Masters Degrees (Conservation Ecology and Entomology) http://scholar.sun.ac.za:80/handle/10019.1/532 2017-07-16T02:58:11Z The population status, habitat use and seasonal diet of African elephant (Loxodonta africana) in Majete Wildlife Reserve, Malawi http://scholar.sun.ac.za:80/handle/10019.1/101294 The population status, habitat use and seasonal diet of African elephant (Loxodonta africana) in Majete Wildlife Reserve, Malawi Forrer, Frances Ann ENGLISH ABSTRACT: The African elephant (Loxodonta africana) is classified as a keystone species as it is critical to the integrity of the ecosystems it occupies. It influences a variety of factors in these ecosystems that include, but are not limited to, canopy cover, seed dispersal and various plant and animal species distributions. In addition to being classified as mixed feeders, elephants are water-dependent and the location and availability of water affects the extent and intensity at which elephants make use of vegetation. Confinement through the fencing of many elephant populations, particularly in Southern Africa, has adversely affected the management of this species. Population numbers tend to rapidly increase due to improved protection and supplementation of resources, intensifying the species negative effects on other herbivore species. Majete Wildlife Reserve, located in Malawi, was almost entirely devoid of wildlife but was revived by African Parks in 2003. The reserve was fenced, artificial waterholes were installed and an abundance of wildlife was reintroduced, including 213 elephants. Five years post reintroduction, elephant numbers have dramatically increased and concern has been raised regarding the potential impact of this species on the vegetation and other herbivore species in the reserve. In this study, a review of all relevant literature was reported and two field studies were conducted on the population status, habitat use and diet of elephants in the reserve. The population status of the elephants was assessed with aerial survey data and individual identification techniques. The population has increased to an estimated 389 individuals, of which 366 were positively identified. Results revealed a sex ratio of 1:1 and a population growth rate of 13.8% per annum. Additionally, habitat use of the elephants was investigated using camera trap gridlines throughout the reserve. It was determined that a higher number of elephant frequented habitat near perennial water sources and at lower altitudes. Furthermore, waterhole usage was determined using camera traps placed at artificial water sources in Majete. Results suggested that fewer elephants utilised artificial waterholes during the wet season and that family herds tended to dominate the use of the majority of the artificial waterholes. Lastly, it was determined that the use of artificial waterholes was increasingly homogenous in the dry season. The increasing elephant population resulted in dispersal to less preferred areas, namely that of higher altitude miombo woodland as lower altitude regions were potentially becoming too densely populated. Diet of the elephants was investigated using stable isotope analysis of faecal samples to determine seasonal grass and browse composition. Elephants’ diets displayed a clear seasonal difference in the proportion of C3 browse consumed. In the dry season the diet contained 98% C3 browse but decreased to 59% in the early wet season and to 65% in the late wet season. This indicates that a greater proportion of C4 grass was consumed in the wetter seasons, typical of other elephant populations. The results from this study will contribute towards the compilation of an elephant management plan that will be provided to African Parks, Majete, for further implementation.; AFRIKAANSE OPSOMMING: Die Afrika-olifant (Loxodonta africana) word geklassifiseer as ’n hoeksteenspesie omdat dit van kritiese belang is vir die integriteit van die ekosisteme waarin dit voorkom. Dit beïnvloed ’n verskeidenheid faktore in hierdie ekosisteme, insluitend, maar nie beperk tot, lowerdekking, saadverspreiding en die verspreiding van verskeie plant- en dierspesies. Buiten dat hulle as gemengde vreters geklassifiseer word, is olifante afhanklik van water en die ligging en beskikbaarheid van water beïnvloed die mate en intensiteit waartoe olifante van plantegroei gebruik maak. Die inperking van baie olifantbevolkings deur heinings, veral in Suidelike Afrika, het ’n negatiewe effek op die bestuur van die spesie gehad. Bevolkingsgetalle neig om vinnig toe te neem as gevolg van verhoogde beskerming en die aanvulling van hulpbronne, wat die spesies se negatiewe effekte op ander herbivore versterk. Die Majete Wildreservaat, wat in Malawi geleë is, was feitlik gestroop van alle wild, maar is in 2003 deur African Parks herleef. Die reservaat is omhein, kunsmatige watergate is geïnstalleer en ’n oorvloed wild is hervestig, insluitend 213 olifante. Vyf jaar ná die hervestiging het olifantgetalle dramaties toegeneem en kommer is uitgespreek oor die potensiële impak van hierdie spesie op die plantegroei en ander herbivoorspesies in die reservaat. In hierdie studie word verslag gedoen oor die relevante literatuur, asook van twee veldstudies wat onderneem is om die bevolkingstatus, habitatgebruik en dieet van die olifante in die reservaat te ondersoek. Die bevolkingstatus van die olifante is geassesseer deur gebruik te maak van data afkomstig van lugopnames en individuele identifikasietegnieke. Die bevolking het toegeneem tot ’n geskatte 389 individue, waarvan 366 positief geïdentifiseer is. Die resultate toon ’n geslagsverhouding van 1:1 en ’n bevolkingsgroeikoers van 13.8% per jaar. Daarbenewens is die habitatgebruik van die olifante ondersoek met behulp van kamerastrikke op ruitlyne in verskeie plekke in die reservaat. Daar is bepaal dat ’n groter getal olifante die habitat in die nabyheid van standhoudende waterbronne en op laer hoogtes bo seespieël meer dikwels besoek het. Die gebruik van watergate is verder ondersoek met behulp van kamerastrikke in die nabyheid van die kunsmatige waterbronne in Majete. Die resultate stel voor dat minder olifante die kunsmatige waterbronne tydens die nat seisoen gebruik het en dat familietroppe geneig het om die gebruik van die meerderheid kunsmatige watergate te domineer. Laastens is daar bepaal dat die gebruik van kunsmatige watergate toenemend homogeen was in die droë seisoen. Die groeiende olifantbevolking het gelei tot verspreiding na minder gunstige gebiede, veral na die hoërliggende miombo bosland soos die laer geleë streke potensieel te dig bevolk geraak het. Die olifante se dieet is ondersoek met stabiele isotoop analise van mismonsters om die samestelling van seisoenale gras en takvoer te bepaal. Die olifante se diëte het ’n duidelike seisoenale verskil getoon in die proporsie C3 takvoer wat gevreet is. In die droë seisoen het die dieet 98% C3 takvoer bevat, maar dit het afgeneem tot 59% in die vroeë nat seisoen en tot 65% in die laat nat seisoen. Dit dui daarop dat ’n groter proporsie van C4 gras in die natter seisoene gevreet is, wat tipies is van ander olifantbevolkings. Die resultate van hierdie studie sal bydra tot die samestelling van ’n olifantbestuursplan wat aan African Parks, Majete verskaf sal word vir verdere implementering. Thesis (MScConsEcol)--Stellenbosch University, 2017. 2017-03-01T00:00:00Z People and protected areas : natural resource harvesting as an approach to support rural communities surrounding Majete Wildlife Reserve, Southern Malawi : a case study http://scholar.sun.ac.za:80/handle/10019.1/101141 People and protected areas : natural resource harvesting as an approach to support rural communities surrounding Majete Wildlife Reserve, Southern Malawi : a case study Gordon, Claire Nicola ENGLISH ABSTRACT: Protected areas across the developing world are increasingly incorporating the needs of local rural communities into their management decisions. The African Parks managed Majete Wildlife Reserve (MWR) in the lower Shire valley of southern Malawi is no exception. Through African Parks’ extension department they aim to incorporate the needs of local communities into their management framework in order to maintain support for their conservation activities. A resource use program (RUP) which facilitates sustainable harvesting was implemented to allow community members access to thatching grass inside the reserve, via 8 RUP gates on the perimeter fence. Each RUP gate is opened once annually for 7 days and game scouts are made available to escort community members into the reserve to harvest grass. As a case study, we assessed the 2015 RUP activities at 5 of the 8 RUP gates to determine the number of community members utilising the program, the biomass of grass removed, the variation in grass bundle masses and the distances walked by community members to access the RUP gates. We determined that a total of 2211 community members accessed the reserve via the 5 monitored RUP gates and removed 134 073kg of thatching grass in 2015. Additionally, we found a significant variation in the bundle masses between individual harvesters, as well as the harvesting characteristics at each RUP gate. We also confirmed anecdotal suggestions from the African Parks extension assistants (EAs) that community members’ walk significant distances from their homes to the RUP gates to harvest grass. To assess the possibility of extending the current RUP to include medicinal plant harvesting we conducted interviews with 12 traditional healers in communities adjacent to the reserve. In conjunction with interviews, we conducted rapid ethnobotanical surveys, where we accompanied the traditional healers into the field to collect and formally identify plants used for medicinal purposes. We identified a total of 96 different plant species used by these healers, the majority of which were trees and shrubs. The most commonly used plant parts were roots, leaves and bark, and traditional healers currently treat 27 different ailments and illnesses. Additionally, we found a substantial variation in the local names for medicinal plants, with some plants having 5-6 local names. Almost all the traditional healers we interviewed listed their healing practise as their main source of formal income (n = 11), while all of the healers stated that prior to the reserve fence being erected they harvested medicinal plants in the reserve (n = 12), and that they would like to be able to harvest medicinal plants in the reserve again (n = 12). We conducted a household survey to determine general perceptions of the current RUP. Our findings suggest that overall; community members are satisfied with the RUP (92%) however there is some room for improvement. The majority of respondents requested that the annual RUP grass harvesting window is increased (96%), as currently it is not long enough for community members to harvest enough grass for their household needs. A significant number of community members also requested the addition of medicinal plant (70%) and firewood (70%) harvesting to the RUP. This feedback adds support to the traditional healers request for medicinal plant harvesting inside MWR. The findings of this study provide useful baseline data from which African Parks can continue to ensure that the RUP stays relevant to communities surrounding the reserve in the future. The long-term success of the reserve will ultimately depend on the continued support from local communities and the RUP is one way in which MWR can continue to engage with community members. The research acts as a useful case study to support the theory that communities are more likely to support continued conservation efforts when they can benefit and extract value from a protected area.; AFRIKAANSE OPSOMMING: Beskermde gebiede dwarsoor die ontwikkelende wêreld inkorporeer toenemend die behoeftes van die plaaslike landelike gemeenskappe in hulle bestuursbesluite. Die Majete Wildreservaat (MWR) in die laer Shire-vallei van suidelike Malawi, wat deur African Parks bestuur word, is geen uitsondering nie. Deur African Parks se voorligtingsdepartement word ’n poging gemaak om die behoeftes van die plaaslike gemeenskappe in hulle bestuursraamwerk in te sluit om sodoende ondersteuning vir hul bewaringsaktiwiteite te onderhou. ’n Hulpbrongebruiksprogram (resource use program (RUP)) wat volhoubare oes fasiliteer, is geïmplementeer om lede van die gemeenskap toegang te gee tot die dekgras binne die reservaat via agt RUP hekke in die grensheining. Elke RUP hek word een keer per jaar vir sewe dae oopgesluit en wildwagters word beskikbaar gestel om gemeenskapslede in die reservaat te vergesel sodat hulle die gras kan oes. Ons het in 2015 die RUP aktiwiteite by vyf van die agt RUP hekke waargeneem om te bepaal hoeveel lede van die gemeenskap die program gebruik, die grootte van die biomassa van die gras wat verwyder is, die afwisseling in die massa van die grasbondels, en die afstande wat deur elke lid van die gemeenskap gestap word om toegang te kry tot die hekke. Ons het bevind dat ’n totaal van 2 211 gemeenskapslede die reservaat via die vyf RUP hekke binnegekom het en 134 073 kg dekgras verwyder het. Daarbenewens het ons ook noemenswaardige afwisseling in die bondelgroottes van individuele plukkers gevind, sowel as in oeskenmerke by elke RUP hek. Ons kon ook anekdotiese voorstelle van die voorligtingsassistente van African Parks bevestig dat gemeenskapslede baie lang afstande vanaf hulle huise tot by die RUP hekke stap om die gras te kan oes. Om die moontlikheid te ondersoek dat die huidige RUP uitgebrei word om die oes van medisinale plante in te sluit, is onderhoude gevoer met 12 tradisionele genesers in gemeenskappe langsaan die reservaat. Tesame met die onderhoude het ons vinnige etnobotaniese opnames onderneem waarvoor ons saam met die tradisionele genesers die veld ingestap het om plante wat vir medisinale doeleindes gebruik word, te versamel en formeel te identifiseer. Ons het ’n totaal van 96 verskillende plantspesies geïdentifiseer wat deur die genesers gebruik word, die meerderheid waarvan bome en struike was. Die plantdele wat die algemeenste gebruik word, was wortels, blare en bas, en tradisionele genesers behandel tans 27 verskillende kwale en siektes. Ons het ook aansienlike verskille in die plaaslike name vir die medisinale plante gevind, met sommige plante wat tot vyf of ses plaaslike name het. Feitlik al die tradisionele genesers met wie ons onderhoude gevoer het, het hulle helende praktyk as hulle vernaamste bron van formele inkomste beskryf, terwyl al die genesers genoem het dat hulle medisinale plante in die reservaat geoes het voor die heining opgesit is en dat hulle graag weer dié plante in die reservaat sou wou oes. Ons het ’n opname van huishoudings onderneem om die algemene persepsies van die huidige RUP te bepaal. Ons bevindings dui aan dat, oor die algemeen, gemeenskapslede tevrede is met die RUP, hoewel daar ruimte vir verbetering is. Die meerderheid respondente het vereis dat die jaarlikse tydperk vir die oes van gras in die RUP uitgebrei moet word, aangesien dit tans nie lank genoeg is vir gemeenskapslede om genoeg gras vir die behoeftes van hulle huishoudings te oes nie. ’n Noemenswaardige getal gemeenskapslede het ook die byvoeging van medisinale plante en vuurmaakhout tot die RUP aangevra. Hierdie terugvoer ondersteun die tradisionele genesers se versoek vir die oes van medisinale plante in die MWR. Die bevindings van hierdie studie verskaf nuttige data waarmee African Parks kan voortgaan om te verseker dat die RUP in die toekoms relevant bly vir die gemeenskappe om die reservaat. Die langtermyn sukses van die reservaat sal uiteindelik afhanklik wees van die volgehoue steun van plaaslike gemeenskappe en die RUP is een manier waarop die MWR kan aanhou om met gemeenskapslede betrokke te bly. Solank die plaaslike mense voordeel trek en waarde in die reservaat kan sien, sal hulle meer geneig wees om die voortgesette bewaringspogings van African Parks in die Majete Wildreservaat te ondersteun. Thesis (MScConsEcol)--Stellenbosch University, 2017. 2017-03-01T00:00:00Z Improving feeding efficiencies of black soldier fly larvae, Hermetia illucens (L., 1758) (Diptera : Stratiomyidae : Hermetiinae) through manipulation of feeding conditions for industrial mass rearing http://scholar.sun.ac.za:80/handle/10019.1/100812 Improving feeding efficiencies of black soldier fly larvae, Hermetia illucens (L., 1758) (Diptera : Stratiomyidae : Hermetiinae) through manipulation of feeding conditions for industrial mass rearing Brits, Devon ENGLISH ABSTRACT: The human population is rapidly expanding and raises several concerns in terms of food security and waste management. To feed the human population, we need to start expanding our horizons in terms of what we eat. Insects may be the answer to this. But due to our many other problems, it helps to create multiple solutions from single ideas that promote green industry and help ‘heal’ our planet rather than only taking from it. This is where the black soldier fly, Hermetia illucens (L., 1758) (Diptera: Stratiomyidae: Hermetiinae) may offer such a solution. Hermetia illucens is a non-pestilent fly that has spread worldwide due to its many innovative uses, for example used as a type of biological control agent for some filth fly species, recycle 1.3 billion tonnes of annual organic waste globally, create high-grade biodiesel and replace (or at least alleviate the demand) for fish or legume-based animal feeds and lipids. However, very little is known about how the protein and lipid rich larvae can be mass reared for industrial purposes. This thesis answers questions about the feeding environment and density of H. illucens larvae in an industrial setting (i.e. food waste, and larger population sizes). By investigating how feed depth and particle size, feed provisioning rations (i.e. larval densities), and population sizes effect the ability of larvae to develop, survive and feed. The results of this thesis were finding the optimal feed depths (i.e. 5-10 cm), provisioning rations (125 mg/larva/day) and population sizes (5 000-50 000 larvae per container) of H. illucens larvae when fed kitchen wastes. Additionally, two new measures of feeding efficiencies were described (i.e. provisioning ration change and optimal bioconversion deficit) and values for larval aggregation heat were also recorded for the first time. Future recommendations and research that came up during this study is also given to continue furthering an industry capitalising on US$ 750 million lost annually in all waste streams worldwide.; AFRIKAANSE OPSOMMING: Die menslike bevolking is besig om vinnig uit te brei, wat verskeie bekommernisse wek ten opsigte van voedselsekuriteit en afvalbestuur. Om die menslike bevolking te voed, moet ons begin om ons horisonne te verbreed in terme van wat ons eet. Insekte sal waarskynlik die antwoord hierop wees. Maar as gevolg van ons baie ander probleme, help dit om verskeie oplossings te skep vanuit enkele idees wat groen bedryf bevorder en wat help om ons planeet te genees eerder as om daarvan te neem. Dit is waar die swart soldaatvlieg, Hermetia illucens (L., 1758) (Diptera: Stratiomyidae: Hermetiinae) 'n oplossing kan bied. Hermetia illucens is 'n nie-pes vlieg wat wêreldwyd versprei het as gevolg van die vele innoverende doeleindes waarvoor dit gebruik kan word, byvoorbeeld as ʼn biologiese beheeragent vir verskeie vullis vliegspesies, vir die herwinning van ʼn jaarlikse 1,3 miljard ton organiese afval wêreldwyd, vir die vervaardiging van hoë-graad biodiesel en die vervanging van (of ten minste verligting van die aanvraag na) vis of peulplant gebaseerde veevoere en lipiede. Baie min is egter bekend oor hoe die proteïen- en lipiedryke larwes in groot maat geteel kan word vir industriële doeleindes. Hierdie tesis beantwoord vrae oor die voedingsomgewing en bevolkingsdigtheid van H. illucens larwes in 'n industriële omgewing (m.a.w. voedselafval en groter bevolkingsgroottes). Dit is gedoen deur te ondersoek hoe voerdiepte en partikelgrootte, voer voorsieningsrantsoene (d.w.s. larwedigthede), en bevolkingsgroottes die vermoë van larwes om te ontwikkel, oorleef en voed, beinvloed. Die resultate van hierdie tesis het die optimale voerdieptes (d.w.s. 5-10 cm), voorsieningsrantsoene (125 mg / larwe / dag) en bevolkingsgroottes (5 000-50 000 larwes per houer) van H. Illucens vasgestel vir larwes wat met kombuisafval gevoer is. Daarbenewens is twee nuwe maatreëls van voedingsdoeltreffendheid beskryf (d.w.s. voorsieningsrantsoen verandering en optimale bio-omsetting), en waardes vir larwale samedrommingshitte is ook aangeteken vir die eerste keer. Toekomstige aanbevelings en navorsing wat in hierdie studie na vore gekom word ook gegee om voort te gaan om 'n bedryf te bevorder wat kapitaliseer op 750 miljoen USD wat jaarliks in afvalstrome wêreldwyd verlore gaan. Thesis (MScConsEcol)--Stellenbosch University, 2017. 