Coming home: modelling the mating roost of the endangered bat Leptonycteris nivalis

Abstract

The Mexican Long-nosed bat (Leptonycteris nivalis) is the largest nectarivorous species in the New World, and one of three migratory nectarivores in Mexico. It is considered an ‘Endangered Species’ under the U.S. Endangered Species Act and ‘Threatened’ by the Mexican Federal List of Endangered Species.  In 1994, a Recovery Plan was developed by the USFWS with the participation of Mexican and American researchers, and the most urgent actions to ensure the species protection were identified.  Locating and protecting roosts are among the most urgent tasks recognized.  With this study, we aimed to identify the most suitable areas potentially holding additional mating roosts of Leptonycteris nivalis, and we conducted surveys of these areas to confirm its presence, and to assess the reproductive state of individuals.  We used Maxent, the Genetic Algorithm for Rule-set Production (GARP), and Bioclim algorithms to generate an agreement map of the potential distribution of additional mating roosts, and we implemented a Euclidian multidimensional distances analysis to identify ecologically similar regions to “La Cueva del Diablo”, the only mating roost known for the species.  We identified suitable areas in the states of Morelos, Puebla and the State of Mexico. We visited seventeen caves distributed in ten different localities in these areas.  For two consecutive years, we found the species in a cave called: “La Cueva de los Coyotes”, located in the State of Mexico, where we captured eighteen individuals, including a pregnant female.  The location of an unknown roost so far, occupied by individuals of L. nivalis, and among them a pregnant female, allows us to reflect about the reproductive dynamics of the species.  In that sense, reproductive populations may be splitting into smaller colonies to mate, other than “La Cueva del Diablo”, or pregnant females might me moving to additional and nearby roosts to spend the rest of the winter season. Using these tools and further refinements we may be able to locate additional mating roosts, thus, providing more possibilities for the application of conservation measures for the protection of the species.