Regional and local factors control of beetles’ community composition in arid steppes Patagonia

Abstract

Understanding how environmental changes impact arthropod communities requires multi-scale studies. Despite their importance, research exploring arthropod diversity across regional gradients while accounting for local factors, such as vegetation structure, remains scarce. This dual approach provides deeper insights into the influence of regional processes on local community dynamics. We employed pitfall traps to investigate diversity and composition changes in ground-dwelling beetles across a latitudinal gradient and local vegetation mosaic within the Occidental District of Patagonia, Argentina. Five sites were selected along the 850 km geographical gradient to capture regional diversity, while within each site, 10 traps were set in shrub-covered areas and 10 in bare-ground areas to assess local variability. The northernmost sites exhibited the highest diversity and abundance, and distinctive species compositions. Species composition differed significantly between sites north and south of latitude 42º, with Carabidae and Tenebrionidae as key families representing this variation. Local microsite characteristics, particularly shrub presence, significantly shape beetle communities, sometimes surpassing the influence of latitudinal changes. Both, regional and local (vegetation mosaic) factors control community composition. The differences in species composition around latitude 42º mirrors patterns seen in other taxa, indicating that historical processes, such as biogeographical processes, substantially affect beetle communities at a regional scale.