2017-03-01T00:00:00Z Assessing the chemical ecology and shelter-seaking behaviour of the grainchinch bug, Macchiademus diplopterus (hemiptera: lygaeidae) for optimisation of trapping during aestivation http://scholar.sun.ac.za:80/handle/10019.1/100362 Assessing the chemical ecology and shelter-seaking behaviour of the grainchinch bug, Macchiademus diplopterus (hemiptera: lygaeidae) for optimisation of trapping during aestivation Ngadze, Masimbaashe ENGLISH ABSTRACT: The grain chinch bug (GCB), Macchiademus diplopterus (Distant) (Hemiptera: Lygaeidae) is a key quarantine pest of South African export fruit and is endemic to the Western Cape Province. The pest is troublesome in the drier wheat growing areas where it disperses from wheat in summer to find sheltered sites in which to aestivate. Aestivating adults can end up contaminating export fruit. The aim of the study was to gather more knowledge on the chemical ecology and shelter-seeking behaviour of the GCB. The involvement of pheromones in the aggregation behaviour of GCBs is yet to be fully elucidated. Further investigating the chemical ecology of the GCB in order to optimize its pheromone trapping was the primary focus of the first research chapter in this study. Headspace volatile compounds were identified from active bugs through gas chromatography-mass spectrometry (GC-MS) analysis. A total of 14 volatile compounds were identified from males and females in varying concentrations. For both sexes pooled, tridecane, (E)-2-hexanal and (E)-2-octenal were the three main components; (E)-2-hexenol, (E)-2-octenol, decanal and pentadecane were in medium amounts, while decanoic acid, dodecane, hexadecanal, hexanal, icosane, nonanal and tetradecanoic acid were minor components. The efficacy of synthetic lures using previously identified aggregation pheromone components, and sex pheromone volatile components (identified in present study) was studied in combination with modified traps using rubber septa dispensers in a field trial. There was no significant difference (P > 0.05) between insects caught in the sex pheromone baited traps and the aggregation pheromone baited traps. Traps caught low numbers of GCBs compared to the level of orchard infestation indicated by the amount of bugs that were found sheltering in corrugated cardboard bands tied around tree trunks. The corrugated cardboard bands showed a significant difference in the number of bugs sheltering between bands placed at bottom and top positions (0.5m and 1.5m above ground respectively) on the trees, at site 1 (P = 0.0058), site 2 (P < 0.0169) and site 4 (P < 0.0496) with the exception of site 3 (P > 0.4115). Cardboard band position influenced catches, as more bugs were found in bottom bands. This can be used advantageously in optimising innovative trap placements in the future in order to improve catches. In the second research chapter investigations into the behavioural responses of GCBs to visual objects were conducted. This was done to increase knowledge on how this behaviour can lead to the development of control measures such as the use of coloured traps of different shapes. Behavioural responses of GCBs to different shapes presented in their visual space indicated that there was a significant difference (P = 0.0001) in the choice of shape. Vertical/upright rectangular shapes had the highest number of GCB visits. GCBs responded to upright rectangles of different colours.Black and red rectangles were not significantly different (P > 0.05) from each other but were both significantly different (P = 0.0001) from green and yellow rectangles, off-target and sedentary insects. Vertical rectangles of two different colour patterns (black & white) and (red & white) did not show any significant difference (P > 0.153) in the number of GCB visits. Both black & white and red & white vertical stripes were significantly different (P = 0.0001) from off-target and sedentary insects. This indicates that GCBs were equally responsive to both colour patterns. These results indicate that GCBs exhibit a positive scototactic reaction towards dark upright surfaces. Information generated from this study will facilitate the development of pre-harvest monitoring and management measures against GCBs, using pheromone traps and physical barriers that prevent GCBs from dispersing into fruit orchards at the wheat to fruit orchard interface. This can help to reduce fruit contaminations, ultimately lowering the rejection risk of export fruit from South Africa.; AFRIKAANS OPSOMMING: Die graanstinkluis, Macchiademus diplopterus (Distant) (Hemiptera: Lygaeidae), is ’n belangrike kwarantynplaag van Suid-Afrikaanse uitvoervrugte en is endemies aan die Wes-Kaapprovinsie. Die plaag is ’n probleem in die droër graanbougebiede waar dit in die somer van graan versprei om skuilplekke te vind om in ’n somerrusperiode in te gaan. Volwasse insekte in hierdie somerrusperiode kan uitvoervrugte besmet. Die doel van hierdie ondersoek was om meer kennis oor die chemiese ekologie en skuilpleksoekende gedrag van die graanstinkluis te versamel. Daar moet nog afdoende bewys van die betrokkenheid van feromone by die aggregasiegedrag van graanstinkluise gevind word. Verdere ondersoek van die chemiese ekologie van die graanstinkluis om die feromoonlokval te optimaliseer was die primêre fokus van die eerste navorsingshoofstuk van hierdie studie. Vlugtige organiese verbindings in die bodamp van saamgetrosde stinkluise is deur gaschromatografie-massaspektrometrie (GC-MS)-ontleding geïdentifiseer. Altesaam 14 vlugtige verbindings is van mannetjies en wyfies in wisselende relatiewe konsentrasies geïdentifiseer. Vir albei geslagte was tridekaan, (E)-2-heksanaal en (E)-2-oktenaal die drie hoofkomponente; (E)-2-heksenol, (E)-2-oktenol, dekanaal en pentadekaan was in mediumhoeveelhede teenwoordig terwyl dekanoësuur, dodekaan, heksadekanal, heksanaal, ikosaan, nonanal en tetradekanoësuur mindere komponente was. Die doeltreffendheid van sintetiese lokmiddels deur gebruik van voorheen geïdentifiseerde aggregasie-feromoonkomponente en seksferomoon vlugtige komponente (in die huidige studie geïdentifiseer) is in ’n praktiese toets bestudeer in kombinasie met gemodifiseerde lokvalle deur gebruik van rubberseptahouers. Daar was geen beduidende verskil (P > 0.05) tussen insekte wat in die lokvalle met seksferomoon-lokmiddels en lokvalle met aggregasieferomoon-lokmiddels gevang is nie. Lokvalle het klein getalle stinkluise gevang in vergelyking met die vlak van boordinfestering wat aangedui word deur die hoeveelheid luise wat gevind is in riffelkartonstroke wat om boomstamme gebind is. Daar was ’n beduidende verskil tussen die aantal luise wat in die riffelstroke onderom en bo-om die bome gebind is (0.5m en 1.5m bo die grond), in terrein 1 (P = 0.0058), terrein 2 (P < 0.0169) en terrein 4 (P < 0.0496), met die uitsondering van terrein 3 (P > 0.4115). Die posisie van die riffelkartonstroke het die vangste beïnvloed aangesien meer luise in die onderste stroke gevind is. Dit kan voordelig aangewend word deur in die toekoms innoverende lokvalplasings te optimaliseer ten einde vangste te verbeter. In die tweede navorsingshoofstuk is gedragsresponse van graanstinkluise op visuele voorwerpe ondersoek. Dit is gedoen om kennis uit te brei oor hoe hierdie gedrag tot die ontwikkeling van beheermaatreëls soos die gebruik van gekleurde lokvalle in verskillende vorms kan lei. Gedragsreaksies van stinkluise op verskillende vorms wat in hulle gesigsveld aangebied word het getoon dat daar ’n betekenisvolle verskil (P = 0.0001) in die keuse van vorm was. Vertikale/regop reghoekige vorms het die grootste aantal besoeke gehad. Stinkluise het teenoor regop reghoeke van verskillende kleure gereageer. Die reaksie op swart en rooi reghoeke was nie beduidend verskillend (P > 0.05) van mekaar nie, maar albei het aansienlik verskil (P = 0.0001) van dié van groen en geel reghoeke, buiteteiken- en sedentarye insekte. Vertikale reghoeke van twee verskillende kleurpatrone (swart & wit) en (rooi & wit) het geen beduidende verskil (P > 0.153) in die aantal besoeke getoon nie. Swart & wit sowel as rooi & wit vertikale strepe het aansienlik verskil (P = 0.0001) van buiteteiken- en sedentarye insekte. Dit dui daarop dat graanstinkluise ewe goed op albei kleurpatrone gereageer het. Hierdie resultate dui daarop dat graanstinkluise ’n positiewe skototaktiese reaksie teenoor donker, regop vlakke toon. Inligting uit hierdie studie sal die ontwikkeling van vooroes-monitering en -bestuursmaatreëls teen die graanstinkluis fasiliteer deur gebruik van feromoon-lokvalle en fisieke grense wat stinkluise verhinder om na vrugteboorde by die graan-tot-vrugteboord-koppelvlak te versprei. Dit kan help om vrugtebesmettings te verminder, wat uiteindelik die afkeuringsrisiko van uitvoervrugte uit Suid-Afrika sal verminder. Thesis (MScAgri)--Stellenbosch University, 2016. 2016-12-01T00:00:00Z The importance of renosterveld conservation based on insect diversity sampled in West Coast Renosterveld in the Western Cape of South Africa http://scholar.sun.ac.za:80/handle/10019.1/100209 The importance of renosterveld conservation based on insect diversity sampled in West Coast Renosterveld in the Western Cape of South Africa Stander, Arne ENGLISH ABSTRACT: Research in the Fynbos Biome mainly focussed on the exceptional high plant diversity, especially of the Cape Floristic Region. However, there remains a poor understanding of the insect life found in this region and throughout the Fynbos Biome. The purpose of this thesis was to reduce this knowledge gap, and to add conservation value to the West Coast Renosterveld based on the insect life. This thesis is also the first to document insect diversity at community-level in a highly threatened and fragmented vegetation type in South Africa. West Coast Renosterveld, along with the other renosterveld types, is threatened by agricultural development due to the nutrient richer soils compared to the other vegetation types of the Fynbos Biome. From a conservation point of view, West Coast Renosterveld is in a critical state, with only 3-4% remaining. I used various sampling methods over four seasons to document insect species found in four West Coast Renosterveld patches in the Cape Winelands district, Western Cape. I analyse the effects of sampling methods, seasons and location on the community composition data, and calculate both alpha and beta diversity measures for the four renosterveld patches. The first part of the thesis investigated the effects of sampling method and season on the documented insect species richness and abundance of the insect communities. D-vac, sweep net, pitfall traps, and pan traps were the sampling methods used for this study. Sampling was done over all four seasons in the first year. The combined sampling methods and seasons delivered a total of 851 morphospecies, consisting of 17 orders and 155 families. The sampling methods used in the West Coast Renosterveld did not have an effect on insect species richness or abundance, but did determine how many species and what number were sampled. In addition, seasons are an important driving factor of insect communities in the remaining renosterveld areas. The sampling effort applied in this study thus suggests that renosterveld is rich in insect fauna. Furthermore, a feasible and logistical sampling strategy is proposed which can be used for future insect sampling in renosterveld and other Fynbos Biome vegetation types. The second part of the thesis compared the insect species richness and abundance of four renosterveld areas and investigated what the possible variables are affecting the variation between these areas. J.N Briers-Louw had the highest insect diversity compared to Papegaaiberg, Kooppmanskloof and Spier. Beta diversity was the smallest between any combination with J.N.Briers-Louw and yielded greater diversity when representing the whole region, compared to any other two renosterveld areas. Based on the results, it can be assumed that habitat characteristics have the biggest effect on insect diversity in renosterveld, which is altered by factors including disturbance and topography. Considering these contributing factors, this study found that insect diversity differs greatly between West Coast Renosterveld remnants with only about 20% of the species shared between patches. This emphasises the importance of conserving all remaining renosterveld patches. Also, with this study’s documentation and explanation for the insect diversity found in West Coast Renosterveld, future research can now focus on specific taxa and plant-insect relationships to better understand the ecological functionality of insects in renosterveld.; AFRIKAANS OPSOMMING: Navorsing in die Fynbos Bioom het grotendeels op die besonderse hoë plant diversiteit gefokus, veral in die Kaap Floristiese Ryk. As ʼn gevolg is daar nogsteeds ʼn gebrek aan kennis en begrip van die inseklewe in hierdie streek en die Fynbos Bioom. Die doel van die tesis was om hierdie gaping in die studieveld kleiner te maak, asook om waarde tot Weskus Renosterveld bewaring toe te voeg. Hierdie tesis is ook die eerste om insekdiversiteit op ʼn gemeenskapsvlak in ʼn hoogs bedreigde en gefragmenteerde plantegroei tipe in Suid-Afrika te dokumenteer. Weskus Renosterveld, tesame met die ander renosterveld tipes, word bedreig deur landbou ontwikkeling as gevolg van die geskikte grond wat hoër in voedingswaarde is, teenoor die ander plantegroei tipes van die Fynbos Bioom. Uit ʼn bewarings oogpunt is Weskus Renosterveld in ʼn kritieke toestand waar daar slegs ʼn oorblywende 3-4% van hierdie plantegroei-tipe oor is. Ek het verkeie versamelingsmetodes gebruik oor vier seisoene om die verskillende insekspesies te dokumenteer wat in die vier afsonderlike Weskus Renosterveld areas in die Kaapse Wynland distrik voorkom. Ek analiseer die effekte van versamilingsmetodes, seisoene en area op spesies voorkoms en getalle, en bereken beide alpha en beta diversiteitwaardes vir die vier renosterveld areas. Die eerste deel van die tesis het die effekte van versamelingsmetodes en seisoene op die gedokumenteerde insekspesies se spesiesrykheid en getalle van die insekbevolkings ondersoek. D-vac, swaainet, pitvalle, en gekleurde pan-lokvalle was die gekose versamelingsmetodes vir hierdie studie. Veldwerk was oor vier seisoene in die eerste jaar uitgevoer. Die gekombineerde versamelingsmetodes en seisoene het ʼn totaal van 851 morfospesies, wat uit 17 orders en 155 families bestaan, opgelewer. Die versamelingsmetodes het geen effek op die spesiesrykheid en getalle van die insekte gehad nie, maar het wel die hoeveelheid spesies en hul ooreenstemmende getalle bepaal. Verder is seisoen ʼn belangrike drywende faktor van insekbevolkings in die oorblywende renosterveld areas. Die geïmplimenteerde versameling van hierdie studie stel voor dat die renosterveld ryk is in insek fauna. Daar is ook ʼn gepaste en logiese versamelingsstrategie voorgestel vir verdere insekversameling in renosterveld en ander plantegroei tipes van die Fynbos Bioom. Die tweede deel van die tesis het die insekte se spesiesrykheid en getalle van die vier renosterveld areas vergelyk en het ondersoek wat die moontlike veranderlikes kan wees wat die variasie tussen hierdie areas beïnvloed. J.N. Briers-Louw het die grootste insekdiversiteit in vergelyking met Papegaaiberg, Koopmanskloof en Spier. Beta diversiteit was die kleinste tussen enige areas met J.N. Briers-Louw as kombinasie en het die grootste diversiteit wat die hele gebied verteenwoordig opgelewer, in vergelyking met enige ander twee renosterveld areas. Op grond van die resultate kan mens aanneem dat habitat karaktereienskappe die grootste effek op die insekdiversiteit van die renosterveld het, wat bepaal word deur faktore soos graad van versteuring en topografie. Deur hierdie bydraende faktore in ag te neem, het die studie bevind dat die insekdiversiteit grotendeels verskil tussen Weskus Renosterveld areas met slegs 20% van die spesies wat tussen areas gedeel word. Dit beklemtoon die belangrikheid om al die oorblywende renosterveld areas te bewaar. Met hierdie studie se dokumentasie en verduideliking van die insekdiversiteit wat in Weskus Renosterveld gevind word, kan toekomstige navorsing nou op spesifieke taksa en plant-insek verhoudings fokus om ʼn beter begrip van die ekologiese funksionaliteit van insekte in renosterveld te kry. Thesis (MScAgric)--Stellenbosch University, 2016. 