Deforestation and extant distributions of Mexican endemic mammals.

摘要

Deforestation threatens biodiversity conservation worldwide, but little quantitative information is available on how it affects individual species' distributions. We modeled potential distributions of 85 continental endemic Mexican mammal species using ecological niche modeling, and produced testable predictions of species' extant distributions by limiting ecological niches to remnant untransformed habitat based on the Inventario Nacional Forestal 2000. We included point occurrence data for all endemics only from collecting localities prior to 1970, before wide areas of habitat transformation occurred nationwide. Most endemics (61 of 85, 72%) showed a high proportion of transformed habitat (34.5%) at the national level. More than one-fourth of the endemics (23 out of 85, 27%) lost more than 50% of untransformed habitat within their potential distributions; two showed drastic areal loss of more than 90%; another two showed a loss of more than 80%. Only 34 of the endemics are listed as endangered or threatened in the Mexican Norma Oficial Mexicana (NOM). No significant association existed between proportional loss and conservation status as assigned in the NOM, nor are correlations significant between original distributional area and area of remnant untransformed habitat. Both findings suggest that geographic location determines extinction risks rather than area per se. Endemics in the state of Veracruz and in the Transvolcanic Belt suffered the most drastic niche reductions and thus appear to be at high extinction risk from further deforestation..