Why do some places have more species than others? What causes one place to have a different set of species to another? These questions have fascinated biologists for decades and it seems that both current interactions and evolutionary history play a role. This project combines evidence on paleo-ecology, genetic and community diversity to examine the effects of Pleistocene climate change on the frogs and lizards species of the tropical rainforests of north-eastern Australia. Previous research has shown that these rainforests contracted under cold, dry periods of the late Pleistocene and that the rainforest-dependent vertebrates underwent range changes and extinctions at varying scales. It is predicted that species most restricted to montane rainforests and with the narrowest current climatic range have been the most sensitive to rainforest fluctuations. This hypothesis will be tested using a combination of molecular evidence, species' distribution data and ecological modeling and with particular attention to three guilds - stream-breeding frogs, terrestrial-breeding microhylid frogs and forest-floor skinks. By showing how individual species responded to past climate change, the project will shed light on why rainforest communities have so many species and vary so much from place to place. By increasing our understanding of how history and current ecology interact, the results will improve prediction of biodiversity in other diverse, but less well known tropical biotas. As these and other montane species are expected to be threatened by global warming, knowing which taxa were sensitive to past climate change and why will help to form plans for conservation.
