Climate-driven shifts in the distribution of sympatric Diplolaemus lizards in Southern Patagonia

Abstract

Global warming is expected to impose a significant challenge for terrestrial ectotherms, including lizards of the genus Diplolaemus, which inhabit arid environments in southern Patagonia. We assessed how climate change may alter the potential distribution of Diplolaemus bibronii and Diplolaemus darwinii using Ecological Niche Models (ENMs) implemented with six algorithms (Random Forest (RF), Generalised Additive Model (GAM), Surface Range Envelope (SRE), Artificial Neural Network (ANN), General Linear Models (GLM), and Maximum Entropy (MaxEnt) within the Biomod2 platform. Models were calibrated with current bioclimatic data and projected under two future scenarios (SSP2–4.5 and SSP5–8.5) for mid- (2041–2060) and late-century (2081–2100) conditions using five general circulation models (GCMs). Model performance was good across algorithms, with RF and ANN showing the highest predictive accuracy. Precipitation in the driest month (Bio14) emerged as the main predictor for both species, with higher suitability associated with low precipitation values, reflecting their adaptation to xeric environments. Future projections indicated species-specific responses to climate change. Although both species showed potential expansions of climatically suitable areas, D. bibronii exhibited a broader increase in climatically suitable habitat, whereas D. darwinii displayed more spatially restricted changes depending on the scenario considered. This response highlights the key role of water availability in shaping species distributions. Further studies focusing on physiological traits are needed to validate these projections. Our findings improve understanding of how climate change may alter the current and future potential distribution of Diplolaemus species within the broader context of global change.