Format: ORAL

Dan-Xiao Peng1, Li-Min Lu1, Andrew H. Thornhill2,3, Brent D. Mishler4, Bing Liu1, An-MingLu1, Joseph T. Miller5, Zhi-Duan Chen1

1 Institute of Botany, Chinese Academy of Sciences, Beijing, China 2 State Herbarium of South Australia, Adelaide, South Australia, Australia 3 The University of Adelaide, Adelaide, South Australia, Australia 4 University of California, Berkeley, California, USA 5 Global Biodiversity Information Facility, Copenhagen, Denmark

One of the best cases for investigating the history of biotic exchange is the convergence of the Sunda (the southeastern extension of the continental plate of Asia) and Sahul (the tectonic plate of the Australian continent) shelves, where the remarkably diverse Wallacean region is located. Located on either side of the Sunda-Sahulzone, the florasof East Asia and Australasia harbor flourishing, distinctive, and comparable plant diversity and shared a considerable number of taxa, which provide an ideal example to test the effects of geological history and ecological conditions on exchange dynamics, to what extent plants could spread over Wallacea, and the contributions of exchangetofloral formation. We investigated the floristic affinites between theChinese and Australian floras, which represent much of the diversity of the florasof East Asia and Australasia, respectively.Based on a comprehensivegenus level phylogeny of the global seedplantsand the literature survey of biogeographic studies for the shared genera, we explored the evolutionary relationship between the two floras throughout geological times.Our results suggestedthatmost exchange came up after the Miocene when the emerging islands of Southeast Asia reduced the geographical isolationbetween the two floras. We also integrated the distribution data to show the spatial pattern of the shared components and correlate the environmental factors which couldhave impact on migration success. Along with the identification of preference for long life-span and tropical traits,the significant role of habitat filtering during the exchange process between the two floras was indicated.