2016-12-01T00:00:00Z Investigating the potential of indigenous nematode isolates to control invasive molluscs in canola http://scholar.sun.ac.za:80/handle/10019.1/100060 Investigating the potential of indigenous nematode isolates to control invasive molluscs in canola Pieterse, Annika ENGLISH ABSTRACT: Terrestrial molluscs (Mollusca: Gastropoda) are important economic pests worldwide, causing extensive damage to a variety of crop types, and posing a health risk to both humans and wildlife. In South Africa, the climate is favourable for invasive European molluscs, especially in the Western Cape province, where there are mild, damp winters. One crop that is particularly targeted by the pests concerned is canola (Brassica napus), which is a winter arable crop that is commercially produced for its use in cooking, food processing, fertilisers, fuels, pet food, plastics, and animal feed. Molluscs on canola in the Western Cape province are currently controlled using chemical molluscicide pellets. These chemicals have the potential to adversely affect the environment and non-target organisms. The use of mollusc-parasitic nematodes is a possible environmentally-friendly alternative. Current knowledge indicates that there are eight nematode families that associate with molluscs, including Agfidae, Alaninematidae, Alloionematidae, Angiostomatidae, Cosmocercidae, Diplogastridae, Mermithidae, and Rhabditidae. To date, Phasmarhabditis hermaphrodita is the only nematode that has been developed as a biological molluscicide. The nematode, which was commercially released in 1994 by MicroBio Ltd, Littlehampton, UK (formally Becker Underwood, now BASF) under the trade name Nemaslug®, is now sold in fifteen different European countries. Due to current legislation, Nemaslug® cannot be sold or used in South Africa. A survey was therefore conducted in the Western Cape province of South Africa to locate a local nematode isolate capable of causing mortality in invasive mollusc pests. A total of 1944 slugs were collected from 12 different study sites. On the identification of slugs, they were dissected alive, and examined for internal nematodes. Nematodes were identified using morphological and molecular techniques (18S rRNA). Seven of the 12 sites had nematodes present, with 8% of the slugs being found to be infected with nematodes. Six nematode species were identified, including Angiostoma margaretae, Angiostoma sp., Caenorhabditis elegans, a mermitid sp., and Phasmarhabditis spp. (SA3 and SA4). Of the six species mentioned, four were previously undescribed. The isolation of new Phasmarhabditis spp. indicates the importance of conducting further surveys of mollusc-parasitic nematodes in South Africa. Nematodes isolated in the survey were tested for their ability to reproduce on decaying organic matter (consisting of dead frozen slugs), with results demonstrating that one of the nematodes, Phasmarhabditis sp. SA4, could complete its life cycle under such conditions. In addition, pathogenicity tests illustrated that Phasmarhabditis sp. SA4 caused significant mortality of the slug D. panormitanum. Phasmarhabditis sp. SA4 was then fully described and characterised by the shape and length of the female tail, and by the presence of males. Phylogenetic analysis demonstrated that Phasmarhabditis sp. SA4 was placed in a monophyletic clade along with Phasmarhabditis sp. SA2, Phasmarhabditis papillosa, and the mollusc-parasitic nematode, Angiostoma dentiferum. The new species brings the total complement of the genus to seven species. Phasmarhabditis sp. SA4 was then established in monoxenic cultures. Five bacterial isolates were isolated from the intestine of slug hosts, identified using 16S rRNA gene sequences, and their pathogenicity tested by means of injecting directly into the haemocoel of D. reticulatum, and monitoring the mortality over time. Kluyvera sp., which was found to cause the highest mortality rate among the slugs concerned, was chosen for monoxenic culturing. Cultures containing Phasmarhabditis sp. SA4 and Kluyvera sp. were optimised using temperatures ranging from 15°C to 25°C, with results showing that 15°C was the optimum growth temperature.; AFRIKAANS OPSOMMING: Landlewende weekdiere (Mollusca: Gastropoda) is wêreldwyd belangrike ekonomiese plae wat aansienlike skade aan ‘n verskeidenheid landbou gewasse veroorsaak en kan ‘n nadelige effek op die gesondheid van mense en dier hê. Die Wes-Kaap provinsie van Suid-Afrika met sy matige, klam winters is veral ‘n gunstige omgewing vir indringer Europese slakke en naakslakke. Een gewas wat veral benadeel word deur die aktiwiteit van hierdie spesies is canola (Brassica napus). Canola word kommersieel produseer vir gebruik in die voorbereiding van voedsel, kunsmis, brandstowwe, voer vir troeteldiere, plastiek en veevoer. Slakke word tans beheer in canola in die Wes-Kaap, deur die gebruik van slakpille. Die chemikalieë in hierdie slakpille het die potensiaal om ‘n negatiewe effek op die omgewing en nie-teiken organismes te hê. Nematodes wat dien as natuurlike parasiete van slakke is ‘n moontlike omgewingsvriendelike biologiese beheer alternatief. Volgens kennis is daar tans agt nematode families wat assosieer met slakke, naamlik Agfidae, Alaninematidae, Alloionematidae, Angiostomatidae, Cosmocercidae, Diplogastridae, Mermithidae, en Rhabditidae. Tot op datum is Phasmarhabditis hermaphrodita die enigste nematode wat al ontwikkel is in ‘n biologiese beheermiddel vir slakke. Die nematode is in 1994 kommersieel vrygestel deur MicroBio Ltd, Littlehampton, UK (voorheen Becker Underwood, nou BASF) onder die handelsnaam Nemaslug® en word tans verkoop in vyftien verskillende Europese lande. Huidige wetgewing verbied die verkoop of gebruik van die produk in Suid-Afrika. ‘n Opname was daarom gedoen van die nematodes geassosieer met slakke in die Wes-Kaap van Suid-Afrika, om ‘n plaaslike nematode te vind met dieselfde biologiese beheer potensiaal. ‘n Totaal van 1944 naakslakke was versamel van 12 verskillende studie areas. Nadat hul geidentifiseer was, was hul lewend dissekteer en ondersoek vir interne nematodes. Nematodes was geidentifiseer deur gerbuik te maak van morfologiese en molekulêre tegnieke (18S rRNA). Nematodes was teenwoordig by sewe van die twaalf studie areas en 8% van naakslakke was geïnfekteer deur nematodes. Ses nematode spesies was geïdentifiseer, naamlik Angiostoma margaretae, Angiostoma sp., Caenorhabditis elegans, ‘n mermitid sp., en Phasmarhabditis spp. (SA3 and SA4). Van die ses spesies wat gevind is, was vier nog nie voorheen beskryf nie. Die ontdekking van die nuwe Phasmarhabditis spesies is ‘n aanduiding van die belangrikheid van verdere opnames vir die voorkoms van nematodes parasiete geassosieer met slakke in Suid-Afrika. Nematodes wat gevind was in die opname se vermoë om voort te plant op organiese materiaal (bestaande uit gevriesde, dooie naakslakke) was getoets. Phasmarhabditis sp. SA4 kon suksesvol sy lewenssiklus voltooi in laboratorium toestande en verdure patogenisiteit toetse het bewys dat die nuwe nematode ‘n merkwaardige effek gehad het op sterftes van die indringer naakslak, D. panormitanum. Phasmarhabditis sp. SA4 was toe volledig beskryf en word gekarakteriseer deur die vorm en lengte van die vroulike nematode se stert asook die teenwoordigheid van manlike nematodes. Filogenetiese analise het getoon dat Phasmarhabditis sp. SA4 geplaas is in ‘n monofiletiese klade saam met Phasmarhabditis sp. SA2, Phasmarhabditis papillosa, en die slak-parasitiese nematode, Angiostoma dentiferum. Die nuwe spesie bring die totale hoeveelheid spesies in die genus na sewe. Om die patogenisiteit van die nematode te verhoog, kan die nematode gegroei word op ‘n bakterieë wat dood veroorsaak van slakke. Vyf bakterieë spesies was geïsoleer vanaf die ingewandes van slak gashere en geïdentifiseer deur die 16S rRNA gene. Die patogenisiteit van die bakterieë was getoets deur dit direk in D. reticulatum in te spuit en sterftes te monitor. Kluyvera sp. het die meeste sterftes veroorsaak in slakke en was gekies vir verdere formulering met Phasmarhabditis sp. SA4. Kulture bestaande uit slegs Kluyvera sp. en Phasmarhabditis sp. SA4 was getoets by 15°C, 20°C en 25°C. Die optimale groeitemperatuur vir Phasmarhabditis sp. SA4 was 15°C. Thesis (MScConsEcol)--Stellenbosch University, 2016. 2016-12-01T00:00:00Z Oxygen safety margins set thermal limits in an insect model system http://scholar.sun.ac.za:80/handle/10019.1/99706 Oxygen safety margins set thermal limits in an insect model system Boardman, Leigh; Terblanche, John S. A mismatch between oxygen availability and metabolic demand may constrain thermal tolerance. While considerable support for this idea has been found in marine organisms, results from insects are equivocal and raise the possibility that mode of gas exchange, oxygen safety margins and the physico-chemical properties of the gas medium influence heat tolerance estimates. Here, we examined critical thermal maximum (CTmax) and aerobic scope under altered oxygen supply and in two life stages that varied in metabolic demand in Bombyx mori (Lepidoptera: Bombycidae). We also systematically examined the influence of changes in gas properties on CTmax. Larvae have a lower oxygen safety margin (higher critical oxygen partial pressure at which metabolism is suppressed relative to metabolic demand) and significantly higher CTmax under normoxia than pupae (53°C vs 50°C). Larvae, but not pupae, were oxygen limited with hypoxia (2.5 kPa) decreasing CTmax significantly from 53 to 51°C. Humidifying hypoxic air relieved the oxygen limitation effect on CTmax in larvae, whereas variation in other gas properties did not affect CTmax. Our data suggest that oxygen safety margins set thermal limits in air-breathing invertebrates and the magnitude of this effect potentially reconciles differences in oxygen limitation effects on thermal tolerance found among diverse taxa to date. CITATION: Boardman, L. & Terblanche, J. S. 2015. Oxygen safety margins set thermal limits in an insect model system. Journal of Experimental Biology, 218:1677-1685, doi:10.1242/jeb.120261.; The original publication is available at http://jeb.biologists.org 2015-03-01T00:00:00Z The ecology of spotted hyena,Crocuta crocuta, in Majete Wildlife Reserve, Malawi http://scholar.sun.ac.za:80/handle/10019.1/98847 The ecology of spotted hyena,Crocuta crocuta, in Majete Wildlife Reserve, Malawi Retief, Francois ENGLISH ABSTRACT: The management of predators plays an important role in conservation management today because of the intensive management requirement of small fenced off protected areas. Apex predators such as spotted hyena, Crocuta crocuta, are situated at the top of food chains and have the ability to influence the composition and density of meso-predators and herbivores. Knowledge of apex predators through research can assist in effective management decisions which will ensure ecosystem functioning. Majete Wildlife Reserve (MWR) in the south of Malawi, is a 700km2 reserve, which had noinformation on the resident spotted hyena population until this study. The aims of this study were to gather and make available as much information as possible on the ecology of this apex predator in the reserve for management purposes. A total of 47 camera traps were stationed throughout the reserve for 22 months from 2013 - 2015 and from these data population size, the number of clans (groups), home range size and activity patterns were determined. Faecal analysis was performed to identify the preferred species preyed upon. The reserve has two small, low density resident spotted hyena populations, each with a large home range. These are distinct traits of hyenas residing in arid regions with a clumped resource distribution. The activity patterns of MWR hyenas were similar to East African hyenas in some aspects but peaks in activity differed between the two populations. A total of 17 prey species were identified, with some obvious preferred species. Based on the results from this study, is it recommended that management should make decisions which would favour an increase in the hyena population. At this stage, further lion, Panthera leo, reintroductions should be avoided, as they are the number one competitor of spotted hyena. Both prey and hyena numbers should be monitored in the future to determine whether the hyena population might be in an Allee effect, in which case hyena reintroduction may be considered to restore the balance. It is also suggested that local communities should be educated about hyenas and their role in the environment. This would increase the protection of hyena clans outside the reserve boundaries. These populations are needed for genetic diversity in the MWR hyena population since contact between the populations has been found. Genetic diversity is important for the long term conservation of small populations such as the spotted hyena population in MWR.; AFRIKAANSE OPSOMMING: Die bestuur van roofdiere speel ‘n belangrike rol in wildbewaring vandag a.g.v die intensiewe bestuur van klein omheinde bewaar-areas. Top roofdiere soos gevlekte hiëna wat bo aan voedselkettings sit, het die vermoë om die samestelling en digtheid van meso-roofdiere en herbivore te beïnvloed. Kennis van top roofdiere deur navorsing, kan bestuur help om effektiewe besluitnemingskeuses te maak wat ekosisteem funksionering sal verseker. Majete Wildlife Reservaat (MWR) in die Suide van Malawi, is ‘n 700km2 reservaat wat geeninligting gehad het tot en met hierdie studie, rondom die residensiële hiëna bevolking nie. Die studie het beoog om soveel as moontlik inligting rondom die residensiële hiëna bevolking te versamel en beskikbaar te stel vir bestuur doeleindes. Kamera lokvalle was gestel regoor die reservaat vir 22 maande van 2013 - 2015 en van hierdie data was bevolkings grootte, die getal groepe, gebieds grootte en aktiwiteitspatrone bepaal. Fekale analises was gedoen om verkose prooi spesies te identifiseer. Die reservaat het twee klein, lae digtheid residensiële hiëna bevolkings, elk met ‘n groot gebied. Hierdie is kenmerkende eienskappe van hiënas wat woon in dorpebiede met oneweredige hulpbron verspreiding. Die aktiwiteitspatrone van hiënas in MWR het ooreengestem met die van Oos Afrika hiënas in sommige aspekte, maar aktiwiteits pieke het verskil tussen die twee populasies. ‘n Totaal van 17 prooi spesies was ge-identifiseer, met duidelike verkose spesies. Op grond van hierdie navorsingsresultate, word aanbeveel dat die bestuur besluite moet neem wat sal lei tot ‘n toename in die hiëna bevolking. Op hierdie stadium moet verdere leeu hervestiging vermy word, aangesien hul die grootste kompetisie vir gevlekte hiëna’s is. Beide prooi en hiëna getalle moet ook gemonitor word om vas te stel of die hiëna bevolking tans in ‘n Allee effek is. Indien wel, kan hiëna hervestiging oorweeg word om die balans te herstel. Dit word ook voorgestel dat plaaslike gemeenskappe opgevoed moet word rondom hiëna’s en hul rol in die omgewing. Dit sal die beskerming van hiëna populasies buite die reservaat grense verbeter. Hierdie populasies is noodsaaklik vir genetiese diversiteit in die MWR hiëna populasie aangesien daar kontak tussen beide populasies gevind was. Genetiese diversiteit is belangrik vir die langtermyn bewaring van klein populasies soos die hiëna bevolking in MWR. Thesis (MSc)--Stellenbosch University, 2016. 2016-03-01T00:00:00Z Diet of key predators responsible for livestock conflict in Namaqualand, South Africa http://scholar.sun.ac.za:80/handle/10019.1/98722 Diet of key predators responsible for livestock conflict in Namaqualand, South Africa Jansen, Corle ENGLISH ABSTRACT: Human-wildlife conflict (HWC) occurs in areas where humans and wildlife occupy the same area or compete for the same resources. Although some carnivores are responsible for incidental attacks on humans, predation on livestock is an increasingly common form of HWC. Understanding the ecology of these predators outside the confines of protected areas could provide insight into decreasing conflict and ensuring the persistence of these animals in non-protected areas. I analysed the diet of leopard (Panthera pardus), caracal (Caracal caracal) and black-backed jackal (Canis mesomelas) in Namaqualand, Northern Cape, South Africa, an area where HWC is commonly reported. Scats were collected for each predator in both protected areas (Namaqua National Park) and surrounding, non-protected farmlands (810 km²). Eight caracals were also collared to analyse caracal diet from GPS-cluster data. The diet of the three predators was assessed across both land classifications (protected vs. non-protected). Prey availability was determined by means of camera and small mammal traps and compared between the two land classifications. The relative abundance index (RAI) was used to determine the abundance of prey species on the two contrasting land classifications and whether prey abundance and availability influenced the feeding ecology of leopard, caracal and jackal in Namaqualand. All three predators relied on the most abundant and easy to catch prey species, reflecting opportunistic feeding behaviour. In the protected national park, where livestock was absent, all three predators selected for natural prey items. These findings coincided with previous studies on leopard, caracal and black-backed jackal in South Africa. A shift in leopard diet was observed on farmlands, as livestock replaced small-to medium-sized ungulates in scats. For black-backed jackals, steenbok (Raphicerus campestris) contributed >20% to the total biomass consumed in protected areas while on farmlands sheep (Ovis aries) contributed > 20% and steenbok only < 5%. These findings in scat are mirrored in ungulate surveys; steenbok was the most abundant small-to medium-sized ungulate in the national park and sheep were the most abundant prey on farmlands. Caracal preferred hyrax (Procavia capensis) and lagomorpha as prey, while predation on livestock occurred in low frequencies (scat analysis, 6.9%), making caracal the predator which depended the least on livestock. Land-use also had very little effect on caracal diet. When analysing caracal diet by means of kill site analysis, sheep contributed the bulk to the total biomass consumed (59.5%). However, GPS cluster analysis is inherently biased towards the overestimation of larger bodied prey items and excludes smaller prey items (< 1 kg) which contributed > 25% to the total biomass consumed according to scat analysis. Predation of livestock by these three predators was not significant in relation to livestock availability on farmlands, especially for caracal. Due to the opportunistic feeding behaviour of these predators it was more likely that livestock was an alternative prey source. A suitable natural prey base on farmlands would decrease livestock losses, especially where leopards depredate on stock. Leopards are the last remaining large predator in this area and the loss of these large felids could be detrimental to the healthy functioning of the ecosystem. If increased vigilance is practiced during the lambing period, lambs could survive to past their vulnerable size when they fall victim to jackals. Improved livestock husbandry methods, implementation of guarding animals and herders and various other holistic methods could decrease livestock losses in Namaqualand.; AFRIKAANSE OPSOMMING: Konflik tussen mense en diere kom gewoonlik voor in areas waar wilde diere en mense dieselfde area beset en vir soortgelyke hulpbronne kompeteer. Deur die ekologie van roofdiere kwesbaar vir hierdie konflik buite beskermde gebiede te bestudeer, kan baie insigte verkry word oor hoe om konflik te vermy en te verminder. Verder kan dit verseker dat sulke predatore nie verlore gaan buite formeel beskermde areas nie. Hierdie studie het die dieet van luiperd, rooikat en rooijakkals in Namakwaland, Noord-Kaap, Suid-Afrika geanaliseer. Mismonsters van die drie predatore is versamel in die Namakwa Nasionale Park en omliggende veeplase (810 km²). Agt rooikatte was ook voorsien met radio-nekbande om rooikat dieët verder te ontleed. Die dieet van die drie predatore is geanaliseer en vergelyk tussen beide die nasionale park en die omliggende plase. Die beskibaarheid van prooi op altwee grondgebruike is ook ontleed deur gebruik te maak van kameras in die veld en klein-soogdier lokvalle. ‘n Relatiewe volopheids-indeks (RVI) is gebruik om te bepaal of die beskibaarheid en getalle van prooi die dieet van luiperd, rooikat en rooijakkals beïnvloed in Namakwaland. Al drie van die predatore het opportunistiese voergedrag getoon. Die dieet was verder grootliks afhanklik van die volopheid van maklik-bekombare prooi. Vorige studies van luiperd-, rooikat- en rooijakkals-dieet stem ooreen met die resultate verkry van die mismonsters versamel in die nasionale park. ‘n Verskuiwing in luiperddieet is op kleinveeplase waargeneem waar vee essensieël die rol van kleiner bok-soorte vervang. ‘n Soortgelyke tendens is waargeneem in jakkalsdieet. Steenbok, wat > 20% bygedra het tot die algehele biomassa gevreet deur jakkals in die nasionale park, is effektief vervang deur skaap, wat > 20% bygedra het tot biomassa op aanliggende plase, waar steenbok slegs > 4%. Steenbok was ook die volopste van die kleiner bok-soorte in die nasionale park, met skaap die volopste prooi item op die plase. Rooikat het dassie en lagomorpha (hase en konyne) verkies in beide die nasionale park en die aanliggende plase. Rooikat het selde gevoed op vee; op 6.9% die laagste van al die predatore in die studie. Rooikat-dieet is ook ontleed van karkasse wat opgespoor is deur middel van GPS-kluster besoeke. Die data verkry bewys dat skaap ‘n beduidende deel van die algehele biomasssa gevreet deur rooikat bydra. Hierdie metode het egter alle prooi kleiner as 1 kg, wat meer as 25% bygedra het tot die algehele biomassa gevreet deur rooikat, uitgesluit. Luiperd was die hoofpredatoor van boerbokke in die droeë seisoen. Volgens die beskikbaarheid van vee was die predasie deur hierdie drie predatore op vee nie beduidend nie. Omdat hierdie predatore so ‘n aanpasbare patroon volg, in terme van hul dieet, is dit meer waarskynlik dat luiperd, jakkals en meer so rooikat vee gevang het as alternatiewe prooi. As daar op plase ‘n voldoende, natuurlike prooi-basis beskikbaar is sal vee verlieste moontlik verminder, veral verlieste as gevolg van luiperd predasie. Luiperds is die laaste oorblywende groot karnivore in hierdie area en die moontlike verlies van hierdie diere sal groot nagevolge hê vir die algehele funksionering van Namakwaland as ‘n gesonde, interaktiewe ekosisteem. As daar meer waaksaamheid uitgeoefen word in tye wanneer ooie lam, kan lammers grootliks ongehinderd groei tot op ‘n punt waar jakkalse hulle nie meer sal teiken nie. Uiteindelik kan dit lei tot ‘n wen-wen situasie vir beide die ekosisteem se gesonde funksionering en produksie. ‘n Toename in vee-bestuur metodes, soos die gebruik van herders in die veld, vee waghonde en ander holistiese metodes kan vee verlieste in Namakwaland effektief verminder. Thesis (MSc)--Stellenbosch University, 2016. 