Pequena Central Hidrelétrica de Pandeiros e seu efeito sobre moluscos aquáticos invasores

Abstract

One of the biggest threats to biodiversity is the introduction of invasive species. These species threaten native species and cause great economic damage. Their presence is closely related to that of hydropower dams, which substantially alter river ecosystems and their biota. However, most studies of their ecological impacts are based on large dams and provide little information on the relationship between invasive species and small hydropower dams, which are much more abundant and numerous in Brazil. Our objective was to characterize the effects of Pandeiros small hydropower dam on the distribution of invasive mollusks in the Pandeiros River. We expected to  nd sensitive native species associated with free- owing sites, while resistant and invasive taxa were expected at sites affected by the dam. We found that the structure of benthic macroinvertebrate assemblages was signi cantly different between the free- owing and dam-affected sites. In addition, we found that the dam and reservoir facilitated the colonization of two invasive species (Corbicula  uminea and Melanoi-des tuberculata) because only in these sites they were found in high abundance. However, although the dam had signi cant effects on the structure of benthic macroinvertebrate assemblages, these effects were limited to sites near to the dam. Our results also highlight the need to understand the physical changes of habitat cau-sed by the presence and management of dams and reservoirs. We recommend the decommissioning of the Pandeiros small hydropower dam as an environmental management measure to reestablish habitat diversity for native species and as a mitigating measure for aquatic mollusk invasive species.