Abstract
Abstract: 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.
Highlights
Human society is highly dependent in electric power, which generation represents a major source of environmental impacts
Shifts in spatial organization, and a variation in beta‐diversity from before to after the dam constructions using a set of multivariate analyses
In summary, our study showed the deep impacts for zooplankton that the formation of a reservoir lake causes
Summary
Human society is highly dependent in electric power, which generation represents a major source of environmental impacts. Compared to nations that generate power mainly by fossil fuels, which has strong environmental impacts associated to atmospheric pollution and greenhouse gases, Brazil has a relatively sustainable matrix of electric power generation – based mainly in hydropower dams (Von Sperling, 2012). Even so, such generation do represent impact for natural ecosystems, given the strong environmental changes that dam construction represents both considering socio-economic features to communities living nearby water bodies (Von Sperling, 2012), as well as to aquatic ecosystem functioning, habitat fragmentation and freshwater biodiversity (Baxter, 1985; Agostinho et al, 2008). The most complete approach, would be to compare before and after trajectories in impacted ecosystems with trajectories in comparable non-impacted ecosystems (see Ribas et al, 2019)
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