Research Articles (Conservation Ecology and Entomology)

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Accelerated microbial degradation of nematicides in vineyard and orchard soils
(South African Society for Enology and Viticulture, 2014-03) Hugo, H. J.; Mouton, C.; Malan, Antoinette P.
Accelerated microbial degradation (AMD) of organophosphate and carbamate nematicides is a phenomenon whereby biodegradation in the soil is increased, leading to a dramatically shortened persistence of nematicides. More intensified agriculture practices in South Africa in response to the future demand for food may lead to increased pest and disease pressure, which in turn will lead to more frequent pesticide application. The same principle applies to plant-parasitic nematode control practices, and the overuse and misuse will have a pronounced effect on the enhancement of AMD. With limited management options available, the responsible use of nematicides becomes more pertinent. Producers should be aware of the problems associated with multiple soil applications of organophosphates and carbamates against plant-parasitic nematodes. This article reviews factors contributing to the AMD of carbamate and organophosphate nematicides in soil and makes practical recommendations to avoid the occurrence of AMD in vineyard and orchards.
Acridid ecology in the sugarcane agro-ecosystem in the Zululand region of KwaZulu-Natal, South Africa
(Pensoft, 2020-01-10) Bam, Adrian; Addison, Pia; Conlong, Desmond
Grasshoppers and locusts are well known crop and pasture pests throughout the world. Periodically they cause extensive damage to large areas of crops and grazing lands, which often exacerbate food shortage issues in many countries. In South Africa, acridid outbreaks rarely reach economic proportions, but in sugarcane plantations, localized outbreaks of native acridid species have been reported for the last eight years with increasing frequency and intensity in certain areas. This study was undertaken from May 2012 to May 2013 to identify the economically important acridid species in the sugarcane agroecosystem in these outbreak areas, to monitor seasonal activity patterns, to assess sampling methods, and to determine the pest status of the major species through damage ratings. Five acridid species of particular importance were identified: Nomadacris septemfasciata (Serville), Petamella prosternalis (Karny), Ornithacris cyanea (Stoll), Cataloipus zuluensis Sjötedt, and Cyrtacanthacris aeruginosa (Stoll). All species are univoltine. Petamella prosternalis was the most abundant species and exhibited a winter egg diapause, while N. septemfasciata, the second most abundant species, exhibited a winter reproductive diapause. Petamella prosternalis and N. septemfasciata were significantly correlated with the damage-rating index, suggesting that these two species were responsible for most of the feeding damage found on sugarcane. This study, for the first time, identified the acridid species complex causing damage to sugarcane in the Zululand area of KwaZulu-Natal, South Africa, and documented their population characteristics and related damage. These data are important information on which to base sound integrated pest management strategies.
Adapting the Dragonfly Biotic Index to a katydid (Tettigoniidae) rapid assessment technique : case study of a biodiversity hotspot, the Cape Floristic Region, South Africa
(Pensoft Publishers, 2017) Thompson, Aileen C.; Bazelet, Corinna S.; Naskrecki, Piotr; Samways, Michael J.
Global biodiversity faces many challenges, with the conservation of invertebrates among these. South Africa is megadiverse and has three global biodiversity hotspots. The country also employs two invertebrate-based rapid assessment techniques to evaluate habitat quality of freshwater ecosystems. While grasshoppers (Acrididae) are known indicators of terrestrial habitats, katydids (Tettigoniidae) could be as well. Here, we adapt a South African freshwater invertebrate-based rapid assessment method, the Dragonfly Biotic Index (DBI), for the terrestrial katydid assemblage, and propose a new assessment approach using katydids: the Katydid Biotic Index (KBI). KBI assigns each katydid species a score based on a combination of: 1) IUCN Red List status, 2) geographic distribution, and 3) life history traits (which consist of mobility and trophic level). This means that the rarer, more localized, specialized and threatened katydid species receive the highest score, and the common, geographically widespread and Least Concern species the lowest. As a case study, we calculated KBI across one of South Africa’s global biodiversity hotspots, the Cape Floristic Region (CFR). We then correlated KBI/Site scores of individual ecosystems with their ecosystem threat scores. The CFR’s katydid assemblage did not differ significantly from that of the overall South African katydid assemblage in terms of its species traits, threat statuses, or distribution among tettigoniid subfamilies. Likewise, KBI/Site scores did not differ significantly among ecosystem threat statuses. This may be explained by the coarse spatial scale of this study or by the lack of specialization of the CFR katydid assemblage. Nevertheless, the KBI holds promise as it is a relatively simple and non-invasive technique for taking invertebrate species composition into account in an assessment of habitat quality. In regions where katydid assemblages are well-known, acoustic surveys and KBI may provide an efficient means for assessing habitats.
