Dispersal mode and flooding regime as drivers of benthic metacommunity structure in a Neotropical floodplain

The metacommunity approach emerged with the interest in investigating how local and regional processes interact to determine community structure. However, species distribution may differ according to biological features (e.g., dispersal mode) or system connectivity. We investigated the distribution patterns and the importance of environmental and spatial variables for benthic invertebrate metacommunity structures in a Neotropical floodplain according to hydrological periods (flood and drought) and dispersal modes (active or passive). We sampled 18 lakes during flood and drought periods in 2011. In both hydrological periods, we found a Clementsian pattern for active dispersers, with environment as the main structuring factor. The high environmental heterogeneity of this floodplain is an important factor providing high availability of favorable habitats for the establishment of active dispersers. Passive dispersers were randomly distributed in both hydrological periods. The importance of only spatial factors during the drought may indicate a restricted dispersal by inability of tracking environmental gradients. We emphasize that understanding biological community determinants could rely on trait-based analysis (i.e., dispersal mode) and complementary approaches (i.e., variance partitioning, and metacommunity structure), considering their variations over time.