Climate change is driving many of Australia's native reptiles toward extinction, and the answers to their future survival may lie in the fossil record.
New research published today in Current Biology originates from an international collaboration with Museums Victoria Research Institute and the Museum für Naturkunde Berlin. The study reveals that the endangered Australian Mountain Dragon (Rankinia diemensis) has been driven into increasingly smaller and more isolated populations over thousands of years as a result of changing climate conditions.
The study combines fossil evidence from natural history museums with genetic data from preserved specimens to uncover how the species has responded to major environmental changes in the past and what this means for its future.
Dr Jane Melville, senior curator of terrestrial vertebrates at Museums Victoria Research Institute, said the research shows the species has been pushed up the mountains by climate change.
'About 20,000 years ago during the last glacial period, Mountain Dragons occupied a much wider range across southeastern Australia, including regions such as Kangaroo Island and Naracoorte in South Australia,' said Dr Melville.
'Today, those populations have vanished. The remaining populations in Victoria, New South Wales and Tasmania have a reduced distribution and are more genetically isolated than in the past, and if global temperatures continue to rise, these lizards will eventually have nowhere left to go.'
By using advanced micro-CT imaging to identify tiny fossil fragments and combining this information with genomic data from modern specimens, the team was able to track long-term shifts in the species' range and genetic diversity.
The findings suggest that low-altitude populations have already suffered genetic decline, while cooler, high-altitude habitats are becoming less suitable due to global warming. This makes Rankinia diemensis a clear warning sign for other reptiles that share the same ecosystem.
Reptiles are particularly vulnerable to climate change because they cannot actively regulate their body temperature. Similar distribution and genetic patterns have been observed in other species, such as the blotched Blue-Tongue Lizard, Tiliqua nigrolutea, suggesting that multiple reptile species across southeastern Australia may face the same fate.
Natural history museum collections proved essential to this discovery. Fossils, bones, and preserved specimens housed at Museums Victoria and other institutions offer an unparalleled record of Australia's biodiversity over time, making it possible to link the past, present, and future of threatened species.
Lead author Dr Till Ramm, former PhD student at Museums Victoria Research Institute, said the study underscores the value of the new research field 'conservation paleobiology' and the urgent need to update conservation strategies to account for climate-driven habitat loss.
'By learning from the past, we can make better predictions and decisions for the future,' said Dr Ramm. 'Our findings show just how fast climate change can disrupt biodiversity and why protecting habitats now is more critical than ever.'
'By studying specimens and fossils preserved in museum collections, we can see how species have responded to past environmental challenges and use those insights to inform future conservation,' said Dr Nurin Veis, Director of Museums Victoria Research Institute. 'The past holds critical lessons for protecting the biodiversity we have today.'
Visitors to Melbourne Museum can see 3D models of the Mountain Dragon in the Research Institute Gallery and explore Our Wondrous Planet, Museums Victoria's newest science and biodiversity gallery, which inspires visitors to care for our planet for generations to come.
