvium Fynbos-Renosterveld mosaicMubamu Makady, ElvisGame herbivoryPlant palatibilityForage preferenceRenosterveldAlluvium fynbosDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyConservation Ecology and EntomologyENGLISH ABSTRACT: An understanding of the interactions of herbivores, plant nutrients and soil properties is crucial for grazing management. Of particular interest are plant palatability and herbivore grazing preferences. These aspects, the focus of this thesis, were studied in a Swartland Shale Renosterveld and Swartland Alluvium Fynbos mosaic in the Western Cape of South Africa. This vegetation is classified as critically endangered due to the transformation of its landscape in favour of agricultural production and urban settlement. Pre-colonial herbivore vertebrates were hunted out by 1700, leading to a sparse knowledge of the early dynamics of the vegetation. However, currently game farmers and landowners are re-introducing selected species into the area. Thus, managers require knowledge on how to implement practical guidelines for best-practice grazing management. This study investigates, firstly, the relationship between plants and animals. This included seasonal assessment of seed germination from dung of bontebok and eland; the effect of stocking rates on plant palatability (crude protein, crude fibre, crude fat, moisture, tannin and mineral) of herbage was studied with the aim to understand how palatability influences herbivore forage decisions. Secondly, this study looked at how stocking rates influence soil nutrients (nitrogen, phosphorus), and others soil properties such as pH and soil moisture. The distribution of alien grasses was facilitated by grazers. About 58 % of grasses germinated from the dung of eland and Bontebok were alien species. Additionally, there was significant variation in palatability related to grazing pressure and plant maturity between sites and over seasons. Grasses on the high grazing site had higher carbohydrate (3%-5% higher) and protein content (1%-5% higher) than at the least grazed site. Mature grasses contained less water (10%-20%), but no obvious variation in tannin concentration than immature grasses. However, species such as Ficinia sp. showed variations with grazing pressure and maturity. Ficinia sp. on the high grazing site had higher tannin concentration (5mg/ml-22mg/ml) and crude protein (4%-9%) than at the least grazed site. When the plant ages, tannin concentration increase (ranging from 15% to19% higher). Two types of plant were recoreded according to their chemical response following grazing pressure. These types are 1) plants that are grazing tolerant and which produce more carbohydrate when grazed and 2) plants that are grazing intolerant under high grazing pressure and which produce chemical defence compounds such as tannin to deter herbivores attacks. The results indicate that in fynbos and renosterveld, the relationship between preference and plant chemical compounds is not consistent since no IV patterns emerged to explain what compounds drive preference. A combination of chemical compounds may be the reason for the selection by the grazers; alternatively, other compounds not included in the study may influence the forage selection by an herbivore. The second part of the study showed that stocking rates appeared to have a significant effect on soil properties investigated. Soil moisture was significantly affected by the stocking rate in autumn. The high grazing intensity site had the lowest soil moisture especially in autumn (10% lower than the control site), likely due to heavy trampling and soil compaction. pH was the lowest at the high grazing intensity site in all seasons compared to the control site. Likely reasons were the high deposition of nitrogen through dung and urine deposition, high removal of basic cations and animal exportation through hunting activities. Lastly, grazing maintains inorganic nitrogen at stable levels regardless of seasonal changes and increases the concentration of phosphorus especially under high grazing pressure compare to less grazed sites. The grazing dynamics of Swartland Shale Renosterveld - Swartland Alluvium Fynbos mosaic system are complex and multifaceted. Farmers need to pay attention to the nutritional status of plant species grazed to know whether they meet the nutritional requirements of the game in the area. Overstocking should be avoided in this system as it triggers the production of tanniferous compounds that could decrease the survivorship of herbivores. Moderate grazing 0.09 LAU/ha pressure provides the best stocking rates for effective grazing management.AFRIKAANSE OPSOMMING: Vir suksesvolle weidingsbestuur is dit noodsaaklik om die interaksie tussen herbivore, plantvoedingstowwe en grondeienskappe te verstaan. Van besondere belang is plantsmaaklikheid en herbivore se weidingsvoorkeure. Hierdie aspekte, wat die fokus van hierdie tesis is, is bestudeer in ‘n Swartland Shale Renosterveld en Swartland Alluvium Fynbos-mosaïek in die Wes-Kaap Provinsie van Suid-Afrika. Hierdie plantegroei word as kritiek bedreigd geklassifiseer weens die transformering van sy landskap ten gunste van landbou-aktiwiteite en stedelike vestiging. Pre-koloniale herbivoor vertebrata is teen 1700 deur jagters uitgeroei, wat gelei het tot min kennis oor die vroeë dinamiek van die plantegroei. Wildsboere en grondeienaars is egter besig om geselekteerde spesies in die area te hervestig. Bestuurders moet dus weet hoe om praktiese riglyne vir beste-praktyk weidingsbestuur te implementeer. Hierdie studie ondersoek eerstens die verhouding tussen plante en diere. Dit sluit seisoenale evaluering van saadontkieming uit die mis van bontebokke en elande in; die effek van veegetalle op plantsmaaklikheid (ruproteïen, ruvesel, ru-vet, vogpeil, tannien en minerale) van die weiveld is bestudeer om vas te stel hoe plantsmaaklikheid herbivore se weidingsbesluite beïnvloed. Tweedens het die studie die invloed van veegetalle op grondvoedingstowwe (stikstof, fosfor) ondersoek, asook ander grondeienskappe soos pH en grondvogpeile. Die verspreiding van uitheemse grasse is deur weidende diere gefassiliteer. Ongeveer 58% van alle grasse wat uit die mis van elande en bontebokke ontkiem het, was uitheemse spesies. Verder was daar beduidende variasie in plantsmaaklikheid verwant aan beweidingsdruk en plantvolwassenheid tussen verskillende persele en oor seisoene. Grasse op die hoogs beweide persele het 3%-5% hoër koolhidraatinhoude en 1%-5% hoër proteïeninhoude gehad as die minder beweide persele. Volwasse grasse het 10%-20% minder water bevat as onvolwasse grasse, maar het nie in terme van tannienkonsentrasie van die onvolwasse grasse verskil nie. Spesies soos Ficinia sp. het variasies getoon met beweidingsdruk en volwassenheid. Ficinia sp. het op die hoog-beweide perseel ‘n hoër tannienkonsentrasie (5mg/ml-22mg/ml) en meer ruproteïen (4%-9%) gehad as op die minste beweide perseel. Wanneer die plant verouder, verhoog die toename in tannienkonsentrasie (met tussen 15% en 19%). Twee tipes plante is aangeteken volgens hul chemiese response ná beweidingsdruk. Hierdie tipes is 1) plante wat beweidingstolerant is en wat meer koolhidrate produseer wanneer hulle as weiding dien en 2) plante wat onder hoë beweidingsdruk beweidingsintolerant is en wat chemiese verbindings VI soos tannien produseer om herbivooraanvalle af te weer. Die resultate dui aan dat die verhouding tussen voorkeur en plante se chemiese verbindings nie konstant bly in fynbos en renosterveld nie, aangesien geen patrone na vore getree het wat kon verklaar watter verbindings bepalend is vir voorkeur nie. ‘n Kombinasie van chemiese verbindings mag die rede wees waarom die herbivore sekere plante verkies; alternatiewelik mag ‘n herbivoor se plantseleksie beïnvloed word deur chemiese verbindings anders as dié wat in hierdie studie ondersoek is. Die tweede deel van die studie het aangetoon dat veegetalle blyk ‘n beduidende invloed te hê op die grondeienskappe wat ondersoek is. Grondvogpeile is in die herfs beduidend beïnvloed deur die veegetalle. Die perseel met die hoë beweidingsintensiteit het die laagste grondvogpeil gehad, veral in die winter (10% laer as dié van die kontrole-perseel), waarskynlik weens erge getrappel en grondkompaktering. Vergeleke met die kontrole-perseel was pH die laagste op die perseel met die hoë beweidingsintensiteit, in alle seisoene. Waarskynlike redes hiervoor is die hoë neeerslag van stikstof deur mis- en uriene-neerslae, hoë verwydering van basiese katione en dierevervoer wat deur jagaktiwiteite teweeg gebring word. Laatstens behou weiding anorganiese stikstof teen stabiele vlakke ongeag van seisoenale veranderinge en toenames in die konsentrasie van fosfor, veral onder hoë beweidingsdruk vergeleke met minder beweide persele. Die weidingsdinamiek van die Swartland Shale Renosterveld - Swartland Alluvium Fynbosmosaïeksisteem is kompleks en veelvlakkig. Boere behoort aandag te skenk aan die voedingstofstatus van die plantspesies wat as weiding dien, sodat hulle kan weet of die voedingsbehoeftes van die wild in die omgewing bevredig word. Die aanhou van te veel vee in hierdie sisteem behoort vermy te word aangesien dit as sneller dien vir die produksie van tannienbevattende verbindings wat die oorlewingsvermoë van herbivore kan verlaag. Matige beweidingsdruk (0.09 LAU/ha) bied vir effektiewe weidingsbestuur die beste veegetalle.Thesis (MSc (Conservation Ecology and Entomology))--Stellenbosch University, 2009.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Krug, Cornelia B.Esler, Karen J.2009-03-04T08:32:22Z2010-08-13T13:11:44Z2009-03-04T08:32:22Z2010-08-13T13:11:44Z2009-03Thesis103 p. : ill., mapshttp://hdl.handle.net/10019.1/4043enStellenbosch University

oai:scholar.sun.ac.za:10019.1/40482013-03-30T22:01:13Zhdl_10019.1_532

Soil nitrogen and phosphorus depletion as a means of restoring degraded lowland fynbos ecosystems invaded by alien grassesRuwanza, SheunesuSucrose additionRestorationMicrobial immobilizationAbandoned agricultural landsHerbicide applicationDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyENGLISH ABSTRACT: Much of South African lowland fynbos vegetation has been transformed by agriculture and invasive alien grass species. The artificial reduction of plant available N and P levels in soils, through the addition of carbon and calcium respectively, may provide a means of retarding the growth of alien grasses stimulated by soil nutrient enrichment. Furthermore, the competitive advantage of native lowland fynbos species adapted to nutrient impoverished soils may be increased by these additions. The above premise was tested in both field- and greenhouse-based trials by applying systemic and contact herbicides to reduce the large alien invasive grass biomass. This was followed by the addition of C as sucrose and Ca as gypsum to reduce plant available N and P respectively in the soils. The effects of these combined herbicide and soil nutrient amendment treatments on plant physiology and growth were examined in both resident alien and indigenous species and in several herbaceous and woody native species introduced as seeds and seedlings. Also, soils sampled from the different treatments in both trials were chemically analyzed. There was a total absence of seedling recruitment from seeds of all 9 indigenous species sown into soils in the field-based trial while introduced juveniles of another 9 indigenous species displayed a high mortality during the dry summer season. These detrimental effects were less severe in the greenhouse-based trial which received more regular watering and where successful seedling recruitment from seeds sown occurred in four indigenous species. Sucrose additions, both exclusively and in combination with gypsum, caused significant reductions in foliar chlorophyll, photosystem II (PSII) function and above-ground biomass of most resident and introduced alien and indigenous species. These reductions were less prominent where herbicides were applied, a possible consequence of N and P supplementation of soils by the decomposing plant biomass. This was supported by the elevated soil K, Na and N concentrations measured in soils where contact and systemic herbicides were applied. However, no significant changes in soil N or P were apparent following sucrose and gypsum additions respectively, the latter attributed to the acidic soils which precluded the formation of insoluble P complexes. A second study tested the hypothesis that exogenous sucrose addition to soils inhibits plant growth by stimulating soil microbial biomass which accumulates soil nitrogen rendering it unavailable to plants. Two native, early seral species (Dimorphotheca pluvialus (L.) Moench and Ursinia anthemoides (L) Poir. subsp anthemoides) were cultured in heat sterilized (2200C for 72 hours) and non-sterilized soils in a greenhouse under four different levels of sucrose (0, 100, 200 and 300 g m-2) supplied monthly over a four-month active growing period. Foliar chlorophyll iii contents, photosystem II (PSII) efficiencies, shoot and root lengths and dry mass, inflorescence numbers and N and P contents were measured in the plants, and N and P contents and bacterial cell and coliform numbers analyzed in the soils. Both D. pluvialis and U. anthemoides displayed significant reductions in PSII efficiency, chlorophyll content, accumulation of biomass and N and P in response increased levels of sucrose, which initially seemingly supported the hypothesis as these reductions were of substantially greater magnitude in plants cultivated in non-sterilized than sterilized soils. Despite this, there was no evidence of any significant increases in bacterial and coliform cell numbers in response to increased levels of sucrose supplied or any significant reductions in soil N and P contents following sucrose additions in both sterile and non-sterilized soils. Greater numbers of bacteria and coliforms were measured in sterilized than non-sterilized soils which corresponded with reduced soil N contents but these were not reflected in like changes in plant PSII efficiency and growth and total amounts of N taken up by plants which displayed massive increases in sterilized soils. The findings did not support the hypothesis and pointed to an abiotic mechanism of sucrose inhibition of plant photosynthesis and growth. The study concludes that the suitability of adding sucrose and gypsum to degraded renosterveld ecosystem soils to promote the competitiveness of native taxa against alien grasses is dubious. Other restoration alternatives such as natural re-colonization, transfer of soils containing viable seeds from pristine communities and top soil removal should be considered.AFRIKAANSE OPSOMMING: Baie van Suid Afrika se laagland fynbos plantegroei is verander deur landbou en uitheemse indringer grasspesies. Die kunsmatige reduksie van plantbeskikbare N en P vlakke in die grond deur die toevoeging van koolstof en kalsium onderskeidelik, kan ’n metode wees om die groei van indringer grasse te vertraag, wat gestimuleer word deur grondvoedingstofverryking. Die kompeterende voordeel van die inheemse laagland fynbosspesies wat aangepas is tot voedingstofarme grond kan verhoog word deur die toevoegings. Bogenoemde postulaat is in beide die veld- en die glashuis-gebaseerde eksperimente getoets deur die aanwending van sistemiese en kontak onkruiddoder om die groot indringer grasbiomassa te verminder gevolg deur die byvoeging van C as sukrose en Ca as gips om die plantbeskibare N en P onderskeidelik te verminder in die grond. Die effekte van die gekombineerde onkruiddoder en grondvoedingstof verbeteringsbehandelings op die fisiologie en groei van die plante is ondersoek in beide inheemse- en residente indringerspesies asook in verskeie kruidagtige- en houtagtige inheemse spesies wat aangeplant was as sade en saailinge. Grondmonsters van die verskillende behandelings in beide studies was versamel en was chemies geanaliseer. Daar was ’n definitiewe afwesigheid van nuwe saailinge van sade van al nege indringerspesies wat gesaai was in grond in die veldgebaseerde studie, en saailinge van nog nege inheemse spesies het ’n hoë mortaliteit getoon gedurende die droë somerseisoen. Hierdie skadelike effekte was minder ernstig in die glashuisgebaseerde studie wat meer benat was, en waar nuwe saailinge suksesvol geproduseer was deur sade in vier inheemse spesies. Sukrose byvoegings, beide uitgesluit en in kombinasie met gips, het ’n afname in blaarchlorofil, fotosisteem II en bogrondse biomassa van die meeste van die residente en aangeplante indringer- en inheemse spesies getoon. Hierdie afnames was minder prominent waar onkruiddoder aangewend was, ’n moontlke oorsaak van N en P aanvulling van grond deur die verrottende plantbiomassa. Dit word ondersteun deur verghoogde grond K, Na en N konsentrasies, gemeet in grond waar kontak en sistemiese onkruiddoder toegevoeg was. Geen noemenswaardige veranderinge in grond N of P was sigbaar na byvoeging van sukrose en gips onderskeidelik nie. Laasgenoemde het bygedra tot suuragtige grond wat die formasie van onoplosbare P komplekse verkom het. ‘n Tweede studie het die hipotese getoets waar eksogene sukrose byvoeging tot grond plantegroei inhibeer deur die grond mikrobe biomassa te stimuleer wat akkumuleer wat in grond stikstof en dit nie beskikbaar maak vir plante nie.Twee inheemse vroeë intermediêre stadium spesies (Dimorphotheca pluvialus (L.) Moench en Ursinia anthemoides (L) Poir. subsp v anthemoides) was gekweek in hitte gesteriliseerde grond (2200 C vir 72 uur) en in nie-gesteriliseerde grond in ’n glashuis onder vier verskillende vlakke van van sukrose (0, 100, 200 en 300 g m-2) bygevoeg maandeliks oor ‘n 4 maande aktiewe groei periode. Blaarchlorofilinhoud, fotosisteem II (FS II) doeltreffendheid, groeipunt en wortel lengte en droë massa, blomgetalle en N en P inhoud was gemeet in die plante sowel as N en P inhoud en bakteriële sel en kolivorm getalle was geanaliseer in die grond. Beide D. pluvialis en U . anthemoides het ’n afname getoon in FS II doeltreffendheid, chlorofilinhoud, biomassa akkumulasie, N en P response op verhoogde vlakke van sukrose, wat aanvanklik aangetoon het dat dit die hipotese ondersteun want hierdie afnames wat heelwat groter in plante wat gekweek was in ongesteriliseerde grond as in gesteriliseerde grond. Daar was geen toename in baketriële en kolivorm sel getalle in rssponse tot verhoogde vlakke van sukrose byvoegings of enige noemenswaardige in grond N en P inhoud na byvoeging van sukrose in beide steriele en nie-steriele grond nie. Groot getalle bakterieë en kolivorme was gemeet in gesteriliseerde grond as in ongesteriliseerde grond. Dit korrespondeer met verminderde grond N inhoud maar dit was nie gereflekteer in veranderinge in plant FS II doeltreffendheid, groei en die totale hoeveelhede N wat opgeneem was deur plante wat ’n massiewe toename getoon het ongesteriliseerde grond nie. Hierdie bevindings het nie die hipotese ondersteun nie en het gewys na ’n abiotiese meganisme van sukrose inhibisie van plant fotosintese en groei. Die studie lei dus af dat die geskiktheid om sukrose en gips by te voeg tot gedegradeerde renosterveld ekosisteemgrond om kompetisie tussen inheemse plante en indringer grasse te promoveer, twyfelagtig is. Ander restorasie alternatiewe soos natuurlike herkolonisasie, oordrag van grond wat lewensvatbare sade bevat van onbeskadigde gemeenskappe en bogrond verwydering word oorweeg.Thesis (MSc (Conservation Ecology and Entomology))--University of Stellenbosch, 2009.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Esler, K. J.Musil, C. F.2009-03-04T10:21:30Z2010-08-13T13:11:47Z2009-03-04T10:21:30Z2010-08-13T13:11:47Z2009-03Thesis94 p. : ill., mapshttp://hdl.handle.net/10019.1/4048enStellenbosch University

oai:scholar.sun.ac.za:10019.1/41132011-06-23T11:57:04Zhdl_10019.1_532

Rearing of the banded fruit weevil, Phlyctinus callosus (Schonherr) (Coleoptera: Curculionidae) and control with entomopathogenic nematodesFerreira, TiarinEntomopathogenic nematodesPhlyctinus callosusRearingDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyFruit weavils -- Biological control -- South Africa -- Western CapeFruit -- Diseases and pests -- Biological control -- South Africa -- Western CapeENGLISH ABSTRACT: The banded fruit weevil, Phlyctinus callosus (Schönherr), is a key pest of apples, nectarines and grapevines in the southern areas of the Western Cape. The control of P. callosus is not satisfactory and the insecticides used to control this insect have not proved to be effective since the development of tolerance to pyrethroids and acephate. A control method that can be used, despite it being very labour-intensive, is that of tree trunk barriers. The use of such a method will prevent the weevils from reaching the fruit, as they are unable to fly. Alternative control options, such as the use of entomopathogenic nematodes, are urgently needed for the control of P. callosus. Entomopathogenic nematodes belonging to the Steinernematidae and Heterorhabditidae are ideal biocontrol agents for incorporation into an integrated pest management programme. In order to develop control strategies for P. callosus, large numbers and a predictable quantity of different weevil stages are needed. Especially large numbers of larvae are needed, as this is the stage that will be targeted with nematodes. One of the aims of the current study was to assess various artificial diets for rearing larvae of P. callosus. Though adult weevils were easily collected from orchards, it was very difficult to obtain large numbers of larvae. Modified versions of an agar diet, as well as different carrot based diets, were tested at 21°C. The highest percentage survival obtained for the agar diet was 50% and 60% for one type of carrot diet. A better rearing method proved to be that of planting full-grown carrots in pots, kept at 25°C, resulting in the attainment of the highest percentage survival rate of 90%. A study was undertaken to assess how long, and at what temperature, P. callosus eggs could be stored. A mean percentage hatch of 45.7% was obtained when eggs were stored at 4°C for 70 days. Eggs started hatching after 47 days and 10 days, when stored at temperatures of 11°C and 14°C, respectively. If the aim of the employment of such a method is only to delay egg hatching, the two temperatures (11°C and 14°C) will be suitable. For the following part of the study, several entomopathogenic nematode isolates were evaluated for their potential use as biological control agents against P. callosus. The susceptibility of P. callosus larvae and adults to nematode infection was assessed in the laboratory by screening for their mortality, using different nematode isolates. Larvae were found to be more susceptible to nematode infection than adults. Heterorhabditis isolates were found to cause higher levels of mortality than the Steinernema isolates during screening, when a concentration of 400 infective juveniles (IJ) per insect V was used. Biological characteristics, such as the effect of different temperatures on nematode activity and the minimum concentration of nematodes needed to obtain acceptable levels of control for P. callosus, were also investigated. The percentage mortality ranged from no infection to 75% after four days for the larvae, and the SF41 isolate of Heterohabditis zealandica was selected as the most promising isolate for further laboratory experiments. The vertical movement of nematodes in sand, compared with such movement in sandy loam soil, and the biology of H. zealandica in P. callosus larvae was also investigated in laboratory bioassays. After four days, the LD50 and LD90 values were 96 IJ/50 μl and 278 IJ/50 μl, respectively. Nematodes were found to be inactive at 11°C, with the highest mortality rate of P. callosus resulting from nematode infection being recorded at 25°C. A higher percentage mortality rate was obtained with the sandy loam soil (95.2%) than with the sand (77.5%). Heterorhabditis zealandica could successfully complete its life cycle in 6th instar P. callosus larvae. The study showed that P. callosus larvae are suitable hosts for H. zealandica, and that the control of P. callosus in the field by the selected isolate holds promise. The persistence of the SF41 isolate of H. zealandica at different concentrations was investigated in the last part of the study. The experiment took place in a blueberry orchard, subject to a high rate of infestation by P. callosus. Concentrations of 0, 20, 30 and 45 IJ/cm2 were topically applied, with persistence being evaluated for days 1, 35 and 84. Percentage persistence for 30 IJ/cm2 was calculated as 87.5% for days 35 and 84. The persistence of soil samples taken on day one, and kept in plastic containers at room temperature, was again evaluated on day 128, with the finding that both 30 IJ/cm2 and 45 IJ/cm2 caused 100% mortality of Tenebrio molitor (L.). Results indicated good persistence of H. zealandica after 84 days in field conditions, with a high maintenance of P. callosus populations. The study indicated the potential use of H. zealandica for the control of P. callosus, with the possibility of persistence for at least three months. Future research into the control of P. callosus with nematodes should aim to investigate the technical aspects of field application. The current study shows that entomopathogenic nematodes have potential for controlling the soil stages of P. callosus. The capacity to rear large numbers of P. callosus larvae in the laboratory, for later use in laboratory and field trials, is of key importance.AFRIKAANSE OPSOMMING: Die gebande vrugtekalander, Phlyctinus callosus (Schönherr), is ʼn groot plaag in appel- en nektarienboorde sowel as wingerde in die suidelike gebiede van die Wes-Kaap. Phlyctinus callosus word nie voldoende beheer nie, en plaagdoders wat voorheen gebruik is om dié insek in toom te hou, het doeltreffendheid ingeboet weens weerstandontwikkeling teen piretroϊede en asefaat. ʼn Alternatiewe beheermetode is stamsperbande. Omdat die kalanders nie kan vlieg nie, moet hulle teen stamme uitklim om die vrugte te bereik. Stamsperbande versper dus die insekte se toegang tot die vrugte, maar is baie arbeidsintensief. Meer haalbare metodes vir die beheer van P. callosus is daarom dringend nodig, en die gebruik van entomopatogeniese nematodes blyk ʼn besliste moontlikheid te wees. Entomopatogeniese nematodes, wat tot die Steinernematidae en Heterorhabditidae behoort, is uitstekende biobeheermiddels vir insluiting by geϊntegreerde plaagbeheerprogramme. Om doeltreffende beheerstrategieë vir P. callosus te bedink, is groot en voorspelbare hoeveelhede kalanders nodig veral groot hoeveelhede larwes, aangesien nematodes op hierdie ontwikkelingstadium gemik sal wees. Die eerste doel met die studie was dus om ʼn kunsmatige dieet vir die teling van P. callosus larwes te ontwikkel. Volwasse kalanders kon maklik in vrugteboorde ingesamel word, maar groot hoeveelhede larwes was moeiliker bekombaar. Aangepaste weergawes van ʼn agardieet sowel as verskillende worteldiëte is by 21°C beproef. Die hoogste persentasie larwale groei en -oorlewing op die agardieet was 50%, en 60% op een bepaalde soort worteldieet. Die beste teelmetode blyk egter volgroeide wortels te wees wat in potte geplant is en by 25°C gehou word. Dié metode het ʼn oorlewingspersentasie van 90% opgelewer. ʼn Studie is onderneem om te bepaal hoe lank en by watter temperature P. callosus eiers vir toekomstige gebruik geberg kan word. ʼn Gemiddelde uitbroeipersentasie van 45.7% is verkry toe eiers vir 70 dae by 4°C geberg is. Eiers wat onderskeidelik by 11°C en 14°C geberg is, het ná 47 en 10 dae onderskeidelik begin uitbroei. Indien die doel is om die eiers slegs stadiger te laat uitbroei, sal hierdie twee temperature dus geskik wees. VII Hierna is verskeie entomopatogeniese nematode-isolate vir moontlike gebruik as biologiese beheermiddels vir P. callosus beoordeel. Phlyctinus callosus larwes en volwassenes se vatbaarheid vir nematode infeksie is in die laboratorium bepaal deur dit met behulp van verskillende nematodeisolate vir mortaliteit te toets. Dié toetse het getoon dat larwes meer vatbaar is vir nematode infeksie as volwassenes. In die proefnemings het die Heterorhabditis-isolate hoër mortaliteit as die Steinernema-isolate veroorsaak teen ʼn konsentrasie van 400 infektiewe larwes (IJ) per insek. Biologiese eienskappe, soos die uitwerking van verskillende temperature op nematode aktiwiteit, sowel as die minimum konsentrasie nematodes om aanvaarbare vlakke van beheer uit te oefen, is ondersoek. Die persentasie mortaliteit vir die larwes het ná vier dae tussen 0% en 75% gewissel, en die SF41-isolaat van Heterohabditis zealandica is as die belowendste isolaat vir die res van die proefnemings gekies. Die vertikale beweging van nematodes in sand teenoor leemgrond, sowel as die biologie van H. zealandica in P. callosus larwes, is ook bestudeer. Ná vier dae was die LD50- en LD90-waardes onderskeidelik 96 en 278 IJ/50 μl. Wat temperatuur betref, is daar bevind dat nematodes onaktief is by 15°C, terwyl die hoogste mortaliteit van P. callosus larwes as gevolg van nematode infeksie by 25°C aangeteken is. Die mortaliteit was hoër in die leemgrond (95.2%) as in die sandgrond (77.5%). Heterorhabditis zealandica kon sy lewensiklus suksesvol in 6de instar P. callosus larwes voltooi. Die studie het derhalwe getoon dat P. callosus larwes geskikte gashere is vir H. zealandica, en dat hierdie isolaat dus in die praktyk ʼn doeltreffende beheermiddel vir P. callosus kan wees. Die oorlewing van verskillende konsentrasies H. zealandica is ten slotte bestudeer. Die proefneming is in ʼn bloubessieboord met ʼn groot populasie P. callosus uitgevoer. Konsentrasies van 0, 20, 30 en 45 IJ/cm2 is op die grond (uitwendig) toegedien, en oorlewing is op dag 1, 35 en 84 gemeet. Die persentasie oorlewing vir die 30 IJ/ cm2 konsentrasie was 87.5% op sowel dag 35 as 84. Oorlewing in grondmonsters wat op dag een ingesamel en by kamertemperatuur in plastiekhouers geberg is, is weer op dag 128 beoordeel. Daar is bevind dat sowel die 30 IJ/cm2 as die 45 IJ/cm2 konsentrasie 100% mortaliteit by T. molitor veroorsaak het. Heterorhabditis zealandica blyk ʼn goeie oorlewing te hê ná 84 dae in veld kondisies wat erg met P. callosus besmet is, en is dus ʼn moontlike beheermiddel vir P. callosus, met potensiële oorlewing vir minstens drie maande.Thesis (MScAgric (Conservation Ecology and Entomology))--University of Stellenbosch, 2010.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Malan, A. P.Addison, P.2010-02-24T10:32:32Z2010-08-13T14:59:11Z2010-02-24T10:32:32Z2010-08-13T14:59:11Z2010-03Thesis103 p. : ill.http://hdl.handle.net/10019.1/4113enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/42032011-06-23T10:00:14Zhdl_10019.1_532

Vulnerability of selected native and invasive woody species to streamflow variability in Western Cape fynbos riparian ecotonesCrous, Casparus JohannesFynbos riparian ecosystems -- South Africa -- Wsetern CapeDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyStreamflow -- South Africa -- Western CapeInvasive alien plants -- South Africa -- Western CapeENGLISH ABSTRACT: Riparian ecosystems of the Mediterranean south-western Cape region are projected to experience significant decreases in streamflow due to climate change and increased demands for water associated with human demographic trends and increasing living standards. Aggravating this problem are woody invasive alien plants, such as Acacia mearnsii, whose impacts, including those on catchment water yields, have justified extensive eradication programmes such as Working for Water (WfW). WfW has been highly successful in managing invasive alien species in some areas, while at the same time enhancing the quality of life of poor South Africans. Unfortunately, the managers of these eradication initiatives often experience a lack of information on the species- and site-specific ecological properties that may aid in prioritising sites more prone to invasion, essentially inhibiting accurate management output. Knowledge, such as that associated with the possible future distribution of invasive species in a changing environment, may help to optimise eradication initiatives. I therefore determined whether woody plants portray different physiological (vulnerability to cavitation) and wood anatomical traits (wood density, vessel resistance to implosion, vessel lumen and wall diameters) across three prominent riparian zones in the south-western Cape that each differ in streamflow quantity – to gain a mechanistic understanding of how woody species, especially invasive species, adapt their hydraulic strategy across this proxy for water availability. Using factorial ANOVA’s, to distinguish any differences in plant physiological and wood anatomical responses to water availability within and between species, showed Acacia mearnsii having consistently higher drought-tolerance (lower P50 values and denser wood) compared to native species under reduced water availability. These results supported the significant variation in drought-tolerance strategies that exist within and between taxonomically different species across different environments. Water availability thus has a strong selective effect on functional traits of species; however, minimum water potentials were more useful in describing in situ hydrological conditions than streamflow. Additionally, a non-causal relationship between wood anatomical traits and drought-induced cavitation was observed. Therefore, using only wood anatomical measurements to assess drought-tolerance of species might not be accurate across all species. This mechanistic approach to assess the invasive potential of species under projected drier conditions has great practical value. It can be used to improve species selection for restoration initiatives, and is of great value for future use in prioritizing eradication programmes.AFRIKAANSE OPSOMMING: Rivieroewer ekosisteme in die Mediterreense Suidwes-Kaap streek kan groot afnames in stroomvloei verwag, wat meestal toegeskryf kan word aan klimaatsverandering en die verhoogde aanvraag na water geassosieerd met stygende populasiegrootte. Uitheemse indringerplante soos Acacia mearnsii vererger hierdie probleem. Laasgenoemde spesies plaas groot druk op opvanggebiede se water opbrengs, en vorm grootliks die rede waarom uitroeiing programme soos Werk vir Water (WfW) gestig is. WfW het al groot suksesse behaal in die bestuur van uitheemse indringerplante, en terselfdertyd die lewenskwaliteit van arm Suid-Afrikaners verhoog. Ongelukkig sukkel hierdie indringer uitroeiing inisiatiewe telkens met ongenoegsame bewyse wat kan help om leiding te verskaf by die prioritisering van areas meer geneig tot indringing. Die gevolg is dat onvoldoende bestuurs besluite gemaak kan word. Gevolglik sal kennis geassosieerd met die moontlike toekomstige verspreiding van hierdie indringerplant in ʼn veranderlike omgewing help om uitroeiing programme meer akkuraat te stel en gevolglik waardevol wees t.o.v. prioritisering van kwesbare areas. Die doel van hierdie studie was om die kwesbaarheid van sleutel inheemse houtagtige rivier spesies en veral die dreigende indringerplant Acacia mearnsii, te bestudeer in terme van verlaagde stroomvloei soos voorspel vir die Wes-Kaap fynbos ekosisteem. Deur te bepaal of houtagtige plante verskillende fisiologiese (kwesbaarheid teen xileem blokkasie) en anatomiese (hout digtheid, vat weerstandbiedendheid teen inmekaarkolking, vat holte en wand deursnee) hidrologiese eienskappe tentoonstel gemeet tussen drie prominente rivieroewer sones in die suidwes Kaap wat variëer in stroomvloei kwantiteit, verskaf ʼn meganistiese begrip van hoe spesies, veral die indringerplante, hul hidrologiese strategieë ten opsigte van droogtes kan aanpas. Faktoriële ANOVAS’s tussen spesies en liggings het getoon dat beide plant fisiologiese en hout anatomiese data beduidend variëer tussen taksonomies verskillende spesies. Veral Acacia mearnsii het deurgaans laer P50 waardes asook hoër houtdigtheid getoon, ‘n teken van hierdie spesies se verhoogde droogte toleransie in vergelyking met die inheemse spesies. Wat beduidend is is dat spesies-spesifieke lewensstrategieë ten opsigte van droogte toleransie in hierdie rivieroewer sones voorkom. Resultate het bevestig dat water beskikbaarheid ʼn groot rol speel in die seleksie van funksionele karaktereienskappe in plante, maar, dat minimum water potensiaal meer akkuraat was om in situ hidrologiese toestande te beskryf as wat stroomvloei kon. Die verhouding tussen plant fisiologiese en hout anatomiese karaktereienskappe was indirek as gevolg van spesies-spesifieke lewensstrategieë. Gevolglik sal die allenige gebruik van hout anatomiese eienskappe om droogte toleransie in plante te assesseer onakkuraat wees omdat daar ʼn swak verhouding tussen hout anatomie en droogte-geïnduseerde xileem blokkasie bestaan. ʼn Meganistiese benadering om die indringing potensiaal van spesies onder voorspelde droër kondisies te assesseer, asook om spesies seleksie vir restourasie doeleindes op te skerp, is prakties uitvoerbaar, en van groot waarde vir toekomstige gebruik in uitroeiing en restourasie inisiatiewe.Thesis (MScConsEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2010.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Jacobs, Shayne M.Esler, Karen J.2010-02-21T22:17:44Z2010-08-13T15:00:09Z2010-02-21T22:17:44Z2010-08-13T15:00:09Z2010-02-21T22:17:44Z2010-03Thesis102 p. : ill., mapshttp://hdl.handle.net/10019.1/4203enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/42082011-06-23T09:45:28Zhdl_10019.1_532

A comparison of standard scientific methods and pastoralists’ perceptions of vegetation responses to livestock exclusion in Namaqualand, South AfricaSnyman, DirkBiodiversity conservation -- South Africa -- NamaqualandRangelands -- South Africa -- NamaqualandGrazing -- South Africa -- NamaqualandLand-user perceptions -- South Africa -- NamaqualandDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyLivestock, Impact on rangeland -- South Africa -- NamaqualandConservation Ecology and EntomologyENGLISH SUMMARY: Protected areas do not always achieve the desired level of biodiversity conservation, while often reducing the welfare of indigenous communities by reducing availability of land for subsistence. Traditional agricultural landscapes are significant biodiversity refugia and can contribute meaningfully to conservation. Rangelands comprise one-third to one-half of the world’s terrestrial surface, providing livelihoods for around 220 million people, usually in a communal subsistence system. Colonial practices impinged on traditional land-use practices with far-reaching social and environmental impacts. This has resulted in management based on assumptions regarding vegetation dynamics and traditional lifestyles that are increasingly shown to be inaccurate. A comparison of a vegetation survey based on conventional scientific methods and a survey of the perceptions of pastoralists was undertaken to highlight differences and similarities between the two knowledge systems with the hope of providing guidelines for more sustainable land-use practices in the communal rangelands of Namaqualand, South Africa. Vegetation responses to removal of grazing pressure revealed complex interactions that do not correspond with the prevailing management paradigm. Rather than a predictive relationship between livestock and vegetation, environmental factors play a large role in determining plant composition, abundance and cover. Pastoralists’ perceptions reflected this complexity in rangeland resource dynamics. The impact of livestock on rangeland resource dynamics was perceived by herders to be secondary to a range of environmental and climatic factors. Both sets of results were at odds with the theories that currently govern management in this system. Studies in rangeland systems must take the complexity of the subject into account. Research into such socio-ecological systems must take a multiplicity of factors – social, environmental, economic, political and other – into account. Implications for management are that it is inappropriate to adhere strictly to the conventional, conservative strategies that are prescribed by conservation and agricultural authorities. Rather, a more flexible, opportunistic grazing strategy would allow the persistence of traditional subsistence livelihoods without serious negative consequences for biodiversity conservation.AFRIKAANSR OPSOMMING: Die instelling van beskermde gebiede lewer nie altyd die gewenste vlak van biodiversiteitsbewaring, terwyl die welvaart van plaaslike gemeenskappe dikwels daaronder ly deur die afname in grond beskikbaar vir bestaanspraktyke. Tradisionele landboulandskappe is beduidende biodiversiteitshawens wat ‘n belangrike bydrae tot bewaring kan maak. Weivelde bevat ‘n derde tot ‘n helfte van die wêreld se landsoppervlakte en ondersteun rondom 220 miljoen mense, gewoonlik binne ‘n gemeenskaplike bestaansstelsel. Kolonialisasie het inbraak gemaak op tradisionele bestuurspraktyke, met verrykende sosialeen omgewingsimpakte. Dit het gelei tot bestuurspraktyke gebaseer op standpunte oor plantegroeidinamika en traditionele lewenswyses wat toenemend verkeerd bywys word. ‘n Vergelyking van ‘n plantegroei opname gebaseer op konvensionele wetenskaplike metodes en ‘n opname van die standpunte van veewagters is onderneem om die verskille en ooreenkomstes tussen die twee kennisstelsels uiteen te lê met die hoop om riglyne vir meer volhoubare bestuurspraktyke in die meentgronde van Namakwaland, Suid-Afrika te verskaf. Plantegroei reaksies tot die verwydering van weidingsdruk wys op komplekse interaksies wat nie ooreenstem met die heersende bestuursparadigma. Eerder as ‘n voorspelbare verwantskap tussen vee en plantegroei, omgewingsfaktore speel ‘n groot rol in die bepaling van plantgemeenskapsamestelling, -getalle en grondbedekking. Die veewagters se standpunte het hierdie kompleksiteit in plantegroeidinamika weerspiëel. Die impak van vee op die weiveldhulpbron is deur veewagters as sekondêr beskou teenoor ‘n reeks omgewings- en klimaatsfaktore. Beide stel resultate is in teenstelling met die teoriëe wat tans bestuur in hierdie stelsel bepaal. Studies in weiveldstelsels moet die kompleksiteit daarvan in ag neem. Navorsing oor hierdie sosio-ekologiese stelsels moet ‘n verskeidenheid faktore – sosiale-, omgewings-, ekonomiese-, politiese- en ander – in ag neem. Implikasies vir bestuur is dat dit onvanpas is om te volhard met konvensionele, konservatiewe strategiëe voorgeskryf deur bewarings- en landboukundige gesagte. ‘n Meer aanpasbare, voordeelnemende weidingsstrategie sal die voortbestaan van traditionele bestaanslewenspraktyke toelaat sonder ernstige negatiewe nagevolge vir biodiversiteitsbewaring.Thesis (MSc (Conservation Ecology and Entomology))--University of Stellenbosch, 2010.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Jacobs, S.Allsopp, N.2010-02-19T07:47:29Z2010-08-13T15:00:11Z2010-02-19T07:47:29Z2010-08-13T15:00:11Z2010-02-19T07:47:29Z2010-032010-03Thesis87 p.http://hdl.handle.net/10019.1/4208enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/44962013-03-19T14:22:43Zhdl_10019.1_532

