Spatial variation of small mammal communities in northwestern Argentina

Abstract

Northwestern Argentina (NWA) is a region characterized by a complex geomorphology, and encompasses six ecoregions in a relatively small area. The environmental heterogeneity of NWA and the sensitivity of small mammals towards environmental and landscape changes constitute a good scenario to assess the factors that influence small mammal diversity patterns in the region. We studied small mammal communities obtained from pellet samples in 24 localities of NWA. We identified 50 non-volant small mammal species and obtained topographic, climate and land cover variables. Our results show that small mammal communities respond to environmental factors at a regional scale. Such variations were explained in different proportions by the geographic position of the collecting sites, landscape and climate. Furthermore, the combined effect of these factors was the main determinant of species abundance patterns. Our results support the need of large-scale approaches to study communities, since the explanations of the observed patterns are simpler and more general. We emphasize the importance of considering the combined effect of different environmental predictors, which allows determining the amount of species variation that is spatially structured, and within that, the amount of variation related to the influence of the measured environmental variables.