The role of environmental, geographical, morphometric and spatial variables on plankton communities in lakes of the arid Patagonian plateaus

Species diversity is one of the most informative community metrics and is influenced by regional and local factors. We studied the spatial patterns of taxonomic and functional phyto- and zooplankton diversity in 33 lakes from two basaltic plateaus of the arid Patagonia. The aims of our study were to evaluate alpha, beta and gamma taxonomic diversity of phyto- and zooplankton; to assess the influence of environmental, spatial, geographical and morphometric factors on phyto- and zooplankton communities and to compare the influence of these variables on the taxonomic and functional composition. beta 1-diversity (within plateaus) was the major component for phytoplankton, rotifers and microcrustaceans taxonomic regional diversities. Planktonic communities were mainly constrained by macrophytes, fish, conductivity, dissolved organic carbon, altitude and spatial factors. The high dispersion of small individuals within plateaus tends to homogenize these communities, as indicated by null model results and the high explanation of fine-scale spatial factors in variation partitioning. This knowledge contributes to explaining the diversity patterns of planktonic communities of these valuable environments and to develop conservation strategies, considering both environmental heterogeneity and spatial effects.