Assessment of toxic baits for the control of ants (Hymenoptera : Formicidae) in South African vineyardsNyamukondiwa, CasperAntsLow toxicity baitsHymenopteraAnt controlVineyard pestsENGLISH ABSTRACT: Ant infestations comprising the Argentine ant Linepithema humile (Mayr), common pugnacious ant Anoplolepis custodiens (F. Smith) and cocktail ant Crematogaster peringueyi Emery are a widespread pest problem in South African vineyards. Integrated Pest Management (IPM) programmes aimed at suppressing the problematic honeydew excreting vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) on grapes must include ant control to optimize the effectiveness and efficacy of mealybug natural enemies. If ants are eliminated, natural enemies are able to contain mealybugs below the Economic Threshold Level (ETL). Current strategies for ant control are limited and generally include the application of long term residual insecticides that are detrimental to the environment, labour intensive to apply and can disrupt natural biological control if applied incorrectly. A more practical method of ant control using low toxicity baits was therefore investigated. Field bait preference and bait acceptance assessments aimed at determining bait repellency and palatability, respectively, were carried out during spring, summer and autumn in three vineyards of the Cape winelands region during 2007/08. Five toxicants comprising gourmet ant bait (0.5%), boric acid (0.5%), fipronil (0.0001%), fenoxycarb (0.5%) and spinosad (0.01%) dissolved in 25% sugar solution were tested against a 25% sucrose solution control. Gourmet ant bait was significantly more preferred and accepted by all ant species than the other baits. Laboratory bait efficacy assessments using four insecticides (gourmet, boric acid & spinosad) at concentrations of 0.25; 0.5; 1; 2 and 4 times the field dose and fipronil at 0.015625; 0.03125; 0.0625; 0.125; 0.25 times the field dose were carried out. Results revealed that boric acid (2%), gourmet ant bait (2%) and fipronil (1.0 X 10-5%) exhibited delayed toxicity for L. humile and C. peringueyi while spinosad (0.01%) showed delayed action on L. humile. Field foraging activity and food preference tests were also carried out for the three ant species during 2007/08. Foraging activity trials revealed that vineyard foraging activity of L. humile is higher relative to A. custodiens and C. peringueyi. This means fewer bait stations are required for effective L. humile control making low toxicity baits a more affordable and practical method of controlling L. humile than the other two ant species. Food preference trials showed that L. humile and C. peringueyi have a high preference for sugar while A. custodiens significantly preferred tuna over other baits. However, all ant species had a preference for wet baits (25% sugar water, 25% honey, tuna & agar) as opposed to dry ones (fish meal, sorghum grit, peanut butter & dog food). This research concludes that low toxicity baits show potential in ant pest management and can offer producers with a more practical, economical and environmentally friendly method of ant control which is compatible with vineyard IPM programmes.AFRIKAANSE OPSOMMING: Mierbesmetting wat uit die Argentynse mier Linepithema humile (Mayr), die gewone malmier Anoplolepis custodiens (F. Smith) en die wipstertmier Crematogaster peringueyi Emery bestaan, is ’n plaagprobleem wat wydverspreid in Suid-Afrikaanse wingerde voorkom. Programme vir geïntegreerde plaagbeheer (GPB) wat daarop gemik is om die wingerdwitluis Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) – wat ’n probleem is weens die heuningdou wat dit afskei – op druiwe te beheer, moet mierbeheer insluit om sodoende die uitwerking en doeltreffendheid van die witluis se natuurlike vyande die beste te benut. As miere uitgeskakel kan word, sal dit vir die natuurlike vyande moontlik wees om die witluis sodanig te beheer dat dit onder die ekonomiese drempelvlakke (EDV) bly. Huidige strategieë om miere te beheer, is beperk en sluit gewoonlik die toediening van insekdoders in wat lank neem om in die grond af te breek, wat skadelik vir die omgewing is, waarvan die toediening arbeidsintensief is en wat die natuurlike biologiese beheer kan versteur indien dit verkeerd toegepas word. Daarom is ’n meer praktiese metode ondersoek waar miere deur die gebruik van lae toksisiteit lokase beheer word. Ondersoeke na lokaasvoorkeure en lokaasaanvaarbaarheid in die praktyk, wat daarop gemik is om te bepaal of die lokaas onderskeidelik afstootlik en smaaklik bevind word, is oor lente, somer en herfs in drie verskillende wingerde in die Kaapse wynlandstreek gedurende die 2007/08-seisoen uitgevoer. Vyf gifstowwe, bestaande uit gourmet ant bait (0.5%), boorsuur (0.5%), fiproniel (0.0001%), fenoksiekarb (0.5%) en spinosad (0.01%) wat in ’n 25%-suikeroplossing opgelos is, is getoets teenoor ’n kontrole wat uit ’n 25%-sukrose-oplossing bestaan. Al die mierspesies het gourmet ant bait bo die ander lokase verkies en aanvaar. In die laboratorium is ondersoeke gedoen om die doeltreffendheid van die lokase te bepaal deur vier insekdoders (gourmet ant bait, boorsuur en spinosad) te gebruik in konsentrasies van 0.25; 0.5; 1; 2 en 4 keer die dosis in die praktyk en fiproniel teen 0.015625; 0.03125; 0.0625; 0.125; 0.25 keer die dosis in die praktyk. Resultate het getoon dat boorsuur (2%), gourmet ant bait (2%) en fiproniel (1.0 X 10-5%) vertraagde toksisiteit getoon het vir L. humile en C. peringueyi, terwyl spinosad (0.01%) ’n vertraagde uitwerking getoon het op L. humile. Toetse om kossoekaktiwiteite in die praktyk en die voedselvoorkeure van die drie mierspesies te ondersoek, is ook gedurende die 2007/08-seisoen gedoen. Proewe oor kossoekaktiwiteite het getoon dat hierdie aktiwiteite in die wingerd by L. humile hoër is in verhouding met A. custodiens en C. peringueyi. Dit beteken dat minder lokaasstasies nodig is om L. humile doeltreffend te beheer en lei daartoe dat lae toksisteit lokaas ’n beter manier is om L. humile te beheer as die ander twee mierspesies. Proewe oor voedselvoorkeure het aangedui dat L. humile en C. peringueyi ’n groot voorkeur toon vir suiker, terwyl A. custodiens ’n duidelike voorkeur vir tuna het. Alle mierspesies het egter ’n voorkeur vir nat lokaas (25% suikerwater, 25% heuning, tuna en agar), eerder as droë lokaas (vismeel, sorghumgruis, grondboontjiebotter en hondekos) getoon. Uit hierdie navorsing word afgelei dat lae toksisteit lokaas potensiaal toon in mierbeheer en dat dit produsente ’n meer praktiese, ekonomiese en omgewingsvriendelike metode van mierbeheer kan bied wat met GPB-programme in die wingerd versoenbaar is.Thesis (MScAgric (Conservation Ecology and Entomology))--Stellenbosch University, 2008.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Addison, PiaAddison, Mathew2010-08-13T15:24:58Z2010-08-26T18:11:42Z2010-08-13T15:24:58Z2010-08-26T18:11:42Z2008-12Thesishttp://hdl.handle.net/10019.1/4496enStellenbosch University

oai:scholar.sun.ac.za:10019.1/45092011-03-15T06:21:22Zhdl_10019.1_532

The impact of State-Of-Rivers Reporting on people’s attitudes towards river conservation : a case study of the Buffalo and Hartenbos & Klein Brak Catchments in South AfricaStrydom, Wilma FernandaRiver conservation -- South AfricaState-of-Rivers reporting -- Soouth AfricaChanging attitudes and behaviour -- South AfricaDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyENGLISH ABSTRACT: During 2007, two evidence-based studies were undertaken in two catchment areas in South Africa. The first study ascertained the relationships between demographic attributes and general awareness, human impacts, attitudes and water use behaviour. The second study determined whether or not State-of-River (SoR) materials developed for foundation phase learners (grades 1 to 3) improved their understanding of and influenced their attitudes towards river conservation. Surveys were conducted amongst learners (n=1178) and parents (n=1144) from different cultures and socio-economic backgrounds. Questionnaires were available in three languages, namely English, isiXhosa and Afrikaans. The SoR reporting materials were not adequately distributed. The first study could therefore not ascertain whether increased awareness or attitudinal and behavioural changes could be ascribed to SoR reporting in the catchments. The majority of respondents (82%) indicated that there was a need for more information on rivers and 60% of the respondents indicated that they would participate in a follow-up survey. Thirty percent of respondents from the Buffalo catchment and 22% of respondents from the Hartenbos and Klein Brak catchment indicated that they use water very sparingly. Respondents from urban areas scored higher in their attitudes towards river conservation and were more aware of water issues than those from rural areas. Both attitudinal and awareness scores did not align with water use behaviour, with rural respondents using water more sparingly. Attitude and awareness improved with increased education levels. Respondents who indicated that they would rather pay more for water than change their water use behaviour showed the lowest score for attitude towards river conservation. Learners from the Buffalo rural area showed a significant increase in understanding the benefits that healthy rivers provide, and this can be ascribed to the distributed SoR activity book and poster. A survey consisting of quantitative and qualitative items, as well as participatory evaluations determined learners’ level of understanding of human impacts on rivers. The quantitative study showed learners from the Hartenbos and Klein Brak area as well as the Buffalo rural area improved the most over time. The qualitative items showed a 35% and 40% increase in the number of correctly listed items as either making a river happy (healthy) or sad (unhealthy) after exposure to SoR materials. Respondents from both catchments taking part in the participatory evaluations displayed an overall increase in their understanding of good practices, as well as the negative impact of human activities on rivers. Those learners that scored low in the participatory evaluations at time 1 showed the most improvement over time, concluding that those learners who knew the least at the start of the study, gained the most understanding of human impacts on rivers. All schools in the Hartenbos and Klein Brak catchment, with the exception of one, showed a slight increase in understanding of human impacts on rivers. Results from the schools in the Buffalo catchment were more variable. Data gathered demonstrated that the SoR materials helped learners to better understand benefits from clean rivers as well as human impact on rivers. Although the learners from urban areas had a better understanding of the concept of river conservation before contact with the SoR materials, learners from the rural areas showed the most improvement over time. There was an increase in the number of learners that showed a willingness to take responsibility for their actions that could impact on river health. Far more learners mentioned remediation types of actions than protection or preventative actions. A change in peoples’ attitudes and behaviour is needed to ensure adequate protection of South Africa’s natural water resources. Imprinting values and perceptions that would last into adulthood need intervention at an early age and throughout children’s’ formative years.AFRIKAANSE OPSOMMING: Gedurende 2007, twee bewysgebaseerde ondersoeke is in twee wateropvangsgebiede in Suid Afrika gedoen. Die eerste studie was gerig op die bepaling van die verband tussen demografiese kenmerke, algemene bewustheid, menslike impak, houdings en waterverbruik. Die tweede studie het bepaal of die Stand-van-Rivier (SvR) inligtingsmateriaal wat vir grondslagfase leerlinge (graad 1 tot 3) ontwikkel is, bygedra het tot hulle begrip van en houding jeens die bewaring van riviere. Steekproeftrekkings het leerlinge (n=1178) en ouers (n=1144) vanuit verskillende kultuur- en sosioekonomiese agtergronde betrek. Vraelyste was in drie landstale naamlik Engels, Xhosa en Afrikaans beskikbaar. Die SvR kommunikasie material is nie toereikend versprei nie. Die eerste studie kon derhalwe nie bepaal of groter bewustheid of veranderings in houding en gedrag in hierdie opvangsgebiede aan die SvR verslaggewing toegeskryf kon word nie. Die meerderheid respondente (82%) het aangedui dat daar ‘n tekort and rivierinligting is en 60% van die respondente het hulself bereidwillig verklaar om aan ’n opvolgstudie deel te neem. Dertig persent van die respondente uit die Buffels- en 22% uit die Hartenbos- en Klein Brak-opvangsgebiede het aangedui dat hulle water spaarsamig gebruik. Respondente afkomstig van stedelike gebiede het beter rivierbewaringshoudings getoon en was meer bewus van wateraangeleenthede as die van landelike gebiede. Houdings en bewustheids-vlakke het nie ooreengestem met waterverbruik nie – landelike respondente gebruik water meer spaarsamig. Beide houdings en algemene bewustheid het toegeneem met hoër onderwysvlakke. Respondente wat aangedui het dat hulle eerder meer vir water sal betaal as om hulle verbruik te verminder, het die swakste houding jeens die bewaring van riviere getoon. Leerlinge uit die landelike gebiede van die Buffels opvangsgebied het groter begrip getoon vir die voordele wat gesonde riviere inhou, en dit kan toegeskryf word aan die aktiwiteitsboek en SvR plakkaat wat onder hulle versprei is. ‘n Steekproef bestaande uit kwantitatiewe en kwalitatiewe items, sowel as deelnemende evaluasies is gebruik om leerlinge se vlak van begrip van menslike impak op riviere te bepaal. Die kwantitatiewe studie het aangedui dat die begrip van leerlinge van die Hartenbos en Klein Brak sowel as die van die landelike Buffelsrivieropvangsgebiede oor tyd die meeste toegeneem het. Op die vraag wat riviere gelukkig (gesond) of hartseer (ongesond) maak, het die kwalitatiewe items, na blootstelling van die leerders aan die SvR materiaal, ‘n toename van 35% en 40% in korrekte antwoorde getoon. In die deelnemende evaluasie het respondente van beide opvangsgebiede ‘n toename in begrip van goeie praktyke sowel as die negatiewe impak van menslike aktiwiteite op riviere getoon. Leerlinge wat swak gevaar het in die deelnemende evaluasie gedurende die eerste rondte het die meeste vordering getoon. Die gevolgtrekking is dus dat leerlinge wat die minste geweet het aan die begin van die studie, die meeste geleer het oor menslike impak op riviere. Op een na, het alle skole in die Hartenbos- en Klein Brakrivieropvangsgebied ‘n geringe verhoging in begrip van menslike impak op riviere getoon. Resultate van skole uit die Buffelsopvangsgebied het meer gevarieer. Data versamel het gedemonstreer dat die gebruik van die aktiwiteitsboek en plakkate gelei het tot ’n beter begrip by leerders van die voordele van skoon riviere asook van menslike impak op riviere. Alhoewel die leerlinge van stedelike gebiede beter begrip getoon het oor rivierbewaring voor kontak met die SvR material, het die landelike leerlinge die grootste toename in begrip oor die verloop van die studie getoon. Daar was ook ‘n toename in die aantal leerlinge wat bereid was om verantwoordelikheid vir hulle aktiwiteite wat ‘n impak op riviergesondheid kon hê, te aanvaar. Veel meer leerlinge het tydens die tweede fase verwys na herstel eerder as beskermings of voorkomende gedrag. ’n Verandering in mense se houdings en gedrag is noodsaaklik om genoegsame bewaring van Suid Afrika se natuurlike waterhulpbronne te verseker. Waarde sisteme en persepsies wat met volwassewording steeds geldig sal wees, word reeds teen ’n vroeë ouderdom, gedurende kinders se vormingsjare, vasgelê.Thesis (MSc (Conservation Ecology and Entomology))--University of Stellenbosch, 2011.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Esler, J.Leslie, A.2010-08-13T14:44:19Z2010-08-26T18:52:24Z2010-08-13T14:44:19Z2010-08-26T18:52:24Z2010-03Thesis94, 20, 30, [17] p., ill., mapshttp://hdl.handle.net/10019.1/4509enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/51382011-06-23T08:54:23Zhdl_10019.1_532

Wildflower farming on the Agulhas Plain : fynbos management and conservationTreurnicht, MartinaWildflower farming -- South Africa -- Agulhas PlainFynbos wildflower industry -- South Africa -- Algulhas PlainDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyWildflower farming -- Impact on populattions -- South Africa -- Agulhas PlainFynbos conservation -- South Africa -- Agulhas PlainENGLISH ABSTRACT: The Agulhas Plain is a constituent of the Cape Floristic Region, internationally known as a global biodiversity hotspot. The species-rich Agulhas Plain consists mainly of fire-prone fynbos shrublands of which sandstone fynbos covers a significant surface area. This lowland region is characterised by mostly infertile soils yet has unique floristic complexity and contains a high amount of threatened lowland species. Natural vegetation on the Agulhas Plain has been prone to large scale land transformation activities, mainly attributed to the extent of alien plant invasions, urbanisation and agricultural expansion. Fynbos wildflower farming, specifically from natural vegetation, is an important economic activity and contributes to the region‟s agricultural sector. Farmers harvest large quantities of commercial fynbos species and supply these to the market in an attempt to sustain a livelihood. Certain wildflower farming practices (burning, ploughing and broadcast sowing) are applied to natural vegetation in an attempt to increase the abundance of commercial species (i.e. augmentation). Numerous farming practices are used in the industry and the application of these methods can be dynamic and divergent. Furthermore, the implementation of farming practices manifest as anthropogenically induced disturbance events and are a concern for conservation. Previous investigations suggest that farming practices could establish monocultures of commercial wildflower species by reducing species richness and plant diversity of wildflower vegetation. Although the impact of natural disturbance regimes (e.g. fire) and flower harvesting activities have been researched, the impact of farming practices on fynbos structure and composition remains largely unknown. This thesis reports on various aspects related to wildflower farming on the Agulhas Plain. Firstly, by administering a questionnaire, the extent and application of farming practices was investigated. Additionally, the opinion of wildflower farmers (referred to as landholders) about the impact of farming practices on wildflower populations was explored. Secondly, a vegetation survey aimed to assess the impact of farming practices on various structural (regeneration mode and growth form) and compositional attributes (plant family, dominant and rare species) of fynbos. Results from the questionnaire indicate that the application of farming methods are seasonally restricted, often used in varying combinations and relatively small in spatial extent. Furthermore, results show that wildflower farmers have an ecologically acceptable knowledge base and awareness of fynbos management and conservation. Secondly results, obtained from the vegetation survey, imply that natural vegetation subjected to particular farming practices differ from pristine fynbos vegetation by having both altered structural and compositional attributes. However, the impact of farming practices on rare species was less apparent. The conflict between commercial and conservation objectives are apparent from consultation with landholders. Nonetheless, landholders are optimistic about fynbos conservation and conservation can build upon these positive sentiments. Importantly, there is a need to communicate locally with landholders if a sustainable wildflower industry is a priority to stakeholders on the Agulhas Plain. Furthermore, fynbos ecosystems naturally entail complex ecological interactions. Wildflower farming practices reduce the ecological integrity (i.e. altered plant diversity, growth form and plant composition) of wildflower vegetation, at least at the local scale. These farming practices ultimately result both in distorted competitive interactions and disturbance regimes. Therefore, from a conservation perspective, the implementation of these farming practices (ploughing and broadcast sowing) should be cautioned against.AFRIKAANSE OPSOMMING: Die Agulhas-vlakte vorm deel van die Kaapse Blommeryk; „n gebied wat internasionale bekendheid verwerf het as „n biodiversiteits-brandpunt. Die spesieryke Agulhas-vlakte bestaan hoofsaaklik uit fynbosstruiklande wat geneig is tot veldbrande. Sandsteenfynbos beslaan „n beduidende oppervlak van die gebied (Agulhas-vlakte). Hierdie laagliggende area (Agulhas-vlakte) word meestal deur onvrugbare grondtipes gekenmerk maar beskik nogtans oor unieke fynbos kompleksiteit wat „n aantal bedreigde laagland spesies insluit. Natuurlike plantegroei op die Agulhas-vlakte is onderworpe aan grootskaalse grondgebruik transformasie; hoofsaaklik toe te skryf aan indringer plantegroei, verstedeliking en uitbreiding van landbou. Fynbos veldblomboerdery, spesifiek van natuurlike plantegroei, is „n belangrike ekonomiese aktiwiteit en lewer „n bydrae tot die Agulhas-vlakte se landbou sektor. Boere oes en lewer groot hoeveelhede kommersiële fynbos spesies aan die mark. Sekere veldblom-boerderypraktyke (brand, ploeg en saadstrooi) word ingespan op fynbosveld ten einde die opbrengs en afwisseling van kommersiële spesies te verhoog. „n Verskeidenheid boerderypraktyke word gevolg en die toepassing van hierdie boerderypraktyke is dinamies en uiteenlopend. Voorts manifesteer die implementering van hierdie boerderypraktyke as mensgemaakte versteurings wat kommerwekkend is vanuit „n bewaringsperspektief. Vorige ondersoeke dui moontlik daarop dat boerderypraktyke monokulture van kommersiële veldblomspesies kan vestig deur die veelheid van spesies en diversiteit van veldblomplantegroei te verminder. Ten spyte daarvan dat die impak van natuurlike versteuringsregimes (bv. vuur) en veldblompluk-aktiwiteite reeds nagevors is, bly die impak van veldblomboerderypraktyke op fynbosstruktuur en -samestelling grotendeels onbekend. Hierdie tesis doen verslag oor verskeie aspekte van veldblomboerdery op die Agulhas-vlakte. Eerstens, deur middel van „n vraelys, is die omvang en aanwending van verskillende boerderypraktyke nagevors. Verder is die menings van veldblomboere (na wie verwys word as grondeienaars) ondersoek met die klem op die impak van boerderypraktyke op veldblombevolkings. Tweedens, is „n plantegroei-opname met die doelwit om die impak van landboupraktyke op verskeie strukturele- (regenerasiemodus en groeivorm) en samestellende eienskappe (plantfamilie, dominante- en seldsame spesies) van fynbos vas te stel gedoen. Die resultate van die vraelys dui daarop dat die aanwending van boerderypraktyke seisoenaal beperk word, dikwels in wisselende kombinasies gebruik word en in ruimtelike omvang redelik klein is. Boonop toon die resultate dat veldblomboere oor „n ekologies-aanvaarbare kennisgrondslag en bewustheid van fynbosbestuur en –bewaring beskik. Tweedens, impliseer die resultate, vanuit die plantegroei-opname, dat fynbosveld wat onderwerp word aan sekere boerderypraktyke van natuurlike fynbosplantegroei verskil deurdat dit gewysigde strukturele- sowel as samestellende eienskappe toon. Die impak van die boerderypraktyke op seldsame spesies was egter minder waarneembaar. Die botsing tussen kommersiële- en bewaringsoogmerke blyk duidelik uit konsultasie met grondeienaars. Nietemin is die grondeienaars optimisties oor fynbosbewaring en bewaring kan op hierdie positiewe sentimente staatmaak en voortbou. Dit is belangrik om daarop te let dat dit noodsaaklik is om plaaslik met grondeienaars oorleg te pleeg indien „n volhoubare veldblomindustrie „n prioriteit vir belanghebbendes op die Agulhas-vlakte is. Verder, aangesien fynbos ekosisteme natuurlik komplekse ekologiese wisselwerkings behels, verminder veldblom-boerderypraktyke die ekologiese integriteit (m.a.w. gewysigde plantdiversiteit, groeivorm en plantsamestelling) van fynbosveld, ten minste op kleinskaal (plaaslik). Hierdie landboupraktyke het uiteindelik beide verwronge kompeterende wisselwerkinge asook versteuringsregimes tot gevolg. Vanuit „n bewaringsperspektief moet daar dus teen hierdie boerderypraktyke gewaarsku word.Thesis (MScConsEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2010.134, 43 p. : ill.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and EntomologyEsler, Karen J.Gaertner, Mirijam2010-11-23T11:04:42Z2010-12-15T10:14:18Z2010-11-23T11:04:42Z2010-12-15T10:14:18Z2010-12Thesishttp://hdl.handle.net/10019.1/5138enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/51602011-06-23T12:31:06Zhdl_10019.1_532

Population genetics of bush-encroaching acacia mellifera at Pniel, Northern Cape Province, South AfricaNxele, Beka JeremiaAcacia mellifera -- South Africa -- Northern CapeBush-encroachment -- South AfricA -- Northern CapePopulation differentiation -- South AfricA -- Northern CapeAllozymesLocal adaptation -- South AfricA -- Northern CapePhenotypic plasticity -- South AfricA -- Northern CapeDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyENGLISH ABSTRACT: Two populations of Acacia mellifera were noted in Pniel, which is a semi-arid savanna, near Kimberley in the Northern Cape province of South Africa. One population appeared on a rocky, andesitic laval ridges (soil pHKCL 6.5-7.0) along the Vaal river. The other appeared in a sandveld area (soil pHKCL 4). Bush encroachment by A. mellifera was found to be more extensive on the rocky areas than in the sandveld and the two habitats differed extensively on soil pH, clay and silt contents and also on water holding capacities. The rocky habitat was thus deduced to have a higher CEC. Seeds were sampled on a logarithmic scale for allozyme analysis and also randomly in each of the two habitats for local adaptation tests, in which case lime (CaCO3) and organic matter (cow-dung) were used in a completely-crossed design. Detected interaction effects (between population source and pH; population source and organic matter and between pH and organic matter) and significant differences could not separate the two populations as the differences occurred across populations. Random genetic differences leading to phenotypic plasticity in the two observed populations, might be responsible for the observed phenotypic differences. Allozymic data showed no significant differences between the two populations and the genetic distance between and within the populations also confirmed that the two populations had not genetically differentiated. The Mantel Test on the two populations, showed nonsignificant results. Nei‟s UPGMA dendrogram revealed that the game farm subpopulations were more primitive and genetically related to each other. Despite differences in allozyme frequencies, between the sampled sites, genetic differentiation was found to be low (FST = 0.337). Nei‟s (1972) original measures of genetic distance ranged between 0.871 and 1.000 with a mean of 0.949 ± 0.053. The study concluded that the two observed populations had not genetically differentiated and no local adaptation could be established rather phenotypic plasticity was evident and resulted in the observed divergent growth forms. Nonetheless, the overall direction of spread of encroachment appeared to be the eastward.AFRIKAANSE OPSOMMING: Twee bevolkings van Acacia mellifera is gevind in Pniel, wat „n semi-ariede savanna is naby Kimberley in die Noord-Kaap provinsie van Suid-Afrika. Een bevolking het voorgekom op klipperige andesitiese lava riwwe (grond pHKCL 6.5-7.0) al langs die Vaalrivier. Die ander het voorgekom in „n sandveld area (soil pHKCL 4). Bos-oorskryding deur A. mellifera was meer uitgebreid op die klipperige areas as in die sandveld en die twee habitats het noemenswaardig verskil ten opsigte van grond pH, klei en silt inhoud asook waterhoukapasiteit. Dit kan was dus afgelei word dat die klipperige habitat „n hoër CEC het. Die sade was versamel op „n logaritmiese skaal vir allosiem-analise en ook ewekansig in die twee habitats vir lokale aanpassings toetse. In dié gevalle was kalk (CaCO3) en organiese material (koeimis) gebruik in „n totaal-gekruisde ontwerp. Bespeurde interaksie effekte (tussen bevolkings bron en pH; bevolkings bron en organiese material en tussen pH en organiese material) en noemenswaardige verskille kon nie die twee bevolkings skei nie, aangesien die verskille voorgekom het regdeur die twee bevolkings. Ewekansige genetiese verskille wat lei tot fenotipiese plastisiteit tussen die twee waargeneemde bevolkings mag dalk verantwoordelik wees vir die waargeneemde fenotipiese verskille. Allosiem-data het geen beduidende verskille gelewer tussen die twee bevolkings nie en genetiese afstand binne en tussen die bevolkings het ook bevestig dat die twee bevolkings nie geneties gedifferensiëer is nie. Die Mantel toets op die twee bevolkings het geen beduidende resultate gelewer nie. Nei se UPGMA dendogram get gewys dat die wildsplaas bevolkings was meer primitief en geneties verwant aan mekaar. Ten spyte van die allosiem frekwensies tussen die gemonsterde gebiede, was die genetiese differensiasie laag (FST = 0.337). Nei (1972) se oorspronlike meeting van genetiese afstand het tussen 0.871 en 1.000 beloop met „n gemiddeld van 0.949 ± 0.053. Die studie het bepaal dat die twee waargeneemde bevolkings nie geneties gedifferensiëer het nie en dat geen lokale aanpassing teenwoordig was nie. Fenotipiese plastisiteit was duidelik waarneembaar en het gelei tot die divergerende groeivorme. Nieteenstaande, was die algehele rigting van oorskryding ooswaarts.Thesis (MScConEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2010.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and EntomologyJacobs, Shayne M.2010-11-23T14:33:13Z2010-12-15T10:16:38Z2010-11-23T14:33:13Z2010-12-15T10:16:38Z2010-12Thesis122 p. : ill., mapshttp://hdl.handle.net/10019.1/5160enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/53752011-06-23T12:55:41Zhdl_10019.1_532

Thermal tolerance of Cydia pomonella (Lepidoptera : Tortricidae) under ecologically relevant conditionsChidawanyika, FrankThermol toleranceSterile insect techniquePlasticityCodling mothDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyENGLISH ABSTRACT: Ambient temperature plays a key role in insect-physiology, -population dynamics and ultimately -geographic distribution. Here, I investigate the survival of codling moth, Cydia pomonella (Linnaues) (Lepidoptera: Tortricidae), which is a pest of economic importance in pome fruit production, to a wide range of temperature treatments. In this thesis, I first explore how temperature affects the survival and limits to activity of codling moth and secondly investigate if thermal acclimation can improve field performance of moths used in sterile insect technique control programmes under ecologically relevant conditions. First, I found that absolute temperature as well as the duration of temperature exposure significantly affects adult C. pomonella survival. Lethal temperatures, explored between -20 °C to -5 °C and 32 °C to 47 °C over a range of durations, showed that 50% of the adult C. pomonella population killed at -12 °C and at 44 °C after 2 hrs for each treatment. At high temperatures a pretreatment at 37 °C for 1 hr dramatically improved survival at 43 °C for 2 hrs from 20% to 90% (p<0.0001). Furthermore, high temperature pre-treatments (37 °C for 1 hr) significantly improved low temperature survival at -9 °C for 2 hrs. In sum, my results suggest pronounced plasticity of acute high temperature tolerance in adult C. pomonella, but limited acute low temperature responses. Secondly, low-temperature acclimated laboratory-reared moths were recaptured in significantly higher numbers (d.f. = 2, χ2 = 53.13 p<0.001), by sex pheromone traps, under cooler conditions in the wild relative to warm-acclimated or non-acclimated moths. However, these improvements in low temperature performance in cold-acclimated moths came at a cost to performance under warmer conditions in the wild. This novel study demonstrates the importance of thermal history on C. pomonella survival and clear costs and benefits of thermal acclimation on field and laboratory performance, and thus, the potential utility of thermal pre-treatments for improved efficacy in the sterile insect technique programme for C. pomonella control under cooler, springtime conditions. Finally, on a global scale, this study highlights that low and high temperatures could play a role in CM adult survival through direct mortality and thus, may influence, or have influenced in the pest, population dynamics.AFRIKAANSE OPSOMMING: Temperatuur speel ‘n belangrike rol in die fisiologie, populasiedinamika en geografiese verspreiding van insekte. In hierdie tesis ondersoek ek die rol van ‘n wye reeks temperature op die oorlewing van kodlingmot Cydia pomonella (Linnaues) (Lepidoptera: Tortricidae), ‘n sagtevrug pes-spesie van ekonomiese belang. Ek ondersoek hoofsaaklik die effek van temperatuur op die fisiologie en fiksheid van kodlingmot, asook die mate waartoe termiese akklimasie (‘n mate van aanpassing) die veldgedrag van die steriele insek beheer-metode (SIT), d.m.v. kodlingot, in relevante omgewingstemperature kan verbeter. Ek het (i) gevind dat die temperatuur en duur van die temperatuur toediening ‘n betekenisvolle toename in volwasse C. pomonella oorlewing tot gevolg het. In die deel van die studie is temperature tussen -20 °C en -5 °C and tussen 32 °C en 47 °C ondersoek oor ‘n reeks van 0.5, 1, 2, 3 en 4 ure van duur. In kort lei -12 °C en 44 °C vir 2 uur onderskeidelik tot die uitsterf van 50% van die volwasse C. pomonella populasie. Indien die motte vooraf gehou is by 37 °C vir ongeveer 1 uur, is oorlewing by 43 °C vir 2 ure betekenisvol verbeter van 20% tot 90% (p<0.0001). Hoër temperatuur vooraf-blootstellings (akklimasie), by 37 °C vir 1 uur, het daartoe gelei dat lae temperatuur lae-temperatuur-oorlewings by -9 °C vir 2 ure betekenisvol verbeter het. Oor die algemeen het die resultate gedui dat hoër akute temperatuurstoleransie in C. pomonella bestaan, maar beperkte akute lae-temperatuur reaksies bestaan. Verder het lae-temperatuur akklimasie (laboratorium geteelde) motte ‘n betekenisvolle hoër getal hervangste deur geslagsferomone in koeler omgewings opgelewer (v.i. = 2, χ2 = 53.13, p<0.001) in vergelyking met warmer-temperatuur geakklimatiseerder motte. Hierdie verbeteringe in laetemperatuur reaksies vanaf lea-temperatuur akklimasie groepe is teen ‘n koste teen warmer reaksie-toestande in die natuur geïs. Hierdie eersdaagse studie demonstreer die belang van historiese temperatuur op die oorlewing van C. pomonella. Die kostes- en voordele van termiese akklimasie op veld- en laboratoriumpopulasie reaksies en die potensiële gebruik daarvan in die verbetering van steriele insek tegniek programme, onder koeler omstandighede, is uitgelig. Laastens, beklemtoon hierdie studie die belangrikheid van temperatuur as bepalende faktor van kodlingmot-oorlewing en die invloed daarvan op die vrugte-pes populasiedinamika.Thesis (MSc (Agric) (Conservation Ecology and Entomology))--University of Stellenbosch, 2010.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and EntomologyTerblanche, J. S.2010-11-22T08:49:50Z2010-12-15T10:39:18Z2010-11-22T08:49:50Z2010-12-15T10:39:18Z2010-12Thesis108 p. : ill., mapshttp://hdl.handle.net/10019.1/5375enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/64652013-04-02T11:21:18Zhdl_10019.1_532

Biodiversity value of grassland ecological networks in afforested areas, KwaZulu-Natal, South AfricaJoubert, LizeEcological network -- South Africa -- KwaZulu-NatalCommercial forestry -- South Africa -- KwaZulu-NatalBiodiversity conservation -- South Africa -- KwaZulu-NatalForest biodiversity conservation -- South Africa -- KwaZulu-NatalDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyENGLISH ABSTRACT: The current biodiversity crisis requires creative initiatives for mitigating further biodiversity loss. The use of ecological networks (ENs) is such an initiative. The South African forestry industry recognizes that there is loss of biodiversity at the smaller patch scale, while attempting to mitigate this loss at the landscape scale by implementing largescale ENs. The aim of this study was to determine how representative grassland biodiversity in ENs are of similar habitat in a nature reserves (NR). The study was conducted in the northeast of the KwaZulu-Natal Province, adjacent iSimangaliso Wetland Park, which is a natural World Heritage site. A systematic approach compared a wide range of taxa, namely plants, decomposition macrofungi, vertebrates (birds and large mammals) and faunal manifestations (e.g. molehills, dung and ant nests) between the EN and nature reserve, while controlling for differences in disturbance regime. Species richness was compared using Mann-Whitney U tests, while differences in species composition were determined using Correspondence Analyses, Multi-Dimensional Scaling and Analyses of Similarity. Grassland ENs had significantly less plant species. In addition, there were differences in plant and fungi species composition. Differences were probably caused by (1) degree of isolation i.e. proximity to source habitat patches in the surrounding matrix, and (2) habitat quality. Habitat quality was determined by local disturbance regimes (e.g. grazing and fire) and plantation-induced drought for plants, and size and amount of coarse woody debris for fungi. In addition, significant differences in abundances of mole hills (NR>EN) and small mammal burrows (EN>NR) might have had an effect on succession and regeneration of plant communities. There were differences in plant species composition between grassland EN and that at the adjacent nature reserve. However, differences between EN and NR were small when compared to differences between habitat types at the landscape spatial scale. It is concluded that grassland ENs among forestry plantations contribute to biodiversity conservation in the commercially-productive landscape. This approach to land use planning should be explored for other commercial land uses.AFRIKAANSE OPSOMMING: Die huidige biodiversiteitskrisis vereis kreatiewe strategieë om ‘n verdere verlies in biodiversiteit te bekamp. Ekologiese Netwerke (EN’e) is een voorbeeld van sulke kreatiewe strategieë. Die Suid Afrikaanse bosbou-industrie erken die verlies in biodiversiteit wat kenmerkend in plantasies gevind word. Implementering van grootskaalse EN’e kan egter die verlies aan biodiversiteit, wat in plantasies ondervind word, temper. Die doel van hierdie studie was om vas te stel hoe goed biodiversiteit in grasveld EN’e soortgelyke habitat in ‘n nabygeleë natuurreservaat verteenwoordig. Die studie was uitgevoer in die noordooste van KwaZulu-Natal, langs iSimangaliso Wetland Park wat ‘n wêrelderfenisgebied is. Ons het ‘n stelselmatige benadering gevolg waartydens ‘n wye verskeidenheid taksa, naamlik plante, makro-fungi, vertebrate (groot soogdiere en voëls) en tekens van diere-aktiwiteit (bv. miersneste, dieremis en molshope), in die EN vergelyk is met die van ‘n natuurreservaat terwyl ons vir verskillende versteuringe gekontrolleer het. Spesiesrykheid is vergelyk met Mann-Whitney U toetse terwyl verskille in spesiessamestelling vasgestel is met Correspondence Analyses, Multi-Dimensional Scaling en Analyses of Similarity. Daar was ‘n statisties beduidende verskil in die hoeveelheid spesies tussen grasveld EN’e en die natuurreservaat. Grasveld EN’e het minder plant spesies gehad. Boonop was daar verskille in die samestelling van plant en fungi gemeenskappe. Verskille was waarskynlik veroorsaak deur (1) isolasie of die hoeveelheid nabygeleë habitatbronne in die omliggende omgewing, en (2) habitat kwaliteit. Habitat kwaliteit word bepaal deur versteuringe (bv. brand en beweiding) en die uitdrogingseffek van plantasies vir plante, en die hoeveelheid en grootte van growwe houtagtige puin vir fungi. Daar was ook beduidende verskille in die hoeveelheid molshope (NR>EN) en klein soogdier gate (EN>NR), wat moontlik ‘n effek kon hê op suksessie en herstel van plantgemeenskappe. Daar was verskille in plantspesiessamestelling tussen grasveld EN’e en die van die langsliggende natuurreservaat. Hierdie verskille was egter klein wanneer dit vergelyk word met die verskille tussen verskillende soorte habitatte in die landskap. Daarom kom ons tot die gevolgtrekking dat grasveld EN’e tussen bosbouplantasies bydra tot die bewaring van biodiversiteit in kommersiële landskappe. Hierdie benadering tot grondgebruik behoort verder verken te word vir ander kommersiële bosbou en boerderypraktyke.Thesis (MSc)--University of Stellenbosch, 2011.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Samways, Michael J.2011-02-02T12:42:39Z2011-03-14T08:09:58Z2011-02-02T12:42:39Z2011-03-14T08:09:58Z2011-03Thesis142 p. : ill., mapshttp://hdl.handle.net/10019.1/6465en_ZAUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/64672011-03-28T08:55:46Zhdl_10019.1_532

