Biodiverse river basins: assessing coverage of protected areas for terrestrial vertebrates

Conservation planning requires information at adequate scales for decision-making and priority definition. Considering the importance of the Usumacinta river basin, we assessed the distribution of vertebrate richness (amphibians, birds and mammals), threatened species, and their representativeness in protected areas (PAs). We overlapped distribution polygons derived from the IUCN Red List of Threatened Species over a 72 km2 grid of the watershed and overlapped the PAs. For the three groups we defined areas of high species richness and threatened species (hotspots), and defined three conservation targets (25, 50 and 75% of species richness of each group) and their representativeness in PAs. We found hotspots for birds and mammals, and high heterogeneity within the three groups. In total 81, 98 and 94% of amphibians, birds and mammals are present in at least in one PA, as well as 69, 78 and 53% of threatened amphibians, mammals and birds, respectively. Most of the high richness cells are not protected—only 26% of the 50% species richness cells and 10% of the 75% target cells. We highlight the need for complementing the PA system in the three countries comprising the study area (Mexico, Belize and Guatemala) in order to protect vertebrate diversity and reduce the growing threats to the basin.