School of Animal, Plant and Environmental Sciences
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Item Using genetics to prioritise headwater stream fish populations of the Marico barb, Enteromius motebensis Steindachner 1894, for conservation action.(AOSIS OpenJournals Publishing AOSIS (Pty) Ltd, 2017-02) van der Walt, K.-A.; Swartz, E.R.; Woodford, D.J.; Weyl, O.South Africa has a relatively large number of threatened freshwater fish species and limited resources to implement conservation programs. Enteromius motebensis was regionally prioritised for action because of its conservation status and flagship status in a nationally important aquatic ecosystem. Genetic diversity of E. motebensis in headwater refugia of the Groot Marico River Catchment was assessed to determine if genetic diversity is important for conservation planning for this species. The results of the genetic analysis indicate that some prioritisation was possible, with two populations showing evidence of recent isolation. Conservation implications: We recommend that at least three populations be prioritised for conservation action to ensure maintenance of most of the remaining genetic diversity of the species.Item Optimising invasive fish management in the context of invasive species legislation in South Africa(National Botanical Institute/AOSIS, 2017) Woodford, D.J.; Jordaan, M.S.; Kimberg, P.K.; Zengeya, T.; Weyl, O.L.F; Ivey, P.South Africa hosts a large number of non-native freshwater fishes that were introduced for various industries. Many of these species are now listed under the National Environmental Management: Biodiversity Act (NEM:BA) Alien and Invasive Species (A&IS) lists and regulations, though the practical options available to conservation agencies to effectively manage these fishes vary greatly among species and regions. Objectives & methods: We assessed the history and status of national legislation pertaining to invasive freshwater fishes, and the practical implications of the legislation for managing different species with contrasting distributions, impacts and utilisation value. Results: The smallmouth bass, despite being a potential conflict-generating species, is fairly straightforward to manage based on current legislation. Two species of trout, which remain absent from the NEM:BA A&IS lists because of ongoing consultation with stakeholders, continue to be managed in regions like the Western Cape province using existing provincial legislation. To maximise the limited capacity for management within conservation agencies, we proposed a decision-support tool that prioritises invasive fish populations that represent high environmental risk and low potential for conflict with stakeholders. Using three case studies, we demonstrated how the tool can be used to set management goals of 'eradicate', 'manage against impacts and further spread' and 'continue to monitor population' as the most pragmatic solutions given the state of an invasion, its socio-economic impact and the capacity of the responsible agency to act. Conclusion: By choosing a pragmatic management strategy, conservation agencies can maximise the effective deployment of limited resources, while minimising avoidable conflicts with stakeholders.