Assessing the vulnerability of a sky island lizard to climate and land-use change

Abstract

Under climate change, species are expected to migrate along with their climate envelope. However, many species’ distribution models do not include the human footprint, thus overestimating distributional zones with high probabilities of occurrence. Species inhabiting sky islands (high-elevation landscapes that differ from landscapes in intermediate valleys) are particularly sensitive to climate and land-use change, given their limited ability to migrate. We aimed to assess the suitability of the climatic conditions for a sky island lizard under different climate scenarios and how that could affect its distribution based on (i) its climate envelope and (ii) the human footprint (croplands and buildings). Using climatic variables to develop a species distribution model and the indicator Human Footprint, we predicted the presence probabilities of Liolaemus nigroviridis Müller & Hellmich, 1932 populations under climate change scenarios (current, year 2040, and year 2080). We analyzed the relevant variables for L. nigroviridis’s climate envelope, which we projected to decrease and shift southward by 2080. The species could track its climate envelope in the Andes, but not in the Coastal mountains, given the strong human footprint. We propose assisted migration as a possible adaptive strategy, and show that conservation of sky islands species can be enhanced by integrating climatic and anthropogenic factors.