Efeito espacial e temporal de uma pequena central hidrelétrica sobre a estrutura e composição funcional da comunidade de macroinvertebrados aquáticos

Abstract

The theme of this thesis has been motivated since graduation, where I have been developing and refining research related to the benthic macroinvertebrate community and its interaction with water resources. Thus, this thesis is structured in two chapters that will address the effects of a small hydroelectric plant on the aquatic invertebrate community namely: Chapter 1: Small hydroelectric plants act as an environmental filter on the structure and composition of the benthic macroinvertebrate community. This chapter aimed to analyze the environmental filtering effect of a small hydroelectric power station (SHP), on a temporal and spatial scale, on the regulatory dynamics of physical, chemical and biological variables. Specifically aimed to i) evaluate the community composition of benthic macroinvertebrates based on their constancy, and behavior of community structuring in the studied scales; ii) identify the temporal and spatial behavior of water quality through physical and chemical variables; iii) evaluate the integrated effect of physical and chemical variables on the structure of the macroinvertebrate community. Chapter 2: Spatial and temporal effects of the construction of a small hydroelectric power plant on the functional diversity of aquatic insect assemblages by means of functional traits and indices. This work aimed to identify changes in the composition and functional structure of the assemblage of benthic aquatic insects in a region affected by a small hydroelectric power station (PCH). Specifically, the aquatic insect assemblage was characterized based on the abundance, constancy and categories of functional traits (reproductive, morphological, trophic and ecological) of the families present. We highlight great effects on the ecological and morphological traits of the organisms, which clearly sought adaptive strategies for survival in the altered environment, especially in the reservoir, which presented the lowest results for the applied metrics and functional indices, however, functioned as a decanter of organic matter from the upstream, improving the physical, chemical and biological conditions of the São Francisco River water downstream of the dam. Another relevant highlight was the performance of biological results in relation to water physics and chemicals, since the integrated analysis of environmental parameters (physical, chemical and biological), deliver with more significant assertiveness the real conditions of the environment than when evaluated individually, reinforcing the fact that physical and chemical parameters of water must be integrated with biological parameters for the assessment of environmental impacts. In addition, the use of the functional approach in research using indexes and functional traits were significant for analysis and conclusion of the work. Thus, we conclude from these chapters that the macroinvertebrate community and benthic aquatic insects were significantly modified by the dam construction of the São Francisco SHP, as the hydrological and structural changes of habitat were largely responsible for the modification of composition and structure and reduction. of the functional diversity of macroinvertebrates.