2016-03-01T00:00:00Z Optimising the use of visual and radar observations for the mitigation of wind energy related impacts on Cape Vultures (Gyps coprotheres) in the Eastern Cape Province http://scholar.sun.ac.za:80/handle/10019.1/98716 Optimising the use of visual and radar observations for the mitigation of wind energy related impacts on Cape Vultures (Gyps coprotheres) in the Eastern Cape Province Becker, Frowin Klaus ENGLISH ABSTRACT: Being one of the leading global renewable energy investors over the last few years, South Africa’s energy sector is undergoing a rapid transformation. This transformation has been driven by the Renewable Energy Independent Power Producers Procurement Programme (REIPPPP) – a competitive bidding process, which has already concluded four bidding windows since 2011. Wind energy has comprised the bulk of the approved projects, thus far. Its accelerated development, however, poses a threat to the country’s airborne wildlife. Birds have been amongst the avifauna, most affected by wind energy facilities (WEF), both directly and indirectly. These impacts include collision-induced mortalities, habitat loss, costly avoidance behaviour, and barrier effects, which have been well documented in Europe and the United States. In response to such impending risks, South Africa’s environmental sector has drawn up a set of guidelines for baseline studies, pre-construction, and post-construction monitoring of birds. Two of the recommended monitoring techniques are direct or visual observations, and radar observation, which formed the foundation of this study. Due to its morphology, phenology and flight behaviour, the Cape Vulture (Gyps coprotheres) is considered as particularly vulnerable to WEFs, and has recently been deemed ‘endangered’, both locally and globally. Considering the species’ somewhat fragile status, using it as the primary subject, only added more significance to the study. The aims were to (1) assess the accuracy of visual observations, and (2) investigate activity patterns amongst Cape Vultures in the Eastern Cape Province, using a marine surveillance radar (EchoTrack Inc.). The proposed Umtathi Emonyeni WEF near Komga (-32.577°, 27.888°) in the Eastern Cape Province, served as the study site. Here, three radar placement sites were established. Vantage point (VP) and radar observations were conducted simultaneously from October 2014 to June 2015. A total of five replicates were completed in that time, one consisting of 12 days. Four days were spent at each placement site. Visually assessed targets were plotted using a cross-platform Geographical Information System (GIS), which allowed for the recording of coordinates. Parameters captured by the radar included latitudinal and longitudinal coordinates, flight height, reflectivity (size), and the airspeed of each target. Using customised EchoTrack software, visual and radar tracks were matched with a certain degree of confidence, depending on temporal, spatial and directional margins. A total of 66.4% of all visual observations were matched with corresponding radar tracks. The mean difference in time and distance, between those tracks, was 108.8s and 262.7m, respectively. Those margins were highly significant between Cape Vultures and other priority species. The dataset also indicated a significant positive relationship between both degree of inaccuracy and the distance of the target from the radar, as well as the degree of inaccuracy and the target’s height. Using the visually verified Cape Vulture radar tracks, target airspeed and size were used to distinguish the remaining unverified dataset from other bird tracks. Movement frequency (observations/hour), climbing rate (m/s), and flight height all exhibited similar patterns, with peaks being reached during the middle of the day. Trends in movement frequencies were valid for both visual and radar observations. Results presented here highlight the inconsistencies that govern visual monitoring. They also demonstrate the broad practical uses of avian radar systems. Implementing a comprehensive pre-construction monitoring regime is of great value to both the developers and bird conservationists. Collecting high-quality data vastly improves the reliability of the mitigation strategies that are put in place, and ensures that impacts are efficiently minimised. This also benefits developers as minimal impacts decrease the probability of costly compensations. While radar’s application is limited to bird movements, and still requires augmentation through visual observations, the quality of data produced adds significant value to both research and management decision-making. Obtaining data of such high quality is even more valuable for the conservation of endangered species, like the Cape Vulture.; AFRIKAANSE OPSOMMING: Suid-Afrika is die afgelope paar jaar een van die wêreld se voorste beleggers in hernubare energie en is tans besig om ‘n vinnige transformasie te ondergaan. Hieride transformasie word aangedryf deur die Renewable Energy Independent Power Producers Procurement Programme (REIPP) – ‘n kompeterende bie proses, wat alreeds vier bedingings vensters afgesluit het vanaf 2011. Windkrag maak so ver die grootste komponent van die goedgekeurde projekte op. Die versnelde ontwikkeling van windkrag hou egter bedreigings in vir die land se vlieënde wild. Voëls word die ergste van alle vlieënde diere geaffekteer deur wind energie fasiliteite (WEF), beide direk en indirek. Hierdie impakte is goed gedokumenteer in Europa en die Vereenigde State van Amerika en sluit in sterftes veroorsaak deur botsings, habitat verlies, kostelike vermydingsgedrag, en versperrings-effekte. Suid-Afrika se omgewingssektor het gereageer op hierdie bedreigings deur riglyne op te stel vir basislyn studies en pre- en post-konstruksie monitering van voëls. Twee moniteringstegnieke word aanbeveel: direkte of visuele waarnemings, of radar waarnemings. Die twee tegnieke vorm die basis van hierdie projek. As gevolg van die morfologie, fenologie en vlieg gedrag word die Kransaasvoël (Gyps coprotheres) beskou as besonder kwesbaar vir WEFe, en is onlangs plaaslik en internasionaal gelys as ‘bedreig’. Die gebruik van die bedreigde Kransaasvoël as hoof onderwerp in hierdie navorsing dra dus by tot die belangrikheid en beduidenheid van hierdie projek. Die doelstellings van hierdie studie was om (1) die akuraatheid van visuele waarneemings te evalueer, en (2) aktiwiteitspatrone van Kransaasvoëls te ondersoek in die Oos-Kaap met gebruik van ‘n mariene waarneming radar (EchoTrack Inc.). Die studie area was die voorgestelde Umtathi Emonyeni WEF naby Komga (-32.577o, 27.888o) in die Oos-Kaap. Die radar is op drie plasingspunte opgestel. Visuele uitkykpunt (VP) en radar observasies is gelyktydig uitgevoer vanaf Oktober 2014 tot Junie 2015. ‘n Totaal van vyf replikas is tydens die periode voltooi, en elke replika het 12 dae geduur. Vier dae is spandeer by elke radar plasingspunt. Visuele geassesseerde teikens is geplot met behulp van ‘n kruis-platform Georafiese Informasie Sisteem (GIS), wat toegelaat het vir die opname van koordinate. Die radar het lengte- en breedtegrade, vlug hoogte, weerkaatsing (grootte) en die lugspoed van elke teiken opgeneem. EchoTrack sagteware is gebruik omvisuele en radar spore te vergelyk met ‘n redelike mate van vertroue, afhangende van temporale, ruimtelike en rigting marges. ‘n Totaal van 66.4% van alle visuele waarneemings het gepas by ooreenstemmende radar spore. Die algemene verskil in tyd en afstand tussen daardie spore was 108.8s en 262.7m onderskeidelik. Die marges was hoogs beduidend tussen Kransaasvoëls en ander prioriteit spesies. Die data stel het ook aangedui dat ‘n beduidende positiewe verhouding bestaan tussen die graad van onakkuraatheid en die afstand van die teiken vanaf die radar, asook die graad van onakuraatheid en die hoogte van die teiken. Deur die gebruik van die geverifieerde Kransaasvoëls radar spore kon teiken lugspoed en grootte gebruik word om die ongeverifieerde datastel van ander voëls se radar spore te identifiseer. Bewegings-frekwensie (waarnemings/uur), klim koers (m/s), en vlug hoogte het soortgelyke patrone gevolg, en hoogtepunte is tydens die middle van die dag bereik. Tendense in bewegings-frekwensies was geldig vir beide visuele en radar waarnemings. Die resultate wat hier aangebied word beklemtoon die teenstrydighede van visuele waarnemings. Verder toon die resultate dat pre-konstruksie monitering van kardinale belang is vir beide die ontwikkelaars en die bewaringsekoloë. Die versameling van hoë gehalte data verbeter die vertroubaarheid van die versagting strategië wat in plek gestel word, en verseker dat impakte op voëls doeltreffend verminder word. Dit bevoordeel ook ontwikkelaars, aangesien ‘n afname in impakte die waarskynlikheid van kostelike vergoeding verminder. Terwyl die radar se toewending beperk is tot slegs die voëls se bewegings, en gelyktydige visuele waarnemings toegevoeg moet word, dra die hoë gehalte van die data wat verkry word by tot navorsing en besluitneming. Verkryging van sulke hoë gehalte data is selfs meer belangrik vir die bewaring van bedreigde spesies, soos die Kransaasvoël. Thesis (MSc)--Stellenbosch University, 2016. 2016-03-01T00:00:00Z Invaded range and competitive ability of the newly invasive Polistes dominula compared to that of its native congener species in the Western Cape, South Africa http://scholar.sun.ac.za:80/handle/10019.1/98524 Invaded range and competitive ability of the newly invasive Polistes dominula compared to that of its native congener species in the Western Cape, South Africa Benade, P. C. ENGLISH ABSTRACT: The European paper wasp Polistes dominula (Christ)(Hymenoptera: Vespidae: Polistinae) established itself as a prolific invader across the globe and has been recorded and studied on all continents, except those with extremely low temperatures. In the invaded ranges it can displace native wasp species. This invader was first recorded in the Western Cape Province of South Africa in 2008 with little subsequent attention given to it after this initial record. In 2012 it was recorded in Stellenbosch, some 28 kilometres from where it was first seen. It is now fairly common in the region which prompted investigations into its ecology and effect on native biodiversity. In this study the current invaded range and habitat preferences of P. dominula in the Western Cape of South Africa was determined. It was found to have increased its range into numerous towns within the Western Cape Province. However, P. dominula seemed for the most part to be confined to the Cape Metropolitan area. The Cape Fold Mountain belt to the east and Atlantic Ocean to the west apparently creating a hinderance to its dispersal. Even so, P. dominula was later also found outside of this area with human mediated distribution thought to be the main driving factor. This because, as demonstrated in this study, P. dominula prefer human altered environments. To successfully invade and persist in a new range, P. dominula may possess a few advantageous characteristics over native species including release from enemies, greater colony productivity, longer activity season and a smaller body size. Here I investigated these factors by comparing P. dominula and the South African native congener species Polistes marginalis where these occur in sympatry. Over a period of 12 months (June 2013 to July 2014) foraging wasp activity of both species was recorded and compared. At the onset of winter and when wasp activity ceased, nests from both species were collected in order to determine enemy release, colony productivity and body size. Activity of the invasive P. dominula started earlier than the native P. marginalis allowing it to have greater abundance than the native species at the onset of P. marginalis activity. Nests of P. dominula also contained more cells than that of P. marginalis denoting greater colony productivity. Body size was not found to be significantly different to that of the native and therefore was not deemed to give P. dominula any advantage. Suprisingly, P. dominula had a greater paratisation rate than that P. marginalis, refuting predictions under the enemy release hypothesis. Polistes dominula is a prolific invader of newly acquired ranges in South Africa. It has already surpassed the natural barrier that once was the Cape Fold Moutain Range and the possibility exists that it could now invade more inland locations towards the east. It also outperforms the native species on several aspects that may lead to an ability to outcompete native congener species. Its effect on native arthropod taxa that forms part of its diet and on plant pollination has yet to be determined, but all evidence suggests that this species should be controlled as much as possible in order to prevent negative impacts on native biodiversity. These programmes should be focussed in urban areas where these wasps proliferate.; AFRIKAANSE OPSOMMING: Die Europese papier perdeby Polistes dominula (Christ) (Hymenoptera: Vespidae: Polistinae) is nou gevestig as 'n effektiewe indringer regoor die wêreld en is aangeteken en bestudeer op alle kontinente, behalwe die met baie lae temperature. In nuutgevonde areas kan inheemse perdeby spesies verdring word deur hierdie indringer. Polistes dominula was vir die eerste keer in die Wes-Kaap Provinsie van Suid-Afrika in 2008 opgemerk. In 2012 was dit aangeteken in Stellenbosch, sowat 28 kilometer van waar dit vir die eerste keer waargeneem is. Dit is nou volop in die streek, wat die studie van hierdie indringer se ekologie en uitwerking op inheemse biodiversiteit belangrik maak. In hierdie studie is die huidige omvang en habitat voorkeure van P. dominula in die Wes- Kaap van Suid-Afrika bepaal. Daar is gevind dat sy verspreidingsarea toegeneem het na verskeie dorpe in die Wes-Kaap. Polistes dominula blyk om grootendeels beperk te wees tot die Kaapse Metropolitaanse gebied. Die Kaapse Vou Bergreeks in die ooste en die Atlantiese Oseaan in die weste skep klaarblyklik hindernisse tot sy verspreiding. Polistes dominula is wel onlangs buite hierdie area gevind en daar word vermoed dat die verspreiding aangehelp is deur die mens. Om 'n suksesvolle indringer te wees en te volhard in 'n nuwe habitat, kan P. dominula beskik oor 'n paar voordelige eienskappe wat nie by inheemse spesies voorkom nie: vyand ontwyking, uiters produktiwe kolonies, ‘n langer aktiewe seisoen en 'n kleiner liggaamsgrootte. Hier ondersoek ek hierdie faktore deur die indringer P. dominula en die Suid-Afrikaanse inheemse Polistes marginalis te vergelyk in areas waar beide spesies saam voorkom. Oor 'n tydperk van 12 maande (Junie 2013 tot Julie 2014) was perdeby getalle tydens hul jag aktiviteite aangeteken en vergelyk. Aan die begin van die winter (toe perdeby aktiwiteit gestaak het) was neste van beide spesies versamel om vyand ontwyking, kolonie produktiwiteit en liggaam grootte te bepaal. Aktiwiteit van die indringer P. dominula is vroeër aangeteken as die van die inheemse P. marginalis wat daartoe gelei het dat daar aansienlik meer aktiewe P. dominula was as die inheemse spesies by die aanvang van P. marginalis aktiwiteit. Neste van P. dominula het ook meer selle as dié van P. marginalis bevat wat 'n aanduiding is van meer effektiewe kolonie produktiwiteit van die indringer. Die indringer het egter nie beduidend verskil van die inheemse spesie in terme van liggaamsgrootte nie en dit was daarom nie oorweeg as ‘n voordeel nie. Polistes dominula was wel meer geparisiteer as die inheemse P. marginalis wat tot gevolg gehad het dat die vyand ontwykings hipotese nie ondersteun word nie. Polistes dominula is 'n produktiewe indringer van nuutverworwe areas in Suid-Afrika. Dit het reeds die natuurlike versperring van die die Kaapse Vou Bergreeks oorgesteek en die moontlikheid bestaan dat dit nou na die binneland in die ooste van Suid Afrika han versprei. Die indringer is ook meer effektief as die inheemse spesie op verskeie vlakke wat kan lei tot die onderdrukking van die inheemse P. marginalis. Die uitwerking van P. dominula op inheemse geleedpotige taksa wat deel van sy dieet uitmaak en die moontlikeid van effekte op plant bestuiwing moet nog bepaal word. Die resultate dui daarop dat hierdie spesie bestuur moet word om negatiewe impak op inheemse biodiversiteit te voorkom. Programme om die impak van P. dominula in Suid Afrika te bestuur moet gefokus word in stedelike gebiede waar dit meerendeels gevind word. Thesis (MSc)--Stellenbosch University, 2016. 