Climate change predicts Quaternary extinctions and extant genetic diversity in a threatened Australian lizard

Anthropogenic climate change poses a major threat to biodiversity worldwide; however, estimating its future impacts remains challenging. To predict and mitigate future biodiversity loss, transdisciplinary approaches are essential yet seldom applied. Here, we integrate population genomics, quantitative fossil identifications, species distribution modeling, and high-resolution digital morphology to assess how Quaternary climate change and projected future climate relate to the extinction vulnerability of the threatened Australian Mountain Dragon (Rankinia diemensis). We show that past temperature and precipitation changes have led to significant range contractions and shifts to higher elevations, resulting in geographic and genetic disconnection between modern populations. Several low-altitude populations are now extinct or show low genetic diversity and high genetic differentiation, consistent with genetic drift in isolation. Models of future habitat suitability predict further climate-related contractions in remnant populations, highlighting the urgent need for updated conservation strategies. Our study demonstrates the power of integrating next-generation data for reconstructing past and modeling future effects of global warming to design tailored conservation strategies for species most at risk of extinction due to anthropogenic climate change.