CONSERVATION OF MAMMALS IN MEXICO Instituto de Ecología UNAM (Ceballos et al., 1999)
This article describes the results of a study, that identifies conservation areas for Mexico’s 462 terrestrial mammals, using a complementarily approach that aims at achieving representation of the greater number of mammal species, in the least number of areas. The study identifies current species within 30 existing protected areas (27 Federal, 2 State and 1 no hunting area), ranks them according to the number of species they include and proposes an optimal group of areas that will include those species not represented.
The number of species contained in these 30 protected areas represents 75% of Mexico’s species, which seems to represent a considerable coverage. Nevertheless, these only include 50% of the endemics, 52% of those with restricted distribution and 62% of endangered species, which means that those groups that are most prone to threats are not covered adequately, specially when most species are only represented by one or two populations. Out of these 30 areas, at least one population is protected within 24 of these. The selection criteria algorithm chooses first the most diverse area, second the one with the most species not represented in the first one and so on.
The 24 sites in the order by which they were chosen are: La Lacandona, Janos-Nuevo Casas Grandes, Manantlan, Islas del Golfo, Ajusco, El Triunfo, San Pedro Martir, Maderas el Carmen, El Cielo, Calakmul, Chamela-Cuixmala, Pinacate, Omiltemi, La Sepultura, Vizcaino, La Michilia, Nevado de Toluca, Izta-Popo, La Laguna, Mapimí, Los Tuxtlas, Sian Ka’an, La Malinche, La Encrucijada. Sites not chosen by the algorithm were: El Ocote, Nevado de Colima, Lagunas de Zempoala, Zoquiapan y Anexas, Desierto de los Leones and El Chico (Ceballos, com. pers).
Selection of additional protection sites was then based not only on complementarity, but also to cover those groups that are most prone to threats. This was achieved by utilizing species distribution over a 0.5° x 0.5° grid, emphasizing endemisms and restricted distribution. Results showed that 13 quadrants could cover 80% of species not previously covered.
The 13 quadrants identified are located in: Northern Baja California, Northern border between Chihuahua and Sonora, Central Coahuila, Northeastern Tamaulipas, Southwestern Chihuahua- Northeastern Sinaloa, Southern Durango-Northeastern Nayarit, Southern Nayarit, Notheastern Colima, Northwestern Puebla-Central Veracruz, Central Oaxaca, Southeastern Chiapas, Northern Quintana Roo and Northcentral Quintana Roo. In some of these areas, protected areas not considered by the study already exist and only need to be managed, to formalize their function.
OTHER PERTINENT INFORMATION ON MAMMALS
Distribution information on select marine mammals can be found on the Atlas Nacional de México, compiled by the Instituto de Geografia UNAM (Raz-Guzmán and Sánchez, 1992 and Aguayo-Lobo et al., 1992).
The Commission for Environmental Cooperation’s list of “Species of Common Conservation Concern in North America” (CEC, in press), includes the following mammal species: Black-tailed Prairie Dog (Cynomys ludovicianus), Sonoran Pronghorn (Antilocapra Americana sonoriensis), Lesser long-nosed bat (Leptonycteris curasoae yerbabuenae), [Greater] Mexican long-nosed bat
(Leptonycteris nivalis), Black Bear (Ursus americanus) and Gray Wolf (Canis lupus).
Geographic variation in species richness of North American terrestrial mammals was compiled by Simpson (1964), dividing the continent into grid squares, tallying the numbers of species whose geographic range overlapped each square and then interpolating and smoothing the data to produce isopleths depicting diversity.