Floristic and structural changes in two arboreal stands of a riparian forest on different environmental conditions in the southern Brazilian Pampa.

Abstract

The aim of this study was to compare two stands of riparian forests in the southemmost part of Brazil at the coastal region of the Pampa biome in Rio Grande do Sul. Seven structural attributes (number of species, density, basal area, median and maxim um height, median and maximum DBH), floristic composition and functional aspects were described and analyzed in 50 plots of 10m x 10m in each stand (Pl- non-Hooded advanced secondary forest on Hat topography, and P2- fiooded clímax forest on rugged topography). All trees With DBH > Scm were measured. Most structural parameters were differed from one to another stand. However, P1 and P2 showed great functional and compositional similarities. The dominance of plants adapted for exploiting disturbed sites had determined the functional and floristic responses. Meanwhile, structural changes were related to differences in the physical environment of two stands. This is the first quantitative analysis of tree Hora in the Piratini River fiodplain, a very important area for biodiversity conservation in the Pampa biome.