Dispersal increases beta diversity in periphytic algae communities of subtropical floodplain lakes

Abstract

Biological traits related to the adherence strategy of periphytic algae determine species’ dispersal ability and the degree of protection against physical disturbance, such as strong currents and flood pulse. To help understand how water level can structure species with distinct adherence strategy in a floodplain, we investigated periphytic algal beta diversity in subtropical floodplain lakes (upper Paraná river floodplain) and evaluate the importance of environmental and spatial drivers in groups with limited dispersal and with higher dispersal abilities. The beta diversity was analyzed considering both presence–absence and species density. We used variance partitioning to evaluate the importance of environmental and spatial processes on periphytic algae. Our results registered 181 species, and the class Bacillariophyceae presented the highest species richness and density. Beta diversity did not differ between months with distinct water levels but differed among lakes. Set of species with higher dispersal abilities presented higher values of beta diversity. Environmental variables were the main driver of periphytic algae composition and density, but spatial variables also drive a significant amount of differences in species composition and density. Beta diversity of species with limited dispersal abilities was mainly driven by environmental factors, and no driver was important to species with higher dispersal. The results of beta diversity indicated that nearest lakes may be more environmentally similar that allows the same species to survive, and also allows species to disperse better among them. These results highlight that the inclusion of functional aspects can clarify the understanding of beta diversity patterns.