Influence of climate stability on endemism of the vascular plants of the Chihuahuan Desert

Abstract The Chihuahuan Desert is one of the warm deserts of North America located in the southwestern of the United States and Mexico, and has a remarkable vascular flora of which approximately one third of its species are endemic. This study focuses on establishing whether climate stability was crucial for the continuity of centers of endemism and phylogenetic endemism for vascular plants distributed in this desert. Using the checklist of the vascular plant species, areas of endemism, phylogenetic diversity and phylogenetic endemism were identified and climate change velocity was estimated. A database was compiled to identify current climate preferences and multivariate analyses were used to identify the most significant variables. The relationship between climate velocity, endemism and phylogenetic diversity was determined by regression analyses. Results indicate that the most significant areas of endemism and phylogenetic endemism were in the northwest and the southernmost zones of the Chihuahuan Desert associated with mountains. These areas should be considered important in conservation planning. Velocity of climate change was low in these areas, however low velocity of change was more evident in areas of phylogenetic endemism than in areas of phylogenetic diversity. Probably these areas have acted as refugia in evolutionary time for the vascular plants of the Chihuahuan Desert.