Caracterização florística e pedológica de dois fragmentos de floresta estacional subtropical no rebordo do planalto do RS

Abstract

The study was conducted in a remnant forest Subtropical Seasonal Forest on the edge of the Plateau of Rio Grande do Sul in Itaara containing two stages of succession, secondary forest and capoeira, having as main objective to analyze floristic and soil characteristics. This dissertation was divided into two studies, with specific objectives of characterize the forest as floristic composition, phytosociology and diversity (Study 1) and to examine relationships between the physiognomy and community structure of vegetation with pedological and topographical environment (Study 2). In secondary forest 23 sampling units were placed and 10 units in capoeira with dimensions of 10 x 20 m, where the vegetation was sampled in three classes of inclusion, in the two smaller classes were considered the natural regeneration of individuals with smaller diameters than 5 cm and in largest class was considered the tree stratum of individuals with diameters larger than 5 cm, and held the classification and morphological characterization of soils. In floristic composition were found 87 species belonging to 36 families and in the analysis phytosociological of the tree stratum, the secondary forest had a density of 2052 ind.ha-1 and basal area of 38.50 m².ha-1, while the capoeira 2105 ind.ha-1 and 14.24 m².ha-1 of basal area. Soil characterization of the sampled area resulted in the classification of four types of soils, Neossolo Litólico, Neossolo Regolítico, Cambissolo Háplico and Argissolo Vermelho. Using principal component analysis and cluster analysis for the soil variables were obtained three groups of plots in each fragment with pedological characteristics and physiognomy and community structure of vegetation distincts. Through the canonical correspondence analysis it was observed that the species are distributed according to the variation of pedological attributes, conditioned by the relief of the area.