AN ANALYSIS OF SPECIES DISTRIBUTION PATTERNS IN THE ATLANTIC FORESTS OF SOUTHEASTERN BRAZIL

Abstract

This study analysed phytogeographic patterns of several Atlantic Forest areas in southeastern Brazil, including forest areas in the Espinhaço Range, to identify species with congruent distribution patterns and possible environmental factors that might influence these. A total of 54 floristic surveys, predominantly from semideciduous woodland sites but also including some rainforest areas, were compared using UPGMA and DCA methods as well as Jaccard analyses. The former identified four main groupings: group 1 included forests located throughout the Espinhaço Range; group 2 was formed by forest areas in the Rio Jequitinhonha basin; group 3 was formed by three distinct subgroups, one (3.1) predominantly of forest areas pertaining to the Alto Rio Grande basin, another (3.2) of upland forests of the Quadrilátero Ferrífero, and a third subgroup (3.3) of upland forests of the Serra da Mantiqueira; and group 4 encompassed forest areas in the Rio Doce, Rio Paraíba do Sul, Rio Itanhém and Rio Itapemirim basins. The prevailing relief in these basins has influenced rainfall and seasonality in these areas which, in turn, have exerted a major influence on the composition of the semideciduous forests. Geographic proximity and altitude, although important factors, play a minor role in the phytogeographic patterns analysed. Despite the floristic heterogeneity of the Espinhaço Range forests, there are physiognomic and floristic affinities among the forests within the campos rupestre vegetation. These are due to the high altitude and features of the soil.