Transport pathways shape the biogeography of alien freshwater fishes in Australia |
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| Authors: | Pablo García‐Díaz Adam Kerezsy Peter J Unmack Mark Lintermans Stephen J Beatty Gavin L Butler Rob Freeman Michael P Hammer Scott Hardie Mark J Kennard David L Morgan Bradley J Pusey Tarmo A Raadik Jason D Thiem Nick S Whiterod Phillip Cassey Richard P Duncan |
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| Institution: | 1. School of Biological Sciences and Centre for Applied Conservation Science, The University of Adelaide, North Terrace, SA, Australia;2. Manaaki Whenua – Landcare Research, Lincoln, New Zealand;3. Dr Fish Contracting, Lake Cargelligo, NSW, Australia;4. Institute for Applied Ecology, University of Canberra, Canberra, ACT, Australia;5. Freshwater Fish Group & Fish Health Unit, Centre for Fish & Fisheries Research, School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA, Australia;6. Department of Primary Industries, Grafton Fisheries Centre, Grafton, NSW, Australia;7. Inland Fisheries Service Tasmania, New Norfolk, Tas., Australia;8. Museum and Art Gallery of the Northern Territory, Darwin, NT, Australia;9. School of Biological Sciences, University of Tasmania, Hobart, Tas., Australia;10. Australian Rivers Institute, Griffith University, Nathan, Qld, Australia;11. School of Biological Sciences, University of Western Australia, Perth, WA, Australia;12. Applied Aquatic Ecology Section, Department of Environment, Land, Water & Planning, Arthur Rylah Institute for Environmental Research, Heidelberg, Vic., Australia;13. Department of Primary Industries, Narrandera Fisheries Centre, Narrandera, NSW, Australia;14. Aquasave–Nature Glenelg Trust, Goolwa Beach, SA, Australia |
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| Abstract: | Aim Changing preferences regarding which species humans have transported to new regions can have major consequences for the potential distribution of alien taxa, but the mechanisms shaping these patterns are poorly understood. We assessed the extent to which changes in human preferences for transporting and introducing alien freshwater fishes have altered their biogeography. Methods We compiled an up‐to‐date database of alien freshwater fishes established in drainages in Australia before and after the number of established alien fish species doubled (pre‐1970 and post‐1970, respectively). Using metacommunity models, we analysed the influence of species traits and drainage features on the distribution of alien fishes that established pre‐ and post‐1970. Results Alien fishes in Australia were introduced via four main transport pathways: acclimatization, aquaculture, biocontrol and ornamental trade. The relative importance of each pathway changed substantially between the two periods, accompanied by changes in the distribution of alien fishes and the variables predicting their distribution. Pre‐1970, most species (64%) were introduced by acclimatization societies for purposes such as angling and biocontrol, and these fish have established in inland drainages more heavily impacted by human activities. In contrast, most of the post‐1970 introductions (69%) were ornamental fishes, with most species established in small, north‐eastern, tropical and subtropical coastal drainages. Main conclusions Substantial changes in introduction preferences and transport pathways over time have altered both the patterns and underlying processes shaping the biogeography of alien fishes in Australia. Our findings highlight the need for caution when using historical data to infer potential future distributions of alien species. The continuing spread of alien species means traditional biogeographical units may no longer be identifiable in the foreseeable future. |
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| Keywords: | acclimatization Australia community alteration human‐induced environmental change ornamental trade species turnover |
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