Does hydroelectric reservoirs affect the structure of surrounding tree communities? A test of hypotheses in subtropical South America

Abstract

Despite its advantages over other energy sources, hydropower facilities are recognized as causes of terrestrial and freshwater environmental impacts. A deeper understanding of hydropower effects on surrounding riparian forests is thus important to the development hydropower facilities of less impact on the environment as well as to define criteria to manage the vegetation in the vicinity of large hydroelectric dams. We compared tree community structure on forest slopes exposed to a hydropower reservoir created in 2005 with control ones, in the biodiversity-rich subtropical forests of southern Brazil. Field data were collected between 2009 and 2011 on six forest slopes of which three were affected by the rise in water level caused by a hydropower dam, while the other three were in nearby sites unaffected by damming. Ninety 10 9 10 plots were set along six 50 m 9 10 m transects. Forest structure was significantly affected by vicinity of reservoir, but this effect differed significantly between different tributaries of the Pelotas River. Rarefaction curves showed homogeneity in species richness among the studied hills. Composition differed significantly between reservoir and control areas. Variance partition results showed that pure reservoir effects explained a fraction of the variance in floristic composition comparable to environmental factors. Vicinity to reservoir was the main factor able to distinguish between communities in the studied system in a multiple regression tree. Our results highlight that hydroelectric facility building produces more extensive damage to remnant native forests than anticipated and that even forests upslope from reservoir border may suffer rapid structural and compositional degradation due to changes in environmental conditions caused by altered hydrology.

Review on Governance in Hydroelectric Projects and Impacts on Natural Resources

“…Reports on environmental impacts on flora, fauna, soil, and landscape were found in the literature, compromising the conservation of biodiversity and ecosystem. Most studies found in this literary review relate the negative effectswhich will be addressed below -as consequences of the "edge effects" caused by fragmentation and alteration of natural habitats due to floods caused by hydroelectric dams (Palmeirim, Vieira, & Peres, 2017;Storck-Tonon & Peres, 2017;Urruth, Souza, & Oliveira, 2017).…”