Protected areas and climate change:: A case study of the cacti in the Tehuacan-Cuicatlan biosphere reserve, Mexico

We examined the effects of climate change on the future distribution patterns of 20 species of Cactaceae in a protected area of Mexico. Our study area was the biosphere reserve of Tehuacan-Cuicatlan in central Mexico. Cactaceae species in the reserve were selected because they are often the dominant elements of the communities and play an important social role as a source of food, construction, and fuel. We used a floristic database and a bioclimatic modeling approach to examine 19 climatic parameters and to obtain the current potential distribution pattern of each species. Three different future climate scenarios were selected, on the basis of the predictions of several authors about future climate change. We considered the following three future scenarios: (1) +1degreesC and -10% rainfall; (2) +2degreesC and -10% rainfall; (3) +2degreesC and -15% rainfall. Each scenario implies different potential distribution patterns for the species involved; these patterns were analyzed in relationship to the reserve boundaries. In particular, the third scenario indicated three distinct possibilities: (1) a drastic distribution contraction in which most of the remaining populations will inhabit restricted areas out of reserve boundaries or will became extinct; (2) restriction of remaining populations mainly within reserve boundaries; and (3) contraction of species distribution pattern but populations remaining within and outside the reserve boundaries. Our results highlight the importance of considering the effects of possible future climate changes on the selection of conservation areas. Accordingly, we believe that our bioclimatic modeling approach represents a useful tool with which to make decisions about the definition of protected areas, once the current potential distribution pattern of some selected species is known.