2016-03-01T00:00:00Z The natural drivers and the effects of landscape transformation for dragonflies of the Cape Floristic Region http://scholar.sun.ac.za:80/handle/10019.1/98495 The natural drivers and the effects of landscape transformation for dragonflies of the Cape Floristic Region Kietzka, Gabriella Joy ENGLISH ABSTRACT: The Cape Floristic Region (CFR) is a biodiversity hotspot. The region has three established biosphere reserves, which all aim to alleviate the impacts that land transformation has on ecosystem integrity, without jeopardizing basic human needs. In addition to its unique plant diversity, the CFR has high endemism levels of other taxa, including dragonflies. Dragonflies are useful bioindicators of freshwater quality, which has led to the development of the Dragonfly Biotic Index (DBI), a biomonitoring tool for freshwater. The combined pressures of urbanisation and agricultural expansion in the CFR are a major concern for rare, endemic dragonfly species, as well as for overall river ecosystem integrity. In view of this, my study aims to determine which variables drive lotic dragonfly diversity in the CFR, and to assess the effects that land transformation has on this diversity. I first determined which environmental parameters were consistently important so that they could be used as mesofilters to conserve dragonfly diversity (Chapter 2). Dragonfly assemblages and various environmental variables were recorded along the untransformed reaches of three CFR rivers. Heterogeneity of water parameters was found to be the most crucial variables for dragonfly assemblages and for affecting species richness. Here, heterogeneity is defined by the natural spatial and temporal variation of water temperature, dissolved oxygen, conductivity and pH. This differed from previous studies, which strongly suggest vegetation-related variables are the primary drivers of dragonfly diversity. However, these studies took place in transformed landscapes where the strong effects related to anthropogenic disturbances could override the importance of other more subtle natural variables. The maintenance of a gradient of water parameters, which accounts for the natural range of each of the selected water variables, would thus aid in the conservation of dragonflies in the CFR. I also investigated the effects of urbanization and agricultural development on dragonfly diversity and DBI scores. Land transformation homogenized dragonfly assemblages as some endemic species could not persist in these areas. However, species richness was not always reduced, because disturbance allowed for additional widespread, generalist species to enter the system. Dragonfly assemblages differed between agricultural and urban sites but these sites were more similar to each other than to undisturbed sites. Each river supported a unique dragonfly assemblage, making it important to conserve each individual river. Mitigating the adverse influences of landscape transformation is essential for the conservation of rare and endemic taxa, particularly in areas of high conservation value, and the DBI provided an effective way to assess ecosystem integrity in the region. In conclusion, land transformation negatively affects dragonfly diversity and ecosystem integrity in CFR rivers. Conservation efforts should aim to rehabilitate the natural heterogeneity of riparian ecosystems. However, conservation plans should not only focus on restoration of riparian vegetation, but also incorporate variation in water quality parameters. There is not a high possibility of reducing land transformation, with the requirements of an ever-increasing human population. An important alternative option, as I show here, is to protect ecological integrity within a biosphere reserve. The proclamation of more biosphere reserves in the CFR, that include other, additional river catchments, will allow for the conservation of more rare, endemic dragonflies and other taxa. Dragonfly assemblages and the DBI should be used in future monitoring programs and to guide conservation actions.; AFRIKAANSE OPSOMMING: Die Kaapse Floristiese Streek (KFR) is 'n biodiversiteit kernarea. Die streek besit drie gevestigde biosfeerreservate, wat poog om die impak van landtransformasie op die integriteit van ekosisteeme te verlig, sonder om basiese menslike behoeftes in gevaar te stel. Benewens sy unieke plantdiversiteit, het die die KFR ook besonderse hoë vlakke van ander endemisme taxa, insluitend naaldekokers. Naaldekokers is uiters nuttig as bioindikatos van varswater gehalte. Dit het geleei tot die ontwikkeling van die naaldekoker biotiese indeks (NBI), 'n biomoniterings hulpmiddel. Die gekombineerde druk vanaf verstedeliking en landbou-uitbreiding in die KFR is 'n groot bron van kommer vir die bewaring van skaars, endemiese naaldekokerspesies, sowel as vir algehele rivierekosisteem integriteit. In lig hiervan, het my studie gepoog om te bepaal watter spesefieke faktore naaldekokerdiversiteit dryf in die KFR. Die gevolge van land transformasie op hierdie diversiteit was ook geevalueer. Eerstens het ek bepaal watter omgewingsfaktore deurgaans belangrik is om naaldekoker diversiteit te bewaar (Hoofstuk 2). Naaldekoker gemeenskappe en verskeie omgewings-veranderlikes was aangeteken langs die ongetransformeerde areas van drie KFR riviere. Heterogeniteit van waterveranderlikes was bevind as die mees kritieke faktore wat naaldekoker gemeenskappe en spesierykheid bepaal. Hierdie resultate verskil van vorige studies wat gewys het dat plantegroei verwante veranderlikes die primêre oorsake van verandering van naaldekoker diversiteit is. Hierdie vorige studies was egter gefokus op getransformeerde landskappe waar die sterk effekte van menslike versteurings die belangrikheid van ander, meer subtiele, natuurlike faktore kon oorheers. Die instandhouding van 'n wye verskeidenheid water veranderlikes blyk dus om die behoud van die naaldekoker gemeenskappe in die KFR the bevorder. Ek het ook die gevolge van verstedeliking en landbouontwikkeling op die diversiteit van naaldekokers en die NBI bepaal. Landtransformasie het naaldekoker gemeenskappe gehomogeniseer deurdat sommige endemiese spesies nie kon bestaan in hierdie gebiede nie. Dit het egter nie altyd gepaard gegaan met ‘n vermindering in spesierykheid nie, want aandui dat addisionele, wydverspreide, generiese spesies versteurde habitatte binnedring. Naaldekoker gemeenskappe het tussen landbou en stedelike areas verskil, maar was steeds meer soortgelyk aan mekaar as aan ongestoorde areas. Elke rivier ondersteun 'n unieke naaldekoker gemeenskap, wat daarop wys dat dit belangrik is om elke individuele rivier te bewaar. Verligting van die negatiewe invloede van landskaptransformasie is noodsaaklik vir die bewaring van skaars en endemiese spesies, veral in gebiede van hoë bewaringswaarde. Die NBI verskaf 'n doeltreffende manier om die integriteit van die ekosisteem te evalueer in hierdie streek. Ten slotte, land transformasie beïnvloed naaldekoker diversiteit en die integriteit van die ekosisteem in KFR riviere negatief. Bewaring moet poog om die natuurlike heterogeniteit van die rivieroewer ekosisteme te rehabiliteer. Bewaring moet egter nie uitsluitlik fokus op die herstel van oewerplantegroei nie, maar moet ook poog om variasie in water faktore te inkorporeer. Vermindering van transformasie area is nie werklik haalbaar in die streek nie aangesien 'n toenemende menslike bevolking se vereistes ook toeneem. 'n Belangrike alternatiewe opsie, soos ek hier uitwys, is om te verseker dat die ekologiese integriteit binne biosfeerreservaate beskerm word. Die proklamasie van meer biosfeerreservate in die KFR, wat bykomende rivieropvanggebiede insluit, sal voorsiening maak vir die bewaring van meer seldsaame en endemiese naaldekokers, asook ander taxa. Naaldekoker gemeenskappe en die NBI behoort gebruik te word in toekomstige moniterings programme en kan dus bewaringsoptredes lei. Thesis (MSc)--Stellenbosch University, 2016. 2016-03-01T00:00:00Z The effect of agriculture and alien plants on natural communities of plants, insect herbivores and parasitoids http://scholar.sun.ac.za:80/handle/10019.1/98462 The effect of agriculture and alien plants on natural communities of plants, insect herbivores and parasitoids Moxley, Courtney ENGLISH ABSTRACT: Habitat transformation and invasions by non-native (alien) plants are two of the most concerning drivers of global environmental change. These factors cause biodiversity declines that disrupt species interactions, with cascading effects throughout ecosystems. On farmlands, this has implications for the provision of ecosystem services and disservices by insects, including crop damage by herbivores, some of which are crop pests, and pest control by natural enemies. In this study, I investigated how plants, insects and their interactions involved in these processes are affected by habitat transformation and alien plants in the Kruger to Cayons Biosphere Region, South Africa. I first determined whether insect pests spill-over from habitats transformed for agriculture into surrounding natural vegetation in a fragmented landscape. Patches of preserved natural vegetation alongside farmlands are believed to be the source of crop pests and farmers manage the natural vegetation as a form of pest control. Using a case study with fruit flies (Ceratitis spp.), cultivated mango (Mangifera indica, Anacardiaceae) and the marula tree (Sclerocarya birrea, Anacardiaceae) as a host species in nearby natural vegetation, I showed that pests appear to spill-over in the reverse direction, from crop fields to natural vegetation when mango is out of season. Marula fruit alongside mango farms were 25 times more likely to be infested by Ceratitis than in the distant vegetation. Ceratitis appears to spill-over into natural vegetation when marula replaces mango as the most apparent resource in the landscape. Marula may represent an important reservoir for Ceratitis to maintain its population between crop seasons, but this may depend on seasonality and the relative timing of marula-mango fruiting. Secondly, I investigated the interactive effects between habitat transformation and alien plants on the structure and composition of communities of plants, herbivores and parasitoids, and their interactions such as herbivory. Insect herbivores and parasitoids were reared from native and alien seeds collected along transects in mango fields, natural vegetation and disturbed margins, and the % alien seed abundance was determined for each transect. Mango fields had the lowest abundance and diversity of plants, herbivores and parasitoids. Across the landscape, high alien seed abundance was associated with lower herbivore and parasitoid species richness. Seed herbivory was lowest in mango fields and was influenced by interactive effects between habitat transformation and alien plants, with high and low alien seed abundance associated with high and low herbivory in mango fields and natural vegetation, respectively. In showing that habitat transformation and alien plants have both independent and interactive effects throughout this food web, this research is important for predicting future declines among plants, insects and their interactions in agricultural landscapes. Managing the negative effects of habitat transformation and alien plants requires co-operation between farmers and conservationists in an area-wide approach. Farmers should manage pests and alien plants in crop fields to limit their dispersal into surrounding natural habitats. Conservation efforts should focus on improving habitat quality in agricultural landscapes by promoting natural vegetation alongside farms, and limiting harmful activities in crop fields, such as the use of pesticides and mowing. By reducing impacts on native plants, insects and their ecological interactions, these efforts will contribute to long-term sustainability of agriculture in the future.; AFRIKAANSE OPSOMMING: Habitat verandering en indringer spesies is twee van die hoof drywers van globale omgewings veranderinge. Hierdie faktore veroorsaak dalings in biodiversiteit wat spesie-interaksies ontwrig, en die gevolge kan gesien word regdeur ekosisteme. Op plaaslande het dit implikasies vir die voorsiening van ekosisteem dienste deur insekte. Dit sluit in gewaskade deur herbivore, waarvan sommige oes peste is, en plaagbeheer deur natuurlike vyande, parasitoïed perdebye ingesluit. In hierdie studie, bespreek ek die invloed van habitat transformasie en indringer plante op die interaksies tussen plante en insekte in die Kruger to Cayons biosfeer, Suid Afrika. Ek het eers bepaal hoe grond transformasie die oordrag van peste en plae tussen plase en natuurlike areas binne gefragmenteerde landskappe beïnvloed. Daar word geglo dat die natuurlike beweiding langs bewerkte lande die bron is van peste en plae. Dus, probeer boere om die natuurlike lande langs hul bewerkte lande te beheer vir plaagbeheer. Deur gebruik te maak van vrugte vlieë (Ceratitis spp.), gekultiveerde mango (Mangifera indica, Anacardiaceae) asook die Marula boom (Sclerocarya birrea, Anacardiaceae) as gasheer spesies in nabygeleë natuurlike areas, is daar `n gevallestudie opgestel. Dit het bewys dat die teenoorgestelde waar is; die peste en plae se oorloopgevolge vind plaas vanaf die bewerkte landerye na die natuurlike omgewing. Marula vrugte langs mango boorde het ‘n 25 keer groter kans om deur Ceratitis besmet te word as die wat in afgleë gebiede gevestig is. Dit dui daarop dat dit onwaarskynlik is dat natuurlike areas die bron is van vrugtevlieë vir mango velde, en lê klem op die negatiewe gevolge wat landbou het op die gasheer-plaag interaksies tussen bewerkte lande en die natuurlike omgewing. Gevolglik, het ek die interaksie tussen habitat transformasie en indringer plante op gemeenskappe van plante, herbivore en parasitoids, en hul interaksies soos saad predasie, ondersoek. Mango boorde het ‘n kleiner verskeidenheid herbivore en parasiete as natuurlike beweidinge en versteurde habitat marges gehad. Oor die landskap, toenemende hoeveelhede van uitheemse saad het dalings veroorsaak in herbivoor en parasitoïed spesierykheid. Saad predasie deur herbivore was die laagste in mango boorde, beïnvloed deur interaktiewe effekte tussen habitat transformasie en indringerplante, soos dat hoë uitheemse saad oorvloed is wat verband hou met hoë saad predasie in mango velde en lae saad predasie in natuurlike areas. Deur te bewys dat habitat transformasie en indringer spesies beide onafhanklike en interaktiewe verhoudings het in die voedsel-web, kan die plant- en insek-bevolkings dalings in die toekoms voorspel word vir die landbou bedryf. Beheer van die negatiewe effekte van habitat transformasie en indringer spesies verg samewerking tussen boere en natuurbewaarders. Boere moet peste en indringer plant spesies op hulle bewerkte lande beheer om die verspreiding na omliggende natuurlike areas te verminder. Natuurbewaarders moet fokus op die bevordering van die natuurlike landskappe deur om die natuurlike plantlewe langs bewerkte landerye te bevorder, en skadelike aktiwiteite in bewerkte landerye, soos die gebruik van plaagdoders en gras sny, te beperk. Deur die impak op die inheemse plante, insekte en hulle ekologiese interaksies te verminder, sal hierdie pogings bydra tot die volhoubaarheid van die landbou in die toekoms. Thesis (MSc)--Stellenbosch University, 2016. 2016-03-01T00:00:00Z Restoration of Cape Flats Sand Fynbos : the significance of pre-germination treatments and moisture regime http://scholar.sun.ac.za:80/handle/10019.1/98424 Restoration of Cape Flats Sand Fynbos : the significance of pre-germination treatments and moisture regime Mukundamago, Mukundi ENGLISH ABSTRACT: The seed ecology of the Cape Flats Sand Fynbos (CFSF) vegetation’s species in Blaauwberg Nature Reserve, in Western Cape South Africa, was investigated within the context of a broader restoration ecology project “Blaauwberg Ecological Restoration Project”1. Cape Flats Sand Fynbos (CFSF) vegetation is considered as a critically endangered vegetation type due to agricultural development, urban transformation, and degradation caused by invasive alien Acacia species. The City of Cape Town is clearing alien plants at Blaauwberg Nature Reserve (BBNR) in an attempt to restore this remaining CFSF fragment. These efforts are associated with challenges, since alien stands have depleted indigenous soil-stored seedbanks. The premise for this seed ecology study was that restoration of degraded CFSF is possible through applied management programmes based on the methodology and practice of active restoration. Active restoration is necessary in order to establish the major indigenous plant guilds and to revive areas that have been degraded due to the effects of the alien plants. Pre-germination treatments including smoke-derived compounds have been known to promote seed germination; however, after a burn in Blaauwberg Nature Reserve, seeds sown in the field had low germination. One reason for the low germination of re-introduced indigenous species could be a lack of pre-germination treatments prior to sowing or drought thereof. The research on the implementation of seed ecology study was carried out in anticipation of three major outcomes. First, to determine pre-germination treatments that can improve germinability of seeds of selected indigenous target species to be used in large-scale restoration projects. Second, to assess the value of smoke as a germination cue for indigenous CFSF species; more specifically, it focuses on the germination of indigenous species following different smoke treatments. Lastly, to assess soil moisture as a potential limiting factor for seed germination and seedling establishment in lowland sand fynbos. In general, the research investigated the effect of desiccation on seed emergence and the survival of seedlings. Seed and soil collections were performed in Blaauwberg Nature Reserve, Western Cape, South Africa and in natural vegetation remnants along the N7 between July 2012 and January 2013. Seeds were collected, cleaned, sorted, and then stored. The main plant guilds that were selected are, Restioids, Ericoids, Proteoids, annual forbs and geophytes. Portions of seeds were set aside for different experiments (i.e. pre-germination treatments, viability test, smoke test and desiccation test). The results of the first study of viability test, germination rate, and germination period were analysed. Species showed varying responses to the different treatments with only the smoke water treatment having a consistent positive effect on seed germination for all functional groups. Only the annual, Senecio elegans, had a negative response to smoke water pre-germination treatment. A positive response was observed in Thamnochortus punctatus and Erica plumosa with the application of combination of smoke water and heat. Another positive response was noticed in Babiana villosula with the application of scarification pre-germination treatment. Additional analyses of germination period, germination lag phase and duration showed the same pattern as germinability wherein species had significant differences in germinability when there was no significant differences on germination period and vice versa. A comparison of different viability tests (i.e. x-ray, tetrazolium