Effects of climate change on a nocturnal gecko: an integrative analysis

Introduction Climate change poses a major threat to biodiversity, especially for ectotherms whose physiology is tightly coupled to environmental conditions. While most studies on climate change emphasize diurnal species, nocturnal reptiles remain largely overlooked. We evaluated the vulnerability of Gymnodactylus amarali —a nocturnal saxicolous lizard from the Brazilian Cerrado—to future climate change scenarios. Methods We combined correlative, mechanistic, and hybrid species distribution models (SDMs) with biophysical simulations to assess the species’ vulnerability. We evaluated range dynamics by measuring rear (lost), stable (retained), and lead (gained) areas under different climate change scenarios. Results By the end of the century, G. amarali is projected to lose more than 96% of its climatically suitable range across all climate change scenarios. Biophysical models revealed additional constraints: the number of annual hours within the species’ thermal range of activity will decline by more than half relative to current levels, despite reduced time needed for surface heating. Cold stress is unlikely to limit the species, but acute heat exposure is predicted to increase under warming scenarios. Rock–air decoupling remained stable, indicating that rocky habitats will continue to buffer microclimates, although not enough to counterbalance the sharp loss in activity time and distributional range. Discussion Our integrated approach shows that G. amarali faces severe contraction risks in both geographic range and functional performance under future climates. Conservation efforts should prioritize protecting rocky habitats and Cerrado remnants that maintain thermal heterogeneity for G. amarali and other saxicolous species, as these features can buffer the impacts of climate change.