Many reptiles around the world are seriously threatened by climate change, but unfortunately it is often difficult to predict their chances of survival. However, a new study published in “Current Biology” demonstrates how Quaternary climate change has affected Australian reptiles. This isolated continent with its unique flora and fauna is threatened by climate change. The scientists were able to plot the effect of climate change on Rankinia diemensis, a small agamid lizard endemic to New South Wales and Victoria.

This new research combines analysis of fossil material from museum collections with genetic data from museum specimens. The team were able to plot population changes over the last twenty thousand years. The collections of natural history museums are a unique resource for studying the effects of climate change on biodiversity and linking the past, present and future of endangered species.

Lead author of the study Dr Till Ramm, a scientist and former doctoral student at the Museum für Naturkunde Berlin and the Museums Victoria Research Institute in Melbourne, says the research shows that R. diemensis was probably displaced to higher altitudes by the changing climate.

Fossils reveal how climate change threatens Australian reptiles. An Australian Mountain dragon lizard (Rankinia diemensis) photographed in the Grampians National Park, Victoria. Picture credit: David Paul, Museums Victoria.

Picture credit: David Paul, Museums Victoria

The Threat to Australian Reptiles

During the last ice age, approximately twenty thousand years ago, Rankinia diemensis had a much wider distribution in south-eastern Australia. Populations on Kangaroo Island and in the limestone region surrounding the town of Naracoorte in South Australia went extinct. The remaining populations are isolated. If temperatures continue to rise, these lizards will also become extinct.

Using X-ray tomographic imaging techniques to identify tiny fossil fragments and combining this information with genomic data from recent museum specimens, the team was able to track long-term changes in the range of this species and its genetic diversity. The team conclude that populations at lower altitudes have already suffered a decline in genetic diversity, while cooler habitats at higher altitudes are also under threat due to global warming. This makes the Australian Mountain Dragon an indicator species for other reptiles inhabiting the same ecosystem.

Ectothermic animals such as reptiles cannot regulate their body temperature. As a result, they are particularly vulnerable to changes in the climate. Many Asian and Australian taxa are under threat including the largest lizard in the world – the Komodo Dragon.

Ectothermic animals such as the Komodo Dragon are threatened with climate change. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

Loss of Reptile Diversity in Victoria

It is also alarming that a particularly large number of reptile species are classified as endangered in the region around the Southern Alps in Victoria. Some other species exhibit similar patterns of decline. Black-and-yellow blue-tongued skinks (Tiliqua nigrolutea), Alpine oak skinks (Cyclodomorphus praealtus) and White’s skinks (Liopholis whitii) had bigger ranges in the past. All these species are threatened by climate change.

Co-author of the paper, Professor Johannes Müller (Museum für Naturkunde Berlin) commented:

“By learning from the past, we can make more accurate predictions and decisions for the future. Our findings show how quickly climate change can affect biodiversity and why habitat protection is more important than ever today”.

This research demonstrates the value of the importance of fossil data for the development of conservation strategies.

Everything Dinosaur acknowledges the assistance of a media release from the Museum für Naturkunde Berlin in the compilation of this article.

The scientific paper: “Climate change predicts Quaternary extinctions and extant genetic diversity in a threatened Australian lizard” by Till Ramm, Emily Roycroft, Jaimi A. Gray, Christy A. Hipsley, Scott Hocknull, Johannes Müller and Jane Melville published in Current Biology.

The Everything Dinosaur website: Scientifically Accurate Prehistoric Animal Models.