Adjuvants to improve aerial control of the citrus mealybug Planococcus citri (Hemiptera: Pseudococcidae) using entomopathogenic nematodes
(Cambridge University Press - CUP, 2013-11) Van Niekerk, S.; Malan, Antoinette P.
The citrus mealybug, Planococcus citri, is a highly destructive pest of citrus, occurring only in the aerial parts of plants. Humidity will be one of the key factors to consider when using entomopathogenic nematodes (EPN) as biological control agents. Different adjuvants can be added to suspensions of EPNs, to improve control as a foliar application. An aqueous suspension containing Heterorhabditis zealandica and 0.3% Zeba® significantly increased P. citri mortality by 22% at 80% relative humidity (RH) with a temperature cycle starting at 22°C for 14 h and 11°C for 11 h. The same polymer formulation was tested for Steinernema yirgalemense and mortality of P. citri increased by 21% at 60% RH and by 27% at 80% RH. The addition of Nu-Film-Pw and Zebaw to H. zealandica suspensions did not significantly retard application run-off on citrus leaves. The combination of Nu-Film-P® and Zeba®, however, was able to significantly retard sedimentation, increasing the average number of nematodes deposited on 2-cm² leaf discs by 10 nematodes. In an aqueous suspension, nematodes settle rapidly to the bottom, resulting in an uneven distribution of nematodes. Xanthan gum, at a concentration of 0.2%, was highly effective at retarding sedimentation, with 72% of the initial nematode number still in suspension after 1 h. Zeba®, at a concentration of 0.3%, despite not being as effective as Xanthan gum, nevertheless still retarded sedimentation significantly. This is the first report of the potential of Nu-Film-P® and Zeba® to improve EPN performance against P. citri when used above ground in citrus orchards.
Alien plants have greater impact than habitat fragmentation on native insect flower visitation networks
(Wiley, 2018) Hansen, Simone; Roets, Francois; Seymour, Colleen L.; Thebault, Elisa; Van Veen, F. J. Frank; Pryke, James S.
Aim: Habitat fragmentation and alien species are among the leading causes of biodiversity loss. In an attempt to reduce the impact of forestry on natural systems, networks of natural corridors and patches of natural habitat are often maintained within the afforested matrix, yet these can be subject to degradation by invasion of non-native species. Both habitat fragmentation and alien invasive species disrupt the complex interaction networks typical of native communities. This study examines whether an invasive plant and/or the fragmented nature of the forestry landscape influences natural flower visitation networks (FVNs), flower–visitor abundance and richness or flower/visitor species composition. Location: The species rich and diverse grasslands in the KwaZulu-Natal Midlands, South Africa is under threat from transformation, particularly by commercial forestry plantations, restricting much of the remaining untransformed grasslands into remnant grassland patches (RGPs). Remaining patches are under additional threat from the invasive Rubus cuneifolius Pursh (bramble). Sites were established in RGPs and in a nearby protected area (PA), with and without brambles present for both areas. Results: Flower abundance and flower area of native plant species were greater within RGP than in PA, but only in the absence of R. cuneifolius. Flower–visitor assemblages differed between invaded and uninvaded sites and also differed between PA and RGP sites. Both areas lost specialist flower–visitor species in the presence of brambles. Network modularity was greatly reduced by the presence of bramble, indicating a reduction in complexity and organization. The structure of FVNs was otherwise unaffected by presence of bramble or being located in RGPs or the PA. Main conclusions: The RPGs contribute to regional biodiversity conservation through additional compositional diversity and intact FVNs. Rubus cuneifolius reduces ecological complexity of both RGPs and PAs, however, and its removal must be prioritized to conserve FVNs.