Structure and function of heuweltjies across a rainfall gradient in the South-Western CapeBooi, NozukoHeuweltjies -- South Africa -- Western CapeTermitaria -- South Africa -- Western CapeSoil processes -- South Africa -- Western CapeEcophysiology -- South Africa -- Western CapeDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyENGLISH ABSTRACT: Heuweltjies are below ground termitaria found along the west coast and the south-western and -eastern Cape. They traversing different climates, soil and vegetation types within the Succulent Karoo and Fynbos biomes. From a birds eye view, heuweltjies appear as near-circular landscape features, demonstrating clear difference in vegetation structure to their surroundings. A study of aspects of the structure and function of heuweltjies, mima-like mounds of south-western South Africa was undertaken. The main aim of the study was to investigate topsoil properties and processes and vegetation structure and the ecophysiology of plants growing on these mounds, and compare it to areas off these patches. Four study sites across a rainfall gradient were chosen for soil and vegetation studies (two within the Succulent Karoo and two at the Fynbos biome). Ten sampling sites on heuweltjies and 10 off heuweltjie (interpatch) were chosen at each study site for these analyses. Soils samples from the top 10 cm were analysed for total nitrogen (N) and carbon (C) content, phosphorus (P) concentrations, particle-size distributions, pH and electrical conductivity (related to salinity). Soil biogeochemistry studies (i.e. potential N mineralization, potential soil respiration and phosphatase activity) were also done in the laboratory. In the field, the cover of soil cryptogams, selected plant growth forms and selected physical variables at each site, on and off heuweltjies, were estimated on 1m2 grids. Two of the study sites, one in the Succulent Karoo and one in Fynbos, were chosen for field measurements of stomatal conductance, predawn and midday xylem water potentials of two growth forms (deciduous and evergreen non-succulent shrubs) at selected times in the duration of the study. Leaf samples were taken to make once-off measurements of specific leaf area, C and N isotope compositions (δ13C, δ15N), and foliar N content. Furthermore, a fertilization experiment that has been running at the Tierberg Karoo Research Centre (Succulent Karoo) since 1997, where 10g m-2 of N have been added to interpatch vegetation twice annually, was included in the stomatal conductance and xylem water potential studies. The aim of including the fertilization experiment was to ascertain whether interpatch vegetation will eventually resemble heuweltjie vegetation in ecophysiology following N fertilization. Soil water probes were inserted, 10 cm deep, on one on heuweltjie and one off heuweltjie site for the long-term estimation of gravimetric water content and temperature at the Tierberg Karoo Research Centre. Heuweltjie soils were found to be hotspots for nutrients and biogeochemical activity. They had elevated levels of total % C, % N and available P (mg kg-1) compared to surrounding interpatch soils. pH and electrical conductivity (μS cm-1) of these soils were also high compared to interpatch areas. Heuweltjie soils have higher silt content and retain more water, and for a longer period following a rainstorm. Potential soil respiration, potential N mineralization and alkaline and acid phosphatase activity were generally higher on heuweltjies.Cover of the selected plant growth forms differed little between heuweltjies and the surrounding vegetation but site differences were observed. Heuweltjies differed from interpatches in the cover of soil cryptogams, with higher cover of mosses and lower cover of lichens on mounds. There was higher cover of plant litter and termite frass on the heuweltjies.There was a decrease in soil available P and increase in non-succulent shrub cover from low to high rainfall areas. On the other hand no significant differences were found in the xylem water potential of interpatch and heuweltjie plants at either of the study sites. At the Tierberg Karoo Research, stomatal conductance of interpatch plants was higher and water use efficiency (δ13C) lower compared to that of heuweltjie plants suggesting some level of water stress for heuweltjie plants at this site. Here, heuweltjie plants also had higher foliar N, lower C/N ratio values, signs of high photosynthetic potential and highly decomposable litter and higher δ15N. At Jonaskop, stomatal conductance and water use efficiency did not differ between heuweltjies and interpatch plants. There were also no differences in foliar N concentrations, C/N ratios and δ15N between heuweltjie and interpatch plants at this site. Plants growing in high N plots (the fertilizer plots) had higher xylem water potential and more variable stomatal conductance than those growing in control plots. The results of this study have shown heuweltjies to be hotspots for nutrients and biogeochemical cycling, and given enough water, will be ideal patches for plant growth. In the Succulent Karoo, high salinity (and finer textured soils) on the heuweltjies may contribute to water stress during dry periods, and together with disturbance, provide bottom-up controls on plant physiology, and ultimately, vegetation structure. In the Fynbos, plants may be limited by nutrients on heuweltjies, possibly because of increased interspecific competition, while increased rainfall may also lead to more nutrients leaching from the topsoils. The results presented are especially relevant to restoration programs, and may shed some light on restoration trajectories after overgrazing, cultivation and mining activities.AFRIKAANSE OPSOMMING: Heuweltjies is ondergrondse termitaria wat langs die weskus, die suid-wes en oos Kaap van Suid Afrika voorkom. Hulle kom voor onder verskillende klimaatstreke, grondtipes en planttipes wat binne die Sukkulente Karoo en Fynbos biome voorkom. Vanuit die lug uitgesien, verskyn heuweltjies as sirkelvormige landskapseienskappe, wat duidelike verskille in plant struktuur en die omringende omgewing demonstreer. ʼn Studie van aspekte van struktuur enfunksie van ʼn heuweltjies, mima-agtige hope vansuidwestelike Suid-Afrikais onderneem. Die hoofdoel van die studie was om die eienskappe van oppervlakgrondeen -prosesse, plant struktuur, en die ekofisiologie van plante wat op heuweltjies groei te ondersoek, en dit te vergelyk met areas af van hierdie kolle. Vier studieareas wat oor „n reënvalgradient strek is gekies vir grond en plantegroei studies (twee binne die Sukkulente Karoo en twee binne die Fynbos biome). Tien monsterareas op heuweltjies en 10 af van heuweltjies (omringende areas) is gekies binne elke studiearea vir die bogenoemde analises. Grondmonsters van die boonste 10 cm van die grond is geneem en geanalieseer vir totale stikstof (N) en koolstof (C), fosfor (P) konsentrasies, gronddeeltjiegrootte, pH, en elektriese geleidingsvermoë, (hou verband met soutgehalte). Grond biogeochemie studies (d.i. potensiële stikstof mineralisasie, potensiële grond respirasie en fosfatase aktiwiteit) is ook in die laboratorium uitgevoer. In die veld was die dekking van grond kriptogame, geselekteerde plant groeivorms en fisiese veranderlikes by elke lokaliteit, beide op en van heuweltjies op 1m2vierkante bereken. Twee studie lokaliteite, een in die Sukkulent Karoo en een in die Fynbos, is gekies vir veld metings van huidmondjiegeleiding, voor dagbreek en middag xileem potensiale van twee groei vorms (bladwisselende en immergroen nie-sukkulente struike) op geselekteerde tye gedurende die studie. Blaarmonsters is geneem om eenmalige metings te maak van die spesifieke blaararea, C en N isotoop komposisies (δ13C, δ15N), en blaar N inhoud. Verder is „nbemestingseksperiment wat by die Tierberg Karoo Navorsing Sentrum (Sukkulente Karoo) loop sedert 1997, waar 10gm-2 van N jaarliks twee keer bygevoeg word by die plante wat tussen heuweltjies groei ingesluit in die stomata geleiding en xileem water potensiaal studies. Die doel van die bevrugting eksperiment was om vas te stel of die omliggende plante (af van heuweltjies) uiteindelik soos die van die heuweltjiessal lyk in terme van ekofisologie nadat dit met stikstof bemes is. Grondwater monitoreringsapparaat was ingesit (10cm diep) op een op heuweltjie en een lokaliteitaf van die heuweltjie vir die langtermyn bepaling van gravimetriese water inhoud (m3m-3) en temperatuur by die Tierberg Karoo Navorsing Sentrum. Daar is gevind dat grond op heuweltjies “skerpkolle” is vir voedingstowwe en biogeochemiese aktiwiteit. Hulle het ook verhoogte vlakke van totale %C, % N, en beskikbare P (mg kg-1) teenoor die omliggende areas om die heuweltjies. pH en elektriese geleidingsvermoë (μS cm-1) van hierdie gronde was ook hoër in vergelyking met die omliggende areas. Heuweltjie grond het „n hoër sout inhoud gehad en behou meer water vir ʼn langer periode na ʼn reënstorm. Potensiële grond respirasie, potensiële stikstof mineralisasie, en alkaliese en suur fosfatase aktiwiteit is oor die algemeen hoër op heuweltjies. Die voorkoms van die geselekteerde plant groeivorms verskil min tussen heuweltjies en die omliggende omgewing, maar verskille tussen studie areas is opgemerk. Heuweltjies het verskil van areas af van heuweltjies in die voorkoms van grond kriptogame, met ʼn hoër voorkoms van mosse en ʼn laer voorkoms van ligene op die heuweltjies. Daar was hoër voorkoms van plantafvalmateriaal en termiet uitwerpsel op die heuweltjies. Daar was ʼn afname in grond P (mg kg-1) en ʼn toename in nie-sukkulente struik bedekking van lae tot hoë reënval areas. Daar was geen verskil in die xileem water potensiaal van plante op die heuweltjies of af van die heuweltjies by enige van die studie lokaliteite nie. By die Tierberg Karoo Navorsing Sentrum was huidmondjie geleiding van plant in die areas tussen heuweltjies hoër en die water gebruik doeltreffendheid (δ13C) laer in vergelyking met die van die heuweltjie plante, wat op„n sekere vlak waterstres dui in heuweltjie plante by hierdie studiearea. Hier het heuweltjie plante ook hoër blaar N, laer C/N waardes, tekens van hoër fotosintetiese potensiaal en hoogs afbreekbare afvalmaterialgehad asook hoër δ15N. By Jonaskop het huidmondjie geleiding en water gebruik doeltreffendheid nie verskil tussen heuweltjie en omliggende plante nie. Daar was ook geen verskille in blaar N konsentrasies, C/N verhoudings en δ15N tussen heuweltjie en omliggende plante by hierdiestudiearea nie. Plante wat groei in hoë stikstof plotte, het hoër xileem water potensiaal (minder stres) en meer veranderlike stomatal geleiding as die plante wat in die kontrole plotte groei. Die resultate van die studie het getoon dat heuweltjies “skerpkolle” is van voedingstowwe en biogeochemiese siklusse, en gegewe genoeg grondwater, sal ideale areas wees vir die groei van plante. In die Sukkulente Karoodra hoë soutgehalte (en fyner grond teksture) op die heuweltjies by tot water stres gedurende droë tye, en saam met versteurings dra dit by tot grond tot plant kontrole op plantfisiologie, en uiteindelik plant gemeenskapsstruktuur. In die Fynbos word plante op die heuweltjies beperk deur te min voedingstowwe, moontlik omdat daar ʼn toename is in intraspesifieke kompetisie, terwyl hoër reenvalkan lei tot hoër loging van voedingstowwe vanuit die bogrond. Die resultate wat hier gerapporteer word is veral relevant vir restourasieprogramme, en mag lig werp op restourasie trajekte na oorbeweiding, aanplanting van gewasse en mynbou-aktiwiteite.Thesis (MScConEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2011.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Jacobs, S. J.Esler, K. J.Milton, S. J.2011-02-24T15:30:14Z2011-03-14T08:10:10Z2011-02-24T15:30:14Z2011-03-14T08:10:10Z2011-02-24T15:30:14ZThesis114 p. : ill., mapshttp://hdl.handle.net/10019.1/6467en_ZAUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/66372011-12-17T22:14:17Zhdl_10019.1_532

Understanding plant resource use by the ≠Khomani Bushmen of the southern KalahariMannetti, LelaniPlant resources -- South Africa and Botswana -- Kgalagadi Transfrontier ParkKhomani Bushmen -- South Africa and Botswana -- Kgalagadi Transfrontier ParkSouthern KalahariIndigenous communities -- South Africa and Botswana -- Kgalagadi Transfrontier ParkEthnobotany -- South Africa and Botswana -- Kgalagadi Transfrontier ParkTheses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyENGLISH ABSTRACT: Previously, conservation activities were mainly focussed upon the establishment of protected areas that safeguarded and shielded the natural world from misuse, often resulting in the forced removal of indigenous communities. In South Africa, the ≠Khomani Bushmen, were one such group forcibly evicted from their homelands. Today, the community has regained access to their ancestral lands in the form of a land claim, settled in 1999, that awarded the community land rights in the form of six farms and land use rights within the now Kgalagadi Transfrontier Park (KTP). This gave them the right to use and manage their property falling within the park together with the conservation authority responsible for the Park, South African National Parks (SANParks). This study aims to improve our understanding of the use of resources by the ≠Khomani Bushmen. By obtaining insight on resource use and how knowledge of this use is transferred and shared, information on how to better involve and integrate the community in management processes is generated. The study identified the most important plants currently used within the ≠Khomani community and assessed this use. Additionally, social network analysis (SNA) was used to investigate how the social network structure depicts the distribution of knowledge which affects the community’s ability to manage their natural plant resources effectively. In an ethnobotanical survey, over 90 individuals were interviewed, using semi-structured interviews, on the farms awarded to the community. In total, 59 plant species from 28 families were found to be in use. Medicinal plants were most frequently cited (60%), with edible plants comprising a further 20%. Data was also collected on social relations surrounding the acquisition, generation and transfer of plant use knowledge. The knowledge networks all depict isolated individuals on the periphery and a few individuals loosely connected to central structures. This study demonstrates that wild plant use remains an important practice for the ≠Khomani people, primarily for medicinal purposes. It serves as baseline data on plant resources being used by the community and adds to our understanding of how traditional knowledge is being transmitted. The insight provided by SNA depicts the current distribution of knowledge and should be used by the community, as supported by network weavers and SANParks, to achieve their joint management goals. Network weaving can potentially counteract ecologically unsustainable practices, promoting collaboration and the transfer of traditional ecological knowledge.AFRIKAANSE OPSOMMING: Voorheen was bewaringsaktiwiteite meestal gefokus op die vestiging van beskermde areas wat die natuurlike wêreld beveilig en beskerm het van misbruik wat dikwels die gevolg was van die geforseerde verwydering van inheemse gemeenskappe. In Suid-Afrika was die ≠Khomani Boesman groep een van die sodanige groepe wat op ʼn indrukwekkende manier van hulle tuislande uitgesit is. Vandag het die gemeenskap weer toegang gekry tot die land van hulle voorvaders in die indiening van ʼn grond eis wat in 1999 vasgestel is, en wat die gemeenskap grond regte toegeken het in die vorm van ses plase en grond regtelike gebruik binne die sogenoemde Kgalagadi Transfrontier Park (KTP). Dit het hulle die reg gegee tot die gebruik en bestuur van hulle eiendom wat binne die park val saam met die bewaringsowerhede wat verantwoordelik is vir die Park, Suid-Afrikaanse Nasionale Parke (SANParks). Die doel van hierdie studie is om ons begrip te verbeter van die gebruik van hulpbronne deur die ≠Khomani Boesman. Met die verkryging van insig oor hulpbron gebruik en hoe die kennis van hierdie gebruik oorgedra en gedeel word, is inligting oor hoe om ʼn beter betrekking en integrering van die gemeenskap in die bestuursprosesse gegenereer. Die studie het die belangrikste plante geïdentifiseer wat tans gebruik word binne die ≠Khomani gemeenskap met die doel om die gebruik van hierdie plante te assesseer. Sosiale netwerkanalise (SNA) is addisioneel gebruik om ondersoek in te stel oor hoe sosiale netwerk struktuur die verspreiding van kennis uitbeeld wat die gemeenskap se vermoë om hulle natuurlike plant hulpbronne effektief te bestuur affekteer. In ʼn etnobotaniese opname, was oor 90 individuele ondervra op die plase wat aan die gemeenskap toegeken was, met die gebruik van semi-gestruktureerde onderhoude. Dit is gevind dat in totaal 59 plant spesies uit 28 families gebruik word. Medisinale plante was meer dikwels aangehaal (60%) met eetbare plante bestaande uit 20%. Data was ook versamel oor sosiale verwantskappe omringende die verkryging, generering en oordra van kennis in die gebruik van plante. Hierdie netwerk van kennis word alles uitgebeeld in geïsoleerde individue op die periferie en ʼn paar individue wat losweg verbonde is tot sentrale strukture. Hierdie studie identifiseer dat die gebruik van wildeplante ʼn belangrike praktyk bly vir die ≠Khomani mense, hoofsaaklik vir medisinale doeleindes. Dit dien as basis inligting van plant hulpbronne wat tans gebruik word deur die gemeenskap en wat by ons begrip gevoeg word oor hoe tradisionele kennis oorgedra word. Die insig wat deur SNA voorsien word beeld die huidige verspreiding van kennis uit, wat deur die gemeenskap gebruik moet word, as ondersteuning van “network weavers” en SANParks om hulle gesamentlike bestuur doelwitte te bereik. “Network weavers” kan potensieel ekologiese onvolhoubare praktyke teenwerk, wat die samewerking en die oordra van tradisionele ekologiese kennis bevorder.Thesis (MScConEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2011.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Knight, Andrew T.Esler, Karen J.2011-03-02T14:35:48Z2011-03-14T08:26:36Z2011-03-02T14:35:48Z2011-03-14T08:26:36Z2011-03Thesis177 p. : ill., mapshttp://hdl.handle.net/10019.1/6637enUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/66852012-04-02T10:00:36Zhdl_10019.1_532

Radiation biology of Eldana saccharina Walker (Lepidoptera: Pyralidae)Walton, Angela JasminSterile insect techniqueEldana saccharina -- Biological controlSugar cane -- Disease and pests -- Biological controlDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyPlease refer to full text to view abstract.Thesis (MSc (Conservation Ecology and Entomology))--University of Stellenbosch, 2011.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Conlong, Desmond, EdwardAddison, Pia2011-03-01T10:53:45Z2011-03-14T08:31:17Z2011-03-01T10:53:45Z2011-03-14T08:31:17Z2011-03Thesis122 p. : ill.http://hdl.handle.net/10019.1/6685Stellenbosch : University of Stellenboschen_ZAUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/67242011-06-23T09:24:15Zhdl_10019.1_532

Elephant movements and human-elephant conflict in a transfrontier conservation areaVon Gerhardt-Weber, Katharina E. M.ElephantsElephant movementsHuman-elephant conflictKavango-Zambezi Transfrontier Conservation AreaDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyENGLISH ABSTRACT: In this thesis I explore how elephant movements are impacted by human activity within the context of the proposed Kavango-Zambezi Transfrontier Conservation Area (KAZA TFCA) in southern Africa. Being a wide-ranging species, the movements of elephants could be an excellent indicator as to the success of TFCAs in supporting species persistence in an anthropogenic matrix. Understanding which areas beyond protected area boundaries are of heightened conservation importance can provide managers and governments with insights for the management of the elephant population of KAZA TFCA, and assist managers and governments in prioritising conservation efforts. Satellite radio collar data were used to model long-range elephant movement within KAZA TFCA. Movement was compared between land use types (protected and nonprotected areas). Home ranges, core areas and seasonal ranges were calculated from collar data. Core and non-core areas were tested for significant differences in distance to settlements, rivers, protected area, AFRI and elevation as these spatial and ecological variables are believed to play a role in elephant habitat selection. Short-range elephant movements were examined in a heterogeneous, patchy landscape mosaic of settlements and agricultural fields, remnant forest patches, and secondary forests which were surrounded on three sides by protected areas. Elephant penetration of the anthropogenic matrix through the use of pathways was explored through ground-based surveys, and the impact of pathways use on human-elephant conflict calculated. I found that elephant behavioural plasticity allows for their persistence in a spatially heterogeneous landscape. Elephants, especially bulls, penetrated the landscape matrix beyond protected area boundaries. Land use planning initiatives are needed to identify and protect reachable core zones/stepping stones of quality habitat outside of protected areas, particularly in riparian zones. Differing male and female ranging behaviour within the landscape matrix may require separate land use management strategies: bulls travelled at night in non-protected areas at speeds that were four times faster than in protected areas, and made use of core zones necessary for species persistence in a fragmented landscape. A habitat corridor in the Zambian West Zambezi Game Management Area was identified. I found that during short range movements in heterogeneous environments, elephants made use of pathways. Pathways may facilitate penetration of the anthropogenic matrix and optimize foraging strategies by connecting predictable resources, such as crop fields, with landscape features such as preferred shelter/ resting areas, crossing points at roads and preferred drinking spots. Pathways were found to be the only significant spatial variable in crop-raiding. Elephants foraged randomly while in homogenous crop patches, but when travelling through a heterogeneous environment (entering or leaving agricultural locales), movement was directional and non-random. Lastly I suggest that crop attractiveness may be enhanced by water availability. Results indicated that at both the landscape and the regional scale, repeat elephant movements to core zones and along elephant pathways provided landscape ecological variables that need to be considered by conservation managers in land use planning. In addition, research on spatial awareness and navigational capabilities with regards to pathway use by elephants should be encouraged, as this research topic has been largely unexplored in the scientific literature.AFRIKAANSE OPSOMMING: In hierdie tesis verken ek die moontlike impak van menslike aktiwiteite op olifant beweging binne die beoogde Kavango-Zambezi Oorgrens Bewaringsarea (KAZA TFCA) in suider-Afrika. Olifante is wydlopende spesies, en dus kan hul ruimtelike strekking ‘n uitstekende indikator wees van die sukses van oorgrens bewaringsareas in terme van die ondersteuning wat dié programme bied om spesies se volharding in ‘n antropogeniese matriks te verseker. Besturrders en regerings kan insig verkry deur te besef watter areas buiten die in beskermde gebiede, van verhoogde bewarings belang in KAZA TFCA is. Hierdie insig verleen ook bystand aan bestuurders en regerings met die prioritisering van bewarings inisiatiewe. Satelliet-radio nekband data was gebruik om olifante se langtermyn ruimtelike beweging binne die KAZA TFCA te modelleer. Olifant beweging was vergelyk tussen verskillende grondgebruik tipes (beskermde en onbeskermde areas). Tuistestrekking, kern areas asook seisoenale strekking was bereken vanaf nekband data. Kern en nie-kern areas was getoets vir betekenisvolle verskille in afstand vanaf nedersettings, riviere, berskermde gebiede, AFRI, en hoogte bo seevlak, omdat hierdie ruimtelike en ekologiese veranderlikes ‘n belangrike rol mag speel in olifant habitat seleksie. Kortafstand olifant bewegings was bestudeer in ‘n heterogene, gelapte landskap mosaïek van nedersettings en landbougrond, oorblywende woudareas, en sekondêre woude waarvan drie sye grens aan bekermde areas. Olifant indringing binne die antropogeniese matriks deur die gebruik van weë/toegangsweë was verken deur middel van landgebaseerde opnames, waarvolgens die impak van olifante se gebruik van hierdie paaie op mens-olifant konflik bereken kon word. My bevindinge wys dat plastisiteit in olifant gedrag dra by tot hul voortbestaan in ‘n ruimtelik heterogene landskap. Olifante, maar meer spesifiek olifantbulle, penetreer wel die landskap matriks buite beskermde area grense. Grondgebruik beplannings inisiatiewe word dus benodig om bereikbare kern areas van kwaliteit habitat buite beskermde areas te identifiseer en te beskerm – veral in rivieroewer sones. Verskille in bul en koei ruimtelike strekking gedrag binne die landskap matriks, mag afsonderlike bestuur stratgieë vereis: bv. bulle beweeg vier keer vinniger in die aand in onbeskermde areas teenoor in beskermde gebiede, daarby maak hulle ook gebruik van kern areas wat kardinaal is vir die voortbestaan van spesies in gefragmenteerde landskappe. ‘n Habitat deurgang was geïdentifiseer in die Zambiese Wes-Zambesie Wildbestuurarea. Die studie het gevind dat olifante gedurende kortafstand bewegings in heterogene omgewings gebruik maak toegangsweë. Toegangsweë mag penetrasie van die antropogeniese matriks fasiliteer, en verleen ook dat olifant weidingstrategieë die optimum bereik deur voorspelbare hulpbronne soos gewaslanderye te konnekteer met landskap eienskappe soos voorrang skuiling/rusareas, kruisingspunte by paaie, asook voorrang drinkplekke. Toegangsweë was gevind om die enigste betekenisvolle ruimtelike veranderlike in gewasstrooptogte te wees. Olifante wei lukraak in homogene gewaslanderye, maar in teenstelling, wanneer hulle deur ‘n heterogene omgewing beweeg het (binnegang of uittog uit landbou lokaliteite) was die beweging gerig. Laastens, die studie stelvoor dat gewas aantreklikheid verhoog kan word deur water beskikbaarheid. Resultate dui aan dat by beide die landskap- en streekskaal verskaf herhaalde olifant beweging na kern areas en langs olifants togangsweë, landskap ekologiese veranderlikes wat in ag geneem moet word deur bewaringsbestuurders tydens grondgebruik beplanning. Bykomend, navorsing op die ruimtelike bewustheid en navigasie vermoëns van savannah olifante met betrekking tot die gebruik van toegangsweë, moet aangemoedig word aangesien hierdie onderwerp grootliks onverken is in wetenskaplike literatuur.Thesis (MScConEcol)--University of Stellenbosch, 2011.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Samways, M. J.Hanks, J.2011-02-28T07:34:04Z2011-03-14T08:35:12Z2011-02-28T07:34:04Z2011-03-14T08:35:12Z2011-03Thesis126 p. : ill., mapshttp://hdl.handle.net/10019.1/6724en_ZAUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/67512011-12-17T22:15:13Zhdl_10019.1_532

Impact of Prosopis (mesquite) invasion and clearing on ecosystem structure, function and agricultural productivity in semi-arid Nama Karoo rangeland, South AfricaNdhlovu, ThabisisaniProsopis -- South Africa -- Beaufort West RegionMesquite -- South Africa -- Beaufort West RegionPlant invasion -- South Africa -- Beaufort West RegionNama KarooRangeland vegetation -- Effect of invasion on -- South Africa -- Beaufort West RegionRangeland vegetation -- Effect of clearing on -- South Africa -- Beaufort West RegionIndigenous species -- South Africa -- Beaufort West RegionAgricultural productivity -- South Africa -- Beaufort West RegionDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyENGLISH ABSTRACT: I evaluated the impact of Prosopis invasion and clearing on ecological structure, function and agricultural productivity in heavily grazed Nama Karoo rangeland on two sheep farms near the town of Beaufort West in the Western Cape Province of South Africa. My aims were to (1) determine the effects of invasion and clearing on rangeland vegetation composition, diversity (alien and indigenous species richness) and structure (alien and indigenous species cover), soil vegetation cover (plant canopy and basal cover) and agricultural productivity (grazing capacity), (2) describe the vegetation processes that underlay the invasion and clearing impacts and (3) evaluate the success of clearing in facilitating unaided restoration of ecological structure, function and agricultural productivity in formerly invaded rangeland. I hypothesised that invasion would significantly change rangeland vegetation composition and structure, leading to greater alien species richness and cover and lower indigenous species richness and cover while clearing would lead to lower alien species diversity and cover and greater indigenous species richness and cover. In addition I hypothesized that invasion would reduce rangeland plant canopy and basal cover and grazing capacity while clearing would substantially increase them. Finally I predicted that vegetation composition, alien and indigenous species cover and richness, plant canopy and basal cover and grazing capacity would revert to pre-invasion status and levels within four to six years of clearing. My results suggest that in heavily grazed Nama Karoo rangeland Prosopis invasion (~15 percent canopy cover) and clearing can significantly change rangeland vegetation composition, with invasion leading to greater alien species cover and lower indigenous species richness, while clearing leads to lower alien species richness and cover and greater indigenous species richness and cover. However invasion seems to have no effect on alien species richness and overall indigenous species cover. Clearing appears to facilitate the spontaneous restoration of alien species cover and indigenous species richness within four to six years but not species composition, alien species richness and indigenous species cover. In addition my results also indicate that Prosopis invasion can lower rangeland plant canopy and basal cover and grazing capacity while clearing, even under heavy grazing, can substantially raise them. Clearing however does not seem to facilitate the restoration of rangeland plant canopy and basal cover and grazing capacity to pre-invasion levels within four to six years after clearing.AFRIKAANSE OPSOMMING: Ek het die impak van Prosopis indringing en verwydering van indringers op ekologiese struktuur, funksie en landbou produktiwiteit in ‘n swaar beweide Nama Karoo gebied op twee skaapplase naby Beaufort-Wes in die Wes-Kaap provinsie van Suid-Afrika geëvalueer. My doelwitte was om (1) te bepaal wat die gevolge van die indringing en verwydering van indringers op die natuurlike plantegroei samestelling, diversiteit (uitheemse en inheemse spesiesrykheid) en struktuur (uitheemse en inheemse spesies bedekking) sal wees, sowel as die effek op plantegroei bedekking (kroon en basalebedekking) en landbou produktiwiteit (weidingkapasiteit), (2) die plantegroei prosesse te beskryf wat onderliggend deur die impakte van indringing en verwydering van indringers veroorsaak word, en (3) die sukses van die verwydering van indringers te evalueer deur die fasilitering van blote restorasie van ekologiese struktuur en funksie en landbou produktiwiteit in voorheen ingedringde gebiede. My hipotese is dat indringing ‘n aansienlike verandering in natuurlike plantegroeisamestelling en struktuur sal veroorsaak, wat sal lei tot groter uitheemse spesiesrykheid en bedekking met minder inheemse spesiesrykheid en bedekking, terwyl die verwydering van indringers sou lei tot minder uitheemse spesie diversiteit en bedekking met 'n groter inheemse spesiesrykheid en bedekking. Verder vermoed ek dat indringing die natuurlike kroon- en basalebedekking en weidingkapasiteit sal verminder, terwyl die verwydering van indringers dit aansienlik sal verhoog. Ten slotte voorspel ek dat plantegroei samestelling, uitheemse en inheemse spesiesbedekking en -rykheid, kroon- en basalebedekking en weidingkapasiteit sou terugkeer na voor-indringing status en vlakke binne vier tot ses jaar na die verwydering van indringers. My resultate daarop dat die indringing van Prosopis (~ 15 persent kroonbedekking) en die verwydering van indringers in swaar beweide Nama Karoo gebiede ‘n aansienlike verandering in die gebied se natuurlike plantegroei samestelling toon, waar indringing gelei het tot groter uitheemse spesiesbedekking en minder inheemse spesiesrykheid, terwyl die verwydering van indringers lei tot minder uitheemse spesiesrykheid en groter inheemse spesiesrykheid en - bedekking. Dit lyk egter of indringing geen effek op uitheemse spesiesrykheid en algehele inheemse spesiesbedekking het nie. Die verwydering van indringers blyk om die spontane herstel van indringerbedekking en inheemse spesiesrykheid binne vier tot ses jaar te fasiliteer, maar nie spesiesamestelling, uitheemse spesiesrykheid of inheemse spesiesbedekking nie. Benewens dui my resultate ook aan dat Prosopis indringing die natuurlike kroon- en basalebedekking sowel as weidingskapasiteit verlaag, terwyl die verwydering van indringers, selfs onder swaar beweiding, die bedekking aansienlik kan verhoog. Verwydering van indringers lyk egter nie asof dit die herstel van die gebied se natuurlike kroon- en basalebedekking en weidingkapasiteit na voor-indringing vlakke toe kan fasiliteer binne vier tot ses jaar na die verwydering van indringers nie.Thesis (MScConEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2011.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Esler, Karen J.Milton, Suzanne J.2011-03-02T13:33:53Z2011-03-14T08:37:49Z2011-03-02T13:33:53Z2011-03-14T08:37:49Z2011-03Thesis122 p. : ill., mapshttp://hdl.handle.net/10019.1/6751en_ZAUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/68052013-04-02T11:28:18Zhdl_10019.1_532

Arthropods associated with commercial Proteaceae in the Western Cape Province, South AfricaSasa, ArchboldProteaceaeArthropodsCommercially-cultivated proteas -- Diseases and pests -- South Africa -- Western CapeDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyENGLISH ABSTRACT: The commercial cultivation of Proteaceae is an important industry in the Western Cape, however, farmers are challenged with arthropod infestation which compels them to solely rely on chemical pesticides. Past studies in South Africa have shown that Proteaceae comprise a rich and diverse arthropod fauna. However, as most of these studies were conducted on wild Proteaceae, they may not be representative of cultivated proteas. Moreover, most of these species remained unidentified due to lack of identification expertise. These past studies, however, form a useful baseline for arthropod studies in proteas, e.g. the feeding guilds found in proteas. The aim of this research was to conduct an intensive and extensive survey of the arthropod-fauna associated with commercially-cultivated proteas across an entire year. Specifically, this survey was designed to document the composition of the arthropod fauna (creating a comprehensive reference collection for pest management purposes) and to assess whether the arthropod fauna differed between seasons and pesticide treatments. Infructescences, inflorescences and foliage of mainly commercial Proteaceae were sampled for arthropods seasonally for a period of twelve months by collection of plant material and direct searching. Seven commercial protea blocks, and a wild protea block (remnant patch of fynbos vegetation), were used as the sampling sites, and two sprayed blocks were used for assessing pesticide efficacy. Individual arthropods were identified as far as possible, with 37% identified to species level. A species accumulation curve showed that rare (minor) arthropod species made up of 70% of arthropods occurring in cultivated proteas. More than 8 700 individuals from more than 140 species and about 80 families were collected and identified, revealing that cultivated proteas have a rich and diverse insect fauna. These arthropods represent the full range of plant-feeding guilds: leaf miners, leaf chewers, flower bud borers, sap suckers and seed feeders. Flower visitors/free living guild was the most abundant (72%) and speciose (25%). In addition to phytophages, there was a large suite of insect predators and parasitoids. A large number of the arthropods were endemic to the Cape Floristic Region (CFR) and some (7.86%) have a pest status, in that they cause significant damage to the protea plants (for example, 60% of Safari sunset cultivar (Leucadendron salignum x L. laureolum) new flush stems and leaves were affected by Epichoristodes acerbella (Tortricidae). Capys alphaeus (Lycaenidae) and Phyllocnistis sp. (Phyllocnistidae) appear to be specialist pests, as they attack mainly Protea cynaroides and Susara cultivar (Protea magnifica x P. susannae) respectively. Arthropod abundance did not differ significantly between seasons, although significant seasonal effects were observed in species richness when the protea cultivars were examined separately. Pesticide application did not affect arthropod abundance, but did decrease species richness in sprayed blocks. Pesticides appeared to negatively affect minor (rare) species disproportionately, probably due to their lack of prior exposure to pesticides and hence sensitivity. Due to this inefficacy of pesticides in cultivated proteas, an increasing emphasis on the importance of non-chemical control measures, and our improved knowledge of the predatory and parasitic species in this system, integrated pest management strategies deserve greater research attention. Monitoring and use of threshold values for arthropod pests were suggested here, as well as the use of biological, cultural, physical and chemical (optimal use) control. For instance, in cultural control, polycropping and intercropping in proteas to increase plant diversity in the monocultures to promote a higher density of predators and parasitoids can be used. Certain flowering plants are known to provide greater temporal and spatial distribution of nectar and pollen sources, which can increase parasitoid reproductive potential and abundance of alternative hosts/prey when the pest species are scarce or at an inappropriate stage.AFRIKAANSE OPSOMMING: Die kommersiële verbouing van Proteaceae (proteas) is 'n belangrike bedryf in die Wes-Kaap. Menige plantasie wemel egter van artropodes, wat boere noop om slegs van chemiese plaagdoders gebruik te maak. Vorige studies in Suid-Afrika toon dat proteas die gasheerplant vir 'n ryke en diverse artropodefauna is. Aangesien die meeste van hierdie studies egter op wilde proteas uitgevoer is, weerspieël dit moontlik nie die stand van sake met verboude proteas nie. Weens 'n gebrek aan kundigheid om die artropodes te eien word baie van die spesies boonop nooit uitgeken nie. Dié studies voorsien egter 'n nuttige grondlyn vir 'n ondersoek na die artropodes op proteas, veral vir die bestudering van die gilde wat van die protea leef (“the feeding guild”). Hierdie navorsing het ten doel om 'n intensiewe en omvattende opname te maak van die artropodefauna wat oor die tydperk van 'n jaar op kommersieel verboude proteas voorkom. Die opname is meer bepaald ontwerp om die samestelling van die artropodefauna te bestudeer (deur 'n omvattende verwysingsversameling vir plaagbestuurdoeleindes te skep), en om vas te stel of seisoene en plaagbehandelings enige beduidende uitwerking op die artropodefauna het. Oor 'n tydperk van 12 maande is seisoenale monsters van die vrug- en bloeistadia, saadkoppe en blare van hoofsaaklik kommersiële proteas gesoek en ingesamel. Sewe kommersiële proteablokke sowel as 'n blok wilde proteas het as proefpersele gedien, en twee bespuite blokke is gebruik om die doeltreffendheid van plaagdoder te beoordeel. Individuele artropodes is so noukeurig moontlik uitgeken – 37% tot op spesievlak. Volgens 'n spesieakkumulasiekurwe maak seldsame (kleiner) artropodespesies sowat 70% van die artropodes uit wat op verboude proteas voorkom. Die meer as 8 700 individue van meer as 140 spesies en sowat 80 families wat ingesamel en uitgeken is, toon die rykheid en diversiteit van die artropodefauna op verboude proteas. Hierdie artropodes verteenwoordig die volle reeks plantvreterspesies – van blaardelwers en blaarkouers tot blomknopboorders, sapsuiers en saadvreters. Blombesoeker-/vrylewende spesies was die volopste (72%) en mees divers (25%). Buiten plantvreters was daar ook 'n groot aantal roofinsekte en parasitoïede. Baie van die artropodes was inheems, en sommige (7,86%) het boonop plaagstatus, aangesien hulle beduidende skade aan die proteaplant aanrig. [By ongeveer 60% van die Safari Sunset-kultivar (Leucadendron salignum x L. laureolum) is nuwe stamme en blare byvoorbeeld deur die Epichoristodes acerbella (Tortricidae) aangetas.] Capys alphaeus (Lycaenidae) en Phyllocnistis sp. (Phyllocnistidae) blyk spesialisplae te wees wat onderskeidelik hoofsaaklik die Protea cynaroides en die Susarakultivar (Protea magnifica x P. susannae) in die visier het. Artropodegetalle het nie juis tussen seisoene gewissel nie, hoewel 'n afsonderlike ondersoek van die proteakultivars 'n beduidende seisoenale uitwerking op spesierykheid aan die lig gebring het. Eweneens het die toediening van plaagdoder nie die artropodegetalle verminder nie, maar wel spesierykheid op die bespuite blokke verswak. Plaagdoders blyk besonder negatiewe uitwerking op kleiner (seldsame) spesies te hê – waarskynlik omdat dié spesies nie voorheen aan plaagdoders blootgestel was nie, en dus gevoelig is daarvoor. Weens die oënskynlike ondoeltreffendheid van plaagdoders op verboude proteas, verg 'n toenemende klem op die belang van niechemiese beheermaatreëls, 'n behoefte aan meer kennis van die roof- en parasitiese spesies in die stelsel, en die vraag na geïntegreerde plaagbeheerstrategieë, meer navorsing. Die studie moniteer en gebruik drempelwaardes vir artropodeplae, sowel as biologiese, kulturele, fisiese én chemiese (‘optimalegebruik’-) plaagbeheer. Met kulturele beheer kan poli- en interverbouing van proteas byvoorbeeld gebruik word om plantdiversiteit in die monokulture te verbeter, ten einde só 'n hoër digtheid van roofspesies en parasitoïede in die hand te werk. Sekere blomplante bied kenmerkend 'n wyer tyd- en ruimtelike verspreiding van nektar- en stuifmeelbronne, wat parasitoïede se voortplantingsvermoë en die getalle van alternatiewe gashere/prooi kan verbeter wanneer die plaagspesies skaars is of in 'n ontoepaslike stadium verkeer.Thesis (MSc)--University of Stellenbosch, 2011.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Samways, Michael John2011-02-28T12:52:32Z2011-03-14T08:43:04Z2011-02-28T12:52:32Z2011-03-14T08:43:04Z2011-03Thesis219 p. ; ill.http://hdl.handle.net/10019.1/6805en_ZAUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/68162011-12-17T22:14:15Zhdl_10019.1_532

Mite communities within Protea infructescences in South AfricaTheron, NatalieProtea -- South Africa -- Western CapeMites -- South Africa -- Western CapeMites -- Biodiversity -- South Africa -- Western CapeInfructescencesDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyENGLISH ABSTRACT: The role of mites as primary vectors of various fungi within Protea infructescences was recently confirmed and raised questions about their general diversity and their role within this unique niche. Although mites evidently form an integral part of Fynbos ecosystems and probably play a significant role in Protea population dynamics, there is a general void in our knowledge of mite diversity within the Cape Floristic Region. These organisms do not only affect ecological processes within the CFR, but also the economic value of Protea exports. This study sets out to describe mite communities within the infructescences of a variety Protea species. In the process, the role of various environmental variables and differences in host characteristics affecting these communities are also explored. A total of 24281 mite individuals, comprising of 36 morphospecies in 23 families, were collected from 16 surveyed Protea spp. Mite community structure and composition were significantly influenced by plant taxonomy, phenology and infructescence architecture in different Protea spp. At a temporal scale, infructescence age and season were influential factors on mite community structure. Collection locality significantly influenced mite communities within the infructescences of a single Protea sp. Host architecture had no influence on mite communities within a single host species. Geographic distance had no significant influence on mite community structure within Protea infructescences. This implies that factors particular to particular host species determine mite communities. These include factors such as the mode of pollination of the host plant, level of serotiny and plant life form. Numerous newly recorded mite species collected from Protea infructescences are also described in this study. An identification key to the Tydeidoidae of South Africa is provided here for the first time. This study forms a baseline dataset for future studies on the biodiversity of mites in this extremely diverse eco-region.AFRIKAANSE OPSOMMING: Die rol van myte as primêre vektore van verskeie funguses binne Protea vrugtekoppe is onlangs bevestig, en het vrae laat ontstaan oor hulle algemene diversiteit en rol binne hierdie unieke nis. Alhoewel myte duidelik ‘n integrale deel vorm van Fynbos ekosisteme en waarskynlik ‘n belangrike rol speel in Protea populasie-dinamika, is daar ‘n algemene leemte in ons kennis van mytdiversiteit binne die Kaapse Floristiese Ryk (KFR). Hierdie organismes affekteer nie slegs ekologiese prosesse binne die KFR nie, maar ook die ekonomiese waarde van Protea-uitvoere. Hierdie studie mik as vertrekpunt om die verkillende myt-gemeenskappe binne die vrugtekoppe van verskeie Protea spesies te beskryf. In die proses is die rol van verskillende omgewingsveranderlikes en verskille in gasheer kenmerke wat hierdie gemeenskappe affekteer, ook ondersoek. ‘n Totaal van 24281 myt individue, saamgestel uit 36 morfspesies in 23 families, mytgemeenskappe is beduidende beinvloed deur die taksonomie van die plant, die fenologie en die vrugtekop-argitektuur van verskillende Protea spesies. Op ‘n temporale skaal is gevind dat vrugtekop-ouderdom en seisoen beduidende faktore is in die samestelling van mytgemeenskapstruktuur. Versamel-lokaliteit het verder mytgemeenskappe binne die vrugtekoppe mytgemeenskappe binne ‘n enkele gasheerspesie getoon nie. Geografiese afstand het geen beduidende invloed op mytgemeenskapstruktuur binne Protea vrugtekoppe getoon nie. Dit faktore in soos die metode van bestuiwing van die gasheer plant, die vlak van saadhoudendheid van die Protea koppe en plant-lewensvorm. Verskeie nuwe myt spesies wat uit Protea vrugtekoppe versamel is, word ook in hierdie studie beskryf. ‘n Identifikasie-sleutel vir die Tydeidoidae van Suid-Afrika word verder vir die eerste keer hier verskaf. Hierdie studie vorm die basis datastel vir toekomstige studies van die biodiversiteit van myte in hierdie besonder diverse eko-omgewing.Thesis (MScConEcol)--University of Stellenbosch, 2011.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Roets, F.Dreyer, L. L.Esler, K. J.2011-02-25T07:14:40Z2011-03-14T08:44:08Z2011-02-25T07:14:40Z2011-03-14T08:44:08Z2011-03Thesis178 p. : ill., mapshttp://hdl.handle.net/10019.1/6816en_ZAUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/68302011-12-17T22:21:25Zhdl_10019.1_532

