Efeitos antrópicos e variáveis ambientais na formação de um mosaico vegetacional em Floresta Estacional Semidecidual Montana em Itumirim, MG, Brasil

Abstract

The forest fragmentation is remarkable in the upper Rio Grande, southeastern Brazil, where is located the district of Itumirim. The study was performed in this region to compare trees from three sectors of a forest remnant on the basis of environmental variables and anthropogenic impacts occurring over time. The first sector suffered clear cutting and burning of vegetation remnants for 40 years and had higher number of individuals, families and species. Its species composition, density on diameter and height classes, number of trees with multiple stems, importance value, and regeneration guilds and indicators species confirmed the occurrence of regeneration stages lower than other sectors. The second sector, which was never cut, but is constantly disturbed by cattle grazing, had composition and structure of forests in advanced successional stages, according to the parameters evaluated, since their environmental conditions were not as differentiated on the sector submitted to cut. Even the third sector has significant environmental differences, it is situated in sloping topography area. This peculiarity and the absence of disturbances give this sector a structure of forest in advanced successional stages, but with species composition characteristic of areas with influence of moisture, which is observed mainly by the composition of guilds and by indicator species. . Thus, we conclude that the first two sectors are different, which depend on the type and intensity of human disturbance, while the third sector differentiate because of the absence of disturbances, the environmental characteristics and due to the riparian influence.