Navigating climate shifts for an endemic lizard from a semi-arid environment

Abstract

Ecological niche models (ENMs) are crucial for understanding species distribution and identifying areas maintaining climatic stability over time (i.e., thermal refugia). Human-induced global climate change underscores the importance of such refugia, which directly impacts species distribution, especially for ectothermic species relying on the environmental temperature to keep their metabolism active. Tropidurus cocorobensis is an endemic, heliothermic, and generalist lizard from Caatinga, a heterogeneous semi-arid domain characterized by low and irregular precipitation patterns and high temperature and solar radiation. Despite its endemism, there is no information concerning temporarily stable (refugial) and unstable (recently colonized) regions for its occurrence, nor future predictions of local thermal suitability in different climate change scenarios. Using ENMs, we assessed Caatinga's past, present, and future thermal suitability for T. cocorobensis, identifying potential changes in its thermal refugia over time. Our results indicated Depressão Sertaneja Meridional (DSM) and Campo Maior Complex (CMC) as climatically stable Caatinga Ecoregions, serving as climate refugia for T. cocorobensis. While DSM covers much of the species' current distribution, CMC lacks occurrence data. Contrastingly, the Chapada Diamantina Complex, a known habitat for the species, was not recovered as a climate refugia nor was suitable for future scenarios, therefore representing a climatically unstable area. Future projections indicate a potential expansion of T. cocorobensis' climate refugia, possibly linked to the species' generalist habits. However, the optimistic outlook for this species may not mirror the overall well-being of the Caatinga domain since generalist species often fill niches left by specialists unable to adapt to stressful environments. Future studies should prioritize comparing the climatic refugia of specialist and generalist species envisioning a comprehensive understanding of the ecological dynamics within the Caatinga ecosystem. This approach will be crucial for formulating effective conservation strategies amid the ongoing challenges of climate change in this domain.