Analysis of the global warming potential of biogenic CO₂ emission in life cycle assessments
(Nature Research, 2017-01-03) Liu, Weiguo; Zhang, Zhonghui; Xie, Xinfeng; Yu, Zhen; Von Gadow, Klaus; Xu, Junming; Zhao, Shanshan; Yang, Yuchun
Biomass is generally believed to be carbon neutral. However, recent studies have challenged the carbon neutrality hypothesis by introducing metric indicators to assess the global warming potential of biogenic CO2 (GWPbio). In this study we calculated the GWPbio factors using a forest growth model and radiative forcing effects with a time horizon of 100 years and applied the factors to five life cycle assessment (LCA) case studies of bioproducts. The forest carbon change was also accounted for in the LCA studies. GWPbio factors ranged from 0.13–0.32, indicating that biomass could be an attractive energy resource when compared with fossil fuels. As expected, short rotation and fast-growing biomass plantations produced low GWPbio. Long-lived wood products also allowed more regrowth of biomass to be accounted as absorption of the CO2 emission from biomass combustion. The LCA case studies showed that the total life cycle GHG emissions were closely related to GWPbio and energy conversion efficiency. By considering the GWPbio factors and the forest carbon change, the production of ethanol and bio-power appeared to have higher GHG emissions than petroleum-derived diesel at the highest GWPbio.
Angiostoma margaretae n. sp (Nematoda: Angiostomatidae), a parasite of the milacid slug Milax gagates Draparnaud collected near Caledon, South Africa
(Springer Verlag, 2011) Ross, Jenna L.; Malan, Antoinette P.; Ivanova, Elena S.
Angiostoma margaretae n. sp. (Angiostomatidae) is described from the oesophagus of the slug Milax gagates Draparnaud collected near Caledon in the Western Cape Province of South Africa. The new species closely resembles another parasite of a milacid slug, A. milacis Ivanova & Wilson, 2009, with a similar head, stoma and spicule shape, the presence of distally outstretched ovaries, coiled oviducts, the same number of caudal papillae and enlarged rectal glands. However, A. margaretae differs from the latter by having: a shorter, wider tail with a rounded vs pointed tip; the distal parts of both ovaries with a particular hook-like shape due to an expansion closely following the short initial zone; ovoviparous females; and a different arrangement of male papillae. A. margaretae is comparable with A. limacis Dujardin, 1845, A. asamati (Spiridonov, 1985), A. coloaense (Pham Van Luc, Spiridonov & Wilson, 2005) and A. stammeri (Mengert, 1953), which have a similar stoma shape and size, but can be readily differentiated by the presence of distally outstretched vs reflexed ovaries and the presence vs lack of enlarged rectal glands. The new species has a similar arrangement of the ovaries to A. kimmeriense Korol & Spiridonov, 1991 and A. zonitidis Ivanova & Wilson, 2009, but is clearly differentiated by the lack of an off-set lip region and presence of a large bowl-shaped vs tubular stoma and less numerous male caudal papillae (seven pairs vs nine in A. kimmeriense and 10 in A. zonitidis). © 2011 Springer Science+Business Media B.V.
Artificial reservoirs complement natural ponds to improve pondscape resilience in conservation corridors in a biodiversity hotspot
(Public Library of Science, 2018-09-20) Deacon, Charl; Samways, Michael J.; Pryke, James Stephen; Chapman, Maura (Gee) Geraldine
Natural ponds are rich in biodiversity, contributing greatly to regional aquatic biodiversity. Artificial reservoirs used for irrigation can be significant additional features of the landscape. They infill the local natural pondscape, and are attractors for aquatic insects. Here, we determine the extent to which artificial reservoirs represent the local natural pond biota, and how they contribute to the pondscape in conservation corridors used to mitigate the impact of plantation forestry in a global biodiversity hotspot. We did this by: 1) identifying the environmental factors, including plants, that drive dragonfly, water beetle, and water bug species richness, diversity and composition, and 2) determining the value of natural ponds vs. artificial reservoirs for maintaining the population size and expanding the area of occupancy for dragonflies, beetles and bugs in conservation corridors. While vegetation cover was central for maintaining species richness and composition of the assemblages in general, many other environmental variables are necessary to encourage the full suite of local diversity. Artificial reservoirs are attractive habitats to many species, overall increasing area of occupancy for 75% of them (ranging from 62–84% for different taxa). These reservoirs provide complementary alternative habitats to natural ponds, leading to improved ecological resilience across the pondscape. We conclude that maintaining a diverse and heterogeneous pondscape is important for conserving local aquatic insect diversity, and that artificial reservoirs increase the local area of occupancy for a range of pond insects in conservation corridors, and improve the biodiversity value of these pondscapes.