Significance of direct and indirect pollination ecosystem services to the apple industry in the Western Cape of South AfricaMouton, MadeleHoneybeesFynbos forageApis melliferaFruit qualityDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyInsect polination -- South Africa -- Western CapeGranny Smith apples -- Pollination -- South Africa -- Western CapeENGLISH ABSTRACT: Insect pollinators play an important role in producing crops in global agriculture. Pollinatordependent crops contribute to maintaining a healthy variety in the human diet and often have a high market value, beneficial for local or regional economies. Insect crop pollinators can either be from natural areas adjacent to orchards, or they can be brought into orchards by beekeepers that manage them. Pollination by wild pollinators is an ecosystem service, while managed pollinators (mostly honeybees) is a humanly managed service, considered not to be related to the ecosystem. Ecosystem services and their economic value have often been used as an incentive for conservation, although it is sometimes difficult to characterise and quantify them. Wild and managed pollinators have been reported to be threatened in several regions around the world, and there is concern about the effect a pollination deficit may have on crop production. Different crops and cultivars have different levels of dependence on insect pollination due to a combination of biological, physical and management factors. In this study, the pollination dependence of the Granny Smith apple cultivar and the respective contributions of wild and managed pollinators are investigated in the Western Cape province of South Africa. Granny Smith apples show a significant increase in production with insect pollination (wild and managed). Managed honeybees are more abundant in orchards than wild honeybees, and also provide a better pollination service. This difference between the pollination service of wild and managed honeybees are specifically noted in the quality, where managed honeybees pollination result in significantly more seeds per fruit and consequently produce a better shaped apple. The study goes further by quantifying the ecosystem services to the managed honeybee industry through a questionnaire completed by beekeepers. It was found that 49% of the managed hives in the Western Cape rely to some extent on natural vegetation as a forage source. Furthermore 18% of honey produced is also from natural vegetation and the wild honeybee population replenish managed honeybee stocks if they become depleted. Although managed honeybees are not usually considered an ecosystem service, it is clear that they are still linked to the ecosystem via these pathways. It is thus obvious that all pollination sources are linked to the environment, not just wild pollinators. A further economic valuation of the ecosystem service studied, and to the argument for conservation of pollinators and the resources they depend on.AFRIKAANSE OPSOMMING: Insek bestuiwing speel ‘n belangrike rol in die produksie van gewasse in landbou wêreldwyd. Gewasse wat bestuiwing-afhanklik is, dra by tot ‘n gesonde verskeidenheid in die mens se dieët en hul hoë mark waarde is voordelig vir plaaslike en streeks ekonomieë. Insek bestuiwers kan of van natuurlike areas langs boorde afkomstig wees, of bestuurde bestuiwers kan deur byeboere in boorde ingebring word. Bestuiwing deur wilde bestuiwers is ‘n ekosisteem diens, maar die byeboere verskaf ‘n bestuurde diens, wat nie altyd gereken word om aan die ekosisteem verwant te wees nie. Ekosisteem dienste en hul ekonomiese waarde word gereeld gebruik as insentief vir bewaring, alhoewel dit soms moeilik is om dit te karaktariseer en te kwantifiseer. In sekere streke wêreldwyd is dit bewys dat wilde, asook bestuurde bestuiwers, bedreig is en daar heers bekommernis dat ‘n tekort aan bestuiwers gewas produksie negatief sal beïnvloed. Verskillende gewasse en kultivars het verskillende vlakke van bestuiwing-afhanklikheid as gevolg van verskillende biologiese en fisiese faktore en bestuurspraktyke. In hierdie studie is die bestuiwings-afhanklikheid van die Granny Smith appel kultivar ondersoek, asook die bydrae van wilde en bestuurde heuningbye in die Wes-Kaap provinsie van Suid Afrika. Granny Smith appels toon ‘n betekenisvolle produksie verbetering met insek bestuiwing (wilde en bestuurde bye). Daar is ‘n groter hoeveelheid bestuurde bye in ‘n boord as wilde bye, en hulle verskaf ook dus ‘n beter bestuiwingsdiens. Die voordeel van bestuurde bye bo wilde bye word veral in vrug kwaliteit opgemerk. As bestuurde bye gebruik word, is daar betekenisvol meer sade per vrug en gevolglik het die appels ook ‘n beter vorm. Verder fokus die studie ook op die kwantifisering van ekosisteem dienste wat aan die bestuurde heuningby industrie verskaf word, deur inligting van byeboere te gebruik. Daar is bevind dat 49% van die kolonies bestuurde bye in die Wes- Kaap is tot ‘n mate afhanklik van natuurlike plantegroei vir voedsel. Verder is 18% van die geproduseerde heuning ook afkomstig van natuurlike plantegroei se nektar en byeboere vang wilde kolonies om uitgestorwe bestuurde kolonies te vervang. Dit is dus duidelik dat alle bestuiwings bronne gekoppel is aan die omgewing, nie slegs wilde bestuiwers nie. ‘n Verdere ekonomiese waardasie van die onderskeie ekosisteem dienste wat bestudeer is, voeg motivering by tot die bewaring van bestuiwers en die hulpbronne waarvan hulle afhanklik is.Thesis (MScConEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2011.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Samways, Michael J.Veltman, RuanDe Lange, Willem2011-03-01T20:58:27Z2011-03-14T08:45:29Z2011-03-01T20:58:27Z2011-03-14T08:45:29Z2011-03Thesis92 p. : ill.http://hdl.handle.net/10019.1/6830en_ZAUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/68502011-04-06T05:24:07Zhdl_10019.1_532

Ectoparasite assemblage of the four-striped mouse, Rhabdomys pumilio : the effect of anthropogenic habitat transformation and temporal variationVan der Mescht, LutherEctoparasitesVegetation fragmentation -- South Africa -- Western CapeFour-striped mouseTemporal variationDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyENGLISH ABSTRACT: Anthropogenic habitat transformation and subsequent fragmentation of natural vegetation is regarded as one of the largest threats to biodiversity in the world. The Cape Floristic Region (CFR) in the Western Cape Province of South Africa is classified as a biodiversity hotspot due to its high plant species diversity and endemism. Increasing growth in agricultural activities in this region has contributed to fragmentation of pristine natural vegetation. A diverse assemblage of small mammal species are found in this region, but very little is known with regard to their ectoparasite diversity. More importantly, no information is available on the effect of fragmentation on parasite burdens or species assemblages. The aims of the study were first to record relative density, average body size and body condition of an endemic rodent, Rhabdomys pumilio, trapped in two habitat types (pristine natural areas and remnant fragments). Secondly, compare diversity and species composition of ectoparasite species on this rodent in the two habitat types. In addition, body size measurements of the two most abundant flea species were recorded and compared for the two habitat types. Lastly, temporal variation in mean abundance of fleas, mites, ticks and the louse were recorded within a habitat fragment surrounded by vineyards. Three hundred and ten individuals of the Four-striped mouse, R. pumilio, were trapped and euthanized at 8 localities (4 remnant habitat fragments and 4 pristine natural areas) in the CFR. All ectoparasites were removed and identified. A total of 8361 ectoparasites that consisted of 6 flea, 1 louse, 8 mites and 11 tick species were recorded. Mites and fleas were found to be more abundant on mice during cool wet months, whereas ticks and the louse were more abundant during the hot dry months of the year. Rodent host body size was larger and they were in better body condition in remnant fragments compared to pristine natural localities. A positive body size relationship was found between the flea, Listropsylla agrippinae, and the host, with larger fleas recorded on rodents that occur in fragments. Mean abundance and prevalence of overall ectoparasites combined and separately for ticks, mites, louse and fleas were higher in fragments compared to natural localities. The study shows that R. pumilio is host to a large diversity of ectoparasite species in the CFR. Moreover, habitat fragments within agricultural landscapes can facilitate higher parasite burdens and prevalence in rodent populations. This can lead to an increase in disease risk given that several of the parasite species are important vectors of pathogens that can cause disease in domestic, wild animals and humans.AFRIKAANSE OPSOMMING: Menslike habitat transformasie en die daaropvolgende fragmentasie van natuurlike plantegroei word beskou as een van die grootste bedreigings vir biodiversiteit in die wêreld. Die Kaap Floristiese Streek (KFS) in die Wes-Kaap Provinsie van Suid-Afrika word geklassifiseer as 'n biodiversiteit ‘hotspot’ as gevolg van sy hoë plant spesies diversiteit en endemisme. Toenemende groei in landbou-aktiwiteite in hierdie streek het ook bygedra tot die fragmentasie van ongerepte natuurlike plantegroei. 'n Diverse versameling van die klein soogdier spesies word in hierdie streek aangetref, maar baie min is bekend met betrekking tot hul ektoparasiet diversiteit. Meer belangrik, geen inligting is beskikbaar oor die effek van fragmentasie op parasietladings of spesie samestelling nie. Die doel van die studie was eerstens om relatiewe digtheid, gemiddelde liggaams grootte en kondisie van Rhabdomys pumilio aan te teken vir twee habitat tipes (ongerepte natuurlike area en oorblyfsel fragment). Tweedens was die diversiteit en spesiesamestelling van ektoparasiete op R. pumilio vergelyk vir die twee habitat tipes. Daarna was die liggaams grootte metings van die twee mees volopste vlooi spesies aangeteken en vergelyk vir die twee habitat tipes. Laastens was die seisonale variasie van die gemiddelde hoeveelheid vlooie, myte, bosluise en die luis aangeteken binne 'n habitat fragment omring deur wingerde. Drie honderd en tien individue van die vier-gestreepte muis, R. pumilio, was gevang op 8 plekke (4 oorblyfsel habitat fragmente en 4 ongerepte natuurlike areas) in die KFS en daarna was die diere uitgesit. Alle ektoparasiete was verwyder en geïdentifiseer. 'n Totaal van 8361 ektoparasiete wat bestaan het uit 6 vlooie, 1 luis, 8 myte en 11 bosluis spesies was aangeteken. Myte en vlooie gevind was meer volop op muise tydens die koel nat maande, terwyl bosluise en die luis meer volop was gedurende die warm droë maande van die jaar. Knaagdier gasheer liggaam was groter en in 'n beter kondisie in die habitat fragmente in vergelyking met ongerepte natuurlike areas. 'n Positiewe liggaam grootte verwantskap was tussen die vlooi, Listropsylla agrippinae, en die gasheer gevind, met groter vlooie aangeteken op knaagdiere wat voorkom in fragmente. Gemiddelde hoeveelheid en voorkoms van die totale ektoparasiete gekombineer en afsonderlik vir bosluise, myte, die luis en vlooie was hoër in fragmente in vergelyking met natuurlike areas. Die studie toon dat R. pumilio gasheer is vir 'n groot verskeidenheid van ektoparasiet spesies in die KFS. Daarbenewens kan habitat fragmente binne landbou landskappe hoër parasietladings en voorkoms in knaagdier bevolkings fasiliteer. Dit kan lei tot 'n toename in siekte risiko, gegee dat verskeie van die parasietspesies belangrike vektore is van patogene wat siektes kan veroorsaak in huishoudelike, wilde diere en die mens.Thesis (MScConsEcol)--University of Stellenbosch, 2011.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Matthee, Sonja2011-02-02T09:16:14Z2011-03-14T08:47:33Z2011-02-02T09:16:14Z2011-03-14T08:47:33Z2011-03Thesis158 p. : ill., mapshttp://hdl.handle.net/10019.1/6850en_ZAUniversity of Stellenbosch, 2011.

oai:scholar.sun.ac.za:10019.1/68552011-12-17T22:14:10Zhdl_10019.1_532

Determining the hydrological benefits of clearing invasive alien vegetation on the Agulhas Plain, South AfricaNowell, Megan SarahInvasive alien vegetation -- Siouth Africa -- Agulhas PlainClearing invasive vegetation - South Africa -- Agulhas PlainWater management -- South Africa -- Agulhas PlainDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyENGLISH ABSTRACT: Invasive alien plants (IAPs) reduce streamflow and threaten the biodiversity of South Africa’s Cape Floristic Region. Up-to-date information on invasive vegetation is required for land management agencies to formulate policies and make appropriate resource management decisions. Invasion maps are typically not updated often enough because of the time and expenses required to do so. As a result, invasion maps for South Africa are limited to coarse resolution data or isolated small scale studies. Invasive alien plants change the landscape by destabilizing catchments and thereby increasing soil erosion, altering fire regimes and hydrology, as well as changing the physical and chemical composition of the soil. Information on IAPs is needed at a landscape scale. Remote sensing is a powerful tool that can be used to characterise landscapes in a biologically meaningful manner. The Normalised Difference Vegetation Index (NDVI) was used to create an up-to-date invasion map of the Agulhas Plain, lying at the heart of the species rich Cape Floristic Region. This information was combined with actual evapotranspiration data from the Surface Energy Balance Algorithm for Land (SEBAL) study done by Water Watch and the Council for Scientific and Industrial Research. The results showed that invasive vegetation uses more water than natural fynbos vegetation and that the greatest amount of water would be made available by clearing the invaded deep sands on the Agulhas Plain. These deep sand areas conflict with the priority areas of the Working for Water programme. This IAP eradication programme targets sparsely invaded upland areas for long-term sustainability. The recommendation of this study is to clear invaded wetland and riparian areas as these zones yield the greatest hydrological benefit per hectare and meet the priorities of Working for Water. Overall, 36 million cubic meters of water would be made available by clearing the Agulhas Plain. It can be concluded that there is a significant hydrological benefit to clearing invasive alien vegetation on the Agulhas Plain.AFRIKAANSE OPSOMMING: Indringerplante (IP) verminder stroomvloei en bedreig die biodiversiteit van Suid-Afrika se Kaapse Floristiese Streek. Die nuutste inligting oor uitheemse plantegroei is nodig vir grondbestuuragentskappe om beleide te formuleer vir die neem van toepaslike hulpbronbestuur besluite. As gevolg van die tyd en uitgawes wat nodig is om indringingskaarte op te dateer, word dit gewoonlik nie dikwels genoeg gedoen nie. Dus is indringingskaarte vir Suid-Afrika beperk tot growwe resolusie data of geïsoleerde kleinskaal studies. Indringerplante verander die landskap deur opvangsgebiede te destabiliseer en sodoende te lei tot gronderosie, verandering van vuurregimes en hidrologie, sowel as die verandering in die fisiese en chemiese samestelling van die grond. Inligting oor IP is nodig op 'n landskapskaal. Afstandswaarneming is 'n kragtige tegniek wat gebruik kan word om landskappe op 'n biologies betekenisvolle manier te karakteriseer. Die Normalised Difference plantegroei-indeks (NDVI) is gebruik om 'n opgedateerde indringingskaart van die Agulhas-vlakte, wat in die hart van die spesiesryke Kaapse Floristiese Streek lê, te skep. Hierdie inligting is gekombineer met die werklike evapotranspirasie data vanaf die Surface Energy Balance Algorithm for Land (SEBAL) studie gedoen deur Water Watch en die Raad vir Wetenskaplike en Nywerheidnavorsing. Die resultate het getoon dat uitheemse plantegroei meer water gebruik as natuurlike fynbosplantegroei en dat die grootste hoeveelheid van hierdie water beskikbaar gestel sal word deur IP op diepsand op die Agulhas-vlakte skoonte maak. Hierdie diepsand areas is in konflik met die prioriteitsgebiede van die Werk vir Water-program. Hierdie IP uitroeiingsprogram fokus op yl ingedringde berggebiede vir langtermyn volhoubaarheid. Die aanbeveling van hierdie studie is om duidelik ingedringde vleilande en oewergebiede skoon te maak, siende dat hierdie sones die hoogste opbrengs en die grootste hidrologiese voordeel per hektaar bied, en voldoen aan die prioriteite van Werk vir Water. In totaal sou 36 miljoen kubieke meter water beskikbaar gestel word deur die skoonmaak van die Agulhas-vlakte. Dus kan dit afgelei word dat die verwydering van hidrologiese indringerplante op die Agulhas-vlakte 'n beduidende voordeel sal inhou.Thesis (MScConEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2011.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Esler, Karen J.Le Maitre, David C.2011-03-02T13:27:08Z2011-03-14T08:48:03Z2011-03-02T13:27:08Z2011-03-14T08:48:03Z2011-03Thesis93 p. : ill., mapshttp://hdl.handle.net/10019.1/6855en_ZAUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/163902011-11-20T08:11:00Zhdl_10019.1_532

Renosterveld restoration : the role of competition, herbivory and other disturbancesMidoko-Iponga, DonaldRevegetation -- South Africa -- Western CapeVegetation dynamics -- South Africa -- Western CapeVegetation management -- South Africa -- Western CapePlant competition -- South Africa -- Western CapePlants -- Effect of grazing on -- South Africa -- Western CapeRemnant vegetation conservation -- South Africa -- Western CapeRemnant vegetation management -- South Africa -- Western CapeTheses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyENGLISH ABSTRACT: West Coast Renosterveld is one of the most threatened vegetation types in South Africa. Less than 5% of the original extent of this vegetation type remains, of which 80% is on private land. In addition to fragmentation, much of the vegetation has been ploughed for crop production and then abandoned and invaded by alien plants. Restoration of transformed areas may improve the conservation status of this vegetation type. Indigenous species do not return to abandoned agricultural fields for decades even if these are adjacent to natural areas since their return is limited either by seed dispersal or seedling establishment. The aim of this study was to examine the recovery of indigenous vegetation on abandoned fields. Renosterveld, as we know it today, is an asteraceous shrubland, dominated mainly by renosterbos (Eytropappus rhinocerotis), but might have been a grassland or a grassland-shrubland mosaic. Historical records indicate that species of large game were common in the Western Cape when the early settlers arrived, but most of these have since disappeared. It is thus impossible to reconstruct exactly the ecological processes and functioning of Renosterveld. The first part of the study was designed to examine the effects of grass competition, grazing by indigenous large herbivores, and interaction of these two factors on the establishment, growth and survival of transplanted Renosterveld seedlings on an abandoned agricultural field. Experimental transplanting of indigenous shrubs into an old field showed that most of the plants investigated competed for resources with lawn grasses on the field, and competition affected the seedlings throughout the experiment. Mortality was higher, and growth was reduced for seedlings exposed to grass competition. With the exception of wild olive (Olea europaea spp.africana), herbivory alone had no significant impact on the target species. Herbivory was at a low intensity (20 ha/large animal unit); higher grazing pressures might have given different results. No interaction between competition and herbivory was found for the species investigated; competition and grazing therefore seem to influence the seedlings independently. The second part of this study was conducted to examine the effects of different management strategies, viz: brush cutting, burning and herbicide application on plant species recruitment and community composition and to ascertain their applicability by farmers for large scale restoration of Renosterveld. My comparison of the different strategies for controlling annual alien grasses indicated that these did not differ significantly in their effects on species richness. Burning reduced shrub cover and increased overall species richness and diversity. Burning also reduced grass biomass, and increased recruitment of indigenous seedlings. The use of herbicide resolved the problem of grass biomass invasion and increased shrub species richness. The herbicide application did not appear to have long-term negative effects on the soil quality. Brush cutting did not remove grass biomass on the old field. Experimental re-seeding with an indigenous grass and shrub species into treated plots resulted in low recruitment. My conclusion is that grass can reduce recruitment and growth of many indigenous shrub species. My recommendation for the restoration of old fields in West Coast Renosterveld is to apply herbicide to remove grass competition, and then, after the herbicide has degraded, to oversow the field with seeds of indigenous shrub and grass species of early successional stages to increase overall species diversity.AFRIKAANSE OPSOMMING: Weskus Renosterveld is een van die mees bedreigde plantegroei soorte in Suid Afrika. Minder as 5% van die oorspronklike omvang van hierdie plantegroei tipe is oor, en dit hoofsaaklik (80%) op privaatlande. Saam met fragmentasie, is baie Renosterveld areas ook omgeploeg vir boerdery en dan net so gelos, met die gevolg dat uitheemse plante hierdie areas ingedring het. Restorasie of herstelling van sulke bewerkte lande kan dalk die bewaringsstatus van hierdie plantegroei tipe verbeter. Natuurlike vestiging van Renosterveld spesies op sulke ou bewerkte lande gebeur nie, selfs al is daar Renosterveld direk langs so ‘n ou veld. Die hervestiging van inheemse spesies is dus tot saadverspreiding or saailingbevestiging beperk. Die doel van hierdie studie is om die stadige terugkoms van inheemse plantegroei na verlate bewerkte velde te verduidelik. Renosterveld is ‘n struikveld waarin die renosterbos (Eytropappus rhinocerotis) domineer, maar kan ook ‘n grasveld of ‘n grasveld-struikland mengsel wees. Groot herbivore was algemeen in die Wes Kaap toe die eerste settelaars gearriveer het, maar intussen het omtrent al die groot wild spesies verdwyn. Dit is dus ontmoontlik om die ekologiese prosesse en funksionering van Renosterveld presies so te herstel. Die eerste deel van hierdie studie bestudeer die effek van graskompetisie, weiding deur inheemse groot herbivore, en die interaksie tussen hierdie twee faktore op die vestiging, groei en oorlewing van oorgeplante Renosterveld saailinge in ‘n verlate ou veld. Die eksperimentele oorplanting van inheemse struike in ‘n ou land het gewys dat die meeste van hierdie plante kompeteer vir hulpbronne met kweekgras wat op die ou veld groei. Kompetisie het die saailinge deur die hele eksperiment geaffekteer. ‘n Hoër mortaliteit en verminderede groei in saailinge wat aan gras kompetisie blootgestel was, is waargeneem. Met die uitsondering van Olea europaea spp. africana, het herbivorie alleen geen betekenisvolle impak op plant spesies gehad nie. Weidingsdruk was laag (20 ha/groot vee eenheid); ‘n groter weidingsdruk sou miskien ‘n ander uitkoms gehad het. Geen interaksie tussen kompetisie en herbivorie is waargeneem in die bestudeerde plantspesies nie. Dit wil dus voorkom of kompetisie en weiding die saailinge onafhanklik van mekaar beïnvloed. Die tweede deel van hierdie studie was onderneem om die effek van verskillende behandelings (kontrole, sny, brand en herbisied toediening) op plantspesie vestiging en samestelling te bestudeer asook om bestuurmetodes te toets was deur boere op groot skaal gebruik kan word om Renosterveld te herstel. In ‘n vergelyking van verskillende bestuur metodes (kontrole, besnoeiing, brand en herbisied) om eenjarige uitheemse gras te beheer, is gewys dat die behandlings nie betekenisvol van mekaar verskil in hulle effek op spesierykheid nie. Vuur het struikbedekking verminder en totale spesies rykheid en diversitiet verhoog. Die gebruik van ‘n herbisied het die probleem van grasindringing opgelos en het ook struikspesiesrykheid verhoog. Die herbisied het nie lang termyn negatiewe effekte op grond kwaliteit gehad nie. Sny het nie gras biomassa verlaag op die ou land nie. Eksperimentele plant van inheemse grasse en struike in die behandelde areas, het lae vestiging tot gevolg gehad. My algemene afleiding is dus dat gras die hervestinging en groei van baie inheemse struikspesies verminder. Ek stel voor dat herbisied gebruik moet word om gras kompetisie te verminder. Nadat herbisied residue in die grond afgebreek is, moet die ou land met inheemse struik en grasspesies, wat in vroeë suksessie stadiums is, beplant word om sodoende totale spesiediversiteit te verhoog en uiteindelik ou bewerkte lande in Weskus Renosterveld te herstel.Thesis (MSc)--University of Stellenbosch, 2004.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Milton, Suzanne.J.Krug, Cornelia B.2011-09-14T07:48:03Z2011-09-14T07:48:03Z2004-12Thesisxi, 126 leaves : ill., mapshttp://hdl.handle.net/10019.1/16390en_ZAUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/164492012-01-27T12:02:48Zhdl_10019.1_532hdl_10019.1_546

Habitat partitioning, and an assessment of habitat suitability using presence data, of a large herbivore communitiy on a Zimbabwean private wildlife reserveTraill, Lochran (Lochran William)Herbivores -- Habitat -- Zimbabwe, SoutheasternHabitat selectionHabitat partitioning (Ecology) -- Zimbabwe, SoutheasternResource partitioning (Ecology) -- Zimbabwe, SoutheasternTheses -- Forest and wood scienceTheses -- Conservation ecology and entomologyDissertations -- Forest and wood scienceDissertations -- Conservation ecology and entomologyENGLISH ABSTRACT: The factors determining habitat selection of large herbivores, on a private wildlife reserve in semi-arid southeastern Zimbabwe, were investigated. Gross vegetative structure, herbaceous composition and topographic features thought to determine herbivore distribution were measured. Seasonal variation in resource distribution was considered, and research therefore extended over an entire year. Herbivore distribution and ecological niche separation was explained through several important environmental variables, and potential for inter-specific competition inferred. Additionally, predictive habitat suitability models were designed for each of the grazing species in the critical dry season. Herbivores showed a large degree of niche overlap in both the hotwet season and the cool-dry season, when food resources were more plentiful. Niche separation between grazers was pronounced in the hot-dry season. Herbivore distribution was associated most closely with distance to water, grass sward height, time since burn, woody plant density and by the presence of predominant grasses, these being Urochloa mossambicensis, Panicum maximum, Heteropogon contortus and Digitaria eriantha. Ecological separation of herbivores by the grasses P. maximum, H. contortus and D. eriantha was more indicative of associated environmental variables than feeding niche separation. A GIS-based analysis, using species presence data and quantitative coverages of environmental variables, produced maps of gradations of habitat suitability for grazing species during the dry season. Results of both analyses were integrated and gave a better understanding of ecological separation, and possible competitive interactions, among the large herbivore community on Malilangwe Estate. Recommendations were made based on the interpretation of findings, within the context of available management options.AFRIKAANSE OPSOMMING: Die bepalende faktore van habitat seleksie by groot herbivore op ‘n privaat wildreservaat in semi-dorre suidoos Zimbabwe is ondersoek. Globale plantegroei stuktuur, kruidagtige samestelling en topografiese eienskappe wat glo herbivoor verspreiding bepaal, is gemeet. Seisoenale variasie in hulpbronverspreiding is in ag geneem en dus het navorsing oor ‘n hele jaar gestrek. Herbivoor verspreiding en ekologiese nisskeiding is verduidelik deur verskeie belangrike omgewingsveranderlikes en die potensiaal vir interspesifieke kompetisie is afgelei. Boonop is voorspellende habitat-geskiktheidsmodelle ontwerp vir elk van die weidingspesies in die krities droë seisoen. Herbivore toon ‘n hoë graad van nis oorvleueling in sowel die warm, nat seisoen as die koel, droë seisoen wanneer voedingsbronne meer volop is. Nis verdeling tussen weidiere was duidelik herkenbaar in die warm, droë seisoen. Herbivoor verspreiding is meestal geassosieer met die afstand na die water, die grasveld hoogte, tydperk sedert ‘n brand, digtheid van houtagtige plantsoorte en met die teenwoordigheid van die oorheersende grasse, Urochloa mossambicensis, Panicum maximum, Heteropogon contortus en Digitaria eriantha. Die ekologiese skeiding van herbivore deur die grasse P. maximum, H. contortus en D. eriantha het meer gedui op geassosieerde omgewingsveranderlikes as op skeiding van voedingsnisse. ‘n GIS-gebaseerde analise wat spesie-teenwoordigheidsdata en kwantitatiewe dekking van omgewingsveranderlikes gebruik, het klassifikasiekaarte geproduseer van habitatgeskiktheid vir weidiere tydens die droë seisoen. Resultate van beide analises is geïntegreer en het ‘n beter begrip van ekologiese skeiding en moontlike kompeterende interaksies tussen die groot herbivore gemeenskap op Malilangwe Estate tot gevolg gehad. Aanbevelings is gemaak, gebaseer op die interpretasie van bevindinge, binne die konteks van beskikbare bestuursopsies.Thesis (MFor)--University of Stellenbosch, 2003.Stellenbosch : University of StellenboschUniversity of Stellenbosch. Faculty of Agrisciences. Dept. of Forest and Wood Science.Bigalke, R.C.2011-09-26T14:26:15Z2011-09-26T14:26:15Z2003-12Thesisxiii, 203 leaves : ill.http://hdl.handle.net/10019.1/16449en_ZAUniversity of Stellenbosch

oai:scholar.sun.ac.za:10019.1/177432013-01-21T08:23:03Zhdl_10019.1_532

The interaction between a keystone plant species and its dominant epiphyte on Marion Island : climate change implicationsBuwa, Ziphokazi SiyasangaKeystone species -- Prince Edward Islands -- Marion IslandEpiphytes -- Prince Edward Islands -- Marion IslandUmbelliferae -- Prince Edward Islands -- Marion IslandClimatic changes -- Environmental aspects -- Prince Edward Islands -- Marion IslandPlants -- Effect of global warming on -- Prince Edward Islands -- Marion IslandTheses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyENGLISH ABSTRACT: Climate has shown some remarkable changes over the past century, especially at the polar and sub-polar regions. Southern Ocean Islands provide good models for studies related to climate change effects, since effects may be evident in the short term and may also be clearer. Marion Island is an example of such a system with a harsh abiotic environment, and low species richness often vulnerable to change. Climate change is predicted, and also reported, to have biological consequences on plant communities, affecting the phenology, morphology, and the interaction between individuals and species. This study examines the association between the keystone plant species, Azorella selago Hook. (Apiaceace), and its dominant epiphyte Agrostis magellanica Lam. (Poaceae). Two complimentary approaches were used, one observational and the other experimental. The main objective for the observational study was to quantify bioticallyrelevant microclimate temperature, as well as the morphology, epiphyte load and phenology of A. selago at three different altitude sites on Marion Island. This provided information on baseline variation for understanding specific variability in plant response to the experimental part of this study, against which future patterns arising from biological monitoring can be compared. Studying plants at different altitudes provides a possible analogue for temperature-related climate change consequences for the ecology of A. selago, and its interaction with A. magellanica. The microclimate temperature associated with A. selago differed between the three sites examined. This difference was related to local topographic conditions and altitude differences. Cushion size differed distinctively between the three altitude sites, with this difference related to environmental heterogeneity such as differences in age and substrate structure. Azorella selago annual growth rate was estimated through stem length and the number of leaves on both exposed and shaded stems. Within-site variability, as well as epiphyte cover were found to be the contributing factors on A. selago annual growth rate. This highlights the importance of site-specificity when estimating growth rate within and between different altitude sites. Leaf characteristics differed between the sites, with this attributed to local habitat conditions, such as topography, as well as epiphyte cover. As expected, the difference in leaf size between exposed and shaded leaves demonstrated a larger specific leaf area on leaves shaded by A. magellanica. Agrostis magellanica abundance and density were altitudinally related, with A. selago demonstrating facilitation effects on A. magellanica. The trend shown in this study suggests that in spite of general facilitative effect of A. selago on A. magellanica towards higher altitudes, the abiotic environmental threshold for A. magellanica occurs at lower altitudes than it does for A. selago. Phenological differences were also apparent between the three sites. The objectives of the experimental part of this study were to quantify the effect of the dominant epiphyte, A. magellanica on biotically-relevant microclimatic temperatures, as well as on the phenology and physical condition of A. selago. Different treatments were applied to cushions at the three altitude sites to examine the shading effect of epiphytic A. magellanica on cushion plants, as well as the effect of treatment-related disturbance. Azorella selago microclimate temperature showed no significant difference between treatments, suggesting that on average epiphytic A. magellanica cover has no effect on cushion microclimate temperature. The percentage of flower budding and flowering of A. selago was negatively related to epiphyte cover. Cushion vitality was also responsive to epiphyte cover, with higher vitality scores on low grass covered cushions than on high grass cushions. This shows that A. magellanica competes with A. selago, while A. selago facilitates A. magellanica. Heavy epiphyte numbers impose negative effects on A. selago vegetative and reproductive performance, as well as cushion vitality. Therefore, the results of this research show that the vegetative and reproductive performance of A. selago and cushion vitality are likely to be negatively affected under ongoing climate change on Marion Island if this brings about heavier epiphyte loads on this keystone cushion plant species.AFRIKAANSE OPSOMMING: In die afgelope eeu het die klimaat in die Antarktiese en sub-Antarktiese gebiede merkwaardige verandering getoon. Die Suidelike See Eilande dien as goeie modelle vir studies verwant aan die gevolge van klimaatsverandering, aangesien die kort termyn effekte in die gebiede duideliker mag wees in die toekoms. Marion Eiland is ‘n voorbeeld van so ‘n sisteem, met ‘n ruwe abiotiese omgewing en lae spesies rykheid, wat vatbaar is vir verandering. Daar word voorspel, en is reeds bevind dat klimaatsverandering biologiese gevolge op plant gemeenskappe het, in terme van morfologie, fenologie en die interaksie tussen individue en spesies. Hierdie studie ondersoek die assosiasie tussen die hoeksteen plant spesie, Azorella selago (Apiaceace), en sy dominante epifietiese gras, Agrostis magellanica Lam. (Poaceae). Die studie is op twee komplimentêre maniere benader, naamlik deur waarneming en eksperiment. Die hoof doel van die studie was om die biotiese belang van mikroklimaat temperatuur te kwantifiseer, en die hoeveelheid epifiete, die morfologie en die fenologie van A. selago te bepaal by drie verskillende hoogtes op Marion Eiland. Laasgenoemde het inligting verskaf oor die variasie in die reaksie van plante tot die eksperimentele aspek van die studie, waarteen patrone vanaf toekomstige biologiese beheer vergelyk kon word. Deur plante te bestudeer by verskillende hoogtes bo seespieël word ‘n moontlike analoog vir die gevolge van temperatuur-verwante klimaatverandering in terme van die ekologie van A. selago, en laasgenoemde se interaksie met A. magellanica verskaf. Die mikroklimaat temperatuur geassosieer met A. selago verskil tussen dié drie liggings. Die versil was verwant aan die plaaslike topografiese toestande en die verskillende hoogtes bo seespieël. Die grootte van die kussingplante het duidelik versil tussen die drie liggings, met die verskille verwant aan die omgewing se heterogeneïteit, byvoorbeeld die verskille in ouderdom en substraat struktuur. Azorella selago se jaarlikse groeitempo was bepaal deur die stingel lengte en die aantal blare, op beide die wat oorskadu is deur die gras, en die was nie oorskadu is nie. Daar is gevind dat die faktore wat bygedra het tot die jaarlikse groeitempo van A. selago, varieër binne die verskillende liggings, en bedekking deur epifiete. Dit beklemtoon die belang van spesifisiteit van ligging wanneer groeitempo in en tussen die liggings van verskillende hoogtes bepaal word. Die blaar eienskappe het verskil tussen verskillende liggings, as gevolg van plaaslike habitat toestande, soos topografie en bedekking deur epifiete. Soos verwag, het die blare wat oorskadu was deur A. magellanica ‘n groter spesifieke blaar area getoon as blare wat blootgestel was. Die hoeveelheid en digtheid van Agrosits magellanica was verwant aan hoogte bo seespieël, met A. selago wat fasiliterende effekte toon op A. magellanica. Die tendens waargeneem in hierdie studie is dat ten spyte van die algemene fasiliterende effek van A. selago op A. magellanica, die abiotiese omgewingsdrempel op ‘n laer hoogte is vir A. magellanica as vir A. selago. Fenologiese verskille was ook duidelik tussen die drie liggings. Die doel van die eksperimentele deel van die studie was om die effek van die dominante epifiet, A. magellanica, te bepaal op bioties relevante mikroklimaat temperature, asook op die fenologie en fiesiese toestand van A. selago. Verskeie behandelings is aangewend op die kussingplante by die drie liggings om die effek van skaduwee van die epifietiese A. magellanica op die plante te bepaal, asook die effek van versteurings versoorsaak deur die behandelings. Azorella selago se mikroklimaat temperatuur het geen betekenisvolle verskille tussen behandelings getoon nie, wat voorstel dat epifitiese A. magellanica oor die algemeen geen effek op die kussingplante se mikroklimaat temperatuur het nie. Daar was ‘n negatiewe verwantskap tussen die hoeveelheid epifiete op A. selago en die persentasie blomme en blomknoppe op die kussingplante. Die plante se vitaliteit was ook afhanklik van epifiet bedekking, met ‘n hoër vitaliteit telling vir kussingplante bedek met lae gras as die bedek met hoë gras. Dit toon dat A. magellanica met A. selago wedywer, terwyl A. selago vir A. magellanica fasiliteer. Hoë epifiet getalle het negatiewe effekte op A. selago se vegetatiewe en reproproduktiewe nakoming, asook die kussingplante se vitaliteit. Die resultate van hierdie studie toon dus dat die vegetatiewe en reproduktiewe nakoming van A. selago en kussingplant vitaliteit heel moontlik negatief geaffekteer sal word indien klimaatsverandering op Marion Eiland hoër epifiet getalle op die sleutel kussingplant spesie tot gevolg sal hê.Thesis (MSc)--University of Stellenbosch, 2007.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.McGeoch, M.A.2011-11-22T07:34:58Z2011-11-22T07:34:58Z2007-12Thesisvi, 153 leaves : ill.http://hdl.handle.net/10019.1/17743en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/178862011-12-21T05:51:48Zhdl_10019.1_532

