Scorpion assemblages in threatened Brazilian forests: The role of environmental factors in explaining beta‐diversity patterns

Abstract

A systematic understanding of the variation in species composition across time and space is urgently needed to protect threatened Brazilian forests. This study has disentangled the among‐site variation in beta diversity among scorpion assemblages from the Caatinga and Atlantic Forest. We calculated the relative contribution of species replacement and differences in species richness in explaining the beta diversity in each forest, correlating such metrics with environmental characteristics. Finally, we estimated the relative site‐specific contribution to identify potential environmental drivers determining unique combinations of species composition. The average among‐site dissimilarity in scorpion assemblages was higher in the Caatinga than that in the Atlantic Forest. The differences in species composition among Caatinga sites were mainly due to the spatial replacement of species. Differences in species richness at the local scale explained most of the variation in species composition among Atlantic Forest sites. Environmental variables related to topography and land use partially explained the variation in among‐site dissimilarity, species replacement, differences in species richness and the ecological uniqueness in terms of species composition in the Caatinga. Environmental variables describing topography and land use were also important in explaining differences in species richness and local contributions to the beta diversity among Atlantic Forest sites. The relative site‐specific contribution to beta diversity was higher in Caatinga sites located in ecotonal zones and Atlantic Forest sites situated within conservation reserves. Using scorpions as biological models, we have demonstrated that the species composition does not vary in a consistent way between different forest types.