Ragged mountain ranges, droughts and flooding rains: The evolutionary history and conservation of Australian freshwater fishes

Australia hosts a unique assemblage of flora and fauna derived from a combination of Gondwanan relict and more recently evolved endemic taxa and is recognised as one of the world’s megadiverse countries. Despite the continent’s high species biodiversity, the Australian freshwater fish fauna is relatively depauperate. The conservation of freshwater fishes in Australia is of increasing importance as many species are listed as threatened by the IUCN. The major threatening processes for Australian freshwater fishes are habitat degradation, river regulation, anthropogenic barriers to dispersal, introduced species, disease and climate change. The use of molecular genetic tools to infer evolutionary history and to inform conservation is well recognised and is one way of predicting how fish may respond to these threatening processes. Nonetheless, there are few Australian cases that allow a bigger picture assessment of evolutionary processes across a broad range of environments, yet within a single taxonomic group. The temperate freshwater perches of the genus Macquaria provide an exception. This chapter uses this fish group as a case study in phylogeography and population genetics to explore and identify evolutionary processes relevant for aquatic conservation across a large section of eastern and central Australia. Australian freshwater fishes: biodiversity and conservation Australia hosts a unique assemblage of flora and fauna derived from a combination of Gondwanan relict and more recently evolved endemic taxa (Allen et al., 2002; Sanmartin & Ronquist,2004)and is recognised as one of the world's megadiverse countries (Mittermeier et al., 1997).