Floristics and phytosocyology of a fragment of Cerrado lato sensu, Gurupi, Tocantins State, Brazil

The objective of this work was to evaluate the floristic and phytosociological composition of a Cerrado lato sensu fragment. A census was carried out in the study area, of 6.7 ha, with inclusion limit of 15 cm of circumference at 1.30 m above ground level. We registered 15,434 individuals, from 78 species, 72 genera and 33 families. Density, dominance and cover value were analyzed, with a total density of 2,303.58 ind ha-1 and a basal area of 94.303 m² ha-1. The species with the highest cover values, in descending order, were Myrcia splendens, Astronium fraxinifolium, Magonia pubescens, Qualea parviflora, Protium heptaphyllum, Curatella americana, Vatairea macrocarpa, Tachigali aurea, Byrsonima stipulacea and Machaerium brasiliense, which represented 53% of all individuals of the area. Species of the genus Qualea presented dominance, representing 11% of the total of individuals. The distribution pattern of the individuals was inverted "J" format, but Astronium fraxinifolium, Magonia pubescens and Tachigali aurea presented lower number of individuals in the initial classes. The Shannon diversity index and the Pielou equability indicated the existence of high species richness and diversity when comparing the studied area with Cerrado fragments nearby.