Research Articles (Conservation Ecology and Entomology)

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    Understanding drivers of human tolerance to gray wolves and brown bears as a strategy to improve landholder– carnivore coexistence
    (Wiley Periodicals LLC., 2020) Marino, Filippo; Kansky, Ruth; Shivji, Irene; Di Croce, Antonio; Ciucci, Paolo; Knight, Andrew T.
    Despite recent recovery of large carnivores throughout Europe such as the brown bear (Ursus arctos) and the graywolf (Canis lupus), some of their populations are still threatened and their viability depends on human tolerance to share mixed landscapes. We investigated the drivers of landholders' tolerance in Abruzzo (Italy), a region with a long history of cohabitation, by applying theWildlife Tolerance Model (WTM) (Kansky et al., 2016, Biological Conservation, 201, 137–145). Using structural equation modeling we assessed relationships between WTM variables. This framework hypothesizes that exposure to a species and experiences with a species drive perceptions of benefits and costs, and ultimately tolerance.We then sought to understand similarities and differences in tolerance drivers between the two species and across two areas that differed in the duration of human–carnivore cohabitation. Results showed both similarities and differences in drivers between species and areas, resulting in seven management proposals to foster tolerance. Increasing intangible benefits and positive experiences were two strategies that were similar for both species and areas,while five strategies differed across species and areas.Our methodological approach can be applied in other landscapes with other species to determine the extent to whichmultispeciesmanagement across landscapes is possible.
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    The influence of biophysical and socio-economic factors on the effectiveness of private land conservation areas in preventing natural land cover loss across South Africa
    (Elsevier B.V., 2021-06-09) Shumba, Tafadzwa; De Vos, Alta; Biggs, Reinette, 1979-; Esler, Karen J.; Clements, Hayley S.
    There is increasing interest in the potential of private land conservation areas (PLCAs) as a complementary biodiversity conservation strategy to state-owned protected areas. However, there is limited understanding of how the diverse social-ecological contexts of PLCAs influence their effectiveness in conserving biodiversity. Here, we investigated how the effectiveness of South African PLCAs in conserving biodiversity varied across social-ecological contexts, using natural land cover as a proxy. Social-ecological contexts were represented by biophysical and legal factors (distance to towns and roads, elevation, slope, terrain ruggedness, rainfall, PLCA size, distance to state-owned national parks, and presence of legal protection) and, for a subset of commercially-operated PLCAs, management factors (adopted business model, and profitability). Biophysical and legal contextual factors had low explanatory power in the best model for the nationwide analysis (n = 5121 PLCAs). For a subset of PLCAs (n = 72) we found that effectiveness depended on the strategy they adopted to generate an income, as opposed to the amount of income itself. PLCAs that attracted high volumes of visitors to small properties to view charismatic “Big 5” wildlife were less effective in conserving natural land cover than larger, more exclusive “Big 5” PLCAs and those focused on hunting. Overall, site-specific management factors were better at explaining the effectiveness of PLCAs than biophysical factors. Our findings indicate that conservation practitioners and policy makers need to recognise the diverse goals, motivations and management models of PLCAs when considering how to support them in conserving biodiversity. Future studies could explore whether these trends hold for other proxies of biodiversity conservation, beyond land cover change.
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    Effects of both climate change and human water demand on a highly threatened damselfly
    (Nature, 2021-04-08) Khelifa, Rassim; Mahdjoub, Hayat; Baaloudj, Affef; Cannings, Robert A.; Samways, Michael J.
    While climate change severely affects some aquatic ecosystems, it may also interact with anthropogenic factors and exacerbate their impact. In dry climates, dams can cause hydrological drought during dry periods following a great reduction in dam water discharge. However, impact of these severe hydrological droughts on lotic fauna is poorly documented, despite climate change expected to increase drought duration and intensity. We document here how dam water discharge was affected by climate variability during 2011–2018 in a highly modified watershed in northeastern Algeria, and how an endemic endangered lotic damselfly, Calopteryx exul Selys, 1853 (Odonata: Calopterygidae), responded to hydrological drought episodes. Analysis was based on a compilation of data on climate (temperature, precipitation, and drought index), water dam management (water depth and discharge volume and frequency), survey data on C. exul occurrence, and capture–mark–recapture (CMR) of adults. The study period was characterized by a severe drought between 2014 and 2017, which led to a lowering of dam water depth and reduction of discharge into the river, with associated changes in water chemistry, particularly during 2017 and 2018. These events could have led to the extirpation of several populations of C. exul in the Seybouse River (Algeria). CMR surveys showed that the species was sensitive to water depth fluctuations, avoiding low and high water levels (drought and flooding). The study shows that climate change interacts with human water requirements and affects river flow regimes, water chemistry and aquatic fauna. As drought events are likely to increase in the future, the current study highlights the need for urgent new management plans for lotic habitats to maintain this species and possible others.
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    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.
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    Weed species, not mulching, affect web-building spiders and their prey in organic fruit orchards in South Africa
    (Wiley Online, 2020) Arvidsson, F.; Addison, P.; Addison, M.; Haddad, C. R.; Birkhofer, K.
    Weed infestation affects economically relevant orchard properties, including tree performance, yield, and fruit quality negatively, and weeds are therefore often controlled by herbicide application in conventional farming. The addition of organic mulch below tree canopies has been proposed as an alternative reliable practice to suppress weeds and preserve soil moisture in organic farming. Mulching, however, may also affect arthropod pest and natural enemy populations, which highlights the need for simultaneously assessing weed, natural enemy, and animal pest communities in mulch experiments. This study addresses the limited knowledge about nonchemical ground cover management strategies for the control of plant and animal pests in orchards as a major constraint for organic growers. Here, we hypothesize that decisions about ground cover management practices in organic temperate fruit orchards affect the composition of web-building spider communities and their functional role as natural enemies of pest arthropods through effects on weed and insect pest communities. We studied weed, prey, and spider communities, as well as spider diet composition, in four temperate fruit types (apricot, peach, plum, and quince) on a single farm in the Western Cape, South Africa. We established experimental plots with and without addition of dead organic mulch under fruit tree canopies. Addition of organic mulch did not significantly affect weed cover under trees or the taxonomic composition of weed or spider communities over the eight-month study period. However, independent of mulching, the taxonomic composition of weed communities was significantly related to the composition of potential prey and spider communities. These relationships indirectly affected the prey composition of web-building spiders. These results suggest that the identity of weed species in the study orchards had a pronounced effect on the diet composition and functional role of web-building spiders. Future research should focus on the value of individual plant species for the promotion of pest control services provided by spiders across larger spatial scales and with higher levels of replication to allow for wider generalizations. The expected results would not only be relevant for weed control but could also be considered during the development of future flower strips in orchards.