Phylogeographic evidence for evolutionary refugia in the Gulf sandstone ranges of northern Australia

Locating and protecting climate change refugia is important to conserving biodiversity with accelerating climate change. Comparative phylogeographic analysis provides an effective tool for locating such refugia, as long-term retention of one or more populations within a refugial landscape will generate unique genetic lineages. The ranges of the western Gulf region of northern Australia are thought to represent a significant arid-zone refugium, in which case low-dispersal organisms should have strong phylogeographic structure across the region. To test for this, we conducted extensive sampling of three species of Gehyra geckos and analysed diversity for mitochondrial DNA and eight nuclear loci. These analyses revealed congruent and high phylogeographic diversity, especially, but not exclusively, in rock-restricted species. This finding, and other recent phylogeographic evidence, demonstrates that these topographically variable landforms have enabled persistence of ecologically diverse vertebrate species through the climate changes of the late Pleistocene. Identification of this relatively under-protected region as a significant climate change refugium points to the need to expand protected areas in this region and to invest in ecological management across existing National Parks and Indigenous Protected Areas.