and cut test) indicated that the cut test is more efficient in determining viability. Nonetheless, it is recommended to collect seeds when they are naturally dispersing since cut test is not practical in the field wherein small seeds are collected. Pre-germination treatments should be applied on target species in all restoration applications to maximise germinability and establishment. The study shows that although pre-germination treatment responses are species-specific smoke water pre-germination treatment could be used for all functional groups. Other treatments can be applied for specific species. The second study showed that plant-derived smoke had the ability to enhance seed germination of a number of plant species. Plant-derived smoke enhancement was species-specific. Some species’ germination increased significantly with pre-smoked seeds only, whereas others’ germination increased significantly with pre-smoked soil only and some other species germination increased significantly with a combination of pre-smoked soil and seeds. Based on these observations, it is recommended that seeds be pre-smoked before sowing in the field, especially in the absence of a prescribed burn. The third study focused on selected Cape Flats Sand Fynbos species that were tested for desiccation tolerance of both germinants and seedlings. I ran experiments in controlled growth chambers in parallel with desiccation tolerance investigation of seedlings of the target species in a greenhouse experiment. Results showed that almost all species germinated and they were all tolerant to desiccation. The results within the scope of this study will help shed some light on and further enhance existing active practical restoration efforts in Cape Flats Sand Fynbos. In order for such efforts to be effective, it is important to use appropriate pre-germination treatments to enhance germination. More importantly, it should be noted that drought or desiccation are unlikely causes of poor germination/ establishment. It is probable that enhanced nutrient levels or a change in the soil microbial community might be the reason for a lack of germination/establishment in the field. Amidst the observations made and the conclusions arrived at, it is recommended that further research should be conducted in the greenhouse alongside a field experiment to compare germination of Acacia saligna and indigenous CFSF species. This is because in the nursery trial, you can control some of the environmental variables such as soil nutrients and moisture and be able to investigate these factors on germination under soil conditions and the field experiment will have a variety of environmental factors involved.; AFRIKAANSE OPSOMMING: Die saadekologie van die Kaapse Vlakte-sandfynbos (CFSF) plantegroei spesies in Blaauwberg Natuurreservaat, in die Wes-Kaap Suid-Afrika, is ondersoek binne die konteks van 'n breër restourasie-ekologie projek "Blaauwberg Ekologiese Restourasie Projek".2 Kaapse Vlakte-sandfynbos (CFSF) plantegroei word beskou as 'n krities bedreigde plantegroei tipe weens landbou-ontwikkeling, stedelike transformasie, en agteruitgang veroorsaak deur uitheemse Acacia spesies. Die Stad Kaapstad haal uitheemse plante uit in Blaauwberg Natuurreservaat (BBNR) in 'n poging om hierdie oorblywende CFSF fragment te herstel. Hierdie pogings gaan gepaard met uitdagings, aangesien uitheemse plotte inheemse grond gestoorde saadbanke uitgeput het. Die uitgangspunt vir hierdie saadekologie studie was dat die herstel van gedegradeerde CFSF moontlik is deur toegepaste bestuursprogramme gebaseer op die metode en praktyk van aktiewe herstel. Aktiewe herstel is nodig om die groot inheemse plant gildes te vestig en gebiede wat ontaard het weens die gevolge van die indringerplante te laat herleef. Voor-ontkiemingsbehandelings waaronder rook-afkomstige samestellings is bekend daarvoor om ontkieming te bevorder; maar na 'n brand in Blaauwberg Natuurreservaat, het sade gesaai in die veld lae ontkieming getoon. Een rede vir die lae ontkieming van her-bekendgestelde inheemse spesies kan wees as gevolg van 'n gebrek aan voor-ontkiemingsbehandelings, voor die saai of droog daarvan. Die navorsing oor die implementering van die saadekologie studie is uitgevoer as gevolg van die afwagting van drie groot uitkomste. Eerstens, om voor-ontkieming behandelings te bepaal wat ontkiemingsvermoë van sade van gekose inheemse teiken spesies, wat gebruik sal word in grootskaalse herstel projekte, te kan verbeter. Tweedens, om die waarde van rook as 'n ontkiemingsteken vir inheemse CFSF spesies te evalueer; meer spesifiek, dit fokus op die ontkieming van inheemse spesies na verskillende rook behandelings. Laastens, om grondvog te evalueer as 'n potensiële beperkende faktor vir saadontkieming en saailingvestiging in laagland sand fynbos. In die algemeen het die navorsing die effek van uitdroging op saad opkoms en die oorlewing van saailinge ondersoek.Saad- en grondinsamelings is gedoen in Blaauwberg Natuurreservaat, Weskaap, Suid-Afrika en in natuurlike plantegroei oorblyfsels langs die N7 tussen Julie 2012 en Januarie 2013. Saad is versamel, skoongemaak, gesorteer en dan gestoor. Die belangrikste plant gildes wat gekies is, is Restioids, Ericoids, Proteoids, eenjarige kruidagtige-plante en geofiete. Gedeeltes van die sade is opsy gesit vir verskillende eksperimente (d.w.s. voor-ontkiemingsbehandelings, lewensvatbaarheidtoets, rooktoets en uitdrogingstoets). Die resultate van die eerste studie van die lewensvatbaarheidstoets, ontkiemingstempo en ontkiemingstydperk is ontleed. Spesies het uiteenlopende reaksies op die verskillende behandelings getoon, met net die rookwater behandeling wat 'n volgehoue positiewe effek op ontkieming vir alle funksionele groepe gehad het. Slegs die eenjarige, Senecio elegans, het 'n negatiewe reaksie op rookwater voor-ontkiemingsbehandeling getoon . 'n Positiewe reaksie is waargeneem in Thamnochortus punctatus en Erica plumosa met die toepassing van 'n kombinasie van rookwater en hitte. Nog 'n positiewe reaksie is opgemerk in Babiana villosula met die toepassing van insnydings in die vel as voor-ontkiemingsbehandeling. Addisionele ontledings van ontkiemingstydperk, ontkiemings-wagperiode en duur het dieselfde patroon as ontkiemingsvermoë getoon, waarin spesies beduidende verskille in ontkiemingsvermoë gehad en daar geen beduidende verskille in ontkiemingstydperk was en omgekeerd. 'n Vergelyking van verskillende lewensvatbaarheidstoetse (d.w.s. x-strale, tetrazolium en die snytoets) het aangedui dat die snytoets meer doeltreffend is in die bepaling van lewensvatbaarheid. Nietemin word dit aanbeveel om saad in te samel wanneer hulle natuurlik versprei, aangesien die snytoets nie prakties in die veld is nie, wanneer klein sade versamel word. Voor-ontkiemingsbehandelings moet toegepas word op teiken spesies in alle herstel toepassings om ontkiemingsvermoë en vestiging te maksimeer. Die studie toon dat hoewel voor-ontkiemingsbehandeling reaksies spesie-spesifiek is, rookwater voor-ontkiemingsbehandeling gebruik kan word vir alle funksionele groepe. Ander behandelings kan toegepas word vir spesifieke spesies. Die tweede studie het getoon dat plant-afkomstige rook die vermoë het om die ontkieming van 'n aantal plantspesies te bevoordeel. Plant-afkomstige rook bevoordeling was spesie-spesifiek. Sommige spesies se ontkieming het aansienlik toegeneem met slegs voor-gerookte sade, terwyl ander se ontkieming aansienlik toegeneem het met slegs voor-gerookte grond en 'n paar ander spesies se ontkieming het aansienlik toegeneem met 'n kombinasie van die voor-gerookte grond en sade. Op grond van hierdie waarnemings word dit aanbeveel dat sade vooraf gerook word, voor dit in die veld gesaai word, veral in die afwesigheid van 'n voorgeskrewe brand. Die derde studie het gefokus op uitgesoekte Kaapse Vlakte-sandfynbos spesies wat getoets is vir uitdroogtoleransie in beide spruite en saailinge. Ek het eksperimente uitgevoer in beheerde groeikaste in parallel met uitdroogtoleransie ondersoeke van saailinge van die teiken spesies in 'n kweekhuis eksperiment. Resultate het getoon dat byna al die spesies ontkiem het en hulle was almal verdraagsaam teen uitdroging. Die resultate binne die bestek van hierdie studie sal help lig werp op en verder die bestaande aktiewe praktiese herstel pogings in Kaapse Vlakte-sandfynbos verbeter. Ten einde vir sulke pogings om doeltreffend te wees, is dit belangrik om toepaslike voor-ontkiemingsbehandelings te gebruik om ontkieming te verbeter. Meer belangrik, moet daarop gelet word dat droogte of uitdroging onwaarskynlike oorsake van swak ontkieming/vestiging is. Dit is hoogs waarskynlik dat verhoogde voedingstofvlakke of 'n verandering in die grond mikrobiese gemeenskap die rede vir 'n gebrek aan ontkieming/vestiging in die veld kan wees. Te midde van die waarnemings en die gevolgtrekkings, dink ek verdere navorsing moet gedoen word in die kweekhuis tesame met veld eksperimente, met vergelyking van waterverhoudings en voedingstofverdraagsaamheid tussen Acacia saligna en inheemse CFSF spesies. Dit is omrede jy in die kwekery 'n paar van die omgewingsveranderlikes kan beheer soos grondvoedingstowwe en vog en in staat is om hierdie faktore op ontkieming onder grondtoestande te ondersoek. Thesis (MSc)--Stellenbosch University, 2016. 2016-03-01T00:00:00Z The effect of commercial forestry plantations and roads on southern Afrotemperate forest arthropod diversity http://scholar.sun.ac.za:80/handle/10019.1/98422 The effect of commercial forestry plantations and roads on southern Afrotemperate forest arthropod diversity Swart, Rudi Crispin ENGLISH ABSTRACT: With only about 12% of the Earth’s surface under some form of official protection and the human population on the rise exponentially, production landscapes can and should contribute significantly towards biodiversity conservation in the future. Globally, management practices that balance production and conservation are important for creating sustainable agriculture and timber production landscape. This study aims to determine how a heterogeneous, unfenced national park in South Africa, containing a mosaic of commercial plantations, natural forests and fynbos is affected by land transformation. This was achieved by focussing on artificially created and natural edges found in this landscape, through analysing and comparing the composition and species richness of arthropods across linear transects. Specifically I determined if natural edges next to southern Cape Afrotemperate forests are altered by anthropogenic influences such as forestry plantations, and their felling, as measured by epigaeic arthropod diversity. The effects of different road types, and directions that these roads dissect the forest, were also assessed. I found that pine plantations provide little suitable habitat for either forest or fynbos arthropods. The natural fynbos-forest ecotone harbours a unique composition of arthropod assemblages, with the smallest edge effect into the forest. Once this is replaced by commercial pine plantations, an edge effect up to 30 m into the forests from the plantation edge is detected. When plantations bordering natural forests are felled, the edge effect increases to 50 m into natural forests. Research on edge effects created by roads showed that both wider, arterial roads as well as secondary roads affected the diversity of forest arthropods up to 50 m into the natural forest. These effects are therefore similar to that observed after clear felling of plantations except that, in contrast to possible regeneration of natural edge habitat after clear felling, these edges are now permanent fragmentary features in the forest with little chance of recovery. Even hiking trails affected overall arthropod assemblages in the adjacent forests up to 10 m. Although this likely does not lead to forest fragmentation due to an in-tact forest canopy, these areas alter natural assemblages with unknown population dynamic consequences. I also show that east-west directed roads have stronger fragmentary effects as determined by arthropod diversity, along their southern edge than north-south directed roads, with east and west facing edges. Increased sunlight penetration, with its accompanying changes in microclimatic conditions is put forward to explain these differences. Habitat loss due to the establishment of commercial plantation forestry in the region not only leads to a decrease in suitable fynbos habitat, but also impacts adjacent natural forest arthropod diversity. The remaining southern Cape Afrotemperate forests are greatly fragmented by a network of roads. Due to the uniqueness of these forests, special management is needed to ensure that the biodiversity in the region is optimally conserved without adversely affecting production yields. Some possible mitigation actions are put forward. However, these should be assessed for their effectiveness in future research studies before they are implemented.; AFRIKAANSE OPSOMMING: Met slegs sowat 12% van die Aardoppervlak tans amptelik beskerm en die aanhoudende, eksponensiële groeikoers van die mens, het die tyd ryp geword vir die mens om te besef dat landskappe wat nie amptelik beskerm word nie kan en sal moet bydra tot biodiversiteitsbewaring. Wêreldwyd is bestuurspraktyke rakende volhoubare landskappe, wat poog om ‘n balans te handhaaf tussen bewaring en produksie, bewys om suksesvol by te dra tot bewaring. Hierdie studie het beoog om te bepaal hoe ‘n heterogene, onomheinde nasionale park in Suid-Afrika, met kommersiële plantasies, natuurlike woude en fynbos wat groot areas binne die grense van die park bedek, geraak word deur die rande van hierdie aangrensende habitat-tipes te bestudeer. Dit was gedoen deur na beide die natuurlike en versteurde woudrand te kyk. Spesifiek het ek bepaal of natuurlike woudrande se grondlewende arthropoda beïnvloed word deur kommersiële denne-plantasies en hul verwydering. Die moontlike effekte van verskillende pad-tipes en padrigtings op woudfragmentasie is ook bepaal. Ek het bevind dat denne-plantasies min geskikte habitat vir beide woud- en fynbos-arthropoda bied. Ook, sodra plantasies aangrensend aan natuurlike woude kaalgekap word, vergroot die afstand wat effekte penetreer tot sowat 50 meter binne woude. Die resultate in verband met paaie wat deur die woud loop toon aan dat wyer, hoofpaaie sowel as sekondêre paaie arthropoda gemeenskappe tot 50 meter in die woud in affekteer. Hierdie rand-effek afstand is vergelykbaar met dié van kaalkap-plantasie areas, alhoewel dit verskil in die feit dat die paaie permanente fragmentasie veroorsaak en kaalkap areas moontlik gerehabiliteer kan word. ‘n Interessante bevinding was dat ook staproetes die diversiteit van arthropoda beïnvloed tot en met 10 meter langs die roetes. Alhoewel dit nie tot fragmentasie lei nie, aangesien die blaredak steeds onbeskadig is, verander die natuurlike gemeenskappe met onbekende gevolge rakende hul populasie dinamika. Resultate toon ook aan hoe paaie wat in ‘n oos-wes rigting loop meer invloed uitoefen op woude aan die suiderkant van hierdie paaie, teenoor noord-suid paaie wat minder invloed uitoefen. Verhoogde vlakke van sonlig-penetrasie, met gepaardgaande mikro-klimatiese veranderings, kan moontlik hierdie bevindings verduidelik. Die verlies van habitat vanweë die plant van grootskaalse plantasies lei nie net tot ‘n vermindering in geskikte fynbos habitat nie, maar dit affekteer ook die aangrensende woude se natuurlike arthropoda diversiteit. Ter opsomming is gevind dat paaie wel die oorblywende Suid-Kaapse woude fragmenteer. Vanweë die uniekheid van hierdie woude, word spesiale bestuur vereis om te verseker dat die groter area se biodiversiteit optimaal bewaar word sonder om opbrengste te danke aan produksie te beïnvloed. ‘n Aantal moontlike versagtings-aksies word ter tafel gesit. Dit word egter aangeraai om die sukses van hierdie metodes eers te bepaal voordat dit geïmplementeer word. Thesis (MSc)--Stellenbosch University, 2016. 2016-03-01T00:00:00Z Pond biodiversity in a sugarcane-forestry mosaic in KZN http://scholar.sun.ac.za:80/handle/10019.1/98397 Pond biodiversity in a sugarcane-forestry mosaic in KZN Briggs, Andrew John ENGLISH ABSTRACT: The wetlands of South Africa are threatened by dam creation, agricultural practices and urbanisation. Farm ponds within these wetlands act as habitat islands and are known to support heterogeneous communities of aquatic organisms which often include rare or unique species not found in other water body types. The timber and sugarcane industries of KwaZulu-Natal (KZN) province, South Africa, are very important to the local economy and make up a large portion of the farmland in the province. Timber, and more recently, sugar farmers in KZN are farming their lands with environmental sustainability in mind. This shift towards more biodiversity friendly agriculture should have positive effects on biodiversity conservation. This study aims to assess the differences in species assemblages of three different taxonomic groups within ponds found in forestry and sugarcane agriculture, and to look at the quality of habitat within the two agricultural mosaics using bioindicators. Sites within protected areas were used as benchmark sites. In Chapter 2, I assessed the conservation value of farm ponds within timber and sugarcane plantations by gathering biodiversity data on plants, aquatic Coleoptera and Odonata. Plants were sampled using transects, aquatic Coleoptera were sampled by sweeping a net through the aquatic area along the banks of the ponds and Odonata were sampled through visual observations. No significant differences were found between the wetland groups regarding species richness of plants, aquatic Coleoptera and Odonata. Species richness of the Coleoptera was low at all sites whilst the species richness of Odonata was highest in sugarcane sites which had a large open water surface, compared to smaller sites within sugarcane and forestry agriculture. Sugarcane sites contained the most invasive alien plants based on high levels of agricultural disturbance whilst still maintaining high levels of Odonata diversity, therefore indicating the importance they possess as alternative habitat for various invertebrates. In Chapter 3, the focus was primarily on utilising the Dragonfly Biotic Index (DBI) and the presences of rare and threatened Odonata to assess the conservation significance of ponds and reservoirs in a sugarcane-forestry mosaic. In order to achieve this I used the Odonata population data that was gathered, and assigned the various species their scores which subsequently allowed me to make deductions about the habitats in which they were found. The results indicate that the protected areas in my overall study area had the highest quality habitat with more Odonata species which are sensitive to disturbance being found at these localities. Despite this finding, ponds within sugarcane agricultural mosaics were able to support many Odonata species, including some which were not found in the protected areas. However, these were predominately widespread generalists with low conservation value. In conclusion, I found that species richness was a poor indication of pond conservation value and subsequently recommend using DBI for