Bark beetle mycobiome : collaboratively defined research priorities on a widespread insect-fungus symbiosis
(Springer, 2020-06-03) Hulcr, Jiri; Barnes, Irene; De Beer, Wilhelm; Duong, Tuan A.; Gazis, Romina; Johnson, Andrew J.; Jusino, Michelle A.; Kasson, Matthew T.; Li, You; Lynch, Shannon; Mayers, Chase; Musvuugwa, Tendai; Roets, Francois; Seltmann, Katja C.; Six, Diana; Vanderpool, Dan; Villari, Caterina
One of the main threats to forests in the Anthropocene are novel or altered interactions among trees, insects and fungi. To critically assess the contemporary research on bark beetles, their associated fungi, and their relationships with trees, the international Bark Beetle Mycobiome research coordination network has been formed. The network comprises 22 researchers from 17 institutions. This forward-looking review summarizes the group’s assessment of the current status of the bark beetle mycobiome research field and priorities for its advancement. Priorities include data mobility and standards, the adoption of new technologies for the study of these symbioses, reconciliation of conflicting paradigms, and practices for robust inference of symbiosis and tree epidemiology. The Net work proposes contemporary communication strategies to interact with the global community of researchers studying symbioses and natural resource managers. We conclude with a call to the broader scientific community to participate in the network and contribute their perspectives.
Benefits of water-related ecological infrastructure investments to support sustainable land-use : a review of evidence from critically water-stressed catchments in South Africa
(Royal Society, 2021) Rebelo, Alanna J.; Holden, Petra B.; Esler, Karen; New, Mark G.
Investments to promote sustainable land-use within critical river catchment areas are often undertaken to provide benefits to society. Investments generally aim to protect or restore ecological infrastructure—the underlying framework of ecosystems, functions and processes that supply ecosystem services—for multiple benefits to society. However, the empirical evidence base from studies across the world on both mechanisms and outcomes to support these assumptions is limited. We collate evidence on the benefits of ecological infrastructure interventions, in terms of ecosystem services provided to society, from three major South African water-providing catchments using a novel framework. In these catchments, millions of US Dollars' worth of investments have been made into ecological infrastructure since 1996. We ask the question: is there evidence that ecological infrastructure interventions are delivering the proposed benefits? Results show that even in catchments with substantial, long-term financial investment into ecological infrastructure, research has not empirically confirmed the benefits. Better baseline data collection is required, and monitoring during and after ecological infrastructure interventions, to quantify benefits to society. This evidence is needed to leverage investment into ecological infrastructure interventions at scale. Investment at scale is needed to transition to more sustainable land-use to unlock greater benefits to nature and people.
Biocultural diversity : a Mongolian case study
(Resilience Alliance, 2019) Seele, Barbara C.; Esler, Karen J.; Cunningham, Anthony B.
