Variações na composição florística e na estrutura fitossociológica de uma floresta ombrófila densa alto-montana na Serra da Mantiqueira, Monte Verde, MG

Abstract

The upper montane forests are known to have a different floristic composition and phytosociological structure from forests located at lower altitudes. A survey was carried out in an area of upper montane forest of the Mantiqueira Range near Monte Verde, municipality of Camanducaia, Minas Gerais State, Brazil. The main objective of this study was to analyze the effect of an altitudinal gradient on the floristic composition and vegetation structure. Seven blocks, each with five of 10 × 10 m plots, were located at altitudes ranging from 1,820 m to 1,940 m, and all bamboos and trees with GHB >15 cm were sampled. A total of 1,191 individuals were included, belong to 64 tree species and two bamboos in a total of 42 genera and 26 families, including the standing dead individuals. The estimated density was 3,403 ind ha-1 and the value of the Shannon-Wiener (H') index was 3.284 nat ind-1. The dead biomass had the highest importance value (42.06), followed by Pimenta pseudocaryophyllus (Gomes) Landrum (24.59), Roupala rhombifolia Mart. ex Meisn. (19.98) and Drimys brasiliensis Miers (18.57). The structural parameters maximum canopy height and number of branched individuals were correlated with altitude. Although the altitudinal gradient is relatively short, a considerable degree of species substitution was observed, leading to a well-marked floristic gradient.