Estruturação e conservação do Cerrado no contexto da paisagem : entendendo a vegetação da Floresta Nacional de Silvânia e seu entorno

Abstract

The Cerrado Biome has been increasingly affected by the advance of agribusiness and the conservation units are alternatives for the preservation of species. The objective of this study was to verify the existence of variations in the composition and distribution of tree species due to soil chemical characteristics in a conservation unit called Silvânia national forest in the municipality of Silvânia - GO. Fifty plots were installed in the study area. In the inside flona, 50m x 20m (1000m2), a total of 11 plots. In the external areas FLONA, 10 permanent plots of 50m x 20m were used and in the remaining the dimensioning of 10m x 10m (100m2). All tree individuals of DAP > 5.0cm in Semideciduous seasonal forest, and all tree individuals with DAB >5.0cm in Cerradão were sampled. There were 11 internal and 24 external plots. A total of 2,841 individuals were cataloged, with an average of 81 species per plot. Among these individuals there was a wealth of 172 species distributed in 51 families and 118 genera. The principal component analysis (PCA) between the plots and the edaphic variables presented consistent groups between the cations linked to soil fertility (Ca2+ , Mg2+ , K + ) with the portions of the Forest, and another group of plots belonging to the Cerrado where the pH in H2O was higher, and also higher levels of Al3+

. A diagram of ordering of species and edaphic variables was generated through canonical correspondence analysis (CCA) and forest species correlated with a greater amount of nutrients (K+ and Ca2+ Mg2+

), cation exchange capacity at pH 7 (CTC

T) and Burlap. Cerrado species correlated with a higher amount of Aluminium (Al3+

) and pH in H2O. The CCA diagram confirmed the floristic gradient due to the tenuous variation of soil fertility. The dendroggram generated by the cluster analysis between the sample modules presented two distinct groups due to dissimilarity. The PCA for landscape analysis indicated that cerrado plots are more correlated with environmental variables and forest plots are more linked to soil variables. The dendroggram generated from the edaphic and environmental variables indicated the similarity between the plots from their disposition in the different locations of the Red and Piracanjuba river basins.