INSELBERGS AS A SOURCE OF β DIVERSITY IN A VEGETATION MATRIX IN COQUEIRAL, MINAS GERAIS, BRAZIL

Abstract

This study aimed to answer the following question: Does habitat heterogeneity affect the tree community? To answer that question, we evaluated the influence of the species composition and structure of the tree community of inselbergs on the tree community of the matrix where the inselberg is located. The correlations between environmental and vegetation gradients were analyzed by canonical correspondence analysis of a species composition matrix constructed from abundance data of 40 plots sampled in two areas, one composed of seasonal semideciduous forest (SSF) and another with riparian forests, a vegetation corridor, and inselbergs. A similarity dendrogram of the four areas was calculated using the Dice-Sorensen index and UPGMA linkage method. The species indicator analysis was used to evaluate which species were characteristic of each area sampled. The eigenvalues of the first two axes were high indicating high species turnover. The correlations between environmental variables and plots indicated the formation of three groups: the first one formed by the SSF patch plots with high clay content; the second group formed by the vegetation corridor and inselberg plots, which did not separate as sharply as the first group, with a small separation in organic matter content; and the third group, formed by the riparian forest plots, which are located in areas of highest soil fertility, with high content of calcium, sum of bases and base saturation. The results showed high species turnover among areas, indicating that even though the areas are geographically close, the occurrence of inselbergs increased habitat heterogeneity, directly affecting the variation in species composition and community structure among areas.