Distribuição temporal e espacial de plecoptera em um córrego no parque ecológico Quedas do Rio Bonito, sul de Minas Gerais

Abstract

To evaluate the integrity or health of a river, the assessment of habitat diversity is importante since it has a strong relationship with the aquatic biodiversity. Adaptations of species of Plecoptera to different microhabitats, temperature and life histories gives these organisms a great utility in studies to evaluate the integrity of rivers. Two samples were taken (rainy and dry seasons), in 15 points, in Vilas Boas stream in the Parque Ecológico Quedas do Rio Bonito, Lavras, Minas Gerais, to evaluate the temporal and spatial distribution of Plecoptera. Abiotic variables and the type of bottom sediment were also evaluated. Usually in the dry season, the abundance of these organisms is greater than in the rainy season. Although the dry season rainfall was considerably lower, the difference in the number of immature Plecoptera varied little between seasons, which may be explained by the flattened shape of their body (Perlidae) and strong tarsal claws and the choice of microhabitats with smaller currents, such as places with leaf retention (Grypopoterygidae). In both seasons, Plecoptera was restricted to points where there sediment consisted of large rocks and well-preserved riparian forest. Although the have been differences in the richness betweem the seasons, these values were significantly different between the points, being that in the ones of less altitude, there weren’t found any Plecoptera, which can be explained by the smallest preservation of these points when compared to the others. The nymphs of Plecoptera showed a preference for higher altitudes and environments where the riparian forest was well-preserved, located close to the source of the stream.