Areas of endemism and environmental heterogeneity: a case study in Mexican legumes

Abstract

Fabaceae is a monophyletic family comprising more than 22 000 species worldwide. In Mexico, it is the second-most species rich family, inhabiting multiple ecosystems with a high diversity of life forms. Our aims were to (1) identify areas of endemism (AEs) by using endemicity analysis at different cell sizes (1°, 0.5° and 0.25°) for 488 Mexican legumes, (2) describe the climatic and topographic heterogeneity of AE, (3) determine whether there is a positive relationship between AEs and climatic and topographic heterogeneity and (4) examine the conservation status of legumes that defined the AEs. We found six general AEs, supported by 63 species, with endemicity index values ranging from 2.05 to 6.86. These general areas had zones where biogeographical provinces intersected and exhibited a higher environmental heterogeneity. Areas detected at 1° showed a positive relationship between endemicity index and environmental heterogeneity. Legume species currently lack legal protection in Mexico, 69% of the endemic species do not have an evaluation category according to the International Union for Conservation of Nature, and eight species are in some risk category. Future conservation efforts should focus on protecting endemism areas from accomplishing representative natural protected areas.