Geographic risks to functional groups of mammals and birds from habitat loss in Mexico

There is a need to quantify the impact of habitat loss due to anthropogenic factors on different aspects of biodiversity, such as functional trait diversity represented by functional groups (FGs). We developed a metric to assess the weighted risk of loss of habitat for 33 FGs of mammals and 36 FGs of birds in Mexico based on potential distribution of species and percentage of distributions lost due to habitat loss according to the Mexican land use and vegetation map. We also determined species' functional redundancy by considering the number of species in each FG. Species were separated into FGs, and the mean risk to species within each FG was calculated for each ecoregion and corrected for the proportion of species per ecoregion relative to FG species richness nationwide. Most FGs for mammals and birds had a similar geographic pattern to their risk due to habitat loss. The highest risk was in the ecoregions in the Gulf of Mexico (GM) and central Mexico (CM). Some FGs were at highest risk in the Nearctic due to low redundancy. Mammalian FGs with the highest overall risk values were invertivorous semifossorial hunters; omnivorous ground browsers; and herbivorous semifossorial or semiaquatic ground browsers. Avian FGs with the highest overall risk values were frugivorous arboreal gleaners; invertivorous semiarboreal hunters; and carnivorous arboreal hunters. Each ecoregion was at risk of losing specific FGs and, thus, specific ecosystem functions. The ecoregions with highest overall ecosystem functional risk were in the GM and CM, which suggests these ecosystems and the services these groups sustain are very fragile. Our framework can be used at broader geographic scales and contributes to conservation planning by identifying protection priorities in ecoregions and nationwide based on FGs of mammals and birds, rather than on their species richness per se.