Although conceptual frameworks describing biodiversity and cultural keystone species have been widely accepted over the past 15 years, there remains a need for an overarching framework that covers the various components of biocultural diversity. We present a conceptual framework to enable the better understanding, monitoring, and maintenance of biocultural diversity across a range of spatial scales, from the landscape and ecosystem level to the species and gene/meme level. This is done by combining the concepts of biological diversity and cultural diversity, including cultural values and symbols, ethnoscientific approaches, as well as power relations and institutions, to form a biocultural diversity framework. To illustrate the framework, we use a systems diagram and practical examples from a case study on the ethnoveterinary knowledge and practices of Mongolian pastoralists. Ethnoveterinary knowledge is an example of traditional ecological knowledge and therefore offers valuable insight into biocultural diversity. Using the conceptual framework as a tool, our investigation of biocultural diversity in the Mongolian pastoralist context strongly suggests that an understanding of the historical, political, and cultural contexts, as well as the interrelatedness of cultural processes and ecological systems, is essential for maintaining biocultural diversity. More specifically, our results indicate that retaining a mobile herding way of life as well as the associated balance and communication with nature, is vital for both the continued transmission of ethnoveterinary knowledge and the sustainable use of ecological resources that Mongolian pastoralists rely on. There is a need for national policies that acknowledge, support, and maintain the important and complex processes underlying the Mongolian landscape and the associated worldviews, knowledge, and practices. The development of a coherent framework for biocultural diversity therefore allows for a clearer understanding of the various components and the selection of appropriate indicators for monitoring biocultural diversity.
Biologically based methods for pest management in agriculture under changing climates : challenges and future directions
(MDPI, 2012) Chidawanyika, Frank; Mudavanhu, Pride; Nyamukondiwa, Casper
The current changes in global climatic regimes present a significant societal challenge, affecting in all likelihood insect physiology, biochemistry, biogeography and population dynamics. With the increasing resistance of many insect pest species to chemical insecticides and an increasing organic food market, pest control strategies are slowly shifting towards more sustainable, ecologically sound and economically viable options. Biologically based pest management strategies present such opportunities through predation or parasitism of pests and plant direct or indirect defense mechanisms that can all be important components of sustainable integrated pest management programs. Inevitably, the efficacy of biological control systems is highly dependent on natural enemy-prey interactions, which will likely be modified by changing climates. Therefore, knowledge of how insect pests and their natural enemies respond to climate variation is of fundamental importance in understanding biological insect pest management under global climate change. Here, we discuss biological control, its challenges under climate change scenarios and how increased global temperatures will require adaptive management strategies to cope with changing status of insects and their natural enemies.
Black rhinoceros avoidance of tourist infrastructure and activity: planning and managing for coexistence
(Cambridge University Press, 2019-09-26) Muntifering, Jeff R.; Linklater, Wayne L.; Naidoo, Robin; Uri-Khob, Simson; Du Preez, Pierre; Beytell, Petrus; Jacobs, Shayne; Knight, Andrew T.
Wildlife-based tourism has been described as a key conservation mechanism (Buckley & Castley, Reference Buckley and Castley2012; Coghlan et al., Reference Coghlan, Buckley and Weaver2012; Buckley et al., Reference Buckley, Morrison and Castley2016) and has increased globally (Tapper, Reference Tapper2006), particularly in developing countries (Balmford et al., Reference Balmford, Beresford, Green, Naidoo, Walpole and Manica2009). However, such tourism can have negative consequences for the wildlife intended to benefit from it. For example, previous studies found the mountain caribou Rangifer tarandus is displaced from preferred habitat by snowmobiles (Seip et al., Reference Seip, Johnson and Watts2007) and the Asian rhinoceros Rhinoceros unicornis by elephant-borne tourists (Lott & Mccoy, Reference Lott and Mccoy1995). Declines in bottlenose dolphin Tursiops sp. abundance linked to tourism (Bejder et al., Reference Bejder, Samuels, Whitehead, Gales, Mann and Connor2006) and increased risks to human safety through habituation of brown bears Ursus arctos (Penteriani et al., Reference Penteriani, López-bao, Bettega, Dalerum, Delgado and Jerina2017) have also been reported. A growing demand for experiences that provide opportunities to interact directly and in close proximity with wildlife (Higham et al., Reference Higham, Bejder and Lusseau2009) has inspired research aiming to quantify the direct impacts of human–wildlife encounters (Buckley, Reference Buckley2011). However, human activity (including conservation-oriented tourism) occurring within wildlife habitat often creates so-called zones of influence in which certain wildlife species may be displaced from otherwise suitable habitat (Noss & Cue, Reference Noss and Cue2001; Taylor & Knight, Reference Taylor and Knight2003; Frair et al., Reference Frair, Merrill, Beyer and Morales2008; Polfus et al., Reference Polfus, Hebblewhite and Heinemeyer2011; Boulanger et al., Reference Boulanger, Poole, Gunn and Wierzchowski2012). Few studies have examined the indirect