Hydrological dynamics drives zooplankton metacommunity structure in a Neotropical floodplain

The maintenance of biodiversity in dynamic landscapes can be explained through the unifying concept of the metacommunity, an ecological system with a changing structure that arises from both the biotic features of its component species and from changing temporal processes. We evaluated the relative importance of environmental factors and spatial factors on the structure of metacommunities of zooplankton in a Neotropical floodplain system, in relation to hydrological dynamics and potential connections among lakes. Zooplankton was sampled from 16 to 22 shallow lakes during droughts and floods in two hydrologically contrasting years. Copepods appeared to be more limited by their dispersal potential, while testate amoebae and rotifers seemed to be controlled mostly by environmental variables. These findings stress the importance of the species sorting metacommunity paradigm for groups with the smallest propagules and adult body sizes. The importance of environmental factors rather than spatial factors was apparent during floods, likely due to the facilitation of animal dispersal by floods. Our results demonstrate that the importance of these factors depends on both the functional traits of major zooplankton groups and the hydrological dynamics of the region.