Terrapene coahuila Schmidt and Owens 1944 – Coahuilan Box Turtle

Abstract

The Coahuilan box turtle, Terrapene coahuila (Family Emydidae), endemic to the Cuatro Ciénegas Basin of central Coahuila, Mexico is internationally recognized as endangered due a naturally restricted geographic range and substantial loss of habitat in the past half-century. The only extant aquatic species of the genus, T. coahuila occupies shallow wetland habitats that are sporadically distributed across the Cuatro Ciénegas valley floor. Water diversion from man-made canals throughout the basin has resulted in widespread wetland habitat desiccation, jeopardizing the species’ viability. The most extensive aquatic habitat loss has occurred in the western portion of the basin, west and northwest of Sierra de San Marcos, where a genetically distinct subpopulation of T. coahuila resides. Habitat loss threatens the persistence of T. coahuila, and if not curtailed, will likely lead to the extinction of the species. Proposed conservation measures include: (1) upgrading the species’ conservation status with the Mexican government from a ‘species of special concern’ to ‘endangered’, (2) formulating an integrative species management plan with the Mexican government that includes local and regional regulation and monitoring of water extraction, (3) long-term monitoring of key subpopulations, including estimation of population size and density, (4) identification and preservation of critical movement corridors associated with long-distance movements of migratory subpopulations, (5) localized protection of degraded wetland habitats through livestock exclosures, and (6) measures to reduce road mortality.