Comparison of phytosociological and multivariate analysis in the determination of the conservation degree from native cerrado areas

Abstract

The strong anthropic pressure in the Cerrado makes studies necessary to ascertain the level of conservation of areas that are subject to this activity. Thus, the objective of the work was to compare and evaluate the floristics, the structure and the degree of conservation of two adjacent areas of Cerrado, one area of ​conserved savanna (CC) and another of anthropized savanna (CA). Conventional phytosociological parameters were used: relative density (DR), relative dominance (DoR), relative frequency (FR) and the importance value (VI), in addition to the Shannon-Wiener diversity index and Pielou’s equitability. Sorting analyzes were performed using the DCA method, classification dendrogram (UPGMA) based on the Sørensen-Dice and Bray-Curtis indices, in addition to the dichotomous hierarchical division by Twinspan. Student’s t-test was used to compare variables, diametric classes and height classes. The conserved savannah presented higher values ​for the number of individuals, diametric classes, basal area and height. The diversity index by plots, number of species, individuals and total basal area were statistically different for the two areas. Through multivariate analyzes it was possible to segregate the plots based on the degree of conservation, both in the ordering analysis (DCA) and in the classification (Dendrogram). The methods used were efficient to demonstrate the differences between the two areas, however the multivariate analysis proved to be efficient in providing greater detail in the differentiation.