People and mammals in Mexico: conservation conflicts at a national scale

Contrary to much supposition, recent studies, typically at global and continent-wide scales, have documented a positive relationship between spatial variations in human density and species richness of selected groups of vertebrates. How widely this pattern generalises remains unknown, and particularly how well it extends to analyses at the extent of a country and at reasonably fine spatial resolution, and to regions with well-developed mechanised agricultural infrastructure. Here, we demonstrate that there is a positive relationship between human density and mammal species richness across Mexico, and that this appears to follow from similar patterns between spatial environmental variation (particularly net primary productivity, precipitation and temperature) and both human density and mammal species richness. These results have some potentially important implications for conservation planning in the region, particularly given that optimal complementary sets of areas to represent all mammal species in Mexico tend to lie in areas of disproportionately high human density.