Species sorting as the major driver of turnover for both planktonic and periphytic bacteria and the subgroup cyanobacteria in a subtropical lake system

ABSTRACT: We explored the ecological drivers of β-diversity patterns in bacterial assemblages sharing a same ecosystem but from different habitats (planktonic and periphytic) and belonging to different functional groups (bacteria and the subgroup cyanobacteria). Assemblages were characterized based on the 16S rRNA gene in a subtropical lake system comprising 5 lakes at a maximum distance of 50 km. We measured the influence of environmental heterogeneity and geographic distance (as a proxy of dispersal) on β-diversity and its components (species replacement and species loss). Bacterial membership clearly differed between planktonic and periphytic assemblages, with most operational taxonomical units being exclusive to a single habitat. Species replacement was the major component explaining the β-diversity patterns of bacteria regardless of habitat and functional group, which was mainly influenced by environmental heterogeneity in all cases. Moreover, when compared to planktonic ones, periphytic assemblages presented higher species replacement rates with geographic distance. In conclusion, our results highlight species sorting as the major driver for bacteria and the subgroup cyanobacteria in both habitat types, with a minor influence of the dispersal limitation for periphytic assemblages, which can be explained due to their substrate-attached trait.