The Effects of Livestock, Proximity to Trees, and Aquatic Characteristics on the Abundance of Ambystoma Altamirani within a Stream

Abstract

The endangered, endemic salamander, Ambystoma altamirani, is distributed in streams in the Transvolcanic Belt around Mexico City. Like other Mexican ambystomatids, A. altamirani is threatened by several anthropogenic stressors, including land use changes. Here we examine how aspects of the terrestrial habitat, such as the distance to wooded habitats and the presence of livestock, as well as several aspects of the aquatic habitat, affect the abundance of adult and larval A. altamirani along the Arroyo los Axolotes. The presence of livestock and proximity to the nearest trees did not affect the abundance of adult or larval A. altamirani. The abundance of adult A. altamirani was positively associated to the proportion of visits with water, mean total dissolved solids, mean stream width, mean bank height, and mean water velocity, and negatively related to mean water temperature and mean water depth. The abundance of larvae was not related to any measured variables. In conclusion, the abundance of A. altamirani along the Arroyo los Axolotes is primarily associated with aquatic factors, with limited influence of terrestrial factors. From a conservation and management perspective it is imperative to conserve the aquatic characteristics of streams where A. altamirani is found.