Amphibians at risk: Effects of climate change in the southwestern North American drylands

Abstract

Climate change can affect species' geographical range in several ways, leading to species' geographical range expansion and contraction. Amphibians are the most threatened vertebrate class, and deterioration is due, in part, to the loss of suitable habitat. This taxonomic group is especially sensitive because of their biphasic life cycles (aquatic and terrestrial) and microhabitat requirements. Herein, we propose a combined approach, which uses biological and life history information to understand species' sensitivity to climate change. The goals of our study were to (1) identify the contribution of environmental variables to the broad-scale distribution of amphibians in drylands of the southwestern United States and Mexico, (2) describe how the habitat suitability of amphibians can potentially respond to a range of climate change scenarios across drylands, and (3) identify amphibian traits related to increased vulnerability and adaptation to the specific pressures and mechanisms of climate change projected for the dryland areas. Results show that climate strongly influences the geographic distribution of amphibian diversity in drylands and that most amphibians are expected to lose habitat in the upcoming decades. This study also shows that areas with the greatest loss of high habitat suitability are related to temperature increases and precipitation reductions. Our results build a framework that will significantly improve the current state of knowledge on the drylands' biogeography while providing comprehensive information and analyses for decision-makers to conserve and protect endangered and threatened amphibian species and their habitats.