Zooplankton trajectory before, during and after a hydropower dam construction

Aim Understanding the impact of anthropogenic activities is central for supporting management and conservation efforts. In aquatic ecosystems, the construction of dams for hydroelectric power plants is a major environmental change that turns the riverine ecosystem into a reservoir lake. Such environmental deep alteration causes profound impacts in biota. The goal of this study is to make a comprehensive description of zooplankton trajectory following the construction of a reservoir in the transition from the hotspot Cerrado to Amazon, Central Brazil. Methods We used data sampled before, during and after the formation of the reservoir lake in 10 sampling units each period. We evaluated compositional changes, shifts in spatial organization, and a variation in beta-diversity from before to after the dam constructions using a set of multivariate analyses. We evaluated effects for Rotifers, Copepods and Cladocerans separately. Results Compositional changes were evident for all zooplankton groups: Rotifers, Copepods and Cladocerans. Besides, spatial community organization was also affected but depending on the beta-diversity facet and data resolution – mainly turnover using abundance data, except for Copepods. Finally, an increase in nestedness occurred for all groups during the formation of the reservoir lake. Conclusions In summary, our study showed the deep impacts for zooplankton that the formation of a reservoir lake causes. We innovate by making a complete assessment, which indicate clearly the complexity of evidencing impacts in aquatic communities. We also suggest that long-term monitoring should continue in reservoirs for scientific purposes. The changes in biota also make clear that the construction of dams should be accompanied by preservation of other pristine riverine ecosystems. Resumo: Objetivo O entendimento do impacto de atividades antrópicas é essencial para subsidiar esforços de manejo e conservação. Em ecossistemas aquáticos, a construção de barragens para usinas hidroelétricas é uma das principais alterações ambientais que tornam o ecossistema fluvial em um reservatório. Tal alteração ambiental causa uma alteração profunda na biota. O objetivo desse estudo é fazer uma descrição completa da trajetória da comunidade zooplanctônica devido à construção de um reservatório na transição entre o hostpot brasileiro Cerrado e a Amazônia, no Brasil Central. Métodos Foram utilizados dados amostrados antes durante e depois da formação do lago do reservat