Monitoring ecological rehabilitation on a coastal mineral sands mine in Namaqualand, South AfricaPauw, Marco JohannNamakwa SandsStrip mining -- Environemntal aspects -- South Africa -- NamaqualandAbandoned mined lands reclamation -- South Africa -- NamaqualandVegetation rehabilitation -- Monitoring -- South Africa -- NamaqualandEcological rehabilitation -- Monitoring -- South Africa -- NamaqualandLandscape Function Analysis (LFA)Dissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyENGLISH ABSTRACT: The Exxaro Namakwa Sands heavy mineral sands mine at Brand-se-Baai, on the west coast of South Africa, is an important source of income, development and job-creation in the region. However, this comes at a great environmental cost, as strip mining causes large scale destruction of ecosystems through the complete removal of vegetation and topsoil. This is particularly problematic in an environment, such as Namaqualand, where the arid and windy climate, as well as saline and nutrient-poor soils, hamper rehabilitation. These environmental constraints create the need to develop a site-specific rehabilitation program. At Namakwa Sands the objective of rehabilitation is to “rehabilitate and re-vegetate disturbed areas and establish a self-sustaining Strandveld vegetation cover in order to control dust generation, control wind and water erosion, as well as restore land capability. In general, vegetation will be rehabilitated to a minimum grazing standard capable of supporting small stock (sheep) grazing.” In order to achieve this Namakwa Sands conducted rehabilitation experiments with topsoil replacement, seeding of indigenous species and translocation of mature plants. Monitoring is an important part of the rehabilitation process as it allows rehabilitation practitioners to evaluate success and to adapt their management strategies and rehabilitation methods, as well as to evaluate and, if necessary, change their rehabilitation objectives. This study forms part of the monitoring process at Namakwa Sands. It assesses the success of sites that were experimentally rehabilitated in 2001 and a site that was rehabilitated in 2008, using current practice, in order to identify possible management requirements on rehabilitated sites as well as improvements on rehabilitation objectives, methods and monitoring. This study also tests the Landscape Function Analysis (LFA) as rehabilitation monitoring tool by correlating LFA indices with traditional measurements of biophysical variables or their surrogates. Results showed that experimental sites were not successful in returning vegetation cover and plant species richness to the required levels, but did achieve the grazing capacity objective. These sites will need adaptive management to achieve the vegetation cover and plant species richness objectives. The recently rehabilitated site achieved the three-year vegetation cover and plant species richness objectives, as well as the grazing capacity objective, within two years after rehabilitation. Namakwa Sands should therefore continue using the current rehabilitation method. However, rehabilitation should be done in multiple stages in future to decrease the mortality of nursery cuttings and to facilitate the return of late successional species to rehabilitated sites. The sustainability of small stock farming on rangeland with the grazing capacity that is identified as the minimum objective is questionable and this merits further investigation. LFA can be a useful tool to monitor nutrient cycling and soil stability at Namakwa Sands, provided that enough replicates are used. However, LFA cannot be used as is to assess water infiltration at Namakwa Sands, due to assumptions in the calculation of this index that do not hold for the Namaqualand environment. Landscape functioning should be monitored annually to complement vegetation surveys.AFRIKAANSE OPSOMMING: Die Exxaro Namakwa Sands swaarminerale-sandmyn by Brand-se-Baai, aan die weskus van Suid-Afrika, is ‘n belangrike bron van inkomste, ontwikkeling en werkskepping in die streek. Daar is egter negatiewe omgewingsimpakte aan verbonde, aangesien die strookmyntegniek grootskaalse vernietiging van ekosisteme veroorsaak deur die algehele verwydering van die plantegroei en bogrond. Dit is veral problematies in ‘n omgewing, soos Namakwaland, waar die droë en winderige klimaat, asook die souterige en voedingstof-arme grond, rehabilitasie belemmer. Hierdie beperkings wat deur die omgewing veroorsaak word skep die behoefte om ‘n rehabilitasieprogram te ontwikkel wat spesifiek is tot die terrein. Die doel van rehabilitasie by Namakwa Sands is om te rehabiliteer en herplant op versteurde gebiede en om selfonderhoudende Strandveld plantbedekking te vestig om sodoende stofgenerering te beheer, om wind- en watererosie te beheer, en om grondgebruik-vermoë te herstel. In die algemeen sal plantbedekking gerehabiliteer word tot ‘n minimum weidingskapasiteit wat kleinveeweiding (skaapweiding) kan onderhou. Om dit te bereik het Namakwa Sands rehabilitasie-eksperimente uitgevoer met terugplasing van bogrond, saai van inheemse spesies en oorplanting van volwasse inheemse plante. Monitering is ‘n belangrike deel van die rehabilitasieproses, aangesien dit rehabilitasie-praktisyns in staat stel om sukses te evalueer en om bestuurstrategieë en rehabilitasiemetodes aan te pas, sowel as om rehabilitasiedoelwitte te evalueer en, indien nodig, aan te pas. Hierdie studie vorm deel van die moniteringsproses by Namakwa Sands. Dit assesseer die sukses op persele wat eksperimenteel gerehabiliteer is in 2001 en ‘n perseel wat in 2008 gerehabiliteer is, volgens die huidige praktyk, om moontlike bestuursbehoeftes op gerehabiliteerde persele en verbeteringe aan rehabilitasiedoelwitte, -metodes en –monitering te identifiseer. Hierdie studie toets ook die geskiktheid van die Landscape Function Analysis (LFA) as ‘n rehabilitasie-moniteringsinstrument deur LFA-indekse met tradisionele metings van biofisiese veranderlikes of hul surrogate te korreleer. Resultate dui daarop dat eksperimentele persele nie suksesvol was om plantbedekking en plantspesies-rykdom tot die vereiste vlakke te herstel nie, maar wel die weidingskapasiteit-doelwit bereik het. Hierdie persele benodig aanpassingsbestuur om plantbedekking- en plantspesiesrykdom-doelwitte te bereik. Die perseel wat onlangs gerehabiliteer is, het binne twee jaar na rehabilitasie die drie-jaar plantbedekking- en plantspesiesrykdom-doelwitte, sowel as die weidingskapasiteitdoelwit bereik. Daarom moet Namakwa Sands voortgaan om die huidige rehabilitasiemetode te gebruik. Rehabilitasie moet egter in die toekoms in veelvoudige stadiums gedoen word om die mortaliteit van kwekery-steggies te verminder en om die terugkeer van laatsuksessionele spesies na gerehabiliteerde persele te fasiliteer. Die volhoubaarheid van kleinveeboerdery op weiveld met die minimum vereiste weidingskapasiteit word betwyfel en vereis verdere ondersoek. LFA kan ‘n bruikbare instrument wees om siklering van voedingstowwe en grondstabiliteit te monitor by Namakwa Sands indien genoeg repliserings gebruik word. LFA kan egter nie in die huidige vorm gebruik word om waterinfiltrasie by Namakwa Sands te assesseer nie, aangesien daar aannames in die berekening van die indeks is wat nie juis is in die Namakwaland omgewing nie. Landskapfunksionering behoort jaarliks gemoniteer te word om plantopnames aan te vul.Thesis (MSc)--Stellenbosch University, 2011.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Esler, Karen J.Le Maitre, David2011-11-24T08:01:18Z2011-12-05T13:08:12Z2011-11-24T08:01:18Z2011-12-05T13:08:12Z2011-12Thesis116 p. : ill., mapshttp://hdl.handle.net/10019.1/17886en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/179792011-12-21T06:26:17Zhdl_10019.1_532

Distribution and bait preference of the Argentine ant in natural vegetationVorster, CarlienArgentine ants -- South Africa -- Western CapeBait preferenceProtected areas -- Ant invasions -- South Africa -- Western CapeDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyENGLISH ABSTRACT: Since its introduction in 1898 into South Africa, the Argentine ant, Linepithema humile [Mayr 1868 (Hymenoptera: Formicidae)], has invaded human-occupied areas (i.e. urban and agricultural areas) and natural areas characterised by few, if any, anthropogenic disturbances. However, compared to other countries in which the Argentine ant has been recorded, and until the past few decades, very little research had been done on this invasive ant in South Africa. Consequently, several issues concerning its ecological and social effects are still under-researched. The first of these issues concerns the lack of knowledge about the distribution of the Argentine ant in the natural areas, particularly the protected areas (PAs), of South Africa. In order to determine how many PAs are occupied by this invasive ant, a study was conducted in the Western Cape Province (WCP). It was found that, of the 614 PAs documented for WCP, ten have a known presence and nine known absence records of the Argentine ant. The remainder of the PAs have no known occupancy records for this ant. A second issue concerns the seasonal bait preference of the Argentine ant in a fynbos habitat. Six bait treatments (two carbohydrate and protein baits, a mixture of the carbohydrate and protein treatments, and a control) were applied in a fynbos habitat across a sampling grid in four different Latin Square designs, i.e. once for every season. Based on these experiments, it was determined that the Argentine ant prefers the mixture of carbohydrate and protein treatments, and that this preference does not change according to season. Furthermore, previous studies conducted in Jonkershoek Nature Reserve [JNR (in WCP)] determined the existence of a distribution boundary of Argentine ants in an area known as Swartboschkloof. Therefore, the third issue concerned the exact location of the distribution boundary and possible reasons for its establishment. This distribution boundary of the Argentine ant was found to be present 450 m from Swartboschkloof hiking trail. A combination of several explanatory variables may contribute to the maintenance of this boundary, i.e. a change in the horizontal and vertical vegetation distribution, as well as in the slope and aspect across the distribution boundary. With these explanatory variables, the increasing presence of an indigenous ant species, Anoplolepis custodiens, from this boundary may also have contributed to the distribution boundary. In addition, the short-term effect of a fire that swept through this area was also assessed, which revealed that Argentine ants are severely negatively affected by fire (at least over the short-term), i.e. their abundance decreased considerably after the fire and their local distribution range contracted. The final issue concerns the public perceptions of invasive alien species (IAS) in general and the Argentine ant specifically, at JNR. This study revealed that the majority of visitors to JNR were aware of the presence of IAS in South Africa and in its PAs, while very few visitors knew about the Argentine ant. This study also revealed that future research concerning South Africans perceptions of IAS might play a strong contributing role in conservation.AFRIKAANSE OPSOMMING: Sedert die Argentynse mier, Linepithema humile [Mayr 1868 (Hymenoptera: Formicidae)], in 1898 in Suid-Afrika ingevoer is, het dié mier mens-bewoonde gebiede (soos stedelike en landbou gebiede) en natuurlike gebiede, gekenmerk deur min, indien enige, antropogeniese versteuringe, binnegedring. Nietemin, in vergelyking met ander lande waar die Argentynse mier opgeteken is, en tot die onlangse paar dekades, is min navorsing oor hierdie indringermier in Suid-Afrika onderneem. Gevolglik is daar verskeie kwessies rondom die mier se ekologiese en sosiale uitwerkinge wat nog nie nagevors is nie. Die eerste kwessie het betrekking op die gebrek aan kennis oor die Argentynse mier se verspreiding in die natuurlike gebiede, veral die beskermde gebiede (BG), van Suid-Afrika. Om te bepaal hoeveel BG deur hierdie indringermier beset word, is ʼn ondersoek in die Wes-Kaapprovinsie (WKP) uitgevoer. Daar is bevind dat, van die 614 BG gedokumenteerd in die WKP, het tien bevestigde aanwesigheid- en nege bevestigde afwesigheidrekords van hierdie mier. Die oorblywende BG het geen bekende besettingsrekords van hierdie mier nie. ʼn Tweede kwessie het betrekking op die seisoenale lokaasvoorkeur van die Argentynse mier in ʼn fynbos habitat. Ses lokaas-behandelings (twee koolhidraat en proteïen lokaas, ʼn mengsel van die koolhidraat en proteïen behandelings, en ʼn kontrole) is aangewend in ʼn fynbos habitat, oor ʼn steekproefruitgebied, in vier verskillende Latyns-kwadraatpatrone (“Latin Sqaure designs”), d.i. een vir elke seisoen. Op grond van hierdie eksperimente is vasgestel dat die Argentynse mier die mengsel van koolhidrate en proteïne verkies, en dat hierdie voorkeur nie seisoenaal verander nie. Boonop, vorige ondersoeke wat in die Jonkershoek Natuurreservaat [JNR (in die WKP)] uitgevoer is, het ʼn verspreidings-grens van Argentynse miere ontdek in ʼn gebied bekend as Swartboschkloof. Gevolglik het die derde kwessie betrekking op die presiese ligging van hierdie grens en moontlike redes waarom dit gevestig het. Dié verspreidings-grens van die Argentynse mier is 450 m vanaf die Swartboschkloof voetslaanpad gevind. ʼn Kombinasie van verskeie verklarende veranderlikes kon tot hierdie grens bygedra het, d.i. ʼn verandering in die horisontale en vertikale plantegroeiverspreiding, sowel as in die helling en ligging oor die verspreidings-grens van die Argentynse mier. Tesame met hierdie verklarende veranderlikes, kon die toenemende teenwoordigheid van ʼn inheemse mier, Anoplolepis custodiens, vanaf hierdie grens ook tot die verspredings-grens bygedra het. Daarbenewens is die korttermyn-effek van ʼn vuur wat deur die area beweeg het, ook bestudeer. Die ondersoek het getoon dat die Argentynse mier (ten minste oor die korttermyn) erg negatief deur vuur beïnvloed is, d.i. hul volopheid het ná die vuur aansienlik verminder en hul plaaslike verspreidings-grens het gekrimp. Die finale kwessie het betrekking op openbare persepsie van uitheemse indringerspesies (UIS) oor die algemeen en spesifiek die Argentynse mier, by JNR. Hierdie ondersoek het aan die lig gebring dat die meerderheid van besoekers aan JNR bewus was van die teenwoordigheid van UIS in Suid-Afrika en in dié se BG, terwyl baie min egter van die Argentynse mier geweet het. Hierdie ondersoek het ook aan die lig gebring dat toekomstige navorsing rakende Suid-Afrikaners se persepsie van UIS ʼn sterk bydra tot bewaring kan maak.Thesis (MSc)--Stellenbosch University, 2011.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.McGeoch, Melodie A.Prozesky, Heidi E.2011-11-22T12:14:02Z2011-12-05T13:16:58Z2011-11-22T12:14:02Z2011-12-05T13:16:58Z2011-12Thesis196 p. : ill., mapshttp://hdl.handle.net/10019.1/17979en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/179812012-04-04T13:56:55Zhdl_10019.1_532

Assessment of the alien marine intertidal invertebrates in the Kogelberg Biosphere Reserve, South AfricaMalherbe, HanlieMarine biological invasions -- South Africa -- Western CapeMarine protected areas -- South Africa -- Western CapeMytilus galloprovincialisWatersipora subtorquataAlien intertidal invertebrates -- South Africa -- Western CapeKogelberg Biosphere ReserveBetty‟s Bay Marine Protected AreaDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyConservation Ecology and EntomologyENGLISH ABSTRACT: The privilege of utilising resources from the globe's marine ecosystems is threatened. Adequate regional and global conservation efforts are vital. Understanding species' distributions and the environmental variables influencing community structures are important for instigating optimum conservation plans. A major threat facing marine ecosystems is the introduction and proliferation of alien invasive species. The distribution and geographical expansion of marine alien invasive species, along with environmental variables driving their increase is also critical for drawing up conservation plans. In response to this point, this study addresses gaps in our knowledge regarding intertidal marine invertebrate species distributions particularly that of marine alien species in the Kogelberg Biosphere Reserve (KBR) and adjacent Betty's Bay Marine Protected Area (MPA) in the Western Cape of South Africa, a prime area for south-coast marine conservation. Species identifications were done in September 2010. Two marine alien invertebrate species were identified along the coastline. These were the invasive mytilid Mediterranean mussel Mytilus galloprovincialis and the bryozoan Watersipora subtorquata. A quantitative systematic survey of the intertidal region, consisting of seven rocky shore sites was then undertaken from October 2010 to December 2010. The abundance of all focal marine invertebrate species, within six selected habitat types was assessed. Environmental variables were also recorded. Statistical tests were done to investigate for significant interaction in mean abundance and mean species richness among intertidal zones and protection status (MPA and non-MPA), and among intertidal sampling units (SU‟s) and protection status. There was also investigated for significant difference in mean abundance and mean species richness across intertidal zones and habitat types where protection status was not taken into account, and to test for significant differences in mean abundance and mean species richness between the intertidal zones and habitat types. Correspondence analyses were used to illustrate relationships between species composition and the defined environmental variables. Tests were done to investigate for significant differences in mean abundance of the identified marine alien species between the MPA and non-MPA, study sites, SU's, and wave exposures. These results indicated that vertical and horizontal stress gradients along the shore mainly influence abundance and species richness. The significantly higher abundance of M. galloprovincialis outside the MPA is due to its preference for wave-exposed areas. The reason for the difference in the total abundance of W. subtorquata in the different habitats is not clear, although it appears that the higher abundance of this species in the MPA is because the sheltered nature of the MPA. M. galloprovincilais displaces indigenous species. W. subtorquata does not cause any significant harm along the coast of South Africa. This study indicates that the abundance of M. galloprovincialis and W. subtorquata in the MPA is relatively low. The MPA is therefore in good condition with regards to intertidal alien species. It is important that the MPA and adjacent KBR's coastline maintain its current pristine status.AFRIKAANSE OPSOMMING: Die voorreg om mariene hulpbronne te benut, word bedreig. Voldoende nasionale en globale mariene bewaring is krities. 'n Deeglike kennis van spesies verspreiding en omgewingsveranderlikes wat gemeenskapstrukture beïnvloed is noodsaaklik vir optimale bewaringspogings. Mariene indringerspesies en verspreiding van indringerspesies bedreig mariene ekosisteme. Dit is belangrik om basiese kennis in te win oor die geografiese verspreiding van indringerspesies saam met die omgewingsveranderlikes wat hierdie verspreiding beïnvloed. Hierdie studie fokus dus daarop om die kennis met betrekking tot intergety ongewerwelde spesiesverspreiding, veral dié wat uitheems is langs die kus van die Kogelberg Biosfeer Reservaat (KBR) en aangrensende Bettys Baai Mariene Beskermde Gebied (MBG) in die Wes-Kaap in Suid-Afrika uit te brei. Hierdie streek word beskou as gesog vir mariene bewaring in Suid-Afrika. Identifikasie van spesies is in September 2010 gedoen. Twee intergety uitheemse ongewerwelde spesies is langs die kus geïdentifiseer; die indringer 'mytilid' Mediterreense mossel - Mytilus galloprovincialis en die 'bryozoa' Watersipora subtorquata. 'n Kwantitatiewe sistematiese oorsig van die intergety rotsagtige streek, bestaande uit sewe lokaliteite, is gedoen. Steekproefneming is vanaf Oktober 2010 tot Desember 2010 uitgevoer. Alle fokale intergety ongewerwelde spesies, in ses geselekteerde habitattipes is getel. Omgewingsveranderlikes is aangeteken. Daar is statisties getoets vir verskille in die talrykheid en spesiesrykheid tussen die intergety zones en beskermingsstatus (MBG en nie-MBG), en tussen die intergety habitattipes en beskermingsstatus. Daar is ook getoets vir verskille in talrykheid en spesiesrykheid tussen die intergety zones en habitattipes waar beskermingsstatus nie in ag geneem is nie. Ooreenstemmende analises is gedoen om die verhoudings tussen die spesiesamestelling en die gedefinieerde omgewingsveranderlikes te illustreer. Daar is statisties getoets vir verskille in die talrykheid van die geïdentifiseerde uitheemse spesies tussen die MBG en nie-MBG, die verskillende lokaliteite, die verskillende habitattipes en tussen die verskillende golf blootstellings. Hierdie studie dui aan dat vertikale en horisontale stresgradiënte die hoofoorsaak is wat talrykheid en spesiesrykheid beïnvloed. Die aansienlik hoër talrykheid van M. galloprovincialis buite die MBG is van die gebied se hoër golfblootstelling. Die beduidende verskil in talrykheid van W. subtorquata is onduidelik. Dit kan egter afgelei word dat die beskutte aard van die MBG 'n rol speel by die aansienlik hoër talrykheid van hierdie spesie binne die MBG. M. galloprovicialis verplaas inheemse spesies. Geen beskikbare bewys dui daarop dat W. subtorquata enige beduidende skade langs die kus van Suid-Afrika aanrig nie. Die lae talrykheid van beide hierdie spesies binne die MBG dui daarop dat hierdie unieke area steeds in goeie toestand ten opsigte van intergety uitheemse spesies is. Dit is noodsaaklik dat die huidige status van die MBG en aangrensende kuslyn gehandhaaf word.Thesis (MScConEcol)--UnStellenbosch University, 2011.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Samways, Michael John2011-10-10T08:19:31Z2011-12-05T13:17:10Z2011-10-10T08:19:31Z2011-12-05T13:17:10Z2011-12Thesishttp://hdl.handle.net/10019.1/17981en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/185892012-02-20T12:48:19Zhdl_10019.1_532

Knowledge and use of traditional medicinal plants by the Setswana-speaking community of Kimberley, Northern Cape of South AfricaMonakisi, Charlotte M.Materia medica, Vegetable -- South Africa -- KimberleyMedicinal plants -- South AfricaTraditional medicine -- South Africa -- KimberleyTswana (African people) -- Medicine -- South Africa -- KimberleyTswana (African people) -- Ethnobotany -- South Africa -- KimberleyTheses -- Ecological assessmentDissertations -- Ecological assessmentENGLISH ABSTRACT: The majority of South Africans still depend on the use of traditional remedies, as these are sometimes the only types of health care systems available, especially within rural communities. South Africa comprises approximately 400 000 traditional healers and an estimated 60 to 80% of individuals consulting such traditional healers. As a result, the over-harvesting of many traditional medicinal plants has become a threat to the country’s species diversity and has resulted in the scarcity of certain medicinal plant species. The non-sustainable use of traditional medicinal plants stems from their intense harvesting from the wild to supply the high demands from urban and rural markets. As a result of the escalating population growth rate; high rural unemployment; and fundamental value attached to traditional medicinal plants (socio-economic factors), the national and regional trade of traditional medicines is currently higher than it has ever been. Another reason for the increased threat to traditional medicinal plants is the degradation and weakening of customary laws that have previously regulated such resources. This study focuses on the use of traditional medicinal plants by the Setswana-speaking community for self-medication and as a form of primary health care. Research was conducted in Kimberley, Northern Cape of South Africa and focuses on the issue of the sustainability of medicinal plant use in the area, specifically on use and users as well as the acquisition of material sold by a single trader and harvesting techniques. This is to determine whether harvesting of medicinal plants is a potential threat to plant communities in the area. To address the shortcomings of medicinal anthropology the study also investigates the impacts of relocation and resettlement of various communities in the area, on plant use, methods of collection, the sustainability of the natural resource, as well as the transmission of Setswana indigenous knowledge inter-generationally. most abundant under high disturbances. Certain species reacted positively to disturbance and were most abundant in disturbed habitats. These included Elephantorrhiza elephantina and a Helichrysum sp. To minimise destructive harvesting in the Kimberley area and to ensure the sustainable harvesting of plant material, it is important that local harvesters are educated on proper harvesting techniques and that local gatherers are educated on sustainability issues as well as other ecologically fundamental issues.AFRIKAANSE OPSOMMING: Die meeste Suid-Afrikaners is steeds afhanklik van tradisionele geneesmiddels aangesien dit soms, veral in landelike gemeenskappe, die enigste beskikbare gesondheidsorg is. Suid-Afrika het sowat 400 000 tradisionele geneeshere wat deur ’n geraamde 60% tot 80% van individue geraadpleeg word. As gevolg hiervan hou die oorontginning van talle tradisionele medisinale-planthulpbronne ’n bedreiging vir die land se spesiediversiteit in en het dit reeds tot ’n skaarste aan sekere medisinale plante gelei. Tradisionele medisinale plante word tans nievolhoubaar aangewend aangesien dit op groot skaal in die veld geoes word om in die groot vraag van stedelike en landelike markte te voorsien. As gevolg van die stygende bevolkingsgroeikoers, hoë landelike werkloosheidsyfer en die grondliggende waarde wat aan tradisionele medisinale plante geheg word (sosio-ekonomiese faktore), is die nasionale en streekhandel in tradisionele geneesmiddels tans groter as ooit tevore. Nog ’n rede vir die toenemende bedreiging van tradisionele medisinale plante is die verslapping en versagting van gewoonteregwetgewing wat voorheen sodanige hulpbronne gereguleer het. Hierdie studie fokus op die gebruik van tradisionele medisinale plante deur die Setswanagemeenskap vir selfbehandeling en as ’n vorm van primêre gesondheidsorg. Die navorsing vir die studie is in Kimberley in die Noord-Kaapprovinsie van Suid-Afrika gedoen en fokus op die kwessie van volhoubare medisinale-plantgebruik in die gebied, met bepaalde klem op gebruik en gebruikers, die verkryging van middels wat deur ’n enkele handelaar verkoop word, en oestegnieke. Die doel van die navorsing was om te bepaal of die oes van medisinale plante ’n moontlike bedreiging vir plantgemeenskappe in die gebied inhou. Om die tekortkominge van medisinale antropologie aan te pak, ondersoek die studie ook die uitwerking van die verskuiwing en hervestiging van verskeie gemeenskappe in die gebied op plantgebruik, oesmetodes, die volhoubaarheid van die natuurlike hulpbronne, asook die oordrag van inheemse Setswana-kennis oor geslagte heen. Selfbehandeling en die gebruik van tradisionele medisinale plante speel steeds ’n groot rol in Kimberley, aangesien die meeste van die individue wat aan die navorsing deelgeneem het steeds tradisionele geneesmiddels as deel van hulle kultuur en tradisie gebruik. Daar word in ’n uiteenlopende verskeidenheid plantmateriaal handel gedryf. Hoewel sommige van die middels plaaslik ingesamel word, word die meeste van ander dele van die land, en in party gevalle van buurlande soos Lesotho en Swaziland, ingevoer. Hoewel die meeste van die materiaal dus nie plaaslik ingesamel word en dus nie bepaald op hierdie studie betrekking het nie, is dit steeds aanduidend van oes- en volhoubaarheidskwessies in ander dele van die land. Die kruiekenner dryf in sewentig tradisionele medisinale-plantsoorte handel, waarvan party beskermd en erg bedreig is, waaronder Prunus africana en Warburgia salutaris wat slegs in beskermde gebiede in die land voorkom. Prunus africana is ’n gelyste spesie in CITES, aanhangsel 2. Ander bedreigde spesies sluit Ocotea bullata, Bersama lucens, Curtisia dentata en ’n Eugenia-spesie in. Die meeste van die plante wat (in Kimberley) geoes word, is in die vorm van ondergrondse bergingsorgane (uitlopers en bolle). Hoewel hierdie plante van stingelskade en die skade aan ondergrondse bergingsorgane kan herstel, vat hulle swak pos indien hulle oorgebruik en oorontgin word, en kan hulle dus mettertyd al hoe minder voorkom. In hierdie studie word die mettertydse afname in plantbevolkings deur die toename in reisafstande na insamelingspunte aangetoon. Hierdie tendens is egter nie in die handelsprys en -materiaalhoeveelhede oor die afgelope eeu weerspieël nie. Die meeste van die studiedeelnemers het bevestig dat die prys en hoeveelheid van die handelsmateriaal deurentyd betreklik stabiel gebly het. Van die teikenspesies wat vir kwesbaarheid of sensitiwiteit vir ontwrigting ondersoek is, het Withania somnifera, Boophane disticha, Dicoma anomala en Bulbine natalensis die laagste oorlewingspotensiaal en die hoogste ontwrigtingsensitiwiteit getoon. Die meeste van hierdie spesies het in baie klein hoeveelhede op die gekose terreine voorgekom. In die geval van Withania somnifera kon die negatiewe resultate egter met die laereënvalseisoen gedurende daardie betrokke jaar in verband gebring word. Hierdie spesie word oor die algemeen as ’n onkruid in ontwrigte gebiede geklassifiseer en kom meestal onder erg ontwrigte toestande voor. Sekere spesies, soos Elephantorrhiza elephantina en ’n Helichrysum-spesie, het positief op ontwrigting gereageer en het volop in ontwrigte habitatte voorgekom. Om vernietigende oestery in die Kimberley-omgewing te minimaliseer en die volhoubare ontginning van planthulpbronne te verseker, is dit belangrik dat plaaslike plukkers in gepaste oestegnieke, en plaaslike insamelaars oor volhoubaarheidskwessies en ander ekologies belangrike sake opgelei word.Thesis (MSc)--University of Stellenbosch, 2007.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Esler, K.J.Ward, D.2012-01-12T12:20:16Z2012-01-12T12:20:16Z2007-12Thesisxiv, 148 leaves : ill.http://hdl.handle.net/10019.1/18589en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/187112012-01-21T22:00:26Zhdl_10019.1_532

Attitudes and behaviour of landholders towards the conservation of Overberg Coastal Renosterveld, a threatened vegetation type in the Cape Floral KingdomWinter, Susan JeanCoastal renosterveld -- Conservation -- South Africa -- OverbergGrassland conservation -- South Africa -- OverbergFynbos -- Conservation -- South Africa -- OverbergLandowners -- South Africa -- Overberg -- AttitudesDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyENGLISH ABSTRACT: This thesis describes the findings of a survey to investigate the attitudes and behaviour of private landholders towards the conservation of Overberg Coastal Renosterveld, a highly endangered grassy-shrubland of the Cape Floral Region (CFR) lowlands, now 94% transformed. Personal interviews were conducted with 36 farmers in the Overberg region of the Western Cape, by administering a questionnaire. The following aspects were quantitatively described using the Statistical Package for Social Scientists (SPSS): Renosterveld management and utilisation behaviour, perceived value of Overberg Coastal Renosterveld; landholder knowledge of its conservation importance and willingness to conserve it. Attitudes towards incentives for conservation; conservancies; and the provincial conservation authorities were also investigated. Willingness to conserve was explored further using SPSS cross-tabulation analyses. It was found that farmers who were more willing to conserve were younger, did not necessarily have a better education, and owned larger farms (> 500 ha) with a greater amount of remnant renosterveld (> 300 ha) than farmers less willing to conserve. Attitudes towards Overberg Coastal Renosterveld were largely negative, due to certain associated plants and animals which are problems for farmers, and because it is not economically advantageous to retain it. However, provision of incentives (of which assistance with fencing and land management was most attractive) and increased extension support will provide practical positive inducements for conservation. There is also a need for more landholder education regarding the scarcity of coastal renosterveld to prevent transformation of remaining fragments. The second component of the study aimed to construct a user-friendly index to measure the conservation attitudes of landholders towards conserving Overberg Coastal Renosterveld. An interative item analysis was executed on the data, using Spearman Rank Order correlations and Cronbach's Alpha. Results yielded an index with two dimensions and a Cronbach Alpha co-efficient of 0.67. The dimensions or components of conservation attitude towards renosterveld included: (i) a landholders' perception of the perceived benefit of Overberg Coastal Renosterveld; and (ii) their willingness to conserve it. The mean conservation attitude score was 0.6 (± 0.03), indicating that landholder attitudes were generally sympathetic towards renosterveld conservation. This suggests that while many landholders do not place a high value on Overberg Coastal Renosterveld due to its low agricultural value, their willingness to conserve it is in some cases higher than expected, which possibly explains the above-average mean conservation attitude score. An analysis of variance showed that the following variables were significantly, positively correlated with conservation attitude: (i) area of Overberg Coastal Renosterveld; (ii) landholder environmental group membership status; (iii) presence of ecotourism activities on the property; and (iv) how long the property had been in the owner's family. The intended application of the index is that index scores (amenable for use in a Geographical Information System database) can assist conservation practitioners in deciding where resources should be allocated, on the assumption that high-scoring individuals are more likely to want to take part in conservation initiatives.AFRIKAANSE OPSOMMING: Hierdie proefskrif beskryf die bevindings van 'n opname waarin die houdings en gedrag van private grondeienaars ten opsigte van Overberg Kustelike Renosterveld ondersoek word. Altesaam 94% van die oorspronklike renosterveld, 'n hoogs bedreigde, grasagtige struikveld in die laaglande van die Kaapse Planteryk (KPR) , is reeds getransformeer en verander. Persoonlike onderhoude is met 36 boere in die Overbergstreek van die Wes-Kaap gevoer en 'n vraelys is aan hulle gestel. Die "Statistical Package for Social Scientists" (SPSS) is gebruik om die volgende aspekte kwantitatief te beskryf: die bestuur en benutting van Overberg Kustelike Renosterveld; die waarde wat toegeskryf word aan hierdie renosterveld; asook grondeienaars se kennis oor die bewaringsbelang van Overberg Kustelike Renosterveld en hul bereidwilligheid om dit te bewaar. Houdings jeens aansporingsmiddele om bewaring te bevorder, bewareas en die provinsiale bewaringsowerhede is ook ondersoek. Private grondeienaars se bereidwilligheid om betrokke te raak by bewaringswerk is verder ondersoek deur gebruik te maak van die SPSS-kruistabelleringsanalise. In vergelyking met boere wat nie bewaring ondersteun nie, is gevind dat die meer bewaringsgesinde boere jonger is, nie noodwendig 'n beter opvoeding het nie, en groter plase (>500 ha) besit waarop meer brokkies oorblywende Overberg Kustelike Renosterveld (>300 ha) gevind word. Grondeienaars se houding jeens Overberg Kustelike Renosterveld was grootliks negatief. Dit is as gevolg van sekere verwante plante en diere wat deur boere as probleme ervaar word, en omdat dit nie ekonomies lewensvatbaar is om renosterveld te behou nie. Die beskikbaarheidstelling van aansporingsmiddele (waarvan hulpverlening met omheinings en grondbestuur die aantreklikste was), en 'n toename in landbou-voorligting is egter praktiese en positiewe dryfvere wat bewaring kan bevorder. Daar is ook 'n behoefte vir meer opvoeding van grondeienaars oor aspekte soos die skaarsheid van Overberg Kustelike Renosterveld, sodat die verdere transformasie van oorblywende fragmente voorkom kan word. Die tweede gedeelte van die studie was daarop gemik om 'n gebruikersvriendelike indeks te ontwikkel waarmee die bewaringsgesindheid van grondeienaars teenoor die bewaring van renosterveld gemeet kan word. Deur gebruik te maak van Spearman se rangorde-korrelasies en Cronbach se Alpha is die data aan 'n herhalende item-analise onderwerp. Die resultate het 'n indeks met twee dimensies en 'n Cronbach Alpha-koëffisiënt van 0.67 gelewer. Die dimensies of komponente van bewaringsgesindheid jeens renosterveld het onder meer ingesluit: i) 'n grondeienaar se opvatting oor die moontlike voordeel van Overberg Kustelike Renosterveld en ii) sy/haar bereidwilligheid om dit bewaar. Die gemiddelde telling vir bewaringsgesindheid was 0.6 (± 0.03), wat in die algemeen 'n simpatieke houding jeens die bewaring van Overberg Kustelike Renosterveld onder grondeienaars aandui. Hiervolgens blyk dit dat alhoewel heelwat grondeienaars weens die lae landbouwaarde van renosterveld nie 'n hoë waarde op hierdie plantegroeitipe plaas nie, hulle bereidwilligheid om dit te bewaar soms verwagtinge oortref. Dit is dalk 'n moontlike verklaring vir die bogemiddelde gemiddelde bewaringsgesindheidtelling. 'n Variansie-analise het 'n noemenswaardige, positiewe korrelasie met bewaringsgesindheid ten opsigte van die volgende veranderlikes getoon: i) area van Overberg Kustelike Renosterveld; ii) die grondeienaar se moontlike lidmaatskap van 'n bewaringsgroep; iii) die teenwoordigheid van ekotoerisme-bedrywighede op die eiendom; en iv) die tydperk wat die eiendom al in besit van die grondeienaar se familie is. Die voorgestelde gebruik van die indeks is toepaslik omdat die indeks-tellings (wat vir gebruik in 'n Geografiese Inligtingstelsel databasis aangepas kan word) bewaringslui kan help met besluite random die toekenning van hulpbronne. Die aanname is dat individuele grondeienaars wie hoë tellings aangeteken het, met alle waarskynlikheid meer geredelik aan bewaringsinisiatiewe sal wil deelneem.Thesis (MScConsEcol) -- Stellenbosch University, 2003.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Esler, K. J.Prozesky, H.2012-01-17T09:58:22Z2012-01-17T09:58:22Z2003-12Thesis98 leaves : ill.http://hdl.handle.net/10019.1/18711en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/196402013-01-21T08:21:32Zhdl_10019.1_532

Distribution and impact of the Argentine ant, Linepithema humile (Mayr), in South AfricaLuruli, Ndivhuwo MordArgentine ant -- South AfricaBiological invasions -- South AfricaTheses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyENGLISH ABSTRACT: Invasion by the notorious tramp species, the Argentine ant (Linepithema humile Mayr) (Hymenoptera: Formicidae) has caused major concern around the globe, owing to its displacement of native ant species and other invertebrates where it invades. This species was first recorded in South Africa in 1901 in Stellenbosch, Western Cape Province (WCP), and has now become a significant pest in most urban and agricultural areas in the country. The Argentine ant has received relatively little attention in South Africa compared to other countries (e.g. California, North America). To date the extent of invasion by this species countrywide, as well as its impact on the local ant fauna inside protected areas, has not been quantified. In this study, the impact of the Argentine ant on native ant fauna inside three protected areas in the WCP (Helderberg Nature Reserve (HNR), Jonkershoek Nature Reserve (JNR) and Kogelberg Biosphere Reserve KBR)) was assessed. Species richness and diversity were compared between invaded and uninvaded bait stations at each protected area. Several native ant species were found to be displaced by the Argentine ant from all three protected areas, although three species: Meranoplus peringueyi, Monomorium sp. 8 and Tetramorium quadrispinosum, were found coexisting with it. Invaded bait stations had significantly lower ant species richness and species turnover than uninvaded bait stations. Uninvaded bait stations contained eight times more native ant species than invaded bait stations. Thus, the invasion of protected areas by the Argentine ant has severe negative consequences for the species richness and assemblage structure of native ants, leading to the biotic homogenization of these local ant communities. The distribution range of the Argentine ant inside the three protected areas (HNR, JNR, KBR), as well as microhabitat preferences that may facilitate the spread of this species inside these reserves, was also assessed. Helderberg Nature Reserve was the most invaded protected area, with the highest level of the Argentine ant occupancy, while JNR and KBR had lower occupancy levels. At all the three protected areas, this species was dominant at lower altitudinal areas, and also showed a clear preference for areas with high anthropogenic disturbances, i.e. around buildings and on lawns (picnic areas). In this study, there was no evidence that moisture availability facilitates the distribution and spread of the Argentine ant inside these reserves. Finally, a combination of published literature records, museum records and records collected in the current study was used to quantify the current distributional extent of the Argentine ant throughout urban South Africa. This is the first study quantifying the distribution and extent of invasion by the Argentine ant throughout the country. The Argentine ant was found in six of the nine South African Provinces, and its extent of occurrence includes approximately half of the country’s land surface area. Discontinuities in the distribution of the Argentine ant across the country revealed that range expansion of the Argentine ant in South Africa is occurring predominantly via human-mediated jump dispersal, rather than naturally via nest diffusion. This study clearly demonstrated that the Argentine ant is well established across South Africa as well as inside protected areas. The Argentine ant invasion was influenced by the presence of human modified landscapes (i.e. buildings) both at low and high altitude, and this was associated with higher rates of native ant species displacement at these areas. Therefore, limiting the development of recreational areas, such as buildings and picnic sites inside protected areas will result in the lower rate of spread of the Argentine ant. This will in turn lower the extent of displacement of native ant species.AFRIKAANSE OPSOMMING: Indringing deur die Argentynse mier (Linepithema humile Mayr) (Hymenoptera: Formicidae) is ‘n bron van groot kommer regoor die wêreld, as gevolg van sy vermoë om inheemse mier spesies en ander ongewerweldes te verplaas. Hierdie spesie is vir die eerste keer aangeteken in Suid-Afrika in 1901, in Stellenbosch, Weskaap Provinsie (WCP), en het ‘n belangrike pes geword in die meeste stedelike en landelike gebiede in die land. Die Argentynse mier het betreklik min aandag gekry in Suid-Afrika, in vergelyking met ander lande (bv. California, Noord Amerika). Tans is die omvang van die landwye indringing van hierdie spesie, sowel as sy impak op die plaaslike mier fauna binne beskermde areas, nog nie bepaal nie. In hierdie studie word die impak van die Argentynse mier op die inheemse mier fauna binne drie beskermde areas in die WCP (Helderberg Natuurreservaat (HNR), Jonkershoek Natuurreservaat (JNR) en Kogelberg Biosfeerreservaat (KBR)) bepaal. Spesierykheid en diversiteit was vergelyk tussen ingedringde en oningedringde lokaas stasies in elke beskermde area. Verskeie inheemse mier spesies was deur die Argentynse mier verplaas in al drie beskermde areas, alhoewel drie spesies: Meranoplus peringueyi, Monomorium sp. 8 en Tetramorium quadrispinosum het saam met dit voorgekom. Ingedringde lokaas stasies het beduidend laer mier spesierykheid en spesies omset gehad as oningedringde lokaas stasies. Dus, die indringing van beskermde areas deur die Argentynse mier het ernstige negatiewe gevolge vir die spesierykheid en gemeenskap struktuur van inheemse miere, wat lei tot die biotiese verarming van hierdie plaaslike mier gemeenskappe. Die verspreidingsarea van die Argentynse mier binne die drie beskermde areas (HNR, JNR, KBR), en die mikrohabitat voorkeure wat die verspreiding van die spesie binne hierdie reservate kan vergemaklik, was ook vasgestel. Helderberg Natuurreservaat was die mees ingedringde beskermde area, met die hoogste vlak van Argentynse mier besetting, terwyl JNR en KBR laer besettingsvlakke gehad het. By al drie die beskermde areas was hierdie spesie dominant by laer hoogtes bo seevlak en het ‘n duidelike voorkeur getoon vir areas met hoë menslike versteuring d.i. rondom geboue en op grasperke (piekniek areas). In hierdie studie was daar geen bewyse dat vog beskikbaarheid die voorkoms en verspreiding van die Argentynse mier binne die reservate vergemaklik nie. Ten slotte, ‘n kombinasie van gepubliseerde literatuur verslae, museum dokumente en verslae wat in hierdie studie versamel is, was gebruik om die huidige verspreidingsomvang van die Argentynse mier te bepaal. Dit is die eerste studie wat die verspreiding en omvang van indringing in stedelike Suid Afrika van die Argentynse mier dwarsdeur die land bepaal. Die Argentynse mier is gevind in ses van die nege provinsies in Suid-Afrika, en die omvang van sy voorkoms sluit bykans die helfte van die land se landoppervlaksarea in. Onderbrekings in die verspreiding van die Argentynse mier deur die land het blootgelê dat die uitbreiding van die voorkomsgebied van die Argentynse mier in Suid-Afrika hoofsaaklik gebeur deur mens bemiddelde verspreiding eerder as natuurlike nesverspreiding. Hierdie studie het duidelik gedemonstreer dat die Argentynse mier goed gevestig is regoor Suid-Afrika sowel as in beskermde areas. Die Argentynse mier indringing was beïnvloed deur mensgewysigde landskappe (d.i. geboue) by lae en hoë hoogtes bo seevlak, en dit was verwant aan hoër vlakke van verplasing van inheemse mier species in hierdie areas. Dus, die beperking van ontwikkeling van rekreasie areas, soos geboue en piekniekareas, in beskermde gebiede sal lei tot laer vlakke van verspreiding van die Argentynse mier. Dit sal, op sy beurt, die omvang van verplasing van die inheemse mier spesies verminder.Thesis (MScAgric)--University of Stellenbosch, 2007.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.McGeoch, M.A.2012-02-08T10:23:12Z2012-02-08T10:23:12Z2007-03Thesisviii, 161 leaves : ill., mapshttp://hdl.handle.net/10019.1/19640en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/199852013-01-21T08:32:47Zhdl_10019.1_532