effects of tourism infrastructure and operational development on free-ranging wildlife. An incomplete understanding of the effects tourism has on wildlife can result in poor management planning (Buckley & Pabla, Reference Buckley and Pabla2012) and reduce the net positive outcomes for conservation (Buckley, Reference Buckley2010). Even when scientific data are available, evidence-based management approaches are not necessarily implemented because research is often not management-oriented (Linklater, Reference Linklater2003) or researchers do not plan for implementation of their findings (Knight et al., Reference Knight, Cowling, Rouget, Balmford, Lombard and Campbell2008). To ensure conservation benefits exceed the costs associated with increased tourism involving rare and threatened wildlife (Karanth & DeFries, Reference Karanth and DeFries2011), it is vital that research is translated into management approaches that are both useful and user-friendly (Pierce et al., Reference Pierce, Cowling, Knight, Lombard, Rouget and Wolf2005; Thirgood et al., Reference Thirgood, Mduma, Keyyu and Laurenson2007). The policy sciences provide both a theory and a practical framework for integrating evidence in an effective decision-making process (Clark, Reference Clark2002). This approach has been used to improve conservation for many threatened species including koalas (Clark et al., Reference Clark, Mazur, Begg and Cork2000), great apes (Eves et al., Reference Eves, Gordon, Stein and Clark2002) and brown bears (Rutherford et al., Reference Rutherford, Gibeau, Clark and Chamberlain2009). The Critically Endangered black rhinoceros Diceros bicornis, an iconic large African mammal that has experienced a 97% population decline since 1970 (Emslie & Brooks, Reference Emslie and Brooks1999) could also benefit from a management-oriented approach.
Building capacities for transformative change towards sustainability: imagination in intergovernmental science-policy scenario processes
(University of California Press, 2019-09-04) Pereira, Laura; Sitas, Nadia; Ravera, Federica; Jimenez-Aceituno, Amanda; Merrie, Andrew
Scenario development has been recognized as a potential method to explore future change and stimulate a reflective process that can contribute to more informed decision-making. The assessment process under IPBES (the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services) has however shown that the current predominantly biophysical and economic models and scenario processes for exploring the future of biodiversity, ecosystem services and their contributions to human wellbeing are insufficient to capture the complexity and context-specific nature of the problems facing these sectors. Several important challenges have been identified that require a more in-depth analysis of where more imaginative scenario efforts can be undertaken to address this gap. In this paper, we identify six key characteristics necessary for scenario processes: adaptability across diverse contexts, inclusion of diverse knowledge and value systems, legitimate stakeholder engagement that foregrounds the role of power and politics, an ability to grapple with uncertainty, individual and collective thinking mechanisms and relevance to policy making. We compared four cases of imaginative, arts-based scenario processes that each offer aspects of meeting these criteria. These approaches emphasise the importance of engaging the imagination of those involved in a process and harnessing it as a tool for identifying and conceptualising more transformative future trajectories. Drawing on the existing literature, we argue that there is value in fostering more inclusive and creative participatory processes that acknowledge the importance of understanding multiple value systems and relationships in order to reimagine a more inclusive and just future. Based on this, we reflect on future research to understand the transformative role that imagination can play in altering and enhancing knowledge-making for global assessments, including IPBES. We conclude that creative scenario co-development processes that promote imagination and create an opening for more empathetic responses should be considered as complementary tools within the suite of methodologies used for future IPBES scenario development.
Challenges and solutions to establishing and sustaining citizen science projects in South Africa
(Academy of Science of South Africa, 2019-07-30) Hulbert, J. M.; Turner, S. C.; Scott, S. L.
Citizen science is a term for research that engages non-scientists in the collection and generation of data. Many citizen science projects exist within South Africa and, because of their success, we expect more projects will be initiated. In this Commentary, we discuss three projects based in, but not confined to, the Western Cape Province to provide context for their methods, specific objectives and overall desired impacts. We then identify a few challenges that we have faced from the researcher perspective and we provide recommendations for those interested in initiating a citizen science project in South Africa. Many projects involve citizen scientists because their participation enhances the breadth of the research through the collection of data over greater spatio-temporal scales.1-3 However, not all projects in South Africa have purely research objectives, some are education-oriented with the specific objective of empowering the participants. In some cases, the educational objectives may be motivated by the desire to engage local communities or by the understanding of ubuntu wisdom. Citizen science is therefore a powerful approach to address multiple objectives, but there are many challenges to achieving the desired outcomes. We outline these challenges below within the context of an education-oriented project, a research-oriented project and a project that combines the two objectives.
