ASSESING CONSERVATION PRIORITIES IN MEGADIVERSE MEXICO:
MAMMALIAN DIVERSITY, ENDEMICITY, AND ENDANGERMENT Instituto de Ecología UNAM (Ceballos et al., 1998)
Information about mammalian species richness, composition and distribution was overlaid in a 2° x 2° grid, characterizing them by: geographic range size; body mass; and, conservation status, in order to select priority areas for conservation. Very low correspondence was found among areas of high diversity, high endemicity, or high number of endangered species. The distribution of many species with restricted geographic ranges, including endemic and non endemic species, did not coincide with areas of high species richness, endemicity or endangerment.
The study suggests that a basic conservation strategy should try to maximize the preservation of species considered endangered or having ecological characteristics correlated with extinction (208 species out of a total of 462 terrestrial species). (numbers from Ceballos, 1999)
Within endangered taxa geographically restricted species (61 spp.) should have priority over species of widespread distribution (35 spp.), and in this case (Ceballos, com. pers.) endemic taxa (49 spp.) should be of higher priority than non-endemic ones (47 spp.).
Non-endangered species with restricted distributions should also be given priority for conservation, because of the extinction threat associated with small geographic ranges.
A higher priority should be assigned to endangered species (96 spp.), followed endangered taxa with restricted distribution, i.e. less than 50,000 km² (112 spp.).
Endangered + Endemic + Restricted Distribution - Endangered + Endemic + Non-Restricted Distribution - Endangered + Non-Endemic + Restricted Distribution - Endangered + Non-Endemic + Non-Restricted Distribution - Non-Endangered + Endemic + Restricted Distribution - Non-Endangered + Non-Endemic + Restricted Distribution -
44 spp. 5 spp. 17 spp. 30 spp. 51 spp. 61 spp.
Non-Endangered + Non-Endemic + Non-Restricted Distribution -
Conservation Priority for Terrestrial Mammals
A comprehensive conservation strategy should be based on a network of reserves that include areas with high concentration of endangered species, high endemicity, high concentration of restricted species and high species (alpha) diversity. Additionally, the network should include areas of high beta diversity (complementarity of the areas as a guiding principle).
Protected are gaps identified by this study include: moist forests - Los Chimalapas, Oax.; dry forests - States of Sinaloa, Nayarit, Michoacan, Guerrero and Oaxaca; restricted neartic species - Janos - Casas Grandes, Chih. and State of Tamaulipas.