This project aims to contribute to the knowledge of the marginal lagoons functioning in a large reservoir through mathematical models, as well as to compare the marginal lagoons' function with the river function. The comparative of these data from different periods allow assessing whether the marginal lagoons are more conservative than the river and whether artificial lagoons have the same functioning of natural environments, moreover to evaluate whether there is any kind of trophic control in the systems and how several perturbations (drought, temperature change, and introduction of exotic fish species) act on the aquatic community structures. To reach these goals, four different marginal lagoons and one point in the river main channel (Paranapanema River SP/PR) were selected. Fieldwork was carried out bimonthly between September of 2004 and August of 2005. The mathematical models will be performed on data of fish assemblages, as well as their feeding content, besides phytoplankton, zooplankton, zoobenthos, periphyton and aquatic macrophytes assemblages. Together with biological data, data of 16 limnological variables, which were concomitantly sampled with the biologic samples, will be used. To validate hypotheses, models of energy and biomass will be fit and compared to each sampling point by the ECOPATH and STELLA software. Finally, the PROTESTE/Procrustes software will be used to assess how the different perturbations influence the several assemblages, and whether there is some association among the abiotic components and communities.
News published in Agência FAPESP Newsletter about the scholarship: