Small rodent assemblage variation across a mountain gradient in an arid region of northwestern Argentina

Abstract

The province of La Rioja is one of the most neglected regarding the knowledge of its biological diversity, and particularly the study of the mammals in the Sierra de Velasco has been reduced to a few articles. This paper aims to study the richness and distribution of the small mammals of the Sierra de Velasco and the environmental factors that influence the assemblage in an environmental gradient. Samplings were made with Sherman-like traps for 9330 trap nights. For the analysis of assemblage variation, an environmental gradient was established based on several characteristics, and three types of environments were delimited: Ravines, Shrublands, and Rocky fields. Alpha and beta diversity were calculated using Hills numbers, and species richness correlation with environmental variables associations was evaluated. Small mammal species richness was up to seven and was higher in the shrublands environment decreasing towards the extremes of the gradient, with the lowest richness found in the rocky fields’ environment. The richness was mainly correlated to variations in the average elevation of the sampling sites. This is an initial approach to understanding the relationships between small rodent species and environmental variations present in the arid mountains of the Sierra de Velasco.