Structure and diversity of tree component in forest remnants in south Brazilian restinga

Abstract

In south Brazilian restinga forests, between latitudes 28°30’S and 33°45’S, several ecological aspects of the tree synusiae are well understood, but studies in a largest geographic scale are still missing. To evaluate the variation in structure and diversity of the tree component, floristic and phytosociological surveys were carried out in 15 remnants distributed across this region. In each remnant, we sampled all trees with DBH ≥ 3.0 cm in ten 10 x 10 m sampling units. Chemical and textural analyses of superficial soil (20 cm depth) of the remnants were also accomplished. The set of structural parameters (density, cover, height and richness) differed significantly among some remnants. Richness ranged from 11 to 43 species, standing out Myrtaceae species. Diversity varied from 1.372 to 3.175nats/ind. Tree synusiae had density from 1.520 to 3.830 ind./ha, low height (1.5 to 15 m) and predominance of diameters from 12.5 to 15 cm. Some remnants presented low soil fertility, acid pH and high amount of aluminium. Differences in structure and diversity of the tree component may be related to local edaphic conditions, atmospheric temperature, rainfall, and anthropogenic alterations. The proximity to other forest formations, as Atlantic Forest, may also influence restinga forest richness.