Structure and Spatial Pattern of Vegetation in a Fragment of Atlantic Forest

Abstract

The degradation of the Atlantic Forest is a reflection of the occupation and irrational exploitation of natural resources, which resulted in a drastic reduction of vegetation cover and fragmentation of these habitats. Thus, the objective of this study was to evaluate the species diversity, horizontal structure and spatial pattern of a fragment of Atlantic. Ten plots with dimensions of 10 m x 25 m (250 m²), were distributed in a completely random manner in the area. The data were obtained from the identification and measurement of the arboreal individuals with circumference at the breast height (Cbh) at 1.30 m of the soil > 15 cm. The total height was estimated by using a 6 m long ruler positioned near the individual to be measured. The horizontal structure was calculated based on the following phytosociological parameters: density, frequency, dominance, importance value and diversity indices (Shannon Index-H ' and Pielou Equability-J). The spatial distribution pattern of the species was analyzed for the ten of the highest absolute density observed in the phytosociological analysis of the fragment. For this, we used the MacGuinnes index. The diversity Shannon Index was 3.37 nats. ind.-1 and the Pielou equability index of 0.83. In general, the species presented an aggregate pattern of distribution in the area, with emphasis on the species Miconia prasina (Sw.) DC. and Myrcia splendens (Sw.) DC. and Byrsonima crassifolia that presented a random pattern, this information is necessary for future management and conservation actions in the region.