future monitoring. Although the sugarcane farms were able to support high numbers of generalist species, these results indicate that farmers could be doing more to encourage environmentally sensitive species into their wetlands, such as restoration through alien clearing.; AFRIKAANSE OPSOMMING: Die vleilande van Suid-Afrika word bedreig deur damskepping, landboupraktyke en verstedeliking. Plaasdamme binne hierdie vleilande funksioneer soos habitat eilande en ondersteun dikwels heterogene gemeenskappe van akwatiese organismes wat gereeld seldsame of unieke spesies insluit wat nie in ander soorte watermassas voorkom nie. Die bosbou en suikerriet nywerhede van KwaZulu-Natal (KZN) is baie belangrik vir die plaaslike ekonomie en beslaan 'n groot gedeelte van die landbougrond in die provinsie. Bosbou, en meer onlangs, suikerboere in KZN boer hul lande met omgewingsvolhoubaarheid in gedagte. Hierdie verskuiwing na meer biodiversiteits-vriendelike landbou behoort 'n positiewe uitwerking op die bewaring van biodiversiteit te hê. Die doel van hierdie studie was om die verskille in spesiesversamelings van drie verskillende taksonomiese groepe binne damme in bosbou- en suikerrietlandbou te evalueer, en om te kyk na die gehalte van die habitatte in die twee landboumosaïeke met behulp van bioindikatore. Liggings binne beskermde gebiede is gebruik as maatstaf liggings. In Hoofstuk 2, beoordeel ek die bewaringswaarde van plaasdamme binne bosbou- en suikerrietplantasies deur die insameling van biodiversiteitdata op plante, akwatiese Coleoptera en Odonata. Plantopnames is gemaak met behulp van transekte, akwatiese Coleoptera is versamel deur 'n net te vee deur die water langs die oewer van die dam en Odonata opnames is gemaak deur visuele waarnemings. Geen beduidende verskille is gevind tussen die vleiland groepe ten opsigte van spesierykheid van plante, akwatiese Coleoptera en Odonata nie. Spesierykheid van die Coleoptera was laag by alle liggings, terwyl die spesierykheid van Odonata die hoogste was in suikerrietliggings wat 'n groot oop water oppervlak het, in vergelyking met kleiner liggings binne suikerriet- en bosboulandbou. Suikerrietliggings bevat die meeste indringerplante gebaseer op die hoë vlakke van landbouversteuring, terwyl dit nog steeds hoë vlakke van Odonata diversiteit handhaaf, wat dus hulle belangrikheid as alternatiewe habitat vir verskillende invertebrate aandui. In Hoofstuk 3, was die fokus hoofsaaklik op die gebruik van die naaldekoker biotiese indeks (DBI) en die voorkoms van skaars en bedreigde naaldekokers en waterjuffers om die bewaringswaarde van damme en reservoirs in 'n suikerriet-bosbou mosaïek te evalueer. Om dit te bereik het ek die Odonata bevolkingsdata wat versamel is gebruik, en DBI tellings toegeken aan die verskillende spesies, wat my toegelaat het om afleidings te maak oor die habitatte waarin hulle voorkom. Die resultate dui daarop dat die beskermde gebiede in my algehele studie area die hoogste gehalte habitat het met meer Odonata spesies wat sensitief is vir versteuring wat gevind word by hierdie plekke. Ten spyte van hierdie bevinding, was damme binne suikerrietlandbou mosaïeke in staat om baie naaldekoker spesies, insluitend 'n paar wat nie gevind word in die beskermde gebiede nie, te ondersteun. Dit was hoofsaaklik wydverspreide generaliste met 'n lae bewaringswaarde. Ten slotte, ek het gevind dat spesierykheid 'n swak aanduiding was van dam bewaringswaarde en dus beveel die gebruik van die DBI aan vir toekomstige monitering. Hoewel die suikerrietplase in staat was om groot getalle generiese spesies te ondersteun, dui hierdie resultate daarop dat boere meer kan doen om omgewingsensitiewe spesies aan te moedig in hul vleilande, soos restorasie deur middel van die verwydering van uitheemse plante. Thesis (MSc)--Stellenbosch University, 2016. 2016-03-01T00:00:00Z Grasshoppers of azonal riparian corridors and their response to land transformation in the Cape Floristic Region http://scholar.sun.ac.za:80/handle/10019.1/98354 Grasshoppers of azonal riparian corridors and their response to land transformation in the Cape Floristic Region Pronk, Bianca Mignon ENGLISH ABSTRACT: The Cape Floristic Region (CFR) is a global biodiversity hotspot with high levels of endemism across many taxa, including Orthoptera. Azonal vegetation, a much forgotten component of the CFR, is a unique vegetation type that forms part of the riparian corridor. This is a complex, unique and diverse ecosystem with high levels of local biodiversity that connects the aquatic and terrestrial realms. The riparian corridor is highly disturbed through anthropogenic activities and invasion by alien vegetation causing deterioration of riparian corridors. Most natural riparian corridors are now confined to the mountainous slopes and higher elevations. Grasshopper assemblages are good bioindicators of environmental change and habitat deterioration. In response to this I determined the grasshopper assemblage which characterizes the natural riparian and adjacent terrestrial zone and their dispersion across the two zones. I also investigated how grasshoppers respond to riparian corridor disturbances (land transformation) and if they are viable candidates for bioindication of riparian corridors. In Chapter 2 I investigated the ecology of grasshoppers (Orthoptera: Acridoidea) within a non-biome specific natural riparian zone along an important river in the CFR (Lourens River). Grasshopper sampling took place in the natural riparian and terrestrial zones along seven sampling units (SU‟s) that were 25 m in length and 35 m wide, in both the riparian and terrestrial zones. The riparian sites were along the river in the riparian corridor whereas the terrestrial sites were farther away. I did find a significant difference between the natural riparian and terrestrial grasshopper assemblages, but I indicated that grasshopper abundance and species richness may be more associated with the riparian vegetation. In Chapter 3, I investigated how grasshoppers respond to land transformation along the riparian corridor of an important river in the CFR (Lourens River), whilst investigating the possibility of grasshoppers as bioindicators. Grasshopper sampling took place in different land use types (LUTs) (natural, agricultural, cleared of invasive alien-trees, invaded by alien-trees and an urbanized riparian area) along the riparian corridor. Each LUT had seven SU‟s per site where grasshopper sampling took place (as per Chapter 2). I found that grasshopper diversity is significantly influenced by the different LUTs and no CFR endemic grasshoppers were present within the invaded or urbanized riparian area. I found that the agricultural and cleared riparian areas had the highest abundance of grasshoppers and were most speciose with a great abundance of CFR endemic grasshoppers. I found that the cleared riparian LUTs had the most CFR endemic grasshopper richness and abundance. In general I found that grasshoppers respond to the different LUTs. In conclusion, there exists a riparian grasshopper assemblage in the natural riparian zone of the CFR. Conservation is hereby critical in this area as it adds to the biodiversity of the region. Land uses had significant influences on grasshopper assemblages, especially on CFR endemic grasshoppers along the riparian corridor. The conservation and maintenance of the mixture between riparian and fynbos plants are important for grasshopper assemblages and more so for the persistence of CFR endemic grasshoppers. Riparian corridor conservation and maintenance is critical for the maintenance and enhancement of grasshopper biodiversity in a biodiversity hotspot, the CFR.; AFRIKAANSE OPSOMMING: Die Kaapse Floristiese Streek (KFS) is 'n wêreldwye kuberkol biodiversiteit met hoë vlakke van endemisme oor baie taksons, insluitend Orthoptera. Azonal plantegroei, 'n veel vergete deel van die KFS, is 'n unieke tipe plantegroei. Die azonal plantegroei vorm deel van die rivieroewers gang wat kompleks, uniek en 'n diverse ekosisteem met hoë vlakke van plaaslike biodiversiteit asook „n verbinding is tussen die land- en akwatiese ryke. Die oewergebied gang is hoogs versteur deur menslike aktiwiteite en inval deur indringerplante dit veroorsaak agteruitgang van rivieroewers gange. Mees natuurlike rivieroewers gange is nou beperk tot die berghellings en hoër hoogtes. Sprinkaan versamelinge is goeie bioindicatoren vir omgewing verandering en habitat agteruitgang. In reaksie op hierdie bepaal ek die sprinkaan versameling wat die natuurlike oewereienaars en aangrensende landelike gebied karaktiseer en hulle verspreiding oor die twee sones. Ek ondersoek ook hoe sprinkane reageer op rivieroewers gang versteurings (land transformasie) en as daar lewensvatbare kandidate vir bioindication van rivieroewers gange bestaan. In Hoofstuk 2 ondersoek ek die ekologie van sprinkane (Orthoptera: Acrididoidea) binne 'n nie-bioom spesifieke natuurlike oewersone langs 'n belangrike rivier in die KFS (Lourens River). Sprinkaan monsterneming het plaasgevind in die natuurlike rivieroewers en terrestriële sones langs sewe monsterneming eenhede (US) wat 25 m in lengte en 35 m breed was, in beide die rivieroewers en aardse sone. Die oewergebied terreine is langs die rivier in die rivieroewers gang terwyl die aardse terreine verder weg is. Ek het 'n „n groot verskil tussen die natuurlike en aardse rivieroewers sprinkaan versameling gevind, maar ek toon aan dat sprinkaan oorvloed en sort rykste miskien „n assosiasie het met die plantegroei van die rivieroewers. In Hoofstuk 3 ondersoek ek hoe sprinkane reageer op land transformasie langs die rivieroewers gang van 'n belangrike rivier in die KFS (Lourens River), terwyl ek ondersoek na die moontlikheid van sprinkane as bioindicatoren. Sprinkaan monsterneming het plaasgevind in verskillende tipes grondgebruike (LUTs) (natuurlike, landbou, verwydering van uitheemse bome, binnegeval deur uitheemse bome en 'n verstedelikte rivieroewers area) langs die rivieroewers gang. Elke LUT het sewe US per staanplek waar sprinkaan monsterneming plaasgevind het (soos per Hoofstuk 2). Ek het gevind dat sprinkaan diversiteit aansienlik beïnvloed word deur die verskillende LUTs en geen KFS endemiese sprinkane teenwoordig is in die binnegeval of verstedelikte rivieroewers gebied was. Ek het gevind dat die landbou- en skoongemaak oewergebiede het die hoogste oorvloed van sprinkane en mees soort rykste is met 'n groot menigte van KFS endemiese sprinkane. In die algemeen het ek gevind dat sprinkane reageer op die verskillende LUTs. Ten slotte, is daar 'n spesifieke rivieroewers sprinkaan fauna in die natuurlike oewersone van die KFS. Bewaring is hiermee krities in hierdie gebied as dit voeg om die biodiversiteit van die streek. landgebruike toon „n beduidende invloed op sprinkaan versamelinge, veral op die KFS endemiese sprinkane langs die rivieroewers gang. Die bewaring en instandhouding van die mengsel tussen oewereienaars en fynbos plante is belangrik vir sprinkaan versameling en meer so vir die voortbestaan van die KFS endemiese sprinkane. Rivieroewers gang bewaring en instandhouding is van kritieke belang vir die instandhouding en verbetering van sprinkaan biodiversiteit in 'n biodiversiteit kuberkol, die KFS. Thesis (MSc)--Stellenbosch University, 2016. 2016-03-01T00:00:00Z How flower visitation of remnant grassland patches is affected by commercial timber plantations and an invasive alien species (Rubus cuneifolius) http://scholar.sun.ac.za:80/handle/10019.1/98051 How flower visitation of remnant grassland patches is affected by commercial timber plantations and an invasive alien species (Rubus cuneifolius) Hansen, Simone ENGLISH ABSTRACT: Our planet is in the midst of a biodiversity crisis, with factors such as land transformation, climate change, anthropomorphic disturbance and invasive species acting together to threaten biodiversity. In South Africa, with minimal natural wood resources, commercial forestry is one of the most abundant forms of landscape transformation. However, a third of the land inside many plantations has been set aside for conservation as unplanted remnant grassland patches (RGPs). These areas are subjected to an additional negative impact by invasive alien species, namely Rubus cuneifolius (American bramble), a weed that is particularly problematic in and around forestry plantations in South Africa. The grassland biome of South Africa is extremely diverse and is of vital importance for the ecosystem services it supplies. Despite this, the grassland biome is under threat as this is where much of South Africa’s forestry plantations are located. Driven by anthropomorphic disturbance, pollinators are in decline. Landscape transformation of natural areas for forestry plantations is likely to affect plant-pollinator interactions which will affect ecosystems and biodiversity. However, it is not known to what extent these ecosystems are affected. It is thought that the impact depends on the complexity of the ecosystem in question, and analyses at the network-level provide insights into the robustness of ecosystems in the face of biodiversity loss. Thus, this study evaluates the effect of natural habitat fragmentation and invasion of the alien species, R. cuneifolius, on flower visitation networks of South African grasslands. The study was conducted in the KwaZulu-Natal Midlands within a commercial timber plantation and a neighbouring protected area (PA). Flower-visitor observations were carried out in uninvaded protected areas and RGPs and in protected areas and RGPs invaded by R. cuneifolius. I found that RGPs within commercial forestry plantations successfully decrease the negative effects of land transformation on the grasslands of the KwaZulu-Natal Midlands, and flower visitation network patterns are largely maintained in these habitat fragments. However, within RGPs, invasion by R. cuneifolius affected the composition and the interaction network structure of flower-visitor and plant communities. The fact that there are unplanted areas within commercial forestry plantations is positive for biodiversity conservation in South Africa. Research has indicated that these areas successfully aid in the conservation of biodiversity and ecosystem functioning. Due to the positive influence that RGPs have on conservation in fragmented and transformed landscapes, it is critical that these unplanted areas are retained. However, the effects of bramble invasion are more intense within RGPs than within protected areas, and therefore, it must be a priority to keep these areas undisturbed. R. cuneifolius has been found to have devastating effects on ecosystem function and network structure. It is also a category 1 invasive plant within South Africa, and its removal is required by law. Therefore, the removal of bramble must be a management priority.; AFRIKAANSE OPSOMMING: Ons planeet is in die middel van 'n biodiversiteit krisis, met faktore soos grond transformasie, klimaatsverandering, antropomorfiese versteuring en indringerspesies wat gesamentlik werk om biodiversiteit te bedreig. Suid-Afrika, besit minimale houtbronne. Daarom is kommersiële bosbou een van die mees algemene vorme van landskap transformasie. Tog is 'n derde van die land binne baie plantasies opsy gesit vir bewaring as oorblywende grasveld kolle (OGKs). Hierdie gebiede word ongelukkig blootgestel aan die bykomende negatiewe impak van die uitheemse spesies, Rubus cuneifolius (Amerikaanse steekdoring), wat veral problematies is in en rondom bosbouplantasies. Die grasveldbioom van Suid-Afrika is baie divers en is van kardinale belang vir die ekosisteem dienste wat dit lewer. Ten spyte hiervan, word die grasveldbioom bedreig waar dit op dieselfde areas as die meerderheid van Suid-Afrika se bosbouplantasies geleë is. Antropomorfiese versteuring lui daartoe dat bestuiwergetalle daal. Landskap transformasie vir bosbou plantasies raak dus plant-bestuiwer interaksies, wat ekosisteme en biodiversiteit beïnvloed. Dit is nie bekend tot watter mate hierdie ekosisteme geraak word nie. Daar word vermoed dat die impak af hang van die kompleksiteit van die ekosisteem. Ontledings van ekosisteme op netwerk vlak kan insigte bied oor die robuustheid van hierdie ekosisteme in die aangesig van biodiversiteitverlies. Dus, die studie evalueer die effek van fragmentasie van natuurlike habitatte en inval van die indringer spesie, R. cuneifolius, op blom-besoekings netwerke van Suid-Afrikaanse grasvelde. Hierdie studie is uitgevoer in die KwaZulu-Natal Midlands binne 'n kommersiële hout plantasie en 'n naburige beskermde gebied (BG). Blom-besoeker waarnemings was in BGs en OGKs sonder R. cuneifolius, en in BGs en OGKs met R. cuneifolius uitgevoer. Ek het gevind dat OGKs binne kommersiële bosbouplantasies suksesvol is om die negatiewe uitwerking van land transformasie te verminder, en blom-besoeking netwerk patrone grootliks gehandhaaf word in hierdie habitat fragmente. Egter, binne OGKs, het R. cuneifolius die samestelling en die interaksie netwerk struktuur van blom-besoekers en plant gemeenskappe negatief geraak. Die feit dat OGKs ongeplant gelaat word, is positief vir die bewaring van biodiversiteit in Suid- Afrika. Navorsing dui aan dat hierdie gebiede suksesvol is om te help met die bewaring van biodiversiteit en ekosisteemfunksionering. As gevolg van die positiewe invloed van OGKs op bewaring in gefragmenteerde en omskepte landskappe, is dit krities dat hierdie areas ongeplant bly. Egter, die gevolge van steekdoring inval is meer intens binne OGKs as binne beskermde gebiede, en daarom moet dit 'n prioriteit wees om hierdie gebiede ongestoord te hou. R. cuneifolius se verwoestende uitwerking op ekosisteem funksie en netwerk struktuur was baie duidelik. Dit is ook 'n kategorie 1 indringerplant in Suid-Afrika, en sy verwydering word deur is die wet vereis. Daarom moet die verwydering van steekdoring ‘n bestuursprioriteit wees. Thesis (MSc)--Stellenbosch University, 2015. 