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The Andes are known to be one of the most species-rich regions on Earth, with their origination promoting formation of new habitats and acting as climatic barriers. This orogenic event was structured latitudinally with 3 major segments having different formation times and with different environmental and historical conditions. The Andean region has been historically important in the evolutionary history of small mammals and is considered the region of Earth with the highest values of rodent species richness and turnover. Therefore, the region provides an excellent opportunity to evaluate mechanisms involved in structuring rodent assemblages and beta diversity patterns. Here, we assessed spatial patterns of rodent beta diversity along the Andes Mountains, with specific goals of examining patterns of turnover and nestedness as 2 recognized processes that drive species composition. We explored the role of spatial, climate, and historical factors on beta diversity patterns using geographic range maps for 432 rodent species to construct a species presence–absence matrix. We used piecewise regressions to identify latitudinal breakpoints in turnover and nestedness, and conducted multiple regressions and variation-partitioning approaches to assess the contribution of each set of postulated drivers in shaping beta diversity patterns. Beta diversity decreases from north to south. The highest turnover was located at the Northern Andes (5°N and 10°S) and western-central Andes (20°S and 35°S). Nestedness was higher below 40°S and in some areas of the western-central Andes between 15° and 20°S. Turnover and nestedness registered breakpoints coincident with the Central and Southern Andes limit. Turnover explained most of the beta diversity for all segments, although within the Southern Andes there was also some contribution of nestedness. In all segments, beta diversity was mainly explained by spatial factors with minor contributions from spatially structured climate (Northern Andes), interaction of all factors (Central Andes), and the interaction between current climate and history (Southern Andes). [ABSTRACT FROM AUTHOR]

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The Yungas or the Subtropical Mountain Forests represent one of the most biodiverse ecoregions in Argentina. Its distribution over the Andean mountain ranges helps retain water, generating the lotic ecosystems. The aim of this work is to describe a dataset of the Baetidae and Elmidae families. This dataset contains 1,183 records, 828 belong to Baetidae (15 genera and 27 species) and 355 to Elmidae (10 genera and 16 species). Ten out of the 24 protected areas were sampled, without records in some of them, such as northeastern Salta province and eastern Jujuy province. This work is intended to expose information gaps in order to contribute to future research projects. [ABSTRACT FROM AUTHOR]