Identifying climate refuges for freshwater biodiversity across Australia
Authors: Cassandra James, Jeremy VanDerWal, Samantha Capon, Lauren Hodgson, Nathan Waltham, Doug Ward, Barbara Anderson and Richard Pearson
This study presents the results of the first attempt to provide a continental-scale assessment of freshwater climate refuges across Australia. Substantial shifts in the distribution of environments suitable for fish, crayfish, turtles and stream frogs under climate change are predicted. Highlands will be important refuges for most taxa. This project assessed future climatic and hydrological stability and then combined this with correlative species-distribution modelling to build statistical relationships between biophysical environments and occurrence of species of interest. Three case studies illustrate how the continental-scale stability surfaces (climate, hydrological and modelled species richness) can be used to identify refuges and explore adaptation options. Higher-elevation and headwater systems including areas of the Australia Alps (New South Wales), the western slopes of the Great Dividing Range (Queensland), and the Pilbara and Kimberley regions of Western Australia are predicted to gain environments suitable for fish. Areas of high stability in environments suitable for turtles include most of the south-east coast of New South Wales, Victoria, Arnhem Land in the Northern Territory, and the Kimberley Plateau in north-west Western Australia. For native crayfish, areas predicted to be the most environmentally unstable, including the south-east region of the continent and, in particular, the South Eastern Highlands, have been identified as areas of high conservation priority for endangered and rare species. Highest stability for stream-dwelling frogs was found in the high-elevation regions, including the Wet Tropics, much of the Great Dividing Range north of Newcastle and the Australian Alps. Climatically and hydrologically stable regions, which are likely to maintain current levels of modelled species richness, will be areas of least concern. Within unstable regions, however, adaptation measures to provide small-scale or micro refuges will be a high priority, and this report identifies five guidelines to aid in the identification and evaluation of appropriate adaptation.