Challenges in invasive alien plant control in South Africa
(Academy of Science of South Africa, 2012) Van Wilgen, Brian W.; Cowling, Richard M.; Marais, Christo; Esler, Karen J.; McConnachie, Matthew; Sharp, Debbie
Working for Water owes much to the community of fynbos ecologists who were instrumental in putting forward an argument to government for its initiation in 1996.2 The 33rd Annual Fynbos Forum (attended by over 250 delegates at Cape St. Francis on 17–19 July 2012) included a plenary workshop on the effectiveness of Working for Water, and discussions on ways for the scientific community to assist in the identification and implementation of improvements. This brief report outlines the issues discussed, including the problems faced by Working for Water, and possible ways for the scientific community to assist in addressing them.
Characterisation of Metarhizium majus (Hypocreales : Clavicipitaceae) isolated from the Western Cape Province, South Africa
(Public Library of Science, 2021-03-19) Mathulwe, Letodi L.; Jacobs, Karin; Malan, Antoinette P.; Birkhofer, Klaus; Addison, Matthew F.; Addison, Pia
Entomopathogenic fungi (EPF) are important soil-dwelling entomopathogens, which can be used as biological control agents against pest insects. EPF are capable of causing lethal epizootics in pest insect populations in agroecosystems. During a survey of the orchard soil at an organic farm, different EPF species were collected and identified to species level, using both morphological and molecular techniques. The EPF were trapped from soil samples taken from an apricot orchard. The traps, which were baited in the laboratory, used susceptible host insects, including the last-instar larvae of Galleria mellonella (wax moth larvae) and Tenebrio molitor (mealworm larvae). The potential pathogenicity of the local Metarhizium majus isolate was tested and verified using susceptible laboratory-reared last-instar T. molitor larvae. The identification of the M. majus isolated from South African soil was verified using both morphological and molecular techniques. The occurrence of M. majus in the South African soil environment had not previously been reported.
Cold tolerance is unaffected by oxygen availability despite changes in anaerobic metabolism
(Springer Nature, 2016) Boardman, Leigh; Sørensen, Jesper G.; Koštál, Vladimir; Šimek, Petr; Terblanche, John S.
Insect cold tolerance depends on their ability to withstand or repair perturbations in cellular homeostasis caused by low temperature stress. Decreased oxygen availability (hypoxia) can interact with low temperature tolerance, often improving insect survival. One mechanism proposed for such responses is that whole-animal cold tolerance is set by a transition to anaerobic metabolism. Here, we provide a test of this hypothesis in an insect model system (Thaumatotibia leucotreta) by experimental manipulation of oxygen availability while measuring metabolic rate, critical thermal minimum (CTmin), supercooling point and changes in 43 metabolites in moth larvae at three key timepoints (before, during and after chill coma). Furthermore, we determined the critical oxygen partial pressure below which metabolic rate was suppressed (c. 4.5 kPa). Results showed that altering oxygen availability did not affect (non-lethal) CTmin nor (lethal) supercooling point. Metabolomic profiling revealed the upregulation of anaerobic metabolites and alterations in concentrations of citric acid cycle intermediates during and after chill coma exposure. Hypoxia exacerbated the anaerobic metabolite responses induced by low temperatures. These results suggest that cold tolerance of T. leucotreta larvae is not set by oxygen limitation, and that anaerobic metabolism in these larvae may contribute to their ability to survive in necrotic fruit.
