Biodiversity and Conservation of
Mesoamerican Dry-Forest Herpetofauna
Mahmood Sasa and Federico Bolaños
THE HERPETOFAUNA of Mesoamerica (defined as the region running south from about central Mexico through Panama) is undoubtedly one of the richest and most complex vertebrate faunas of the New World. It involves more than 210 genera, comprising approximately 693 species of reptiles and 598 species of amphibians. Such high diversity results from the divergence of species that evolved in situ in Mesoamerica, as well as from the interchange of species between North and South America (Duellman 1966; Savage 1966).
Based on the distribution of reptiles and amphibians in Mesoamerica, Duellman (1966) recognized five major ecological assemblages: humid tropical, humid mountain, high mountain, arid mountain, and arid tropical. This last ecological unit, the tropical arid assemblage, includes species distributed in subhumid lowlands covered by scrub forest, savannas, and deciduous vegetation and is the primary focus of this chapter. We based our account on preliminary studies of the amphibians and reptiles of northwestern Costa Rica (Sasa and Solórzano 1995) and on extensive material recently collected from the dry forests of Mexico (Oaxaca, Chiapas), Guatemala, Honduras, and Nicaragua. We begin by summarizing biodiversity and biogeographical aspects of reptiles and amphibians associated with dry environments in Mesoamerica. We then describe general patterns of resource use of dryforest reptiles and amphibians and their adaptation to arid conditions, emphasizing the roles that some species have in the community and the threat that human activities might pose to them. Finally, we discuss the importance of conservation of this herpetofaunal assemblage in terms of area selection and conservation.
Approximately 26 percent of the surface of Mesoamerica is seasonally dry, covered by different