Tree community structure in a restinga swamp forest in the coastal plain of Southern Brazil

Abstract

The restinga forests develop under environmental conditions that make them unique when compared to other Atlantic forest formations. In this study, we evaluated the composition, diversity and phytosociological parameters of the tree community structure in a restinga swamp forest in the North coast of Rio Grande do Sul state, Brazil. Individuals with DBH (diameter at breast height) ≥ 5 cm were sampled in 50 plots of 10 x 10 m located in the interior of a forest remnant. We assessed tree diversity through species richness, Shannon index (H’) and Pielou evenness (J). We produced graphics of height and diameter distribution and a vegetation profile. We sampled 1,027 individuals belonging to 38 species. The species with the greatest importance in community were Myrcia brasiliensis Kiaersk., Ocotea pulchella (Nees & Mart.) Mez and Guarea macrophyla Vahl, the first ones occurring in the upper stratum and the latter occurring predominantly in the lower stratum of the forest. The low species richness and the low diversity indices (H’ = 2.75 nats.ind-1, J = 0.75), as well as the dominance of some species, corroborate the pattern found in southern and southeastern Brazilian swamp forests and highlight the peculiarity of this forest when compared to the adjacent more diverse and more developed Atlantic forests.