Temporal Beta Diversity Increases with Environmental Variability in Zooplankton Floodplain Communities

Temporal changes in community structure (temporal beta diversity) are expected to be driven by temporal environmental variation as different conditions may select for different sets of species. Here, we tested this hypothesis using a zooplankton dataset from the Araguaia River floodplain, Central Brazil. Data on zooplankton abundance and environmental variables (pH, water temperature, conductivity, turbidity, transparency, depth and concentrations of total phosphorus, total nitrogen, and chlorophyll-a) were collected at 30 sites in January (high water period) and July 2006 (low water period). For each site, we used the Bray-Curtis dissimilarity coefficient to measure temporal beta diversity (between January and July 2006), while the standardized Euclidean distance was used to calculate the temporal environmental variability. Then, we tested the hypothesis that temporal beta diversity would be higher in habitats that underwent larger variation in environmental conditions using a Pearson correlation analysis. We found a positive correlation between temporal beta diversity and environmental variability (r = 0.46; P = 0.043). Furthermore, we found that temporal beta diversity was mainly driven by an increase in zooplankton abundance between high and low water periods. Our results add to the increasing evidence that hydrological variation is key to understanding zooplankton community dynamics in floodplains. We suggest that future studies should search for correlates of temporal beta diversity (such as environmental variability) in other highly seasonal systems.