The ecology and potential factors limiting the success of Sable antelope in south eastern Zimbabwe : implications for conservation.Capon, Simon DavidDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologySable antelope -- ZimbaweSable antelope -- Conservation -- ZimbabweENGLISH ABSTRACT: The decline of sable antelope through much of the lowveld region of Zimbabwe and South Africa has become an issue of concern for wildlife managers. On Malilangwe Wildlife Reserve (MWR) alone, sable numbers crashed from 237 animals in 1994 to only 62 by 2005. The purpose of this study was to determine the cause of the decline and the continued lack of success in the sable population. The study had three specific aims: 1) to assess the current viability of the sable population at MWR and understand the sensitivity of the population to environmental changes, 2) to gain an understanding of the space-use and habitat selection of sable at the landscape scale, and 3) to speculate on the possible causes of the decline in sable antelope numbers at MWR. GPS collars were fitted to four sable herds at MWR and a fifth herd was monitored opportunistically over the study period. From these, life history data were collected and fed into a VORTEX population viability model to assess the current viability of the sable population at MWR. Vital rates input into the model were then manipulated, simulating the effect of natural pressures placed on the population. A sensitivity analysis was used to determine the sensitivity of the population to these natural pressures, using the long term growth rate as a relative measure of overall fitness. The results suggest the current population will remain extant but that natural pressure placed on the adult female segment of the population could have a drastic impact on the success of the sable population. The evidence indicates that the decline in sable numbers at MWR must have been driven by an increase in mortality in the adult segment of the population. The GPS collars gave regular fixes enabling the development of a spatial pattern of home-range and habitat use over time. LoCoH was used to develop seasonal home ranges and utilization distributions for the sable herds at MWR. A multiscale approach was used to investigate habitat selection by sable over time at MWR, using a Bonferonni Z-statistic, time series graphs and Maximum Entropy modeling. Sable used much larger ranges during the early wet season than during any other season at MWR and were highly selective at the broad scale spending more than 92% of their time foraging on the nutrient rich basalt derived soils. At the finer scale sable generally chose for areas characterized by a well developed grass layer on shallow calcareous soils moving onto areas of deeper clay rich soils during the dry season and consistently made use of areas further than average from water. Data from the collars were then used to conduct bi-monthly tick drags along the sable foraging paths to assess the level of tick challenge faced by each herd over time and this was related back to the survival rate of calves within each herd using linear regressions. The effects of predation were assessed again using the GPS collar data and a novel method of determining predation risk using motion sensor camera traps. The level of predation risk was then related back to the survival rate of each age class in the sable population. The long term effects of predation on the sable population was investigated using historical data on sable carcasses discovered and the annual rate of population decline. These were regressed against lion population numbers to determine whether any relationship existed between lion population numbers and the rate of population decline. Tick challenge had no effect on the survival of sable calves and the overall tick challenge at MWR was extremely low during the study period. Predators however seemed to have an impact on the sable population in a number of ways. Hyaena’s seemed to have a major impact on the survival of sable calves, particularly during the first few weeks of life and lion numbers showed a strong relationship with the overall rate of population decline. Sable antelope are highly susceptible to predators and lions seem primarily to blame for driving the decline in the species at MWR. The relationship is however not entirely clear and evidence suggests that a number of variables including vegetation cover and water distribution play a role in determining the impact that predators have on sable populations.Thesis (MScConEcol) Stellenbosch University, 2012.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Leslie, AlisonClegg, Bruce2012-03-09T09:20:41Z2012-03-30T10:31:03Z2012-03-09T09:20:41Z2012-03-30T10:31:03Z2012-03Thesis110 p. : ill., mapshttp://hdl.handle.net/10019.1/19985en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/200462013-01-21T08:32:05Zhdl_10019.1_532

Chemical ecology and eco-physiology of the grain chinch bug, Macchiademus diplopterus (Distant) (Hemiptera: Lygaeidae: Blissidae), a phytosanitary pest of South African export fruitOkosun, Olabimpe OlayemChinch-bugs -- South Africa -- Western CapeChinch-bugs -- Ecology -- South Africa -- Western CapeChinch-bugs -- Ecophysiology -- South Africa -- Western CapeChinch-bugs -- Control -- South Africa -- Western CapeFruit -- Diseases and pests -- South Africa -- Western CapeGrain -- Diseases and pests -- South Africa -- Western CapeDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyConservation Ecology and EntomologyENGLISH ABSTRACT: The grain chinch bug, Macchiademus diplopterus, is an endemic pest of cultivated grain crops and wild grasses in the south-western Cape region of South Africa. In early summer when host plants dry out, adult grain chinch bugs aggregate in large numbers in shelter sites in surrounding areas and enter into aestivation. These shelter sites sometimes include the stalk or calyx ends of fruit, and shelter-seeking bugs can also contaminate export fruit cartons, consequently posing a phytosanitary/quarantine risk to importing countries. Presently, there are no feasible pre- or post-harvest control measures to manage this quarantine risk. The aggregating behaviour of grain chinch bugs suggests the involvement of pheromones. Therefore, investigating the chemical ecology of grain chinch bugs for potential use in control measures is the focus of the first research chapter of this study. Gas chromatography-mass spectrometry (GC-MS) was used to identify headspace volatiles collected from aggregating bugs. Olfactometer bioassays were conducted to assess the attractiveness of each gender to separate sexes, individual compounds and a mixture of the compounds as a formulated lure. The lure was tested in field trapping trials with delta and bucket traps. In the bioassays with the live insects the response of each gender to live females was greater than the responses of each gender to live males, suggesting that females may disseminate the pheromones more efficiently than males. The following eight volatile compounds were indentified from the GC-MS analysis: hexanal, (E)-2-hexenal, (E)-2-hexenol, (E)-2-hexenyl acetate, (E)-2-octenal, (E)-2-octenol, (E)-2-octenyl acetate and tridecane. In the bioassays with individual compounds, three of these eight compounds, hexanal, (E)-2-hexenal, and tridecane, elicited attraction of both females and males. The formulated lure was attractive to both males and females in the laboratory bioassay, but this attraction was not evident in the field. In the field, there was only one occasion when a significantly higher number of bugs were caught in baited traps compared to unbaited traps. Trap catches were very low compared to the actual level of infestation in the field which was evident from corrugated cardboard bands tied around tree trunks which contained many sheltering bugs. The low trap catches seen in the field were partly due to competition between the synthetic pheromone lure and the natural pheromones emitted by aggregating live insects. Also, the characteristic shelter-seeking behaviour of grain chinch bugs influenced trap catches, as more bugs were found in places that provide shelter, like cardboard bands and walls of the delta traps. This behavior of aestivating bugs could be used to the advantage of trapping bugs by integrating sheltering sites into traps in future trials. Also, the lure needs to be improved for optimum efficiency in the field. The second research chapter also addresses the quarantine risk posed by grain chinch bugs, by investigating the thermal biology of bugs to ultimately facilitate the development of effective post-harvest treatments. Critical thermal minimum and maximum temperatures (CTmin and CTmax) of both active and aestivating bugs were subjected to critical thermal limits analysis. The CTmin and CTmax of aestivating bugs were not affected by gender (p > 0.05). There was a decrease in CTmin from the active period into aestivation for both males (2.8°C to 1.0°C (± 0.1)) and females (2.1°C to 0.6°C (± 0.1)). Also, for CTmax there was an increase in tolerance from the active period into the aestivation period for both males (49.9°C to 51.0°C (± 0.1)) and females (49.9°C to 51.5°C (± 0.1)). To determine the plasticity of grain chinch bug thermal tolerance, aestivating bugs at 27 weeks into aestivation, were acclimated at different temperatures and photoperiods [18°C (10L:14D) and 26°C (16L:8D)] for a period of seven days. Both low (18°C) and high (26°C) acclimation temperatures and photoperiods increased CTmin of aestivating grain chinch bugs at 14 weeks from 0.8°C to -1.2°C and -0.1°C (± 0.1) respectively. However, CTmax was not altered by acclimation temperatures (p > 0.82). Field temperatures at collection sites were recorded to compare to grain chinch bugs thermal tolerance levels exhibited in the laboratory. These results, as well as the effects of acclimation treatments on the CTmin of bugs, have implications for post-harvest treatments, and understanding the quarantine risk posed to importing countries. The information generated from this study can be used to further advance the development of both effective pre-harvest and post-harvest control measures to reduce grain chinch bug quarantine risk.AFRIKAANSE OPSOMMING: Die graanstinkluis, Macchiademus diplopterus, is 'n endemiese plaag van aangeplante graangewasse en wilde grasse in die Suidwes Kaap-provinsie van Suid-Afrika. In die vroeë somer wanneer gasheerplante uitdroog, soek groot getalle volwasse graanstinkluise skuiling in die omliggende gebiede en gaan in ʼn somerrusperiode. Hierdie skuilplekke sluit soms die stam of kelk eindes van vrugte in en graanstinkluise kan ook uitvoer-vrugte kartonne kontamineer. Gevolglik word lande wat vrugte uit Suid-Afrika invoer, aan die fitosanitêre kwarantynrisiko van stinkluisbesmetting blootgestel. Tans is daar nie haalbare voor- of na-oes beheermaatreëls om hierdie kwarantyn risiko te bestuur nie. Die aggregasiegedrag van graanstinkluise dui op die betrokkenheid van ʼn feromoon. ‘n Ondersoek van die chemiese ekologie van die graanstinkluis vir moontlike gebruik in beheermaatreëls is die fokus van die eerste gedeelte van hierdie studie. Gaschromatografie-massaspektrometrie (GC-MS) is gebruik om die vlugtige organiese verbindings in die bodamp van die saamgetrosde stinkluise te identifiseer. Olfaktometriese biotoetse is uitgevoer om die aantreklikheid van die insekte vir die teenoorgestelde geslag te bepaal, asook van die individuele verbindings en 'n mengsel van die verbindings as 'n geformuleerde lokmiddel in lokvalle. Die lokmiddel is getoets in veldproewe met deltatipe en emmertipe lokvalle. In die olfaktometriese biotoetse met die lewende insekte is die reaksie van beide geslagte teenoor lewende wyfies groter as die reaksie van die geslagte teenoor mannetjies, wat daarop dui dat wyfies die feromoon meer doeltreffend as mannetjies versprei. Die volgende agt verbindings is geïdentifiseer met behulp van GC-MS-analise: heksanaal, (E)-2-heksenaal, (E)-2-heksenol, (E)-2-heksenielasetaat, (E)-2-oktenaal, (E)-2-oktenol, (E)-2-oktenielasetaat en tridekaan. In die biotoetse met individuele verbindings het drie van die agt verbindings, hexanal, (E)-2-hexenal, en tridecane, lokaktiwiteit vir beide geslagte getoon. Die geformuleerde lokmiddel was aantreklik vir beide geslagte in laboratorium toetse, maar soortgelyke lok is nie in die veld gevind nie, waar daar net een keer 'n aansienlike groter getal graanstinkluise met lokmiddel gevang is in vergelyking met lokvalle sonder lokmiddel. Die getal graanstinkluise in lokvalle was baie laag in vergelyking met die werklike vlak van besmetting in die veld, wat duidelik geblyk het uit die getalle graanstinkluise wat skuiling gesoek het in die geriffelde karton bande wat om boomstamme vasgemaak was. Die lae lokvalvangste in die veld was deels te wyte aan die kompetisie tussen sintetiese feromoon en die natuurlike feromoon van saamgetrosde insekte. Die kenmerkende aggregasiegedrag van graanstinkluise het lokvalvangste beïnvloed, aangesien meer stinkluise gevind is in plekke wat skuiling bied, soos die kartonbande en die binnekant van die delta-lokvalle. Hierdie skuilings van graanstinkluise kan in toekomstige proewe uitgebuit word deur vir meer skuilplek in lokvalle voorsiening te maak. Die formulering en die aanbieding van die lokmiddle moet ook verbeter word vir 'n optimale doeltreffendheid in die veld. In die tweede hoofstuk word die kwarantynrisiko van die graanstinkluis aangespreek deur die ondersoek van die termiese biologie van stinkluise om uiteindelik die ontwikkeling van doeltreffende na-oes behandelings te fasiliteer. Kritiese termiese minimum en maksimum temperature (CTmin en CTmax) van beide aktiewe en rustende graanstinkluise is bepaal deur analise van die kritiese termiese beperkings van die insek. Die CTmin en CTmax van rustende graanstinkluise is nie geraak deur geslag nie (p > 0.05). Daar was 'n afname in CTmin van die aktiewe tydperk tot in rus, vir beide manlike (2.8°C tot 1.0°C (± 0.1)) en vroulike insekte (2.1°C tot 0.6°C (± 0.1)). Ook vir die CTmax was daar 'n verbetering in toleransie vanaf die aktiewe tydperk tot in die rusperiode vir beide manlike (49.9°C tot 51.0°C (± 0.1)) en vroulike insekte (49.9°C tot 51.5°C (± 0.1)). Om die aanpasbaarheid van die termiese toleransie van die graanstinkluis te bepaal, is graanstinkluise 27 weke na aanvang van die rusperiode geakklimatiseer by verskillende temperature en fotoperiodes [18°C (10L: 14D) en 26°C (16L: 8D)] vir 'n tydperk van sewe dae. Beide lae (18°C) en hoë (26°C) akklimatiseringstemperature en fotoperiodes het onderskeidelik die CTmin van rustende graanstinkluise op 14 weke verhoog van 0.8°C tot -1.2°C en -0.1°C (± 0.1). Daar is egter geen effek op CTmax deur akklimasie temperature nie (p > 0.82). Veldtemperature is ook bepaal om te vergelyk met graanstinkluis termiese toleransie vlakke wat in die laboratorium bepaal is. Hierdie resultate, sowel as die gevolge van die akklimasie behandelings op die CTmin van graanstinkluise, het implikasies vir na-oes behandelings, en begrip van die kwarantyngevaar wat dit inhou vir vrugte-invoerlande. Die inligting wat uit hierdie studie voortvloei, kan gebruik word om die ontwikkeling van beide effektiewe voor-oes en na-oes beheermaatreëls te bevorder en om die kwarantynrisiko wat graanstinkluise inhou, te verminder.Thesis (MScAgric)--Stellenbosch University, 2012.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Johnson, ShelleyAddison, Pia2012-03-07T09:59:28Z2012-03-30T10:37:24Z2012-03-07T09:59:28Z2012-03-30T10:37:24Z2012-03Thesis95 p. : ill.http://hdl.handle.net/10019.1/20046en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/201472012-05-14T07:23:13Zhdl_10019.1_532

The use of entomopathogenic nematodes to control citus mealybug, Planococcus citri (Hemiptera: Pseudococcidae) on citrus in South AfricaVan Niekerk, SonnicaEntomopathogenic nematodesMealybugs -- Biological control -- South AfricaDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyCitrus -- Diseases and pests -- Biological control -- South AfricaConservation Ecology and EntomologyENGLISH ABSTRACT: Planococcus citri (Risso) (Hemiptera: Pseudococcidae), the citrus mealybug, is a highly destructive pest of citrus in South Africa. The ability of mealybugs to develop resistance to chemicals, as well as their cryptic nature and protective wax coverings, all individually and combined, impair the ability of insecticides to control them. Furthermore, chemicals deplete natural enemy populations that usually establish control over mealybug populations well before harvest in March to May. The inability of chemicals to control P. citri successfully and the growing public awareness of the detrimental environmental effects and health risks that are associated with pesticides are pressuring citrus growers to find alternative methods to chemical control. Entomopathogenic nematodes of the Rhabditida order, belonging either to the families Heterorhabditidae or Steinernematidae, have proven to be valuable biocontrol agents of a variety of insect pest species. These nematodes are, however, not yet commercially available in South Africa. Various laboratory bioassays were conducted to determine the potential of entomopathogenic nematodes to control P. citri. Adult female P. citri were screened for susceptibility to six indigenous nematode species. Planococcus citri was found to be most susceptible to Steinernema yirgalemense and Heterorhabditis zealandica, causing 97% and 91% mortality, respectively. Both H. zealandica and S. yirgalemense completed their life cycles inside adult female P. citri. Under optimal conditions, H. zealandica and S. yirgalemense, at an application rate of 170 infective juveniles (IJs) / insect (LD90), were able to control P. citri efficiently with a discriminating dosage of 11(LD50). The water activity (aw) bioassay indicated that S. yirgalemense was two times more tolerant to lower levels of free water than H. zealandica, with aw50 = 0.96 and aw90 = 0.99, compared to H. zealandica with aw50 = 0.98 and aw90 = 1.01. Furthermore, S. yirgalemense proved able to locate and infect P. citri at a faster rate than H. zealandica. Nematode activity was not significantly affected when exposed to 15°C, 20°C and 25°C. Results of the exposure trial also showed that the first 2−4 h post-application was the most decisive time for establishing successful infection of mealybugs. Further experiments were conducted to determine the ability of two polymer products, Zeba® and Xanthan gum, and a surfactant, Nu-Film-P®, to improve nematode application suspensions. Despite not being as effective as Xanthan gum, Zeba® still retarded sedimentation significantly. The addition of 0.02% Xanthan gum did not improve the ability of nematodes to control P. citri at 60% and 80% relative humidity containing H. zealandica and 0.03% Zeba® increased mortality by 14% at 60% RH and by 22% at 80% RH. The same polymer formulation was tested with S. yirgalemense, with mortality being found to have increased by 21% at 60% RH and by 27% at 80% RH. The combined addition of Nu-Film-P® and Zeba® was able to retard sedimentation significantly, increasing the average number of nematodes deposited on 2-cm2 leaf discs. To illustrate those factors that should be taken into consideration before applying nematodes in an integrated pest management (IPM) programme for citrus, the compatibility of H. zealandica and S. yirgalemense with biological control agents and agrochemicals to which they are most likely to be exposed was determined. Bioassays showed the coccinellid beetle, Cryptolaemus montrouzieri, to be susceptible to both nematode species. Beetle larvae proved to be highly susceptible, with H. zealandica obtaining 80%, and S. yirgalemense obtaining 92% control. Adult beetles were found to be twice as susceptible to S. yirgalemense, with 64% mortality recorded, as to H. zealandica, with 30% mortality recorded. Tolerance of H. zealandica and S. yirgalemense infective juveniles to the affect of aqueous solutions of an insecticide (Cyperphos 500 E.C.®), two biopesticides (CryptogranTM and HelicovirTM), and two adjuvants (Nu-Film-P® and Zeba®) on the infectivity and survival of H. zealandica and S. yirgalemense was evaluated. Heterorhabditis zealandica proved to be highly compatible with all products tested. Significant increase in mortality of S. yirgalemense was recorded after 12 h exposure to CryptogranTM, HelicovirTM and Cyperphos 500 E.C.®, and after 6 h exposure to Nu-Film-P®. However, there was no decrease in the ability of S. yirgalemense to infect the insect hosts. Towards selecting the appropriate nematode species for field studies, the ability of S. yirgalemense and H. zealandica to control P. citri was first evaluated under less harsh simulated glasshouse conditions. The ability of both the above-mentioned nematode species to control P. citri, with and without the addition of 0.03% Zeba® and 0.06% Nu-Film-P®, was evaluated in a growth chamber at 75 ± 8% relative humidity and 22°C. All treatments resulted in significantly higher mortality of adult female P. citri than did the control. The addition of 0.03% Zeba® and 0.06% Nu-Film-P® to an H. zealandica and an S. yirgalemense suspension increased resultant mortality from 26% to 30%, and from 34% to 45%, respectively. This increase in mortality was, however, not significant. The ability of this formulation to prolong the ability of S. yirgalemense to infect P. citri and to prolong nematode survival was also evaluated under the same conditions and showed the formulation to improve both infectivity and survival for up to 2–3 h post-application. In the semi-field trial, S. yirgalemense was unable to obtain significant control of P. citri without the addition of 0.03% Zeba® to nematode application suspensions. However, with the addition of 0.03% Zeba® S. yirgalemnse was able to obtain up to 53% control. The study established that the polymer product Zeba® improves the ability of S. yirgalemense to infect P. citri by retarding desiccation and by buffering nematodes from suboptimal environmental conditions.AFRIKAANSE OPSOMMING: Planococcus citri (Risso) (Hemiptera: Pseudococcidae), die sitrus witluis, is ʼn baie skadelike pes van sitrus in Suid Afrika. Die vermoë van witluise om weerstand teen chemiese middels te ontwikkel, hul kriptiese lewenswyse en die beskermende waslaag wat hul liggame omhul inhibeer gesamentlik en individueel die vermoë van insektisiede om witluis bevolkings te beheer. Chemiese middels verminder ook die natuurlike vyande wat gewoonlik witluis bevolkings beheer voor die sitrus oestydperk in Maart tot Mei. Die onvermoë van chemiese middels om P. citri suksesvol te beheer en verhoogde bewustheid van die publiek rond om die vernietigende omgewings impak en gesondheidsrisiko’s verbonde aan chemiese insek beheer, noodsaak sitrus produsente om alternatiewe beheermetodes te ontwikkel. Entomopatogeniese nematodes, van die orde Rhabditida wat aan die families Heterorhabditidae of Steinernematidae behoort, is bekend as effektiewe biologiese beheeragente van ʼn verskeidenheid insek pes spesies. Hierdie nematodes is egter tans nie kommersieel beskikbaar in Suid- Afrika nie. Om ten einde die vermoë van plaaslike nematode spesies te bepaal om P. citri te beheer, is verskeie biotoetse in die laboratorium uitgevoer. ʼn Vinnige siftings proses is uitgevoer om vas te stel watter plaaslike nematode spesies die hoogste persentasie mortaliteit van P. citri wyfies veroorsaak. Daar is bevind dat P. citri die mees vatbaarste is vir Steinernema yirgalemense en Heterorhabditis zealandica wat 97% en 91% mortaliteit respektiewelik veroorsaak het. Die ontwikkeling van beide H. zealandica en S. yirgalemense na die infektering van volwasse P. citri wyfies is gevolg en daar is bevind dat beide nematode spesies hul lewensiklusse kon voltooi in insek kadawers. Onder optimale toestande was H. zealandica en S. yirgalemense in staat om P. citri effektief te beheer, as hul teen ʼn konsentrasie van 170 infektiewe larwes (JIs) per insek (LD90) toegedien word, met ʼn diskriminerende toedienings dosis van 11 (LD50). ʼn Water aktiwiteit biotoets het gewys dat S. yirgalemense twee keer so verdraagsaam is teenoor laer vlakke van vrye water as wat H. zealandica is met aw50 = 0.96 en aw90 = 0.99, in vergelyking met H. zealandica met aw50 = 0.98 en aw90 = 1.01. Resultate van ʼn blootstellings toets het ook gewys dat S. yirgalemense die vermoë het om P. citri vinniger op te spoor en te infekteer as H. zealandica. Die blootstellings toets was uitgevoer teen 15°C, 20°C en 25°C en daar is bevind dat die aktiwiteit van H. zealandica nie beduidend verhoog het met ʼn verhoging in temperatuur nie. Resultate vir die blootstellings toets het ook gewys dat die eerste 2 tot 4 uur na toediening van nematodes die mees kritieke tyd is om suksesvolle infektering van witluise te bevestig. Verdere eksperimente is uitgevoer om te bepaal of die byvoeging van twee polimeer produkte nl. Zeba® en Xanthan gum en ʼn benatter Nu-Film-P®, nematode toedienings suspensies kan verbeter. Deur 0.02% Xanthan gum by nematode toedienings suspensies te voeg is die vermoë van nematodes om P. citri by 60% en 80% relatiewe humiditeit (RH) te beheer nie beduidend verhoog nie, terwyl die byvoeging van 0.03% Zeba® wel ʼn beduidende verhoging in mortaliteit veroorsaak het. ʼn Suspensie van H. zealandica en 0.03% Zeba® het beheer met 14% by 60% RH en met 22% by 80% RH verhoog. Die invloed van dieselfde polimeer formulasie was ook getoets op S. yirgalemense en mortaliteit het verhoog met 21% by 60% RH en met 27% by 80% RH. Ten spyte daarvan dat “Xanthan gum” nie so effektief was om afsakking van nematodes te verhoed nie, het die byvoeginging van 0.03% Zeba® by toedienings suspensies steeds ʼn beduidende invloed gehad. Die gekombineerde byvoeging Nu-Film-P® en Zeba® was in staat om die gemiddelde aantal nematodes gedeponeer op 2-cm2 blaar skyfies te verhoog. Om te wys watter faktore in ag geneem moet word voor EPNs as deel van ʼn geïntegreerde pes beheer program toegedien word, is die verenigbaarheid van H. zealandica en S. yirgalemense vir biologiese beheer agente en landbouchemikalieë, waaraan hulle heel waarskynlik blootgestel gaan word, bepaal. Biotoetse het gewys dat die liewenheersbesie, Cryptolaemus montrouzieri, vatbaar is vir beide nematode spesies. Die larwale fase was hoogs vatbaar met mortaliteit van 80% en 92% verkry deur die toedeining van H. zealandica en S. yirgalemense respektiewelik. Daar is ook bepaal dat volwasse besies twee maal so vatbaar is vir S. yirgalemense wat 64% mortaliteit veroorsaak het, as vir H. zealandica met 30% mortaliteit aangeteken. Verdraagsaamheid van IJs van H. zealandica en S. yirgalemense met oplossings van ʼn insektisied (Cyperphos 500 E.C.®), twee bio-plaagdoders (CryptogranTM en HelicovirTM), en twee byvoegmiddels (Nu-Film-P® en Zeba®), vir infektiwiteit en oorlewing is bepaal. Resultate het gewys dat H. zealandica hoogs verenigbaar is met alle produkte wat getoets is. ʼn Beduidende verhoging in mortaliteit van S. yirgalemense is aangeteken na 12 ure se blootstelling aan CryptogranTM, HelicovirTM en Cyperphos 500 E.C.®, en na 6 ure se blootstelling aan Nu-Film-P®. Resultate het egter ook gewys dat die vermoë van S. yirgalemense om om gashere te infekteer nie deur beinvloed word nie. Om ten einde te bepaal watter een van H. zealandica of S. yirgalemense die beter isolaat sou wees om te gebruik in veldproewe, is hul vermoë om P. citri te beheer eers evalueer onder minder ongunstige gesimuleerde glashuis toestande. Die vermoë van beide nematode spesies om P. citri te beheer is bepaal in ʼn groeikamer by 75 ± 8% (RH) met en sonder die byvoeging van 0.03% Zeba® en 0.06% Nu-Film-P®. Mortaliteit verkry deur alle behandelings was beduidend hoër as die kontrole. Deur 0.03% Zeba® en 0.06% Nu-Film-P® by toedienings suspensies van H. zealandica en S. yirgalemense te voeg is die gevolglike mortaliteit van P. citri verhoog van 26% na 30% en van 34% na 45%, respektiewelik. Hierdie verhoging in mortaliteit was egter nie beduidend nie. Die vermoë van die bo-genoemde formulasie om oorlewing van S. yirgalemense en infeksie tydperk van P. citri te verleng was bepaal onder dieselfde toestande en daar is gevind dat die formulasie beide die infektiwiteit en oorlewing van nematodes met 2 tot 3 uur na toediening verleng het. Tydens die semi-veldproef was S. yirgalemense nie in staat om beduidend hoër mortaliteit van P. citri te verkry, in vergelyking met die kontrole, sonder die byvoeging van 0.03% Zeba® by toedienings suspensies nie. Met die byvoeging van Zeba® is daar tot 53% beheer verkry. Die studie het onweerlegbaar gewys dat die polimeer produk Zeba® die vermoë van S. yirgalemense om P. citri te infekteer verbeter deur die uitdroging van nematodes te vertraag en deur hul te beskerm teen ongunstige omgewings toestande.Thesis (MScAgric)--Stellenbosch University, 2012.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Malan, AntionetteAddison, Pia2012-03-05T16:44:41Z2012-03-30T10:47:00Z2012-03-05T16:44:41Z2012-03-30T10:47:00Z2012-03Thesis129 p, : ill.http://hdl.handle.net/10019.1/20147en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/201812012-05-14T07:16:19Zhdl_10019.1_532

The in vivo production of Heterorhabditis zealandica and Heterorhabditis bacteriophoraVan Zyl, CarolinaSteinernematidaeHeterorhabditisInsect pests -- Biological controlEntomopathogenic nematode productionDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyConservation Ecology and EntomologyENGLISH ABSTRACT: The agricultural industry in South Africa is dominated by the use of insecticides. Producers rely heavily on chemicals that cause increased risk to health, the environment and ecology, rapid resistance development in key insect pests and pesticide residues on crops. The increased concern regarding the impact of these pest management practices on the environment and alternative pest management strategies are being investigated. Entomopathogenic nematodes (EPNs) have been identified as being promising biological control agents of key insect pests. The two EPN genera that have shown promise for use as biological control agents within an integrated pest management programme areSteinernema and Heterorhabditis. Commercialisation and the successful use of EPNs to control pests in North America, Australia, Europe and Asia have confirmed the effectiveness of these organisms as biological control agents. Unfortunately, EPNs in large enough numbers for commercial field applications are not yet available on the South African market. Large numbers of EPNs can be produced through either in vivo or in vitro culturing practices. The objective of this study was to streamline the in vivo production process by using two endemic EPN species, Heterorhabditis zealandica (SF41) and H. bacteriophora (SF351). These EPN isolates have been shown to be effective control agents of codling moth Cydia pomonella, false codling moth Thaumatotibia leucotreta, obscure mealybug Pseudococcus viburni, and the banded fruit weevil Phlyctinus callosus. A comparative study was conducted to identify suitable host insects for EPN production of local H. zealandica (SF41) and H. bacteriophora (SF351) strains. Hosts were selected according to their susceptibility to the two EPN species used, their general availability and the ease and cost of rearing. Wax moth larvae Galleria mellonella (WML) and mealworms Tenebrio molitor (MW) were selected as hosts. In order to produce nematodes of consistent quality, a continuous source of host insects reared on a standardised diet was required. WML and MW were each reared on five different diets in the dark at ±26°C. A superior diet for each host was selected according to the diet that produced, on average, the larvae with the highest body mass within a specific timeframe. The heaviest WML, at an average weight of 0.19 g per larva, were produced on a diet consisting of 118 g wheat flour, 206 g wheat bran, 118 g milk powder, 88 g brewer‟s yeast, 24 g wax powder, 175 ml honey and 175 ml glycerol. The heaviest MW larvae weighed, on average, 0.0154 g per larva, and were produced on a diet consisting of 100% wheat bran. To confirm the hypothesis that a linear relationship exists between the weight of a host and the number of nematodes produced from that host, a study was conducted to determine the number of H. zealandica and H. bacteriophora produced per g of host. WML, MW, codling moth larvae and false codling moth larvae were weighed individually and inoculated with the two nematode species respectively. In addition, nematode production in frozen MW and WML was tested. The number of nematodes harvested from each host was counted, and the average number of nematode progeny produced in each host was calculated. A significant linear correlation between the weight of WML and MW and the number of H. zealandica and H. bacteriophora respectively produced confirmed the hypothesis that nematode production within the specified host increases with an increase in host weight. WML produced the highest number of H. zealandica and H. bacteriophora per g of host (1 459 205 ± 113 670 and 1 898 512 ± 94 355), followed by MW larvae (836 690 ± 121 252 and 414 566 ± 67 017). Lower numbers of H. zealandica and H. bacteriophora per g codling moth (57 582 ± 10 026 and 39 653 ± 8 276) and per g false codling moth (192 867 ± 13 488 and 97 652 ± 23 404) were produced. Successful infection of a suitable insect host is one of the key factors in an efficient in vivo nematode production process. Three inoculation techniques were compared using H. zealandica and H. bacteriophora: inoculation with a pipette; shaking of hosts in the nematode inoculum; and immersion of hosts in the nematode suspension. With each inoculation technique, WML and MW were used as host larvae and were inoculated with nematodes at a concentration of 200 infective juveniles (IJs) / larva. The percentage mortality of insect hosts was determined after two days, and EPN infectivity, confirmed by colour change and dissection, after seven days. The highest percentage EPN infection was obtained using pipetting for both nematode isolates and hosts. Nematode infection rates for all nematode-host combinations obtained with pipetting were above 90%, with the exception of MW inoculation with H. bacteriophora, where the percentage of infection obtained was 76%. The current study conclusively demonstrated that variations in infection levels occur, depending on the inoculation technique used. In an additional effort to enhance infectivity during inoculation, H. zealandica, H. bacteriophora and MW were subjected to host-stressor regimes and to nematode- infectivity-enhancing additives. Three treatments, plus a control treatment, were compared. Exposing MW to 70°C tap water prior to inoculation did not increase infection levels. On the contrary, reduced infection levels were observed with host immersion in 70°C tap water followed by inoculation with H. bacteriophora, compared to the control. Only 12% infection was obtained compared to the 48% infection achieved in the control. Infection obtained using H. zealandica was 21%. Treating H. zealandica and H. bacteriophora IJs withMn2+SO4.H20 in a suspension, prior to inoculating MW, did not significantly enhance nematode virulence. Inoculation of MW with treated H. zealandica IJs led to an infection rate of 81%, compared to the control, with which 80% infection rate was obtained. Heterorhabditis bacteriophora caused 47% MW infection, compared to the control, which was subject to 48% infection. A combination of the two above-mentioned treatments did not enhance the infection levels either. Immersing MW into 70°C tap water prior to inoculation with nematodes treated with Mn2+SO4.H20 led to infection levels of 13% and 9% respectively when H. bacteriophora and H. zealandica were used. Future research is required to optimise the protocol used in this study of subjecting MW and local nematode isolates to stressor regimes. The ability of two formulations to maintain biological activity and virulence of H. zealandica was investigated. A quality standard control measure was used to measure the percentage survival and virulence of formulated H. zealandica over a period of 21 days. IJs were formulated into Pesta granules and coconut fibres, while nematodes stored in tap water served as the control. The numbers of live H. zealandica in Pesta granules and coconut fibres decreased drastically after seven days of storage. The survival of nematodes in Pesta granules dropped to 9.79% after 21 days compared to the control, where the survival rate was 79.79%. Nematode survival in coconut fibres was even lower, at 25.84% after seven days and 2.25% after 21 days. After 21 days in storage, 100%+of nematodes survived in the control for coconut fibres. The application of the standard quality control measure, which was used to determine the virulence of formulated H. zealandica, proved to be ineffective. Higher MW mortality rates were obtained in the control where no nematodes were added to larvae, compared to where nematodes were added in varying dosages. However, adjusting certain aspects in the protocol of this quality control measure specifically to accommodate local conditions could possibly make it a more effective tool for measuring endemic nematode virulence.AFRIKAANSE OPSOMMING: Die landboubedryf in Suid-Afrika word oorheers deur die gebruik van insekdoders. Vervaardigers steun swaar op chemikalieë wat toenemend gesondheids-, omgewings- en ekologiese risiko's, asook die snelle ontwikkeling van weerstand in sleutelinsekteplae veroorsaak, en wat reste van plaagdoders op gewasse laat. Na aanleiding van toenemende besorgdheid oor die impak van hierdie plaagbestuurspraktyke op die omgewing, word alternatiewe plaagbestuurstrategieë ondersoek. Entomopatogeniese nematodes (EPNs) is geïdentifiseer as belowende biologiese beheeragente van sleutelinsekteplae. Die twee EPN genera wat belofte inhou vir gebruik as biologiese beheeragente binne 'n geïntegreerde plaagbestuursprogram is Steinernema en Heterorhabditis. Kommersialisering en die geslaagde gebruik van EPNs om insekplae te beheer in Noord-Amerika, Australië, Europa en Asië, het die doeltreffendheid van hierdie organismes as biologiese beheeragente bevestig. Ongelukkig is EPNs in groot genoeg getalle vir kommersiële aanwending in die veld nog nie op die Suid-Afrikaanse mark beskikbaar nie. Groot getalle EPNs kan deur in vivo en in vitro teling verkry word. Die doelwit van hierdie studie was om die in vivo produksieproses te stroomlyn deur die gebruik van twee endemiese EPN spesies, Heterorhabditis zealandica (SF41) en H. bacteriophora (SF351). Hierdie EPN isolate is deur navorsing bewys om doeltreffende beheeragente van kodlingmot Cydia pomonella, vals kodlingmot Thaumatotibia leucotreta, ligrooswitluis Pseudococcus viburni, en gebande vrugtekalanders Phlyctinus callosus te wees. 'n Vergelykende studie is gedoen om geskikte gasheerinsekte vir EPN produksie van plaaslike H. zealandica (SF41) en H. bacteriophora (SF351) isolate te vind. Gashere is geselekteer op grond van vatbaarheid vir die EPN spesie wat gebruik word, en algemene beskikbaarheid en gemak en koste van teling. Wasmotlarwes Galleria mellonella (WML) en meelwurms Tenebrio molitor (MW) is as gashere gekies. Ten einde nematodes van konsekwente kwaliteit te teel, word 'n deurlopende bron van gasheerinsekte benodig wat op 'n gestandaardiseerde dieet voed. WML en MW is onderskeidelik op vyf verskillende diëte geteel by ±26°C in die donker. Die beste dieet vir elke gasheer is gekies op grond van die dieet wat, gemiddeld, die swaarste larwes binne 'n spesifieke tydsraamwerk opgelewer het. Die swaarste WML, teen 'n gemiddelde massa van 0.19 g per larwe, is geteel op 'n dieet wat bestaan het uit 118 g koringmeel, 206 g semels, 118 g melkpoeier, 88 g brouersgis, 24 g verpoeierde was, 175 ml heuning en 175 ml gliserol. Die swaarste MW larwes het gemiddeld 0.0154 g per larwe geweeg en is geteel op 'n dieet van 100% semels. Ten einde die hipotese te bevestig dat 'n lineêre verwantskap bestaan tussen die massa van 'n insekgasheer en die aantal nematodes wat deur daardie gasheer geproduseer word, is 'n studie gedoen om die aantal H. zealandica en H. bacteriophora per gasheergram te bepaal. WML, MW, kodlingmotlarwes en vals kodlingmotlarwes is individueel geweeg en met infektiewe larwes van die twee onderskeidelike EPN spesies geïnokuleer. Daarbenewens is die vermeerdering van nematodes in bevrore MW en WML ook getoets. Die aantal nematodes wat in elke gasheer geoes is, is getel, en die gemiddelde nematode-afstammelinge in elke gasheer bereken. 'n Beduidende lineêre korrelasie tussen die massa van WML en MW en die aantal H. zealandica en H. bacteriophora wat onderskeidelik geproduseer is, het die hipotese bevestig dat nematode-vermeerdering binne hierdie gashere toeneem namate die gasheermassa toeneem. WML het die meeste H. zealandica en H. bacteriophera per gasheergram opgelewer (1 459 205± 113 670 en 1 898 512± 94 355 onderskeidelik), gevolg deur MW larwes (836 690± 121 252 en 414 566± 67 017 onderskeidelik). Laer getalle H. zealandica and H. bacteriophora per gram kodlingmot (57 582 ± 10 026 en 39 653 ± 8 276) en per gram vals kodlingmot (192 867 ± 13 488 en 97 652 ± 23 404) is egter geproduseer. Een van die sleutelfaktore vir die doeltreffendheid van die in vivo vermeerdering van nematodes is geslaagde gasheerinfeksie. Drie inokulasietegnieke is dus geëvalueer en vergelyk deur H. zealandica en H. bacteriophora te gebruik: inokulasie met 'n pipet, skud van gashere in 'n nematode-inokulum, en gasheerindompeling in 'n nematode-suspensie. WML en MW is as gashere gebruik vir elke inokulasietegniek, en is geïnokuleer met nematodes wat uit 'n konsentrasie van 200 infektiewe larwes (ILs) / insek larwe bestaan het. Die persentasie dooie insekgashere is na twee dae bepaal, en infeksie soos bevestig deur kleurverandering en disseksie, na sewe dae. Die hoogste persentasie infeksie deur sowel nematode-isolate as gashere te gebruik, was met die pipet-tegniek. Die infeksiekoerse vir alle nematode-gasheerkombinasies met die pipet-tegniek was hoër as 90%, met die uitsondering van MW-inokulasie met H. bacteriophora, waar die infeksie 76% was. Hierdie studie toon dat afwykings voorkom in die mate van gasheerinfeksie, na gelang van die inokulasietegniek wat gebruik is. In 'n bykomende poging om infeksie na inokulasie te verhoog, is H. zealandica, H. bacteriophora en MW onderwerp aan stressors en bymiddels om nematode-infeksie te bevorder. Drie behandelings, asook 'n kontrole-behandeling, is vergelyk. Infeksievlakke het nie verhoog deur MW voor inokulasie aan kraanwater van 70°C bloot te stel nie. Inteendeel, laer infeksievlakke is opgemerk waar gashere in kraanwater van 70°C gedompel is en daarna met H. bacteriophora geïnokuleer is, vergelyke met die kontrole. Gasheerinfeksie van slegs 12% is verkry, vergelyke met 48% in die kontrole. Infeksie van 21% is met H. zealandica verkry. Die virulensie van nematodes het nie beduidend toegeneem deur H. zealandica en H. bacteriophora IL in 'n suspensie met Mn2+SO4H20 te behandel voor MW geïnokuleer is nie. Inokulasie van MW met behandelde H. zealandica IL het tot 'n infeksie van 81% gelei, vergelyke met die kontrole waar 'n infeksie van 80% behaal is. H. bacteriophora het 'n MW-infeksie van 47% veroorsaak, vergelyke met die kontrole se infeksiekoers van 48%. 'n Kombinasie van die twee bogenoemde behandelings het eweneens nie gasheerinfeksievlakke verhoog nie. Die indompeling van meelwurms in kraanwater van 70°C voor inokulasie met nematodes wat met Mn2+SO4H20 behandel is, het tot gasheerinfeksie van 13% en 9% onderskeidelik gelei wanneer H. bacteriophora en H. zealandica gebruik is. Toekomstige navorsing is nodig om die protokol te verbeter wat in hierdie studie gebruik is om MW en plaaslike nematode-isolate aan stressors te onderwerp. 'n Ondersoek is gedoen na die vermoë van twee formulasies om biologiese aktiwiteit en virulensie van H. zealandica te onderhou. 'n Kwaliteitsstandaardtegniekis gebruik om weekliks die persentasie oorlewing en virulensie van geformuleerde H. zealandica oor 'n tydperk van 21 dae te meet. IL is in Pesta korrels en klappervesel geformuleer, terwyl nematodes in kraanwater gedien het as kontrole. Die aantal lewende H. zealandica in Pesta korrels en klappervesel het drasties verminder na sewe dae in die formulasie. Oorlewing van nematodes in Pesta korrels het gedaal tot 9.79% na 21 dae vergyleke met die kontrole, waar 79.79% oorleef het. Nog minder nematodes - 25.84% - het na sewe dae in die klappervesel oorleef, en slegs 2.25% na 21 dae. Na 21 dae van berging het 100%+ van nematodes oorleef in die kontrole vir klappervesel. Die toepassing van die kwaliteitsstandaardtegniek om die virulensie van geformuleerde H. zealandica te bepaal, het ondoeltreffend geblyk. Verhoogde MW sterftesyfers is verkry in die kontrole waar geen nematodes by die inseklarwes gevoeg is nie, vergelyke met die byvoeging van hoër dosisse nematodes. Nietemin, die aanpassing van sekere aspekte in die protokol van hierdie kwaliteitsbeheermeting om spesifiek plaaslike toestande in ag te neem, sou dit moontlik 'n meer doeltreffende middel kon maak om die virulensie van endemiese nematodes te bepaal.Thesis (MScAgric)--Stellenbosch University, 2012.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Malan, A. P.Addison, P.Addison, M. F.2012-02-27T12:47:43Z2012-03-30T10:50:11Z2012-02-27T12:47:43Z2012-03-30T10:50:11Z2012-03Thesis97 p. : ill.http://hdl.handle.net/10019.1/20181en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/203252012-05-14T07:07:10Zhdl_10019.1_532

