Zooplankton metacommunity structure: Regional vs. local processes in highly interconnected ponds

Local communities can be structured by both local interactions (competition, predation, environmental variables, etc.) and by regional interactions (dispersal of individuals between habitats). Using data from a three-year study on 34 neighboring ponds in an interconnected pond system, we tested whether zooplankton communities show a metacommunity structure, how much variation in zooplankton community structure is related to local environmental factors vs. spatial configuration (taking into account the dispersal pathways), and what environmental variables are the locally structuring forces. In three different years, we found evidence for a metacommunity structure. We also found that spatial and environmental components act independently of each other due to the small Geographic area and the high dispersal rates in this system. Despite these homogenizing forces. local environmental variables (associated with alternative equilibria in shallow lakes) were strongly related with zooplankton community structure in the studied years. This suggests that, even in this system of highly interconnected ponds, local environmental constraints can be strong enough to structure local communities.