Beta Diversity Patterns In Zooplankton Assemblages From A Semiarid River Ecosystem

The study of beta diversity patterns, as well as their underlying mechanisms, is fundamental for the understanding of community structure in aquatic ecosystems. Here, we aimed to investigate patterns of beta diversity in cladoceran, copepod, and rotifer assemblages in the Parnaiba and Poti rivers, along the urban perimeter of the city of Teresina (Piaui, Brazil) and to evaluate the effect of environmental, spatial, and temporal factors on beta diversity in the zooplankton assemblages. We used the Simplex analysis to represent the relative importance of replacement and abundance difference to beta diversity. The decomposition of beta diversity into its components was performed using the Ruzicka dissimilarity index, for abundance data. Distance-based Redundancy Analyses and variation partitioning were used to explore the relations between explanatory variables and beta diversity and its components. We found that beta diversity was high both spatially and temporally, and the abundance difference component showed greater relative importance than the replacement component. Environmental factors showed a greater contribution to the total explained variability in beta diversity and abundance difference, while replacement received most importance of temporal and spatial variables. Our study provides new insights on how environmental, spatial, and temporal factors shape beta diversity patterns in zooplankton assemblages in impacted aquatic ecosystems.