Diversity and Endemism of the Marsupials of Australia’s North-Eastern Tropics

Abstract

Australia’s north-eastern tropics (the Wet Tropics and Cape York Peninsula bioregions) comprise diverse assemblages of environments, from the world’s oldest rainforests in the south across the expansive savannahs of Cape York, to the scattering of disparate Torres Strait islands in the north. Together these landscapes represent one of the most important centers of Australian marsupial diversity. Just over one third of Australia’s marsupials can be found in the region. Over a third of these again are regional endemics, some of which are the sole living members of their family or genus. More widespread Australian taxa further bolster this diversity, in many cases with endemic subspecies delineated by well-recognized external or internal biogeographic breaks. For a third group of species with distributions centered on New Guinea, this is the only part of Australia where they exist. Peak marsupial diversity and endemism is centered on the western margins of the Wet Tropics bioregion, and rainforests of the eastern side of Cape York Peninsula feature as a secondary high value area. Many taxa have small distributions and occur at low density. This, combined with high endemism, places the north-eastern tropics as an important conservation priority.