Priority areas for conservation of the vascular flora in the Sierra Madre del Sur, Mexico

The Sierra Madre del Sur (SMS) concentrates the greatest plant diversity in Mexico (9,524 species) and 10% of the endemism. And 8.3% of its surface is covered by Natural Protected Areas (NPAs). Strategies to create NPAs are based on identifying biodiversity hotspots to preserve the maximum number of species with the least resources. Areas with high biodiversity reflect geographic patterns and evolutionary processes useful for designing NPAs. The objectives were: were 1) to identify Priority Areas for Conservation (PACs) in the SMS based on taxonomic richness, endemism, and phylogenetic diversity, and 2) to seek the geographic congruence of the identified PACs with current NPAs. In a 10 x 10 km grid cell, indices of taxonomic richness, weighted endemism, and phylogenetic diversity were calculated for a set of 9,524 species. Furthermore, consensus areas of endemism were identified for a total of 1,133 endemic species. In the SMS, 33 consensus areas of endemism were rescued, and the taxonomic richness, weighted endemism, and phylogenetic diversity were heterogeneous and 94% correlated. Similarly, 27 PACs were identified. Three NPAs completely cover four PACs, 12 PACs are partially found in three NPAs, and in 38 Areas Voluntarily Designated for Conservation (AVDCs). Finally, 12 identified PACs are not found within any NPA. In the SMS it is necessary to promote the establishment of new NPAs or AVDCs that protect with high plant diversity.