A comparative analysis reveals weak relationships between ecological factors and beta diversity of stream insect metacommunities at two spatial levels
(John Wiley & Sons Ltd., 2015-02-23) Heino, Jani; Melo, Adriano S.; Bini, Luis Mauricio; Altermatt, Florian; Al-Shami, Salman A.; Angeler, David G.; Bonada, Nuria; Brand, Cecilia; Callisto, Marcos; Cottenie, Karl; Dangles, Olivier; Dudgeon, David; Encalada, Andrea; Gothe, Emma; Gronroos, Mira; Hamada, Neusa; Jacobsen, Dean; Landeiro, Victor L.; Ligeiro, Rapael; Martins, Renato T.; Miserendino, Maria Laura; Rawi, Che Salmah Md; Rodrigues, Marciel E.; Roque, Fabio de Oliveira; Sandin, Leonard; Schmera, Denes; Sgarbi, Luciano F.; Simaika, John P.; Siqueira, Tadeu; Thompson, Ross M.; Townsend, Colin R.
The hypotheses that beta diversity should increase with decreasing latitude and increase with spatial extent of a region have rarely been tested based on a comparative analysis of multiple datasets, and no such study has focused on stream insects. We first assessed how well variability in beta diversity of stream insect metacommunities is predicted by insect group, latitude, spatial extent, altitudinal range, and dataset properties across multiple drainage basins throughout the world. Second, we assessed the relative roles of environmental and spatial factors in driving variation in assemblage composition within each drainage basin. Our analyses were based on a dataset of 95 stream insect metacommunities from 31 drainage basins distributed around the world. We used dissimilarity-based indices to quantify beta diversity for each metacommunity and, subsequently, regressed beta diversity on insect group, latitude, spatial extent, altitudinal range, and dataset properties (e.g., number of sites and percentage of presences). Within each metacommunity, we used a combination of spatial eigenfunction analyses and partial redundancy analysis to partition variation in assemblage structure into environmental, shared, spatial, and unexplained fractions. We found that dataset properties were more important predictors of beta diversity than ecological and geographical factors across multiple drainage basins. In the within-basin analyses, environmental and spatial variables were generally poor predictors of variation in assemblage composition. Our results revealed deviation from general biodiversity patterns because beta diversity did not show the expected decreasing trend with latitude. Our results also call for reconsideration of just how predictable stream assemblages are along ecological gradients, with implications for environmental assessment and conservation decisions. Our findings may also be applicable to other dynamic systems where predictability is low.
Comparative phylogeography between two generalist flea species reveal a complex interaction between parasite life history and host vicariance : parasite-host association matters
(BioMed Central, 2015-06) Van der Mescht, Luther; Matthee, Sonja; Matthee, Conrad. A; Conservation Ecology and Entomology
Background: In parasitic taxa, life history traits such as microhabitat preference and host specificity can result in differential evolutionary responses to similar abiotic events. The present study investigates the influence of vicariance and host association on the genetic structure of two generalist flea species, Listropsylla agrippinae, and Chiastopsylla rossi. The taxa differ in the time spent on the host (predominantly fur vs. nest) and level of host specificity. Results: A total of 1056 small mammals were brushed to collect 315 fleas originating from 20 geographically distinct localities in South Africa. Phylogeographic genetic structure of L. agrippinae and C. rossi were determined by making use of 315 mitochondrial COII and 174 nuclear EF1-α sequences. Both parasites show significant genetic differentiation among the majority of the sampling sites confirming limited dispersal ability for fleas. The generalist fur flea with a narrower host range, L. agrippinae, displayed geographic mtDNA spatial genetic structure at the regional scale and this pattern is congruent with host vicariance. The dating of the divergence between the L. agrippinae geographic clades co-insides with paleoclimatic changes in the region approximately 5.27 Ma and this provides some evidence for a co-evolutionary scenario. In contrast, the more host opportunistic nest flea, C. rossi, showed a higher level of mtDNA and nDNA spatial genetic structure at the inter-populational scale, most likely attributed to comparatively higher restrictions to dispersal. Conclusions: In the present study, the evolutionary history of the flea species could best be explained by the association between parasite and host (time spent on the host). The phylogeographic pattern of the fur flea with a narrower host range correspond to host spatial genetic structures, while the pattern in the host opportunistic nest flea correspond to higher genetic divergences between sampling localities that may also be associated with higher effective population sizes. These findings suggest that genetic exchange among localities are most likely explained by differences in the dispersal abilities and life histories of the flea species.

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