Influence of species invasion, seasonality, and connectivity on fish functional and taxonomic beta-diversity in a Neotropical floodplain

Studies that combine functional and taxonomic beta-diversity are essential for explaining some ecological processes, including the process of species invasion. We evaluated whether environmental (such as lake connectivity, subsystem and seasonality) and biological factors (occurrence and richness of non-native and native fish species) affect beta-diversity components (total, richness and replacement) of fish communities living in the Upper Paraná River floodplain in Brazil. For this, a distance-based redundancy analysis was performed for both taxonomic (BDtax) and functional (BDfunc) approaches. In order to see which variables influence the local contribution to BDtax and BDfunc (LCBD), mixed effects regression models were fitted. In our research, environmental factors influenced the replacement component for both taxonomic and functional beta-diversity, while biotic factors (occurrence and richness of non-native species) influenced the richness component. The richness of native and non-native species, the occurrence of non-native species and seasonality showed an influence on LCBD values. Although in our study the occurrence and richness of non-native species are positively related to beta-diversity, some studies have found that, in the long term, these species can cause a decrease in functional and taxonomic beta-diversity, altering the ecological multifunctionality of the environment. Our study emphasizes that both changes in environmental factors and species diversity (such as the introduction of a non-native species) can impact the beta-diversity of Neotropical fish.