Biodiversity conservation of high-altitudinal wetlands of Andean regions is relevant because they are suppliers of several ecosystem services; even more if we consider the putative consequences of climatic and land-use changes projected for the near future. These environments, characterized by severely stressing climatic and edaphic conditions, house a unique biodiversity, large levels of endemism and constitute a refuge and reproductive area for several species. The Laguna Brava reserve includes a system of high-altitude (mainly above 3000 m a.s.l.) Andean lagoons, peat bogs, and streams mostly situated in environments characteristic of the Puna and Altos Andes ecoregions of the province of La Rioja, Argentina. Except for some bird species, most components of the biota of Laguna Brava are scarcely known. There are not exhaustive inventories of the small terrestrial mammals, and all we know regarding this group comes from occasional mentions of a few species registered in a few localities. Here we present the results from field surveys of small terrestrial mammals conducted in the reserve between 2021 and 2023. We registered seven species of small terrestrial mammals for the reserve: Abrothrix andina, Akodon spegazzinii, Ctenomys eileenae, Eligmodontia moreni, Neotomys ebriosus, Phyllotis vaccarum, and Thylamys pallidior. The new records represent the first mention of T. pallidior, A. spegazzinii, E. moreni, and N. ebriosus for this protected area, adding localities for taxa scarcely known for their geographic distribution and constituting notable geographic range extension. The alpha diversity pattern shows a decrease in small mammal diversity (species richness decreases and dominance increases) from lower (east) to higher (west) altitudinal places (from approximately 3000 to more
than 4300 m a.s.l.). Although our work has improved the knowledge of small terrestrial mammals in the Laguna Brava area, we note that at least four other small terrestrial rodent species could be registered in this reserve in the following years, including Calomys lepidus, Abrocoma cinerea, Galea comes, and Spalacopus cyanus.
Jayat, J.P., Lobo Allende, I.R., Zaia, G. and Olivera, E.A. 2026. Small terrestrial mammals (Rodentia and Didelphimorphia) of the Laguna Brava reserve, a high-altitude wetland in the province of La Rioja, western Argentina. Journal of Neotropical Mammalogy/Mastozoología Neotropical 33 (1).
 | Jorge Pablo Jayat Investigador Independiente CONICET Mastozoología |