Fynbos riparian biogeochemistry and invasive Australian acaciasNaude, MinetteAcacia -- South Africa -- Western CapeInvasive plants -- South Africa -- Western CapeFynbos -- South Africa -- Western CapeRiparoan areas -- South Africa -- Western CapeBiogeochemistryDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyConservation Ecology and EntomologyENGLISH ABSTRACT: Riparian ecotones, transitional areas between upland terrestrial communities and aquatic ecosystems, are very dynamic and complex ecosystems with intrinsic ecological properties differing in spatial structure, function and temporal dynamics. Riparian habitats along rivers of the Mediterranean south-western Cape are sensitive to environmental change and particularly vulnerable to invasion by invasive alien plants (IAPs), especially nitrogen-fixing Acacia spp., and yet relatively little work has focused on how riparian ecosystems in this region respond to such stressors. The important roles that intact riparian vegetation play in maintaining ecosystem integrity and services have been increasingly highlighted as we acknowledge the degradation of these habitats. While the Working for Water (WfW) programme has been shown to be very successful in eradicating IAPs in riparian zones in the short-term, the extent to which riparian ecosystems recover following alien clearing activities remains poorly understood. The results presented in this study addressed several different aspects of riparian structure and function and acts as a steppingstone for guiding future research and management in riparian zones by adding to the evaluation of the success of clearing initiatives and restoration thereof. The aim of this study was to assess plant functional type (PFT) cover, soil physical and chemical properties, and selected biogeochemical processes in natural, Acacia- invaded and cleared riparian ecotones and associated non-riparian upland fynbos. Fieldwork was performed in mountain and foothill sections of six perennial river systems within the south-western Cape. Eleven sites of three categories were chosen: four natural sites (uninvaded); four moderate to highly invaded sites (predominantly A. mearnsii); and three cleared sites (a formerly invaded site that had been cleared more than 7 years prior to the study). Within each site, four to five replicate plots were established along each of three geomorphological zones (wet bank, dry bank, and upland fynbos). Seasonal soil samples were collected for a period of one year. Results from this study showed that PFT cover and composition, soil physical and chemical properties and rates of nitrogen (N) and phosphorus (P) mineralization differed amongst invasion status, between geomorphological zones and across seasons. Regarding most soil physical and chemical properties and indices N and P cycling, river floodplains (dry banks) were very similar to terrestrial uplands. Acacia spp. changes soil properties and affects plant functional attributes by i) enriching the system with N; ii) enhancing litter inputs; iii) altering soil physical properties; iv) changing the composition and reducing the cover of PFT; and v) enhancing P mineralization rates. Although measured soil physical and chemical properties and N and P mineralization rates were reduced to levels that were similar to or resembled the situation at natural areas, available inorganic N remained two times higher after more than seven years of clearance. Furthermore, cleared areas were characterized by sparse woody cover and a high cover of alien grasses. Correlations between soil silt and clay content and several soil properties measured in this and other studies indicates important linkages between soil texture and resource availability. Clearing Acacia spp. may initiate restoration of invaded riparian ecosystems, but changes in ecosystem function (e.g. elevated soil N availability) as a result of invasion may necessitate active restoration following the removal of the alien species. Active restoration under such conditions would be required to facilitate the restoration of cleared riparian communities. However, we still lack the mechanistic understanding around fynbos riparian recovery after clearing, as the success of restoration may depend on complex interaction and feedback cycles between plants and their physical environment. A greater comprehensive understanding of fynbos riparian ecological processes will not only improve the effectiveness of restoration initiatives by integrating science and management, but also advance the field of riparian ecology.AFRIKAANSE OPSOMMING: Rivier oewerwal-areas, oorgang gebiede tussen aangrensende terrestriële gemeenskappe en akwatiese ekosisteme, is baie dinamiese en komplekse ekosisteme met intrinsieke ekologiese eienskappe wat verskil in struktuur, funksie (bv. biogeochemie siklusse) en temporale dinamika. Oewerhabitatte langs riviere van die Mediterreense suid-wes Kaap is sensitief vir omgewingsveranderinge en kwesbaar vir indringing deur uitheemse plante (bekend as “invasive alien plants” (IAPs)), veral stikstof-fiksering Acacia spp., en relatief min werk het nog gefokus op hoe ekosisteme in die streek reageer op sulke veranderinge in die omgewing. Die belangrike rol wat gesonde oewerwal plantegroei speel in die handhawing van ekosisteemdienste- en integriteit, is al hoe meer uitgelig soos ons die agteruitgang van hierdie habitat in ag neem. Terwyl die Werk vir Water (WvW)-program al dat baie suksesvol was in die uitwissing van IAPs in oewersones in die kort termyn, is die mate waarin oewer-ekostelsels herstel na skoonmaakaksies swak verstaan. Fynbos oewerwal-areas is grootliks ingeneem deur houtagtige IAPs, veral stikstof fiksering Acacia spp. (soos Acacia mearnsii). Die resultate wat in hierdie studie aangebied is, het verskillende aspekte van oewer- struktuur en funksie aangespreek en dien as middel vir toekomstige navorsing en bestuur van oewerwal ekosisteme deur by te dra tot die evaluering van die sukses van skoonmaak inisiatiewe en die herstelproses daarvan. Die doel van hierdie projek was om die moontlikhede vir herstel van fynbos owerwal-ekostelsels te evalueer deur middel van verskeie grond- fisiese en chemiese eienskappe; plant funksionele groep dekking (genoem ‘plant functional types’ (PFT)); en geselekteerde grond biogeochemie prosesse in natuurlike, Acacia- aangetaste, en skoongemaakte rivierstelsels en nabygeleë terrestriese areas te vergelyk. Veldwerk is gedoen in bergstroom en voetheuwel rivierseksies van ses standhoudende rivierstelsels in Suid-wes Kaap, Suid Afrika. Van uit hierdie geselekteerde rivierstelsels is elf studie areas van drie kategorieë (of indringing status) gekies: vier natuurlike areas (nie aangetas); vier gematig- tot hoogs aangetaste areas (hoofsaaklik A. meanrsii); en drie skoongemaakte areas (rivieroewers wat meer as sewe jaar van te vore skoongemaak is). Binne elke studie area was vier tot vyf soortgelyke persele gevestig by elke van drie breë geomorfologiese sones: naamlik nat-, droë en hoogliggende terrestriese fynbos. Seisoenale grondmonsters vir 'n tydperk van een jaar is geneem. Resultate van hierdie studie het getoon dat PFT dekking en samestelling, grond fisiese- en chemiese eienskappe en N-mineralisasie en suur fosfatase aktiwiteit verskil tussen indringing status, geomorfologiese sones en oor seisoene. Ten opsigte van meeste grond fisiese en chemiese eienskappe en indekse van stikstof (N) en fosfor (P) siklusse kom die rivier vogregimes (droë oewersones) baie ooreen met die terrestriële gebiede. Aan die anderkant is die natbanksones gekenmerk deur grondeienskappe wat baie verskil van die ander twee geomorfologiese gebiede. Die gegewens ondersteun die hipotese dat indringing deur Acacia spp. verskeie grondeienskappe verander en plante se funksionele kenmerke beïnvloed deur i) die sisteem met voedingstowwe te verryk (veral N); ii) verhoog die toevoeging van plantmateriaal; iii) verander grond fisiese eienskappe; iv) verander die samestelling en verminder die dekking van PFT; v) en verhoog P biogeochemie. Hoewel grond fisiese -en chemiese eienskappe, en indekse van N en P mineralisasie verminder is tot vlakke wat soortgelyk aan natuurlike areas, het beskikbare anorganiese N twee keer hoër gebly by skoongemaakte gebiede. Nietemin, voorheen skoongemaakte gebiede is weer-binnegeval deur eksotiese grasse en die regenerasie of hertelling van inheemse fynbos gemeenskappe is taamlik beperk, veral houtagtige oewer struike en bome. Korrelasies tussen grond slik-en klei-inhoud en verskeie grondeienskappe gemeet in hierdie en ander studies dui op belangrike skakeling tussen die grondtekstuur en voedingstof beskikbaarheid. Die opruiming van Acacia spp. mag as aansporing dien vir die herstellingsproses van rivieroewerstelsels, maar veranderinge in die funksie van ekosisteme (bv. verhoogte grond N beskikbaarheid), as gevolg van indringing, mag aktiewe herstel noodsaak nadat die indringer spesies verwyder is. Aktiewe herstel onder sulke omstandighede sal verwag word om die herstel van skoongemaak oewer gemeenskappe te fasiliteer. Ons het wel egter nog 'n gebrek aan die meganistiese begrip in verband met die herstel van fynbos oewerwal areas na opruimings-inisiatiewe, sedert die sukses van herstel kan afhang van komplekse interaksie en terugvoer siklusse tussen die plante en hul fisiese omgewing. ʼn Meer omvattende begrip van fynbos rivieroewer ekologiese prosesse sal nie net die doeltreffendheid van opruimings-inisiatiewe deur die integrasie van wetenskaplike navorsing en bestuur verbeter nie, maar ook vooraf die gebied van rivieroewer-ekologie.Thesis (MScConEcol)--Stellenbosch University, 2012.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Jacobs, Shayne M.Esler, Karen J.2012-03-12T09:32:00Z2012-03-30T11:03:59Z2012-03-12T09:32:00Z2012-03-30T11:03:59Z2012-03Thesis180 p. : ill., mapshttp://hdl.handle.net/10019.1/20325en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/203892013-03-19T08:08:31Zhdl_10019.1_532

A perspective on the seed bank dynamics of Acacia salignaStrydom, MatthysInvasive alien plantsSeed densitySpatial distributionBiological controlSeed rainTheses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyENGLISH ABSTRACT: Acacia saligna, or Port Jackson, is an Australian Acacia which has spread throughout the Western and Eastern Cape provinces of South Africa where it has become invasive and a prominent feature of the vegetation. In areas where A. saligna establishes it replaces natural vegetation, alters ecosystem processes and interferes with agricultural practices. Consequently large management efforts have been made to eradicate this invasive alien tree. However, its large and persistent soil stored seed bank, even in the presence of management and biological control agents, poses a serious obstacle to its successful removal. Furthermore the reproductive output and the size of the seed bank of A. saligna over its whole distribution as well as the variation of seed production and the seed bank with environmental conditions in time and space is poorly known. Understanding the seed bank dynamics of A. saligna in time and space is essential for reducing invasive success and achieving management objectives. This study has filled this knowledge gap through studying the seed production and seed bank of A. saligna over its invaded range in South Africa, including how environmental factors influence these factors in time and space. The seed rain of A. saligna was assessed at 10 sites across its distribution in South Africa. The seed rain of A. saligna at the sites was determined through the use of seed rain traps. Twenty five traps were placed out at every site during November 2010 (pre-dehiscence) which was collected again during April 2011 (postdehiscence). The seed bank of A. saligna was estimated through sampling at 25 sites across its distribution range in South Africa. The seed bank was sampled during April 2010 (postdehiscence), November 2010 (pre-dehiscence) and April 2011 (post-dehiscence) through taking 50 litter and soil samples at every site which gave a total sampling size of 3 750 for both the seed in the soil and litter over its distribution in South Africa. In addition the average tree diameter, tree density, average number of Uromycladium tepperianum induced galls per tree, the summer aridity index, De Martonne aridity index, winter concentration of precipitation, temperature of coldest month and the soil texture for every site was determined. The damage done by the seed feeding weevil, Melanterius compactus, was also estimated for the seed rain study sites. Water availability during the hot summer months was assessed as the most important factor governing seed production and seed bank size. Riparian and non-riparian water regimes were shown to be important in understanding the seed bank dynamics of A. saligna over its distribution range in the Cape Floristic Region. In non-riparian A. saligna populations the seed production and consequently the size of the seed bank and its rate of accumulation is limited by both water and temperature and in riparian A. saligna populations, only by temperature. Therefore, two environmental gradients influence the seed bank dynamics of Port Jackson in South Africa. In non-riparian A. saligna populations the number of seed produced and the accumulation of seed in the seed bank generally increases along the west coast of South Africa from Clanwilliam towards Cape Town and along the south coast from Cape Town towards Port Elizabeth. Seed banks are larger closer to the coast, when A. saligna populations of similar age are compared. In riparian A. saligna populations, the number of seed produced generally increases from Port Elizabeth towards Cape Town and from Cape Town towards Clanwilliam, again, with larger seed banks being accumulated closer to the coast, when populations of similar age are compared. This study provides managers with a useful tool for prioritising management efforts.AFRIKAANSE OPSOMMING: Acacia saligna of Port Jackson is ‘n indringerplant in Suid-Afrika wat afkomstig is uit Suid-Wes Australië. Acacia saligna is ‘n onmisbare kenmerk van die plantegroei in die Wes en Oos-Kaap. Waar Port Jackson vestig, verplaas dit natuurlike plantegroei, verander dit ekosisteem prossesse en verhinder dit landbou praktyke. Gevolglik is groot bestuurspogings aangewend om hierdie indringer plant uit te roei. In die teenwoordigheid van bestuursprogramme en biologiese beheer bly A. saligna lewensvatbaar as ‘n gevolg van die plant se groot blywende grond saadreserwes. Verder is die saad produksie en saadbank grootte van A. saligna oor sy verspreiding bereike asook hoe dit met omgewingstoestande in tyd en ruimte interreageer en varieer grootendeels onbekend. ‘n Goeie en omvattende begrip van die saadbankdinamika is belangrik om die indringings vermoë van die plant te verlaag en om bestuursdoelwitte te bereik. Hierdie studie vul die bestaande gaping in die kennis aangaande die saadbank dinamika van A. saligna aan deur die saadproduksie en die saadreserves van die indringerplant oor sy verspreiding in Suid-Afrika te bestudeer, insluitend hoe omgewingstoestande die saadbankdinamika beïnvloed in tyd en ruimte. Die saadreën vir 10 A. saligna populasies was bepaal deur die gebruik van saadlokvalle. Vyf-entwintig lokvalle was uitgeplaas in elke bestudeerde Port Jackson perseel gedurende November 2010 (voor-saadval) wat weer gaan haal is gedurende April 2011 (na-saadval). Die saadbank van A. saligna was bepaal in 25 populasies van die boom gedurende April 2010 (na-saadval), November 2010 (voor-saadval) en April 2011 (na-saadval) deur die neem van 50 blaar- en grondmonsters by elke perseel wat ‘n totaal van 3 750 blaar- en grondmonster gee oor die hele verspreiding van A. saligna in Suid-Afrika. Verder is die gemiddelde boomdeursnee, boomdigtheid, gemiddelde Uromycladium tepperianum geinduseerde galle per boom, die somers droogtheids indeks, De Martonnes droogtheids indeks, die winter konsentrasie van presipitasie, die temperatuur van die koudste maand en die grond tekstuur van elke Port Jackson stand bepaal. Die skade wat die saad voedende kewer, Melanterius compactus, aanrig aan die sade van A. saligna is ook vir die persele waar die saadreën eksperiment uitgevoer is, bepaal. Die beskikbaarheid van water vir A. saligna in die droë somermaande is bepaal as die belangrikste faktor wat die grootte van die saadproduksie en saadbank beïnvloed. Oewer en nie-oewer water omgewings is bevind as noodsaaklik om die saadbank dinamika van A. saligna oor die indringerplant se verspreidingareas in die Kaap Floristiese Streek te verstaan. In nie-oewer A. saligna populasies word saadproduksie en gevolglik die grootte en tempo van akkumulasie van die saadbank deur beide water en temperatuur omstandighede beperk, terwyl in oewer A. saligna populasies word die indringerplant slegs deur temperatuur omstandighede beperk. Gevolglik blyk dit dat twee water beskikbaarheids gradiënte bestaan waarop die plant reageer wat dan uitgedruk word in die plant se saad produksie en gevolglik ook die plant se saadbank. In nie-oewer Port Jackson populasies neem die saadproduksie en die tempo waarteen die saadbank akkumuleer algemeen toe langs die weskus van Clanwilliam na Kaapstad en van Kaapstad na Port Elizabeth, met grootter saadproduksie en saadbank akkumulasie nader aan die kusgebiede, wanneer A. saligna populasies van dieselfde ouderdom vergelyk word. In oewer Port Jackson populasies neem die saadproduksie en die tempo waarteen die saadbank akkumuleer algemeen toe van Port Elizabeth na Kaapstad en van Kaapstad na Clanwilliam, met grootter saadproduksie en saadbank akkumulasie nader aan die kusgebiede, wanneer A. saligna populasies van dieselfde ouderdom vergelyk word. Hierdie studie verskaf bestuursplanne met ‘n nuttige raamwerk waarvolgens uitroeiing en beheer programme vir A. saligna beplan kan word.Thesis (MScConEcol)--Stellenbosch University, 2012.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Esler, Karen J.Wood, Alan R.2012-03-13T08:04:31Z2012-03-30T11:10:02Z2013-03-01T22:10:02Z2012-03Thesis170 p. : ill., mapshttp://hdl.handle.net/10019.1/20389en_ZA

oai:scholar.sun.ac.za:10019.1/208992012-05-07T12:18:03Zhdl_10019.1_532

Invasive perennial species in an agricultural area of the Western Cape Province : distribution and relationship with various land-use typesMidgley, John ClaudeNoxious weeds -- South Africa -- Western CapeAcacia mearnsii -- South Africa -- Western CapeHakea sericeaTheses -- Ecological assessmentDissertations -- Ecological assessmentInvasive plants -- South Africa -- Western Cape -- Geographical distributionENGLISH ABSTRACT: This project consists of two botanical investigations in an agricultural area of the Western Cape Province. A farm known as De Rust, in the Elgin Valley, was used to sample the geographic location, density, height and life stage of six prominent invasive plant species in various land-use categories. In the first investigation, the density, height and age structures of the six invasive species populations were analyzed. The density distribution of the six species was also displayed cartographically. Species were then ranked according to the potential threat that they pose to the conservation of the remaining natural areas on the farm. Results indicated that Acacia mearnsii and Acacia saligna are the major invaders at De Rust and that Hakea sericea can be considered as an emerging invader. The second investigation explores the statistical relationship between the various land-use categories and density, height and age of the six prominent invaders identified in the first investigation. The loglikelihood ratio analysis of observed frequencies resulted in statistically significant (P<0.01; P-values range between 1.35 x 10-3 and 2.7 x 10-224) relationships between certain land-use types and certain invasive species. A conclusion was reached that it could be useful to include land-use categories in simulation models of invasive plant species distribution and spread.AFRIKAANSE OPSOMMING: Hierdie projek behels twee botaniese ondersoeke in ‘n landbou gebied van die Weskaap. Die plaas bekend as De Rust, in die Elgin Vallei, was gebruik vir die versameling van data te doen met die geografiese ligging, plant digtheid, lengte en lewens stadium van ses prominente indringer plant spesies in verskeie landgebruik kategorieë. Die digtheid, lengte en ouderdomstruktuur van ses indringerspesies was in die eerste ondersoek geanaliseer. Die verspreiding van digtheid was ook in kaarte uitgelê. Spesies was daarna volgens hulle potentiële dreiging teen die bewaring van oorblywende natuurlike dele van die plaas in ‘n rangorde geplaas. Resiltate dui aan dat Acacia mearnsii en Acacia saligna die belangrikste indringer plante op De Rust is en dat Hakea sericea as ‘n opkomende indringer beskou kan word. Die tweede ondersoek kyk na die verhouding tussen verskeie grondgebruik kategorië en die digtheid, lengte en ouderdom van die ses prominente indringer spesies wat in die eerste ondersoek identifiseër is. ‘n Log tipe ratios ontleding van bewaarde frekwensies het ‘n statisties belangrike uitkoms gehad (P<0.01; P-waardes tussen 1.35 x 10-3 en 2.7 x 10-224) vir die verhoudings tussen sekere grondgebruik tipes en sekere indringer spesies. Die gevolgtrekking was dat dit handig mag wees om grondgebruik kategorieë in simulasies van indringer plant verspreiding te gebruik.Thesis (MSc)--University of Stellenbosch, 2005.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.McGeoch, M.A.Esler, K.J.2012-05-03T13:10:28Z2012-05-03T13:10:28Z2005-04Thesis75 leaves : ill.http://hdl.handle.net/10019.1/20899en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/209162013-01-21T08:22:11Zhdl_10019.1_532

Gap regeneration in the Tsitsikamma forest (Easter Cape, South Africa) : the effect of gap size and originElla, GhislainForest canopy gaps -- South Africa -- Tsitsikamma ForestForest biodiversity -- South Africa -- Tsitsikamma ForestUnderstory plants -- South Africa -- Tsitsikamma ForestClearcutting -- South Africa -- Tsitsikamma ForestForest ecology -- South Africa -- Tsitsikamma ForestForest soils -- South Africa -- Tsitsikamma ForestForest regeneration -- South Africa -- Tsitsikamma ForestTheses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyENGLISH ABSTRACT: Recognizing the biological significance of gaps, the South African Department of Water Affairs and Forestry (DWAF) in 1989 initiated a Gap Dynamics Project in the indigenous forests of Tsitsikamma (Eastern Cape, South Africa). This consists of three sub-projects: Koomansbos (9300 m2), created by a ground fire in 1989; Plaatbos (1600 m2), made by a Podocarpus falcatus (Thunb.) R. Br. ex Mirb. (Podocarpaceae) windfall in 1994; and nine gaps of different sizes, artificially created by selective tree felling in 1995: three small (100-150 m2), three medium (300-500 m2) and three large (800-1000 m2). All the gaps were surveyed after creation and permanent plots were established for subsequent monitoring. The current timber harvesting system practiced in South African indigenous forests attempts to minimize gap size. It has been proposed by Euston-Brown et al. (1996) that this practice is likely to benefit the more shade tolerant species, but may inhibit the regeneration of less shade tolerant plants in the forest. Therefore, the present study aimed to verify two hypotheses: gaps may close in a process that is determined by their size, their origin and the plant species characteristics; soil quality might change inside those gaps. For the purpose of the study, the gaps cited above were re-surveyed between 2002 and 2003. It was found that: 1) there was little clear difference in the community structure of plant species between gaps of different sizes and origins; as expected from the species-area relationship, large gaps had higher species richness, plant diversity and herbaceous percentage cover than medium and small gaps; diversity indices were higher in the large windfall gap than in the large fire and artificial gaps; generally, context and stochastic events were largely more important in determining gap diversity and regeneration than gap sizes and origins; 2) diversity indices in the gaps were higher than recorded previously; 3) soil pH and Electrical Conductivity were respectively lower and higher inside the gaps than adjacent to them; these variations were statistically significant. Present data on the vegetation in the gaps were compared to past measurements, and future vegetation structure has been predicted, as a function of current gap vegetation. Recommendations have been made for sustainable management of the indigenous forest of Tsitsikamma.AFRIKAANSE OPSOMMING: Voortspruitend uit die erkenning van die biologiese belang van gapings, het die Suid-Afrikaanse Departement van Waterwese en Bosbou (DWB) in 1989 'n projek oor gapingsdinamika in die inheemse woude van Tsitsikamma (Oos-Kaap, Suid-Afrika) geïnisieer. Dit bestaan uit drie subprojekte: die gaping in Koomansbos (9300 m2) wat in 1989 deur 'n grondvuur geskep is; die gaping in Plaatbos (1600 m2) wat veroorsaak is toe bome van die spesie Podocarpus falcatus (Thunb.) R. Br. ex Mirb. (Podocarpaceae) in 1994 omgewaai is; en nege gapings van verskillende groottes wat in 1995 kunsmatig deur geselekteerde boomkappery geskep is: drie is klein (100-150 m2), drie mediumgrootte (300-500 m2) en drie groot (800-1000 m2). Alle gapings is ná hulle ontstaan opgemeet en ondersoek en permanente terreine is vir daaropvolgende monitering gevestig. Die stelsel wat tans vir die oes van hout in Suid-Afrikaanse inheemse woude gebruik word, poog om die grootte van gapings te minimaliseer. Euston Brown et al. (1996) doen aan die hand dat hierdie praktyk spesies wat meer skaduweeverdraagsaam is waarskynlik sal bevoordeel, maar die regenerasie van plante in die woud wat minder skaduweeverdraagsaam is, kan inhibeer. Hierdie studie het dus ten doel gehad om twee hipoteses te verifieer: Gapings kan toegroei in 'n proses wat deur hul grootte, oorsprong en die eienskappe van die plantspesies bepaal word; en die gehalte van die grond binne daardie gapings kan verander. Die gapings waarna hierbo verwys is, is vir die doel van hierdie studie tussen 2002 en 2003 weer gemonitor. Daar is bevind dat: 1) daar min duidelike verskille was tussen die gemeenskapstruktuur van plantspesies tussen gapings van verskillende groottes en oorsprong; soos van die verhouding tussen spesies en area verwag kan word, het groter gapings 'n hoër spesierykheid, plantdiversiteit en persentasie niehoutagtige dekking as medium- en klein gapings gehad; diversiteitsindekse was hoër in die groot Plaatbosgaping as in die groot Koomansbosgaping of die kunsmatige gapings; in die algemeen was konteks en stochastiese gebeure grootliks belangriker in die bepaling van gapingsdiversiteit en -regenerasie as gapingsgrootte of -oorsprong; 2) diversiteitsindekse in die gapings was hoër as wat voorheen aangeteken is; en 3) grond-pH en elektriese geleidingsvermoë was onderskeidelik laer en hoër binne die gapings as neffens hulle; hierdie variasies was statisties beduidend. Huidige data oor die plantegroei in die gapings is met vorige metings vergelyk, en 'n toekomstige plantegroeistruktuur is as 'n funksie van huidige gapingsplantegroei voorspel. Aanbevelings is gemaak rakende die volhoubare bestuur van Tsitsikamma se inheemse woud.Thesis (MSc(For))--University of Stellenbosch, 2005.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of Agrisciences. Dept. of Conservation Ecology and EntomologyPepler, DaveMcGeoch, Melodie A.2012-05-07T13:01:43Z2012-05-07T13:01:43Z2005-12Thesisvi, 107 leaves : ill., mapshttp://hdl.handle.net/10019.1/20916en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/209172012-05-12T22:00:47Zhdl_10019.1_532

An assessment of water quality and endocrine disruption activities in the Eerste/Kuils River catchment system, Western Cape, South AfricaFourie, ShaniWater quality -- South Africa -- Western Cape -- MeasurementWater quality -- Eerste River (South Africa) -- MeasurementWater quality -- Kuils River (South Africa) -- MeasurementEndocrine glands -- DiseasesWater -- Pollution -- Environmental aspects -- South Africa -- Western CapeEerste River Catchment (South Africa)Kuils River Catchment (South Africa)Theses -- Ecological assessmentDissertations -- Ecological assessmentENGLISH ABSTRACT: Water quality analysis forms the basis in assessing and monitoring catchments. As urban development continuously increase, pollution sources increase in either point source (wastewater treatment works, industrial effluents) and/or non-point source origin (storm water discharge, domestic pollutants), accumulating pollutants in the environment. It was only recently discovered that certain pollutants have subtle disrupting effects on the endocrine system resulting in health related problems associated with the reproductive system and thyroid system (growth and development) of animals and potentially humans. Natural water resource management proves to include limited biological assays measuring endpoints for cytoxicity, inflammatory activity and endocrine disruption. The broad objective of this study was therefore to include several bioassays, not normally used in municipal (City of Cape Town) monitoring programmes, along with water quality data collected by the City of Cape Town. The Eerste/Kuils River catchment system, Western Cape, under the auspices of the City of Cape Town was chosen, and although this catchment does not contribute to drinking water resources, is subjected to a range of anthropogenic influences (industrial effluents, household wastewater, agricultural runoff). Within the short time-frame available for this study (six months) two months, July (following a dry summer and autumn season) and October (following a wet winter and early spring season) were selected for water quality monitoring. Spatial variation (with relevance to specific point and non-point contamination) among sampling sites were also obtained by choosing several (n=10) along the catchment. Specific aim of the study therefore included: Firstly (Chapter 2), the use of in vitro bioassays, lactate-dehydrolises assay (LDH) for cytotoxic activity, pro-inflammatory hormone Interleukin-6 (IL-6) secretion by human blood cells and a specific Salmonella ELISA for faecal contamination, in conjunction with routine chemical and biological (mostly microbiological) monitoring activities. The study indicated significant variation among sites in all microbiological measures as well in IL-6 secretion and Salmonella presence. Between months, variations were also evident in certain variables. Secondly (Chapter 3), two bioassays using the yolk precursor protein, vitellogenin (Vtg) as endpoint was implemented in a) an in vitro Xenopus laevis liver slice assay (five day exposure) and b) an in vivo Zebrafish (Danio rerio) bioassay (seven day exposure) assessing estrogenic activity in the Eerste/Kuils River catchment. Although estrogen spiked positive control water samples stimulated Vtg production in vitro as well as in vivo, no dramatic estrogenic activity was measured at any of the selected sites. Thirdly (Chapter 4), a bioassay using the thyroid controlled metamorphosis in Xenopus laevis tadpoles to assess effects on the thyroid hormonal system was implemented. Thyroid stimulatory activity, compared with a negative control sample, was measured at two sites along the catchment. Although the practical implementation of the tadpole semi-static exposure protocol (water replacement) proved to be labour intensive, all the added bioassays proved to be valuable tools to add valuable information regarding water quality. It is clear that more research related to anthropogenic influences along the Eerste/Kuils River catchment system are needed, specifically in monitoring monthly variations to better understand annual variation in several of the endpoints studied.AFRIKAANSE OPSOMMING: Waterkwaliteit vorm die basis vir die evaluering en monitering van opvangsgebiede. Voortdurende stedelike ontwikkeling gee aanleiding tot ‘n toename in die voorkoms van besoedelstowwe in die natuurlike omgewing deur gelokaliseerde (punt) bronne (rioolwerke/industriële uitvloeisel) en/of nie gelokaliseerde (nie punt) bronne (vloed uitlaat/huishoudelike uitvloeisels) van besoedeling. Dit het onlangs aan die lig gekom dat van hierdie chemise besoedelstowwe subtiel die endokriene sisteem versteur en so aanleiding gee tot gesondheidsprobleme in terme van die voortplantingsisteem en tiroied sisteem (groei en ontwikkeling) by diere en moontlik ook die mens. Daar is beperkte gebruik van biologiese toetse wat inligting verskaf oor sitotoksiteit, inflammatoriese aktiwiteit en endokriene versteuring. Die doel van hierdie studie was dus om van hierdie biologiese toetse, wat normaalweg nie deel uitmaak van die roetine munisipale (Stad van Kaapstad) opvangsgebied monitering nie, gebruik te maak. Die Eerste-, Kuilsrivier, Wes Kaap, onder beheer van Stad Kaapstad is gekies en alhoewel die opvangsgebied nie water bydra tot drinkwaterbronne nie, word die opvangsgebied beïnvloed deur verskeie mensgemaakte bronne van besoedeling (afloop vanuit omliggende lanbougebiede). Binne die kort tydsraamwerk van die projek (ses maande) is besluit om twee maande, Julie (volg ‘n droë somer en herfs seisoen) en Oktober (volg ‘n nat winter en vroeë lente seisoen) vir water kwaliteit monitering te kies. Ruimtelike variasie langs die loop van die opvangsgebied is ingesluit deur moniteringspunte (n=10), met in ag name van die potensiële besoedelingsbronne. Spesifieke doelwitte van die projek sluit in: Eerstens (Hoofstuk 2), om die in vitro biotoetse, laktaat hidrolise (LDH) vir sitotoksisiteit, proinflammatoriese hormoon Interleuikin-6 (IL-6) vir inflammatoriese aktiwiteit, vrygestel deur menslike bloedselle en ‘n Salmonella ELISA vir ontlasting besoedeling saam met bestaande chemise en biologiese (hoofsaaklik migrobiologiese) veranderlikes te gebruik. Die studie het getoon dat beduidende variasie in alle mikrobiologiese toetse asook IL-6 vrystelling en Salmonella voorkoms bestaan het tussen versamelpunte. Maandelikse variasie in sekere van die veranderlikes het ook voorgekom. Tweedens (Hoofstuk 3), is twee biotoetse wat die dooiervoorloperproteïen, vitellogeen (Vtg) as eindpunt gebruik geimplimenteer in a) ‘n in vitro Xenopus laevis lewersnit biotoets (vyf dag blootstelling) en b) ‘n in vivo Zebravis (Danio rerio) biotoets (sewe dag blootstelling) om estrogenisiteit in die Eerste-, Kuilsrivier opvangsgebied te evalueer. Alhoewel, die estrogeen behandelde positiewe kontrole water monsters Vtg produksie veroorsaak het in beide die in vitro lewer-kulture en in vivo vistoets, is geen dramatiess estrogeniese aktiwiteit by enige van die moniteringspunte gevind nie. Derdens (Hoofstuk 4), is ‘n biotoets wat die tiroïedbeheerde metamorfose in Xenopus laevis paddavisse gebruik om effekte op die tiroïedsisteem te evalueer. Die differensiële stimulering (versnelling), in vergelyking met ‘n negatiewe kontrole watermonster, van die tiroied sisteem is by twee moniteringspunte in die opvangsgebied waargeneem. Alhoewel die praktiese implementering van die paddavis semi-statiese (water word gereeld vervang) biotoets arbeidsintensief is, het alle bykomstige biotoetse waardevolle bykomstige inligting oor water kwaliteit verskaf wat ‘n belangrike bydrae tot ingeligte bestuursbesluite kan verleen. Dit is duidelik dat meer navorsing int verband met die menslike invloed langs die Eerste-, Kuilsrivier opvangsgebied nodig is, veral met maandlikse monitering vir seisoenale veranderinge.Thesis (MSc)--University of Stellenbosch, 2005.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Van Wyk, J.H.Pool, E.J.2012-05-07T13:15:56Z2012-05-07T13:15:56Z2005-04Thesisxi, 111 leaves : ill.http://hdl.handle.net/10019.1/20917en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/209372013-01-21T08:25:32Zhdl_10019.1_532

Rapid bioassessment of the ecological integrity of the Lourens, Palmiet and Hout Bay Rivers (South Western Cape, South Africa) using aquatic macroinvertebratesOllis, Dean JustinStream ecology -- South Africa -- Western CapeEcological integrity -- South Africa -- Western CapeEcological assessment (Biology) -- South Africa -- Western CapeAquatic invertebrates -- South Africa -- Western CapeTheses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyENGLISH ABSTRACT: The primary aim of this study was to assess and compare the ecological integrity of the Lourens, Palmiet and Hout Bay Rivers (South Western Cape, South Africa) by examining the macroinvertebrate community structure at a series of representative sampling sites along the course of each river, using the South African Scoring System - Version 5 (SASS-5) rapid bioassessment method. Secondary aims included an examination of the effects of seasonal variability, biotope availability and site-specific environmental variables on the macroinvertebrate community structure at sampling sites, as well as the preliminary testing of the Integrated Habitat Assessment System (IHAS) for aquatic macroinvertebrates. According to results obtained, the ecological integrity of sampling sites in the Mountain Stream Zone of the three rivers was consistently good. The Hout Bay River in the upper portions of the Orange Kloof Reserve was particularly near-pristine, with this area having been identified in this study as a potential biodiversity ‘hot-spot’ for aquatic macroinvertebrates. Downstream of the Mountain Stream Zone, there was a significant deterioration in the ecological integrity of all three rivers due to a number of probable causes. Results based on recorded SASS Scores and Average Score per Taxon (ASPT) values, using ‘biological bands’ generated from reference sites in the South Western Cape, were generally similar to and supported by the corresponding multivariate analyses undertaken. From the results of the various analyses undertaken in this investigation and some of the problems encountered in interpreting the data, a number of recommendations are made regarding future bioassessment studies based on the SASS within the national River Health Programme (RHP). To test the IHAS, secondary data were obtained from reference sites in the Mpumalanga and Western Cape Provinces of South Africa. Assuming that SASS Scores at reference sites are the highest scores attainable, one would expect to find a positive relationship between SASS Scores and IHAS scores at reference sites. The assumption in this investigation was that this relationship should be linear. Non-parametric correlation analyses were undertaken between SASS-4/5 Scores and IHAS scores, using Kendall’s Rank-correlation Coefficient (τ), with separate analyses undertaken for different geomorphological zones and biotope groups. Correlations between SASS Scores and IHAS scores were generally weak (τ-values mostly < 0.3) and unsatisfactory, with no significant correlations (p < 0.05) for two-thirds of the data sets analysed and a wide degree of scatter generally observed amongst data points in respective scatter plots. The performance of the IHAS varied between geomorphological zones and biotope groups, with the Foothill: Gravel-bed Zone in Mpumalanga showing the best results, particularly when the stones-in-current biotope group was analysed separately. Further testing of the IHAS is required to confirm its relative performance in different bioregions/ecoregions, geomorphological zones and biotope groups, which should be undertaken as a priority research area within the RHP. Unsuccessful attempts to test the IHAS by means of multiple regression analyses were undertaken, suggesting that such techniques should be avoided in further testing of the IHAS.AFRIKAANSE OPSOMMING: Die hoofdoel van hierdie studie was om die ekologiese toestand van die Lourens-, Palmiet- en Houtbaairiviere (Suidwes Kaap, Suid Afrika) te bepaal en te vergelyk deur die bestudering van die makroinvertebraatgemeenskapstruktuur by verteenwoordigende monsterpunte langs die riviere, met gebruik van die “South African Scoring System” – Weergawe 5 (SASS-5) snelle biologiese bepalingsmetode. Sekondêre doelwitte het die bepaling van die gevolge van seisoenele veranderlikheid, biotoop beskikbaarheid en ligging-bepaalde omgewingsveranderlikes op die makroinvertebraatgemeenskapstruktuur by monsterpunte ingesluit, asook die inleidende toetsing van die “Integrated Habitat Assessment System” (IHAS) vir watermakroinvertebrate. Volgens die resultate verkry, was die ekologiese toestand van monsterpunte in die Bergstroomsone van die drie riviere konsekwent goed. Die Houtbaairivier in die boonste gedeelte van die Oranjekloofreservaat was veral feitlik onversteurd en hierdie streek is in die studie as ‘n potensiaal biodiversiteit “hot-spot” vir watermakroinvertebrate geidentifiseer. Stroomafwaarts van die Bergstroomsone was daar ‘n beduidende verswakking in die ekologiese toestand van al drie riviere, as gevolg van ‘n aantal moontlike oorsake. Resultate gebaseer op bepaalde “SASS Scores” en ‘Gemiddelde Waarde per Takson’ (“Average Score per Taxon” - ASPT) waardes, met gebruik van ‘biologiese bande’ wat van verwysingsmonsterpunte in die Suidwes Kaap afgelei is, was oor die algemeen soortgelyk aan en gestaaf deur die ooreenstemmende multiveranderlikke (“multivariate”) statistiese analises wat gedoen is. Uit die resultate van die verskeie analises wat in hierdie ondersoek gedoen is en sommige van die probleme wat in die dataverklaring gevind is, is ‘n aantal aanbevelings gemaak met betrekking tot toekomende biologiese bepalingstudies vir die nasionale Riviergesondheidsprogram (“River Health Programme” - RHP) wat op die SASS gebaseer is. Om die IHAS te toets is sekondêre data van verwysingsmonsterpunte in die Mpumalanga en Wes Kaap Provinsies van Suid Afrika verkry. As aangeneem word dat die “SASS Scores” by verwysingsmonsterpunte die hoogste moontlike tellings is wat bereik kan word, sou ‘n positiewe verwantskap tussen “SASS Scores” en IHAS tellings by verwysingsmonsterpunte verwag word. Die veronderstelling in hierdie studie was dat dié verwantskap lineêr moet wees. Nie-parametriese korrelasieanalise tussen “SASS-4/5 Scores” en IHAS tellings is gemaak, deur gebruik van Kendall se Rangkorrelasiekoëffisiënt (τ), met afsonderlike analises vir verskillende geomorfologiese sones en biotoopgroepe verrig. Korrelasies tussen “SASS Scores” en IHAS tellings was algemeen swak (τ-waardes < 0.3) en onbevredigend, met geen beduidende korrelasies (“p” < 0.05) vir twee-derdes van die datastelle wat geanaliseer is nie en ‘n wye verspreiding tussen datapunte in die onderskeie “scatter plots” wat waargeneem is. Die funksionering van die IHAS was verskillend tussen geomorfologiese sones en biotoopgroepe. Die beste resultate is vir die Voorheuwel: Gruisbeddingsone in Mpumalanga verkry, veral indien die klippe-in-stroom biotoopgroep afsonderlik geanaliseer is. Verdere toetsing van die IHAS is nodig om die relatiewe funksionering in verskillende biostreke/”ecoregions”, geomorfologiese sones en biotoopgroepe te bevestig en dit behoort voorangs te geniet binne die RHP. Pogings om die IHAS deur middel van veelvoudige regressie analise te toets het misluk, wat aandui dat sulke tegnieke vermy moet word in verder toetsing van die IHAS.Thesis (MSc)--University of Stellenbosch, 2005.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Boucher, C.Esler, K.J.2012-05-09T09:49:50Z2012-05-09T09:49:50Z2005-12Thesisix, 192 leaves : ill., mapshttp://hdl.handle.net/10019.1/20937en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/212182013-01-21T08:24:51Zhdl_10019.1_532

