Structure and diversity of restingas along a flood gradient in southeastern Brazil

Abstract

This study aimed to relate changes in structure and species diversity with edaphic variables (soil type and flooding regime) in a gradient of forest formations within the Brazilian restingas (coastal woodlands). The study was carried out in the Jacarenema Municipal Natural Park, in the city of Vila Velha, in the Espírito Santo State, Brazil. We evaluated the structure of shrub and tree components by sampling 80 plots of 5 × 25 m each, equally distributed among four forest types (well-drained, transitional, floodplain and flooded). We included all individuals with a ≥ 3.2 cm diameter at breast height. From each plot, soil samples (for chemical and physical analysis) were collected at a depth of 0-10 cm. We identified a significant fertility gradient (of soil nutrient availability) and a strong influence of groundwater on each forest type. We also found significant differences among the forest types in terms of individual basal area and height, as well as density. Diversity increased along the environmental gradient, from flooded to well-drained forest. We conclude that variations in structure and diversity among the four forest types were correlated with the flooding regime, as well as with chemical and physical characteristics of the soil.