No evidence for environmental and spatial processes in structuringphytoplankton communities

摘要

The relative importance of local and regional processes in shaping natural communities within a meta-community context has been a focus of intense debate in recent years. Floodplain lakes provide a goodsystem for testing this theoretical approach, as they undergo seasonal variations in physical, chemicaland biological factors, as well as in their degree of connectivity. Here, we investigated how localphytoplankton communities in lakes of a tropical river-floodplain system (Araguaia River floodplain -Central Brazil) were affected by environmental and spatial (dispersal) predictors in two rainy and two dryseasons (two consecutive years). Partial redundancy analysis indicated that during the periods analyzedthe effects of neither predictor were significant. Although we cannot exclude the possibility that thesetropical phytoplankton communities could be regulated by stochastic events, we suggested that furtherstudies will have greater explanatory power if they include other variables related to biotic interactions(e.g., abundance of grazers) and fine-scale environmental variation.