Models of Bontebok (Damaliscus pygargus pygargus, Pallas 1766) habitat preferences in the Bontebok National Park and sustainable stocking ratesLuyt, Eustatius du ChavouxDamaliscus -- Habitat -- South Africa -- Bontebok National ParkGrazing -- Environmental aspects -- South Africa -- Bontebok National ParkDamaliscus -- South Africa -- Bontebok National Park -- Geographical distributionTheses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyENGLISH ABSTRACT:This study concentrates on the Bontebok (Damaliscus pygargus pygargus Pallas 1766) population of the Bontebok National Park. Using a combination of literature research, field observations, satellite imagery, Geographic Information System mapping and dung analysis, their habitat preferences within the Park are ascertained and compared to different behavioural and environmental factors. Considering vegetation composition and height, grass cover, burning history, general topography, water availability, actual diet quality (from faecal analysis) and population distribution, the best predictor of spatial pattern are investigated with GIS Dempster-Shafer models. The historical density distribution of the animals in the Park can be used to predict sustainable stocking rates. As far as possible, the results for the Bontebok are compared to those of the other larger herbivores in Bontebok National Park i.e. Red Hartebeest, Cape Mountain Zebra and Grey Rhebuck. These results should be useful for Wildlife Managers to know how to manage veld for Bontebok and at what stocking rates this can be done sustainably.AFRIKAANSE OPSOMMING: Hierdie studie fokus op die Bontebok (Damaliscus pygargus pygargus, Pallas 1766) bevolking van die Bontebok Nasionale Park. Deur ‘n kombinasie van literatuurstudie, veldobservasies, satlietbeelde, Geografiese Inligtingstelsel (GIS) kartering en mis-analise te gebruik, word Bontebok habitatvoorkeure in die Park vasgestel en met verskillende gedrags- en omgewingsfaktore vergelyk. Deur te kyk na plantegroei-samestelling en hoogte, grasbedekking, brandgeskiedenis, algemene topografie, water-beskikbaarheid, diëet kwaliteit en die Bontebokke se waargenome ruimtelike verspreiding, word die faktor wat die verspreidingspatroon die beste voorspel, m.b.v. GIS Dempster-Shafer modelle ondersoek. Die historiese digtheidsverspreiding van diere in die Park word gebruik om volhoubare veldladings te voorspel. Sover moontlik word die resultate vir Bontebok vergelyk.met die ander groter herbivore in die Bontebok Nasionale Park, te wete Rooi Hartebees, Kaapse Bergsebra en Vaalribbok. Hierdie resultate behoort vir Natuurlewe-bestuurders tot nut te wees as riglyne vir veldbestuur en volhoubare veldladings van Bontebok.Thesis (MSc)--University of Stellenbosch, 2005.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.Ward, D.2012-06-06T07:42:17Z2012-06-06T07:42:17Z2005-12Thesis111 leaves : ill., mapshttp://hdl.handle.net/10019.1/21218en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/215512013-01-21T08:20:50Zhdl_10019.1_532

Conservation in human-influenced areas : epigaeic arthropods in the Cape Floristic Region LowlandsBoonzaaier, CarmenBiodiversity conservation -- South Africa -- Western CapeAnts -- Habitat -- Conservation-- South Africa -- Western CapeArthropoda -- Habitat -- Conservation -- South Africa -- Western CapeFragmented landscapes -- South Africa -- Western CapeRemnant vegetation conservation -- South Africa -- Western CapeTheses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyENGLISH ABSTRACT: The conservation of biodiversity is becoming increasingly challenging as habitats are disturbed, fragmented or destroyed. Although nature reserves now cover more than 10 % of the earths’ surface it has become clear that more will have to be done to ensure the long-term survival of species. Therefore, focus is increasingly shifting towards conserving biodiversity in natural and semi-natural remnants in human-influenced areas. This study aimed to determine the contribution of remnants in human-influenced areas to the conservation of biodiversity in the Cape Floristic Region (CFR) lowlands, using ground-dwelling arthropods, specifically ants, as the focal taxon. Initially, base-line information of arthropods and in particular ants was obtained. Sampling arthropods generally involves a large sample effort. Therefore maximizing sampling effort for ants in the CFR was investigated by trapping ground-dwelling ants at a single locality. Doubling the number of grids of pitfall traps was found to be more effective in trapping a greater number of species than doubling the duration of sampling. Therefore increasing spatial sampling intensity rather than sampling duration maximizes sample effort for CFR ants. Also, the seasonal changes of ground-dwelling arthropods, including ants, were determined by sampling four times during the year at a single locality. Overall arthropod abundance was found to peak in summer while dropping to a minimum in winter. This pattern was mirrored by that of the ants, indicating that ant results have a broader relevance than to ants only. The ground-dwelling fauna was dominated by ants emphasizing their importance in the CFR lowlands, and demonstrating that ants are an appropriate flagship taxon for epigaeic arthropod diversity in the CFR. Finally the contribution of remnants in human-influenced areas to the conservation of the CFR was investigated. A nested hierarchical approach was used, where five localities were selected across the CFR, each containing one reserve site and one site with natural remnants. Ants were sampled, along with environmental variables, namely weather, vegetation and soil. Overall, remnants were found to support similar ant assemblages to those of reserves. However for individual localities some remnants were significantly different to their reserve counterparts. Differences in ant assemblages were found to be greater between localities than between reserves and remnants. The relatively high heterogeneity of ants found in this study emphasizes the conservation significance of invertebrates along with that of plants in the CFR. Remnants clearly show the potential to conserve ant assemblages, however correct management is needed for these areas to maximize their potential. Disturbances such as the presence of the invasive Argentine ant and increasing soil nutrients by fertilization, pose a distinct threat to the ability of remnants to conserve ant assemblages. This study has shown that remnants currently support ant assemblages representative of those present in the CFR today. Therefore, some remnant patches of habitat in agricultural areas currently do contribute highly to the conservation of a functional important taxon in this global biodiversity hotspot, and if managed correctly, may continue to do so in the future.AFRIKAANSE OPSOMMING: Die vernietiging en fragmentering van habitatte maak die bewaring van biodiversiteit al hoe meer van ‘n uitdaging. Alhoewel natuur reservate reeds meer as 10 % van die aarde se oppervlak beslaan is dit duidelik dat meer gedoen sal moet word vir die lang-termyn voortbestaan van spesies. Dus word die fokus van biodiversiteit-bewaring toenemend gerig op bewaring van natuurlike en semi-natuurlike fragmente in menslik-beinvloede gebiede. Die doel van hierdie studie was om te bepaal wat die bydrae van fragmente van natuurlike veld in menslik-beinvloede gebiede is tot die bewaring van die streek. Dit is gedoen deur van grond-lewende geleedpotiges en spesifiek, miere in die Kaapse floraryk (CFR) gebruik te maak. Aanvanklik is kennis ingewin oor die geleedpotiges en spesifiek miere in die omgewing. Omdat die versameling van geleedpotige diere gewoonlik baie moeite vereis is ‘n maksimum steekproef gedoen by ‘n enkele lokaliteit. Daar is gevind dat ‘n verdubbling van die aantal ruitsteekproefnemings met vanggate meer effektief is om miere te vang as ‘n verdubbling in die tydperiode wat vanggate oop is. Dus, is ‘n hoër ruimtelike steekproef intensiteit meer effektief in vergelyking met ‘n langer tydsduur vir miere in die CFR. Die seisoenale veranderinge van grond-lewende geleedpotiges, sowel as miere, was ook bepaal. Dit was gedoen deur vier seisoenale steekproewe te doen by ‘n enkele lokaliteit. Die totale geleedpotige-talrykheid was die meeste gedurende die somer en die minste in die winter. Die miertalrykheid het ook hierdie patroon weerspieël. Dit dui daarop dat veranderinge in mier versamelings van breër belang is vir alle grondlewende geleedpotiges. Miere was die dominante grond-lewende geleedpotiges en beklemtoon die belangrikheid van miere in die CFR, sowel as hulle toepaslikheid as vlagskip taksa vir grond-lewende geleedpotige diversiteit in die CFR. Laastens was die bydrae van gefragmenteerde natuurlike veld in menslik–beinvloede gebiede tot die bewaring van die CFR ondersoek. ’n Krimpende/ genestelde hiërargies benadering is gebruik in vyf geselekteerde lokaliteite, elk het bestaan uit ‘n area in ‘n natuur reservaat en ‘n area in ‘n naasliggende fragment. Miere was versamel saam met ‘n verskeidenheid omgewings veranderlike, naamlik weer, plantegroei en grond. In die algemeen is gevind dat fragmente en reservate gelyksoortige mier versamelings het. Daar was wel gevind dat party fragmente aansienlik verskillend was van die reservaat teenstuk. Verskille in mier versamelings tussen lokaliteite was groter as verskille tussen reservate en fragmente. Die relatief hoë heterogeniteit van miere beklemtoon die bewaringsbelang van invertebrate saam met dié van plante in die CFR. Dit is duidelik dat fragmente wel ‘n potensiale bydrae kan maak om die mier versamelinge te bewaar, maar gepaste bestuur is nodig om hierdie potentiaal te maksimaliseer. Versteurings soos die teenwoordigheid van die indringer Argentynse mier en toenemende grondvoedingstofkonsentrasie as gevolg van bemesting is ‘n groot bedreiging tot die vermoë van fragmente om mier versamelings te bewaar. Hierdie studie wys dat mier versamelings in gefragmenterde areas verteenwordigend is van die algemene mier versamlings wat op die oomblik in die CFR is. Dus lewer party fragmente in landbou gebiede op die oomblik ‘n wesenlike bydrae tot die bewaring van ‘n funksioneel belangrike takson in hierdie globale biodiversiteitsbrandpunt en die bydra sal volhoubaar wees met korekte bestuur.Thesis (MSc)--University of Stellenbosch, 2006.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.McGeoch, M.A.Parr, C.L.2012-07-04T10:51:40Z2012-07-04T10:51:40Z2006-12Thesisviii, 184 leaves : ill., mapshttp://hdl.handle.net/10019.1/21551en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/216962013-01-21T08:23:41Zhdl_10019.1_532

Patterns of variability in Azorella selago Hook. (Apiaceae) on sub-Antarctic Marion Island : climate change implicationsNyakatya, Mawethu JusticeUmbelliferae -- Prince Edward Islands -- Marion IslandClimatic changes -- Prince Edward Islands -- Marion IslandPlants -- Effect of global warming on -- Prince Edward Islands -- Marion IslandTheses -- Conservation ecology and entomologyDissertations -- Conservation ecology and entomologyENGLISH ABSTRACT: Understanding the responses of species to climate change is a scientific problem that requires urgent attention, especially under current conditions of global climate change. The large and rapid rates of climate change reported for sub-Antarctic Marion Island makes the island highly suitable for studying the biotic consequences of climate change. Furthermore, the extreme environments on the island result in a close coupling of the biotic (e.g. population dynamics) and abiotic (e.g. climate) factors. Therefore, examining the response of the dominant and keystone plant species on the island, Azorella selago Hook. (Apiaceae), to climate-associated environmental change (e.g. temperature) may provide insight into how A. selago and the associated species communities will be affected by climate change. This study described the variability in microclimate temperatures associated with A. selago across altitudinal gradient and between the eastern and western sides of Marion Island. Microclimate temperatures were also compared to the island’s Meteorological data to determine variation between temperatures experienced by A. selago cushion-plants in the field and those recorded at the island’s Meteorological Station. Temperature variation inside and outside A. selago cushions was also examined. Azorella selago cushions were found to have a buffering effect on temperature, such that species occurring epiphytically on A. selago experience more moderate temperatures than the surrounding environment. However, A. selago were found to experience more extreme temperatures than temperatures recorded at the Meteorological Station. Therefore, A. selago may possibly experience greater environmental warming than recorded by the Meteorological Station. While temperatures decline with altitude, temperature conditions on the western side of the island were more temperate than the eastern side. This presents the first record of temperature conditions on the western side of the island. This study also quantified fine-scale (e.g. within-site) and broad-scale (e.g. island-wide) variability patterns of A. selago (morphology, phenology, and epiphyte load) across Marion Island. Altitudinal gradient and climatic exposure at different sides of the island were used to understand the likely effects of climate associated environmental change on this dominant component of the fellfield habitat. Site-specific processes were found to determine the spatial structure of A. selago characteristics at fine-scales. However, broad-scale observations established strong responses of A. selago characteristics to altitudinal gradients and different sides of the island. Azorella selago morphological features (e.g. plant size and leaf size) were found to be more responsive to differences between the eastern and western sides of the island than to altitudinal gradient. Azorella selago micro-morphological features (e.g. leaf trichomes and stomatal densities) were also found to be more responsive to climatic exposure at different sides of the island than to altitudinal gradient. However, differences in A. selago epiphyte density (e.g. Agrostis magellanica) and phenology resembled microclimate temperatures in that they were more responsive to altitudinal gradient than to side of the island differences. From these results it can therefore be predicted that the A. selago of Marion Island is likely to be morphologically fairly resilient to moderate climatic shifts, although at lower altitudes and on the eastern side of the island, it may be outcompeted by the epiphytic grass, Agrostis magellanica. The results also suggest that the warming climate of Marion Island may result in an early occurrence of phenological processes particularly at lower altitudes and the eastern side. Azorella selago at lower altitudes and on the eastern side of Marion Island are therefore expected to largely show more symptoms of climate change (e.g. warming) on this species. Azorella selago is also predicted to move up altitudinal gradients in response to warming.AFRIKAANSE OPSOMMING: ’n Begrip van hoe spesies reageer op klimaatsverandering is ’n wetenskaplike vraag wat onmiddellike aandag benodig, veral onder huidige globale klimaatsverandering. Die groot en snelle tempo waarteen klimaatsverandering waargeneem word op sub-Antarktiese Marion Eiland, maak die eiland hoogs geskik om die biotiese gevolge van klimaatsverandering te bestudeer. Verder veroorsaak die uiterste omgewing van die eiland tot ’n nabye koppeling tussen die biotiese (bv. populasie dinamika) en abiotiese (bv. klimaat) faktore. Dus, deur die reaksies van ’n dominante- en sleutel-spesie op die eiland, Azorella selago Hook. (Apiaceae), op klimaat-geassosieerde omgewings verandering (bv. temperatuur) te bestudeer, mag insig verskaf hoe A. selago en geassosieerde spesie gemeenskappe geaffekteer sal word deur klimaatsverandering. Hierdie studie beskryf die wispelturigheid in mikroklimaat temperature geassosieer met A. selago oor ’n hoogte gradiënt asook tussen die oostelike en westelik dele van Marion Eiland. Mikroklimaat temperature was ook vergelyk met die eiland se Meteorologiese data met die doel om die mate van variasie tussen temperature verduur deur A. selago kussing-plante in die natuurlike omgewing met die van die eiland se Meteorologiese stasie te vergelyk. Temperatuur variasie binne en buite A. selago kussing-plante is ook vasgestel. Dit was gevind dat Azorella selago kussing-plante die temperatuur buffer, met die gevolg dat spesies wat epifities op A. selago voorkom, meer gematigde temperature ondervind as die onmiddellike omgewing om die plant. Daar is egter gevind dat A. selago meer uiterste temperature ondervind as temperature gemeet by die Meteorologiese stasie. Dus mag A. selago groter omgewings verwarming ervaar as wat temperature gemeet by die Meteorologiese stasie dui. Terwyl temperatuur afneem met ’n toename in hoogte, was temperatuur aan die westekant van die eiland mere gematig as die oostekant. Dit verskaf die eerste rekord van temperatuur toestande aan die westekant van die eiland. Hierdie studie bepaal ook die fyn-skaal (e.g. binne-terrein) en groot-skaal (e.g. oor die eiland) variasie patrone van A. selago (morfologie, fenologie, en epifiet lading) oor Marion Eiland. Die hoogte gradiënt en klimaat blootstelling aan verskillende kante van die eiland is gebruik om die waarskynlike effekte van klimaats-geassosieerde omgewings verandering op die dominante deel van die felfield habitat te verstaan. Daar is gevind dat terrein spesifieke prosesse die ruimtelike struktuur van A. selago se klein-skaal eienskappe bepaal. Groot-skaalse waarnemings dui egter ’n sterk antwoord van A. selago eienskappe op die hoogte gradiënt en aan verskillende kante van die eiland. Azorella selago morfologiese eienskappe (e.g. plant- en blaar grootte) is gevind om meer te reageer op verskille tussen oostelike en westelike kante van die eiland as op die hoogte gradiënt. Azorella selago mikromorfologiese eienskappe (e.g. blaar trigome en stomata digtheid) is ook gevind om meer te reageer op omgewings blootstelling tussen verskillende kante van die eiland as op die hoogte gradiënt. Verskille in A. selago epifiet digtheid (e.g. Agrostis magellanica) en fenologie het egter mikroklimaat temperature gevolg, in dat beide meer gereageer het op die hoogte gradiënt as eiland-kant verskille. Hierdie resultate voorspel dus dat dit waarskynlik is dat A. selago van Marion Eiland morfologies redelik terugspringend sal wees ten opsigte van matige klimaatsverandering, al mag dit uitgekompeteer word deur die epifitiese gras, Agrostis magellanica by lae hoogtes en aan die oostekant van die eiland. Hierdie resultate dui ook dat verwarming van Marion Eiland se klimaat ’n vervroeging van fenologiese prosesse mag hê, veral by lae hoogtes en aan die oostekant van die eiland. Dus word dit verwag dat Azorella selago by lae hoogtes en aan die oostekant van Marion Eiland om meer simptome van klimaatsverandering (e.g. verwarming) te dui. Dit word ook voorspel dat Azorella selago opwaarts teen die hoogte gradiënt sal beweeg in reaksie tot verwarming.Thesis (MSc)--University of Stellenbosch, 2006.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.McGeoch, M.A.2012-07-13T13:23:19Z2012-07-13T13:23:19Z2006-12Thesisvi, 115 leaves : ill., mapshttp://hdl.handle.net/10019.1/21696en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/217592013-03-23T13:26:10Zhdl_10019.1_532

Synergistic impact of invasive alien plants and the alien Argentine ant on local ant assemblages in the Western CapeSchoeman, Colin StefanAlien plants -- South Africa -- Western CapeInvasive plants -- South Africa -- Western CapeBiological invasions -- South Africa -- Western CapeArgentine ant -- South Africa -- Western CapeNonindigenous pests -- South Africa -- Western CapeInsect-plant relationships -- South Africa -- Western CapeTheses -- EntomologyDissertations -- EntomologyENGLISH ABSTRACT: Alien trees, Pinus spp. and Eucalyptus spp., affect ants negatively in the Cape Floristic Region (CFR), a global biodiversity hotspot in South Africa. They reduce ant abundance and species richness, thus also changing ant assemblage structure. This is alarming, because almost 1300 species of plant species in the CFR are dispersed by certain indigenous ants, and thus there is concern for an indirect effect on indigenous plant assemblages. One of the most impacting ant species on seed dispersal is the invasive Argentine ant (Linepithema humile (Mayr)), which discards seeds outside its nest, where they do not germinate. Ten sites, on Vergelegen Wine Estate, were selected to explore these effects of alien plants. These varied from invaded to non-invaded sites. Each site consisted of six sampling points, which in turn consisted of four pitfall traps left out for seven days, during December 2005, February 2006, May 2006 and September 2006. Forty species of ant were sampled, and various analyses used to illustrate the comparative effects of plant invasion. All analytical methods showed that invasive alien plants had a significant impact on the abundance and richness of the ant species assemblage, by creating a dense canopy cover that changed the abiotic environment of the epigaeic ants’ habitat. Furthermore, increased alien tree invasion correlated significantly with Argentine ant abundances. The Argentine ant displaced Pheidole capensis and Camponotus spp., while it decreased the abundances of commonly-occurring indigenous ants, such as Lepisiota capensis and Plagiolepis spp. Displacement by the Argentine ant may be a result of indirect competition for food resources. The effects of invasive aliens are synergistic in that there is a cascade effects from initial plant invasions to subsequent animal invasion.AFRIKAANSE OPSOMMING: Indringer bome, Pinus en Eucalyptus, affekteer miere op negatiewe wyse in die Kaap Florsitiese Streek (KFR), ‘n area in Suid Afrika van belang t.o.v. globale biodiversiteit. Hierdie uitheemse indringer bome verminder hulle hoeveelheid en spesies rykheid. Die bogenoemde is kommerwekkend omdat meer as 1300 plant spesies in the KFR versprei word deur miere. Die verandering in hoeveelheid en versameling van inheemse miere kan dus ernstige implikasies hê op die saad verspreiding van inheemse plant spesies. Een van die mees verwoestende effekte op saad verspreiding is veroorsaak deur die indringer Argentynse mier (Linepithema humile (Mayr)), wat sade neer werp buite hulle neste, waar hulle nie suksesvol kan ontkiem nie. Tien monsterings-tereine was geselekteer om die bogenoemde effekte te ondersoek op Vergelegen Landgoed. Hierdie het afgewissel van indringer tot skoon tereine. Elke terrein is op ses versamelings-plekke gemonster, met vier pitvalle, wat oopgelê het vir sewe dae gedurende Desember 2005, Februarie 2006, Mei 2006 en September 2006. 40 spesies van miere was gemonster. Indringer plante het ‚n betekenisvolle impak gehad het op die hoeveelheid en rykheid van die mier gemeenskappe, deur die skepping van ‚n dig baldakyn wat die abiotiese omgewing van die miere se habitat verander het. Die vermeerdering van indringer plante veroorsaak die vermeerdering van Argentyne miere. Kanonieke Mede-Respons Analise illustreer dat die Argentynse mier Pheidole capensis en Camponotus spp. verplaas het, terwyl dit ander inheemse mier getalle verminder het, soos Lepisiota capensis en Plagiolepis spp. Die verplasing deur die Argentynse mier mag die resultaat wees van indirekte wedywering vir hulpbronne. Die effekte van indringer species is dus sinergisties deur dat ‚n kaskade effek ontstaan vanaf plant tot dier indringer spesies.Thesis (MSc)--Stellenbosch University, 2008.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Samways, Michael2012-07-18T12:54:52Z2012-07-18T12:54:52Z2008-03Thesisiv, 81 leaves : ill., maphttp://hdl.handle.net/10019.1/21759en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/507722013-03-22T07:10:56Zhdl_10019.1_532

The pentatomidae of South AfricaVan Heerden, P. W. (Pieter Willem),1907-Stinkbugs -- South AfricaDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyENGLISH ABSTRACT: This thesis is presented in partial fulfilment of the requirements for the degree of MSc. Agric in Entomology. In this work an attempt has been made to gather all the available literature on the family Pentatomidae and to work out keys where possible for the genera and species recorded in South Africa . The keys for the species in either the University Collection or those of the South Africa Museum did not present much difficulty as I had access to the latter through the courtesy of Dr gill and the museum Entomologist, Dr. A. J. Hesse. I especially wish to thank Dr. Hesse for his kind assistance in connection with this work. Where I had to rely on the meagre descriptions of some entomologists it has in a few cases been impossible for me to include some of species in the keys, but I have, however, incorporated the original descriptions of the species in this work. The writer hopes, that, with the aid of the drawings and the general descriptions, the keys will be of value for the correct determination of the members of this family. The Literature available on the South African Pentatomidae is very comprehensive and scattered through various publications, some of which are hardly obtainable . This is the first attempt which has been made in this country to co-ordinate the literature on this subject and it will doubtlessly prove of value to those entomologists who have not the time or the opportunity of working through the voluminous records on this interesting group. The work has been done under the direction of Dr. T. J. Potgieter, Professor of Entomology at the Stellenbosch-Elsenberg College of Agriculture of the University of Stellenbosch and I am greatly indebted to him for advice and the kindly way in which he assisted me.Thesis (MScAgric)--Stellenbosch University, 1931.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgricScience. Dept. of Conservation Ecology and Entomology.Potgieter, T. J.2012-08-27T11:34:08Z2012-08-27T11:34:08Z1931-09Thesis154 p., [135] p. of plates : ill.http://hdl.handle.net/10019.1/50772en_ZAStellenbosch University

oai:scholar.sun.ac.za:10019.1/800892013-04-05T08:19:47Zhdl_10019.1_532

Nematode soil community structure and function as a bio-indicator of soil health in fynbos and deciduous fruit orchardsKapp, CaroIndicators (Biology) -- South Africa -- Western CapeSoils -- South Africa -- Western Cape -- QualitySoils -- Environmental aspects -- South Africa -- Western CapeNematodes -- Ecology -- South Africa -- Western CapeDissertations -- Conservation ecology and entomologyTheses -- Conservation ecology and entomologyOrchards -- Soils -- South Africa -- Western CapeFruit trees -- Sois -- South Africa -- Western CapeFynbos -- Soils -- South Africa -- Western CapeENGLISH ABSTRACT: Soil is a fundamental, non-renewable resource in any ecosystem. To uphold food production for increasing global human populations, it is imperative to develop ways in which to sustain healthy biological productivity and sustainability of agricultural soils. Nematodes are one of the most abundant groups of Metazoa occurring in all soils, and form an integral part of the soil food web at several trophic levels. They respond rapidly to changes within their environments, and can easily be extracted from soil, identified and characterised into functional guilds. Nematodes thus have the potential to impart insight into the condition of the soil food web. This study aims to establish whether nematodes will be suitable bio-indicators of soil health for the deciduous fruit industry in the Western Cape. Three different objectives have been set to determine the practical use of nematode community structures as a tool for the measurement of soil health. The objectives include describing the nematode community structure, biodiversity and functionality within Fynbos soils; the characterization of organic and conventional orchards; and the differences in nematode soil communities in differently managed soils in an apple orchard. The number of nematodes in each soil sample was quantified and identified to family level. The nematode biodiversity and functionality for each site was determined by evaluating the nematode food webs for trophic group distribution, as enumerated by the Maturity Index (MI), the Enrichment Index (EI), the Structure Index (SI), the Basal Index (BI) and the Channel Index (CI), based on the weighted abundance of coloniser-persister guilds. The functional guild analysis of Fynbos samples indicated that the enrichment and the structure of any given sample were not bound to a certain area, but it was representative of each of the four quadrats within the faunal analysis. Different geographic areas were found to differ in nematode diversity and functionality, which was mainly associated with dominant plant families and species (such as strong associations between Fynbos families Fabaceae, Solanaceae and Celestraceae with the nematode family Pratylenchidae). The most abundant nematode families present in the Fynbos were Tylenchidae, which are plant-feeding nematodes, and Cephalobidae which are bacterial-feeding nematodes. Despite Tylenchidae and Cephalobidae both having coloniser-persister values (cp-values) of two, they are split up into different feeding types. Cp-2 nematodes are tolerant to disturbances, and occur in all environments. Only one omnivorous family, the Dorylaimida, was identified in Fynbos samples. The average MI value for Fynbos was found to be very low, with a mean value of 1.26. The value obtained indicated the presence of taxa with tolerance to disturbance, which, in turn, indicated the presence of a disturbed soil, in general. The number of plant-parasitic nematodes within the Fynbos soils was low, which was supported by the low plant-parasitic index (PPI) of 0.85. The diversity, richness and evenness values were low, indicating low nematode diversity, but a distribution of abundances amongst the families. The average Hill’s N0 index value was 8.0, indicating that, in general, eight nematode families would have been present in a Fynbos soil sample. A study was done to determine the biodiversity and the functionality of the nematodes associated with deciduous fruit orchards that were conventionally, or organically, managed. Herbivores were dominant in all the orchards. The organic apple orchard had the lowest numbers of herbivores and fungivores, with the highest number of carnivores. When comparing organic and conventional apricot orchards, higher numbers of plant-parasitic nematodes were found in the organic orchard. Criconematidae occurred in higher numbers in conventional apricot orchard soil. When comparing organic apricots and apples, higher numbers of Criconematidae occurred within the organic apple soil. Overall, higher levels of plant-parasitic nematodes occurred in the organic apricot orchard. The MI indicated that all orchard soils had values below 1.5, indicating disturbance. Conventionally managed apricot orchard soil had the highest MI value of 1.48. The PPI value was highest in organically managed apricot orchards. All orchard soils were located within Quadrat B of the faunal analysis, indicating enrichment and structure. Regarding the diversity, richness and evenness of the distribution, conventional apricot soil had the highest species richness, while organic apple soil had the most even family distribution. Different management practices did not show marked differences in community composition and structure. The species richness of Fynbos soils was comparable to those of deciduous fruit orchards. Soil samples from eight different soil surface treatments were collected from an apple orchard in the Grabouw area. Treatments were combined according to the soil surface treatments received (chemical control of cover crops and weeds, mulch and mulch + effective micro-organism spray). Bacterivores were dominant in all soil treatments, with the least number being present in the chemical control (of cover crops and weeds) treatment. Sites which received chemical control of cover crops and weeds had higher levels of fungivores, compared to the levels at the other sites. High numbers of Rhabditidae occurred within mulch and mulch + effective micro-organism (EM) treatment sites, while high numbers of Aphelenchidae occurred in chemical control sites. The carnivorous family Ironidae only occurred in mulch + EM sites. Strong associations were found between soil surface applications and nematode families present within the soil. Chemical control (of cover crops and weeds) applications had the highest MI value, while values were equal for the other soil applications. The faunal analysis indicated that the mulch and the chemical control fell within Quadrat A, indicating enriched, but unstructured, soil, while the mulch + EM treatment fell within Quadrat B, indicating enrichment and structure, as well as good overall soil conditions. All the systems were dominated by bacterial decomposition pathways. Controversially, sites that received chemical control of the cover crops and weeds had the highest species richness of all three applications, as well as the highest level of diversity, according to the Simpson Index. As only the cover crops and the weeds were chemically controlled, the soil can be regarded as undisturbed, which explains the results obtained in this study. Clear differences in nematode community structure and composition were observed between the different soil applications in the apple orchard.AFRIKAANSE OPSOMMING: Grond is 'n fundamentele, nie-hernubare hulpbron binne enige ekosisteem. Ten einde voedselproduksie vir die toenemende globale menslike bevolking te handhaaf, is dit noodsaaklik om maniere te ontwikkel om gesonde biologiese produktiwiteit en volhoubaarheid van landbougrond in stand te hou. Nematodes is een van die volopste Metazoa in alle gronde en vorm 'n integrale deel van die grond voedsel-web op verskeie trofiese vlakke. Hulle reageer vinnig op veranderinge binne hul omgewings, kan maklik ekstraheer en identifiseer word; en ook maklik in funksionele gildes ingedeel word. Nematodes het ook die potensiaal om insig oor te dra ten opsigte van die toestand van die grond voedsel-web. Hierdie studie het ten doel om vas te stel of nematodes geskikte bio-indikatore van grond gesondheid kan wees spesifiek vir die sagtevrugte bedryf in die Wes-Kaap. Drie verskillende doelwitte is gestel om die praktiese gebruik van nematode populasie samestelling as 'n instrument vir die meting van grond gesondheid te gebruik. Die doelwitte sluit in die nematode populasie samestelling, biodiversiteit en funksionaliteit binne natuurlike Fynbos; organies verboude versus konvensionele boorde; en die verskil in nematode populasie samestelling tussen verskillend behandelde en bestuurde grondpersele binne ʼn appel boord. Die nematode biodiversiteit en funksionaliteit vir elke perseel was bepaal deur die evaluering van die nematode voedselweb vir trofiese groep verspreiding en enumerering deur die Maturity Index (MI) en die Enrichment Index (EI), Strukturele Indeks (SI), Basale Indeks (BI) en Channel Index (CI) wat gebaseer is op die geweegde oorvloed van koloniseerder-persister gildes. Die funksionele gilde vir Fynbos monsters het aangedui dat die verryking en struktuur van enige gegewe perseel nie gebonde is aan ʼn bepaalde gebied nie, aangesien dit verteenwoordig was in elk van die vier kwadrante van die Fauna Analiseerder. Daar is gevind dat verskillende areas verskil in nematode diversiteit en funksionaliteit, wat hoofsaaklik geassosieer was met die dominante plant families en spesies in die omgewing. Die volopste nematode familie wat teenwoordig was in die Fynbos was Tylenchidae, wat plant-voedende nematodes is, en Cephalobidae, wat bakterie-voedend is. Tylenchidae en Cephalobidae het beide ʼn cp-waarde van twee, maar is verdeel in verskillende VIII tipes voedingsgroepe. Die cp-2 nematodes is verdraagsaam vir versteurings en kom in alle omgewings voor. Slegs een omnivoor familie is geïdentifiseer in Fynbos monsters, nl. die Dorylaimidae. Die gemiddelde MI waarde vir Fynbos was laag, met 'n gemiddelde waarde van 1.26. Hierdie waarde is ʼn aanduiding van die teenwoordigheid van taxa met verdraagsaamheid tot versteuring, wat op sy beurt 'n versteurde grond in die algemeen aangedui het. Die aantal plant-parasitiese nematodes binne die Fynbos-gronde was laag, wat ondersteun word deur die lae PPI-waarde van 0.85. Die waardes vir die diversiteit, spesie-rykheid en egaligheid was laag, wat dui op 'n lae nematode diversiteit, maar 'n egalige verspreidings onder families. Die Hill’s N0 indeks waarde was gelyk aan 'n gemiddelde van 8.0 en dui daarop dat in die algemeen agt nematode families teenwoordig sal wees in 'n Fynbos grondmonster. 'n Studie is gedoen om die biodiversiteit en funksionaliteit van nematodes wat verband hou met vrugteboorde wat organies en konvensioneel bestuur is te bepaal. Herbivore was dominant in alle boorde. Organiese appels het die laagste aantal herbivore en fungivore gehad en die hoogste aantal karnivore. Wanneer organiese en konvensionele appelkoosboorde met mekaar vergelyk is, was hoër getalle van plant-parasitiese nematodes gevind in die organiese boord. Criconematidae was teen ʼn groter aantal in die grond van die konvensionele appelkoosboord gevind. Met die vergelyking van organiese appelkose en appels word, is ʼn hoër aantal Criconematidae binne die organiese appelgrond aangetref. In die algemeen was hoër vlakke van plant-parasitiese nematodes gevind in die organiese appelkoosboord. Die MI het getoon dat alle boord waardes laer as 1.5 gehad het, wat daarop dui dat die gronde versteurd is. Die konvensioneel bestuurde appelkoosboord het die hoogste MI waarde gehad met ʼn vlak van 1.48. Die waarde vir die PPI was die hoogste in organies bestuurde appelkoosboorde. Alle boord gronde is geleë binne kwadrant B van die Fauna Analiseerder, wat dui op verryking met struktuur. Met betrekking tot die diversiteit, spesie-rykheid en egaligheid van die verspreiding van families, het konvensionele appelkoos grond die hoogste spesierykheid, terwyl die gronde van die organiese appelboord die mees egalige familie verspreiding vertoon het. Verskillende bestuurspraktyke nie toon nie merkbare verskille in die gemeenskap samestelling en struktuur nie. Die spesie-rykheid van Fynbos gronde is vergelykbaar met dié van sagtevrugte-boorde. Monsters is geneem van agt verskillende grondeoppervlak-behandelings in ‘n appelboord in die Grabouw area. Die behandelings is gekombineer volgens die grond toediening wat dit ontvang het (chemiese beheer van dekgewasse en onkruid, deklaag en ‘n deklaag + effektiewe mikro- IX organismes). Bakterievoedende nematodes was dominant in elke grondoppervlak-behandeling, met die minste teenwoordig in die behandelings wat chemiese beheer van die dekgewasse en onkruid ontvang het. Behandelings wat chemiese beheer van die dekgewasse en onkruid ontvang het, het ook hoër vlakke van fungivore in vergelyking met die ander behandelings. ʼn Hoë aantal Rhabditidae het voorgekom in grondmonsters van die deklaag en die deklaag + EM (effektiewe mikro-organismes) behandeling persele, terwyl ʼn groot aantal Aphelenchidae voorgekom het in chemiese beheer persele. Die predatoriese familie, Ironidae, het slegs voorgekom in persele wat die deklaag + EM behandeling ontvang het. Sterk assosiasies bestaan tussen grond behandeling en nematode families wat in die grond teenwoordig was. Die chemiese beheer behandeling het die hoogste MI waarde getoon, terwyl waardes vir die ander behandelings laer en gelyk was. Die fauna analise het daarop gedui dat die deklaag en chemiese beheer binne kwadrant A is en dus verryk, maar ook ongestruktureerd is. Die deklaag + EM behandeling het binne kwadrant B geval wat aandui op toestande van verryking en struktuur wat 'n goeie algehele grondtoestand tot gevolg gehad het. Al die stelsels is oorbruggingsweë wat oorheers was deur bakteriële ontbinding. Kontroversieel, het persele wat chemiese beheer van die dekgewasse en onkruid ontvang het, die hoogste spesierykheid van al drie behandelings getoon asook die hoogste vlak van diversiteit volgens die Simpson-indeks. Slegs die dekgewasse en onkruid is chemies behandel, nie die grond nie, en dus kan die grond as onversteurd beskou word en die resultate wat verkry is in die studie verklaar. Duidelike verskille in die nematode gemeenskap struktuur en samestelling is waargeneem tussen die verskillende grond behandelings in appel boorde.Thesis (MScAgric)--Stellenbosch University, 2013.Stellenbosch : Stellenbosch UniversityStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.Malan, A. P.Addison, P.Storey, S. G.2013-02-20T12:59:08Z2013-03-15T07:34:21Z2013-02-20T12:59:08Z2013-03-15T07:34:21Z2013-03Thesis139 p. : ill., mapshttp://hdl.handle.net/10019.1/80089en_ZAStellenbosch University