Combined effects of life-history traits and human impact on extinction risk of freshwater megafauna |
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Authors: | Fengzhi He Simone D Langhans Christiane Zarfl Roland Wanke Klement Tockner Sonja C Jähnig |
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Institution: | 1. Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, Berlin, 12587 Germany;2. Center for Applied Geosciences, Eberhard Karls Universität Tübingen, Hölderlinstr. 12, Tübingen, 72074 Germany;3. Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, Berlin, 12587 Germany
Institute of Biology, Freie Universität Berlin, Königin-Luise-Str. 1-3, Berlin, 14195 Germany |
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Abstract: | Megafauna species are intrinsically vulnerable to human impact. Freshwater megafauna (i.e., freshwater animals ≥30 kg, including fishes, mammals, reptiles, and amphibians) are subject to intensive and increasing threats. Thirty-four species are listed as critically endangered on the International Union for Conservation of Nature (IUCN). Red List of Threatened Species, the assessments for which are an important basis for conservation actions but remain incomplete for 49 (24%) freshwater megafauna species. Consequently, the window of opportunity for protecting these species could be missed. Identifying the factors that predispose freshwater megafauna to extinction can help predict their extinction risk and facilitate more effective and proactive conservation actions. Thus, we collated 8 life-history traits for 206 freshwater megafauna species. We used generalized linear mixed models to examine the relationships between extinction risk based on the IUCN Red List categories and the combined effect of multiple traits, as well as the effect of human impact on these relationships for 157 classified species. The most parsimonious model included human impact and traits related to species’ recovery potential including life span, age at maturity, and fecundity. Applying the most parsimonious model to 49 unclassified species predicted that 17 of them are threatened. Accounting for model predictions together with IUCN Red List assessments, 50% of all freshwater megafauna species are considered threatened. The Amazon and Yangtze basins emerged as global diversity hotspots of threatened freshwater megafauna, in addition to existing hotspots, including the Ganges-Brahmaputra and Mekong basins and the Caspian Sea region. Assessment and monitoring of those species predicted to be threatened are needed, especially in the Amazon and Yangtze basins. Investigation of life-history traits and trends in population and distribution, regulation of overexploitation, maintaining river connectivity, implementing protected areas focusing on freshwater ecosystems, and integrated basin management are required to protect threatened freshwater megafauna in diversity hotspots. |
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Keywords: | assessment biodiversity body size IUCN Red List prediction recovery potential threats vertebrate amenazas biodiversidad evaluación Lista Roja UICN potencial de recuperación predicción tamaño corporal vertebrado 生物多样性 评估 IUCN红色名录 脊椎动物 物种大小 恢复潜能 预测 威胁 |
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