Variação das assembleias de invertebrados em riachos com diferentes graus de conservação pertencentes à sub-bacia do Ribeirão Marmelos, Juiz de Fora, Minas Gerais

Abstract

This study focused on the variation of the assemblies of invertebrates in streams with different degrees of conservation belonging to the subbasin of Ribeirão Marmelos, Rio Paraibuna , Juiz de Fora, Minas Gerais, Brazil. The dissertation is divided into two sections: the first deals with evaluating assemblies of invertebrates in mesohabitats backwater and rapids in nine streams with different degrees of conservation; the second addresses the variation in assemblies in dry and rainy seasons in streams with different degrees of conservation. Data were used in the dry season of backwaters and rapids to conduct the study in the first section; already the second section comprises the rapids samples obtained in both periods. Were recorded throughout the study fifty-three thousand seven hundred and ninety-four aquatic invertebrates , over forty-five samples of rapids and forty-five samples of backwater in the dry season , and forty- five samples of rapids in the rainy season . The mesohabitats rapids were characterized by the greatest influence on the speed and availability of coarse substrate, lower values of width and depth. Have backwater was characterized by deposition of ultrafine fractions of sand and greater width and depth. The results widened the knowledge of ecosystems and streams as the characteristics of the environment influence the distinction of mesohabitats rapids and pools and associated invertebrate fauna, and once in the richness and diversity of taxa. From the results of the first section it was concluded that changes in the natural characteristics of low-order streams such as the removal of riparian vegetation lead to losses in habitat heterogeneity and faunal diversity. The results of the second section showed that environments with different land uses are influenced differently to the way rain events. We attribute the presence of riparian vegetation as the main component of the system, influencing the stability of the habitat of organisms and thermal regulation. The results obtained in this work have been contributing significantly to the understanding of how environments with different conservation influence the characteristics of mesohabitats and how these are influenced by the rainy season.