2015-12-01T00:00:00Z Orchard and bin treatment with entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) for the control of the codling moth (Cydia pomonella) http://scholar.sun.ac.za:80/handle/10019.1/97962 Orchard and bin treatment with entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) for the control of the codling moth (Cydia pomonella) Odendaal, Deidre ENGLISH ABSTRACT: The codling moth, Cydia pomonella (Lepidoptera: Tortricidae), is the key pest of apples and pears worldwide. The withdrawal of certain fundamental chemicals from codling moth management spray programmes, due to concerns about human, environmental and ecosystem health, has resulted in the search for softer, more environmentally friendly, and safer control measures. Entomopathogenic nematodes (EPNs), naturally occur in the soil, and actively search for hosts. The interest in using EPNs from the families Heterorhabditidae and Steinernematidae as a control measure was sparked in 1953, when an EPN was discovered in an insect. The aim is to incorporate EPNs in an integrated pest management (IPM) programme, to ensure minimal residue and eventually residue-free pome fruit production in South Africa. In order to ensure EPN success, both the environmental and technical factors influencing their efficacy, were investigated in this study. The biocontrol potential of three imported EPN isolates, being Steinernema feltiae and two isolates of Heterorhabditis bacteriophora (Hb1, Hb2), as well as a local isolate, Steinernema yirgalemense, were evaluated for the control of the codling moth under local conditions. All concentrations of S. yirgalemense, applied by immersion in a suspension of nematodes, gave > 98% control. The two formulated isolates of H. bacteriophora, Hb1-f and Hb2-f, gave < 30% control. When using the same nematode isolates, produced in vivo, S. yirgalemense still resulted in a higher codling moth control of > 90%, compared to 54% and 31% control of the H. bacteriophora Hb1 and Hb2 isolates, respectively. In follow up field trials, S. feltiae resulted in ≥ 80% control, and was thus more effective than both S. yirgalemense and the H. bacteriophora (Hb1) isolates, with 66% and 24%, and 24% and 9% control, for two separate trials, respectively. To validate the data obtained from the field trials, subsequent laboratory bioassays were conducted evaluating temperature regimes, following the same cycle as under natural conditions, with a constant humidity of 100%. Steinernema feltiae proved to be most effective, causing > 90% mortality, followed by S. yirgalemense, with 78% mortality. The two H. bacteriophora isolates (Hb1, Hb2) under the above-mentioned laboratory conditions, resulted in 73% and 59% control, respectively. Humidity thus seems to be the most important factor affecting EPN efficacy during above-ground applications. Steinernema feltiae proved to be a better candidate than S. yirgalemense for the control of the codling moth. The efficacy of different EPN isolates in controlling diapausing codling moth larvae at different temperatures was also evaluated, under local conditions, using spray application. Steinernema feltiae and two isolates of H. bacteriophora Hb1 and Hb2, including two local isolates, S. yirgalemense and Steinernema jeffreyense, were evaluated. The use of S. jeffreyense resulted in the most effective control, with 67% mortality, followed by H. bacteriophora (Hb1) with 42%, and then by S. yirgalemense with 41%. Laboratory bioassays simulating field conditions revealed that S. feltiae was most virulent to codling moth larvae, with 67% mortality by infection, followed by S. yirgalemense with 58%, the H. bacteriophora strain Hb1 with 48%, and the Hb2 strain with 24%. A comparison of the infection and penetration rate of two isolates of H. bacteriophora (Hb1, Hb2), S. feltiae and S. yirgalemense, which was carried out in multiwell plates at 14°C and 25°C, respectively, confirms the dramatic effect of temperature on EPN efficacy. At 14°C, all treatments with EPN species resulted in slower codling moth mortality than they did at 25°C, as after 48 h, < 15% mortality was recorded for all species, whereas at the warmer temperature, > 98% mortality was recorded for all species. After the exposure of washed, cool-treated larvae to 25°C for 24 h, the application of both S. feltiae and S. yirgalemense resulted in 100% mortality, whereas the application of the two H. bacteriophora isolates, Hb1 and Hb2, resulted in 68% and 54% control, respectively, over the same time period. At 14°C, S. feltiae had the highest average penetration rate of 20 IJs/insect, followed by S. yirgalemense with 14 IJs/insect, whereas S. yirgalemense had the highest penetration rate at 25°C, with 39 IJs/insect, followed by S. feltiae, with 9 IJs/insect. The two H. bacteriophora isolates had higher average penetration rates at the higher temperature. This study has highlighted the biocontrol potential of S. jeffreyense, as well as showing that S. feltiae is a cold-active nematode, whereas the other three EPN isolates prefer warmer temperatures. Stacked wooden fruit bins are regarded as preferred overwintering sites for codling moth diapausing larvae. Control strategies against the codling moth in South Africa have been hampered by the reinfestation of orchards by nearby stacked infested fruit bins or by the movement of bins between orchards. Worldwide, wooden fruit bins are systematically being replaced with plastic bins, which, in South Africa, will only be phased out over a few years. The objective of this study was to evaluate the potential of H. bacteriophora, S. feltiae, and S. yirgalemense, to disinfest miniature wooden fruit bins under controlled conditions in the laboratory. After dipping minibins in a suspension of 25 IJs/ml of all three EPN species, under optimum conditions of temperature and humidity, the highest percentage of control was obtained using S. feltiae (75%) followed by S. yirgalemense (57%), and then by H. bacteriophora (Hb1) (27%). The addition of adjuvants significantly increased (p < 0.001) S. feltiae infectivity to > 95%, whereas it did not result in a significant increase in H. bacteriophora or S. yirgalemense infectivity. The results indicated that H. bacteriophora would not be a suitable candidate to use for the control of the codling moth larvae in wooden fruit bins. The current preferred candidate for control would be S. feltiae, whose efficacy could be increased by means of the addition of an adjuvant. During winter, when the whole codling moth population are larvae and in diapause, no control measures are applied in orchards. This study has shown that EPNs can be sprayed in orchards to lower the codling moth cohort emerging after winter, as well as be included in an IPM programme. EPNs can act as a second line of defence, through supplementary control, and ensure effective control of the codling moth larvae which survived chemical spray applications, to safeguard against resistant codling moth populations in the next season.; AFRIKAANSE OPSOMMING: Kodlingmot, Cydia pomonella (Lepidoptera: Tortricidae), is ‘n belangrike plaag van appels en pere wêreldwyd. Die onttrekking van sekere fundamentele chemikalieë vanuit die kodlingmot beheerprogram weens die kommer oor menslike, omgewings en ekosisteemgesondheid, het gelei tot die soektog na sagter, meer omgewingsvriendelike en veiliger beheermaatreëls. Entomopatogeniese nematodes (EPNs) kom natuurlik in die grond voor en soek aktief na gashere. Die belangstelling in die gebruik van EPNs van die families Heterorhabditidae en Steinernematidae as 'n beheermaatreël is te danke aan die ontdekking van 'n EPN in ‘n insek in 1953. Die doel is om EPNs in 'n geïntegreerde plaagbeheerprogram (GPB) te inkorporeer om sodoende minimale residue te verseker en uiteindelik residu vrye produksie van kernvrugte in Suid-Afrika. Ten einde die sukses van EPNs te verseker, is beide die omgewings- en tegniese faktore wat hul doeltreffendheid beïnvloed in die studie ondersoek. Die biologiese beheer potensiaal van drie ingevoerde EPN isolate, Steinernema feltiae en twee Heterorhabditis bacteriophora (Hb1, Hb2) isolate, sowel as 'n plaaslike isolaat, Steinernema yirgalemense, is vir die beheer van kodlingmot onder plaaslike toestande geëvalueer. Alle konsentrasies van S. yirgalemense, wat deur indompeling in ‘n suspensie van nematodes toegedien is, het > 98% beheer tot gevolg gehad. Die twee geformuleerde isolate van H. bacteriophora, Hb1-f en Hb2-f, het < 30% beheer gegee. Met die gebruik van dieselfde nematode isolate, wat in vivo geproduseer is, het S. yirgalemense nog steeds 'n hoër kodlingmot beheer van > 90% opgelewer, in vergelyking met die 54% en 31% beheer van die H. bacteriophora Hb1 en Hb2 isolate, onderskeidelik. Steinernema feltiae het in opvolg veldproewe ≥ 80% beheer tot gevolg gehad en was dus meer effektief as beide S. yirgalemense en die H. bacteriophora (Hb1) isolate, met 66% en 24% en 24% en 9% beheer onderskeidelik in twee afsonderlike veldproewe. Om die resultate van die veldproewe te bevestig, is daaropvolgende laboratorium biotoetse uitgevoer en temperatuur regimes is geëvalueer deur die selfde siklus as onder natuurlike toestande te volg, met 'n konstante humiditeit van 100%. Die studie het bewys dat S. feltiae die mees doeltreffende isolate was met > 90% mortaliteit, S. yirgalemense het gevolg met 78% mortaliteit. Die twee H. bacteriophora isolate (Hb1, Hb2) het onderskeidelik onder bogenoemde laboratorium toestande 73% en 59% beheer tot gevolg gehad. Humiditeit blyk dus die belangrikste faktor te wees wat EPN se doeltreffendheid tydens bogrondse toediening affekteer. Die studie het bewys dat S. feltiae 'n beter kandidaat as S. yirgalemense vir die beheer van kodlingmot is. Die doeltreffendheid van verskillende EPN isolate vir die beheer van diapause kodlingmot larwes sowel as EPN se aktiwiteit by verskillende temperature is ook onder plaaslike toestande, deur bogrondse bespuitings, geëvalueer. Steinernema feltiae en twee isolate van H. bacteriophora (Hb1, Hb2), S. yirgalemense en ‘n ander plaaslike isolaat, Steinernema jeffreyense, is geëvalueer. Die gebruik van S. jeffreyense, het tot die mees effektiewe beheer gelei, met 67% mortaliteit, gevolg deur H. bacteriophora (Hb1) met 42%, en dan S. yirgalemense met 41%. Laboratorium biotoetse wat veldtoestande simuleer, het bewys dat S. feltiae die mees doeltreffend teen kodlingmot larwes is, met 67% mortaliteit tydens infeksie, gevolg deur S. yirgalemense met 58%, die H. bacteriophora Hb1 isolaat met 48%, en die Hb2 isolaat met 24%. 'n Vergelyking van die infeksie- en penetrasie tempo van twee isolate van H. bacteriophora (Hb1, Hb2), S. feltiae en S. yirgalemense wat in 12-put plate teen 14°C en 25°C uitgevoer is, het die dramatiese effek van temperatuur op EPN doeltreffendheid bevestig. By 14°C het alle EPN spesies behandelings stadiger kodlingmot mortaliteit as by 25°C na 48h tot gevolg gehad. ‘n Mortaliteit van < 15% is vir alle spesies aangeteken terwyl by die warmer temperature is > 98% mortaliteit vir alle spesies aangeteken. Na die blootstelling van afgespoelde, koel behandelde larwes aan 25°C vir 24 uur, het die toediening van beide S. feltiae en S. yirgalemense, 100% mortaliteit van larwes tot gevolg gehad terwyl die toediening van die twee H. bacteriophora isolate, Hb1 en Hb2, onderskeidelik 68% en 54% beheer tot gevolg gehad, oor dieselfde tydperk. By 14°C, het S. feltiae die hoogste gemiddelde penetrasie tempo van 20 ILs/ larwe, gevolg deur S. yirgalemense met 14 ILs/ larwe tot gevolg gehad, terwyl S. yirgalemense die hoogste penetrasie tempo getoon het by 25°C met 39 ILs/ insek, gevolg deur S. feltiae met 9 ILs/ insek. Die twee H. bacteriophora isolate (Hb1 en Hb2) het ook hoër gemiddelde penetrasie tempo by die hoër temperatuur getoon. Hierdie studie het die biobeheer potensiaal van S. jeffreyense beklemtoon, asook weereens bevestig dat S. feltiae ‘n koue-aktiewe nematode is, terwyl die ander drie EPN isolate warmer temperature verkies. Hout vrugtekratstapels, word beskou as ‘n ideale oorwintering skuiling vir kodlingmot diapause larwes. In Suid-Afrika word beheerstrategieë teen kodlingmot in die wiele gery deur die herbesmetting van boorde deur nabygeleë besmette hout vrugtekratte of deur die beweging van kratte tussen boorde. Hout vrugtekratte word wêreldwyd stelselmatig vervang met plastiek kratte. Dit sal egter eers oor ‘n aantal jare in Suid-Afrika uitgefaseer word. Die doel van hierdie studie was om die potensiaal van H. bacteriophora, S. feltiae, en S. yirgalemense te evalueer deur miniatuur hout vrugtekratte onder gekontroleerde toestande in die laboratorium te disinfekteer. Na die onderdompeling van die mini vrugtekratte in 'n nematode suspensie van 25 ILs/ml van al drie EPN spesies, onder optimale toestande van temperatuur en humiditeit, is die hoogste persentasie van beheer met die gebruik van S. feltiae (74,85% ± 3.64%) verkry. Die byvoeging van toevoegings middels het S. feltiae se vermoë om te infekteer betekenisvol (p <0,001) tot > 95% verhoog, maar dit het nie tot 'n betekenisvolle toename in die infektiwiteit van H. bacteriophora of S. yirgalemense gelei nie. Die resultate dui daarop dat H. bacteriophora nie 'n geskikte kandidaat is om te gebruik vir die beheer van kodlingmot larwes in besmette hout kratte nie. Die voorkeurkandidaat tans vir beheer is S. feltiae, waarvan die doeltreffendheid verhoog kan word deur middel van die byvoeging van 'n bymiddel. Gedurende die winter wanneer die hele kodlingmot populasie as larwes in diapause is, word geen beheer in boorde toegepas nie. Hierdie studie het getoon dat EPNs in boorde gespuit kan word om sodoende die opkomende kodlingmot populasie na die winter te verlaag en kan ook ingesluit word in 'n GPB program. Die EPNs kan as 'n tweede verdedigingslinie optree en doeltreffende beheer van kodlingmot larwes verseker wat chemiese bespuitings oorleef het, en sodoende beskerming teen weerstandige kodlingmot populasies in die volgende seisoen bied. Thesis (MSc)--Stellenbosch University, 2015. 2015-12-01T00:00:00Z The Harlequin ladybeetle Harmonia axyridis (Coleoptera: Coccinellidae) in the Western Cape Province, South Africa: effects on arthropods in urban, agricultural and natural ecosystems http://scholar.sun.ac.za:80/handle/10019.1/97870 The Harlequin ladybeetle Harmonia axyridis (Coleoptera: Coccinellidae) in the Western Cape Province, South Africa: effects on arthropods in urban, agricultural and natural ecosystems Mukwevho, Vuledzani Oral ENGLISH ABSTRACT: Invasive arthropod predators are one of the largest and most diverse groups of invasive insects in the world. Many are generalist predators, with cosmopolitan distributions due to their use as biological control agents in agriculture. Harmonia axyridis (Coleoptera: Coccinellidae), an invasive arthropod predator species native to Asia, which now has a world-wide distribution. It is considered one of the most successful biological control predator species and is generally considered to be economically beneficial. However, negative effects have recently emerged in agricultural and natural systems. Harmonia axyridis poses a threat to biodiversity as it outcompetes native species for food resources. It can also feed directly on native predatory arthropods that disrupt natural ecosystem processes. Their movement in-and-out of agricultural landscapes may depend on food availability with natural vegetation alongside agricultural areas often utilised for refuge and alternative food resources. This beetle has also been recorded in urban areas. The aim of this study was to determine how the invasive H. axyridis beetle uses the local landscape in the Western Cape province, South Africa, and to determine its threat to native species. I sampled urban landscapes, vineyards, natural vegetation/vineyard edge zones and pristine natural areas for arthropods every second month using a suction sampler. Data collected included the abundance and diversity of H. axyridis, herbivores, local predators and non-Harmonia ladybeetles. Most H. axyridis were collected in urban areas during all sampling periods. Highest abundance was recorded in May and July (winter). This indicates that urban areas were the preferred landscape feature and that these act as ovipositing areas, particularly as larval H. axyridis were also only collected in urban areas. Significantly, vineyards and natural vegetation had very low abundance of H. axyridis, questioning their value as a biological control agent in this region. Harmonia axyridis had a negative effect on the overall local arthropod community, as well as the predator and herbivore guilds, although it was positively correlated with the abundance of non-Harmonia ladybeetles. This suggests that H. axyridis and non-Harmonia ladybeetles are responding to the same resources in these landscapes. A negative correlation found between H. axyridis and the abundance of predators is most likely due to competition for the same resources (e.g. prey items). These negative impacts, along with their negligible value as biological control agents in agriculture, suggest that a programme should be implemented to control this invasive species. More specifically, control should be aimed in urban areas during winter when and where the species aggregates and when larvae are present.; AFRIKAANSE OPSOMMING: Geleedpotige roofdiere is een van die grootste en mees diverse groepe van uitheemse insekte in die wêreld. Die meeste is veelsydige roofdiere, met wêreldwye verspreiding te danke aan hul gebruik as biologiese beheer agente in landbou gebiede. Byvoorbeeld, Harmonia axyridis (Coleoptera: Coccinellidae), 'n indringer geleedpotige roofdier spesies inheems aan Asië, het nou 'n wêreldwye verspreiding. Dit word beskou as die mees suksesvolle roofdier spesies wat gebruik word vir biologiese beheer en word oor die algemeen beskou as ekonomies voordelig. Negatiewe effekte was onlangs aangeteken beide in landbou gebiede en natuurlike areas. Harmonia axyridis hou 'n bedreiging in vir inheemse biodiversiteit as dit inheemse spesies uitkompeteer vir voedsel bronne. Dit kan ook direk voed op plaaslike roofsugtige geleedpotiges wat trofiese vlakke ontwrig en uiteindelik, biodiversiteit. Hulle beweging in-en-uit landbou landskappe kan gekoppel word aan die beskikbaarheid van voedsel, en gebruik natuurlike plantegroei langs landbou gebiede dikwels as 'n toevlugs oord en area vir alternatiewe voedsel bronne. Harmonia axyridis word ook in stedelike gebiede aangeteken. Die doel van hierdie studie was om te bepaal hoe die indringer Harlekynkewer die plaaslike landskap gebruik met die fokus op wingerde in die Wes-Kaap provinsie van Suid-Afrika, en tweedens om die bedreiging wat hierdie kewer moontlik vir inheemse spesies te bepaal. Ek het arthropoda in stedelike landskappe, wingerde, natuurlike plantegroei / wingerd rand sones en ongerepte natuurlike areas elke twee maande met behulp van 'n D-vac versamel. Monsters was ontleed deur gebruik te maak van die getalle van H. axyridis, herbivore, plaaslike roofdiere en nie-Harmonia liewenheers kewers. Die meeste H. axyridis was in stedelike gebiede versamel gedurende al die seisoene, maar meeste individue was gedurende Mei en Julie (winter) versamel. Hierdie toon dat stedelike gebiede die voorkeur-landskappe is vir hierdie kewers en dat hierdie gebiede opgetree as eierleggende gebiede, veral omdat larwes van H. axyridis slegs in hierdie gebiede aangeteken was. Wingerde en die natuurlike plantegroei het baie lae getalle H. axyridis gehuisves wat hul waarde as biobeheermiddel bevraagteken. Harmonia axyridis het 'n negatiewe uitwerking op die algehele plaaslike geleedpotige gemeenskappe gehad, asook op die die roofdier en herbivoor gildes, maar hul getalle was positief gekorreleer met die getalle van nie-Harmonia liewenheerskewers. Dit dui daarop dat H. axyridis en nie-Harmonia liewenheerskewers beide reageer op dieselfde hulpbronne in hierdie landskappe. 'n Negatiewe korrelasie was gevind tussen die getalle van H. axyridis en die getalle van ander predatoriese geleedpotiges at waarskynlik te danke was aan mededinging tussen hierdie groepe vir dieselfde hulpbronne (bv prooi). Hierdie negatiewe invloede, asook hul verminderde waarde as biobeheeragente in die landbou, dui daarop dat 'n program in werking gestel moet word om hierdie indringerspesies te beheer. Meer spesifiek, beheer moet gedurende die winter en in stedelike gebiede geskied, waar en wanneer hierdie spesie op sy volopste is en waar larwes teenwoordig is. Thesis (MSc)--Stellenbosch University, 2015. 2015-12-01T00:00:00Z