Variação espacial da estrutura da comunidade arbórea de um fragmento de floresta semidecídua em Piedade do Rio Grande, MG, Brasil

Abstract

A survey of the tree community, topography and soils of a fragment of tropical semideciduous forest was carried out with the objective of assessing alleged correlations between the variations in community structure and species composition and variations in edge effect and soil water regime and chemical fertility. The fragment (30 ha of area) is situated at 21°29'03'' S and 44°06'05'' W, in Piedade do Rio Grande, Minas Gerais State, SE Brazil. A topographic survey and a detailed soil classification were accomplished in the forest area. Individual trees with diameter at breast height (dbh) ≥ 5 cm were sampled in 30 plots with 400 m 2, 12 of which were placed at the forest edges and 18 in the forest interior. Samples of surface soil (0-20 cm of depth) were collected from each plot for analyses of chemical and textural properties. The survey registered 1,778 individuals belonging to 174 species, and three soil subgroups. Tree density and species diversity was higher in edge than in interior plots, but no difference was found for basal area. An interactive canonical correspondence analysis (CCA) of the patterns emerging from the environmental variables, spatial variables and species abundances indicated that these are distributed in the fragment under a strong influence of spatial proximity, edge effects, soil water regime expressed by topographical elevation and soil chemical fertility expressed by the bases saturation.