Edge effect in Cerrado Seasonal Semideciduous Forests

Efeito de borda em Florestas Estacionais Semideciduais do Cerrado

ABSTRACT

Edge effects are changes in vegetation, microclimate conditions and soil in transition bands between the edge and interior of the forest. The objective of this study was to verify for how many meters it is possible to perceive structural floristic variations caused by the Edge Effect by analyzing the tree and regenerative strata of four seasonal semi-deciduous forests located in the Cerrado Biome, Brazil. Samples were taken from four fragments of semi-deciduous forests in the Cerrado and analyzed by dendrograms and regressions for structural parameters that could distinguish edge and interior regions. In the Bray-Curtis Index and in the Sørensen Coefficient, for the tree stratum, the fragments presented groups with plots close to 40 meters from the edge. For the regenerative stratum the groups were more difficult to distinguish, even with a tendency to floristic dissimilarity of 15 to 20 meters. The groups were statistically confirmed by the Similarity Analysis (ANOSIM). The similarity percentage (SIMPER) can relate the species according to their contribution to the division into groups and to the areas of greatest interest. In the analysis of the structural data, the relationships between the number of trees, species and basal area as a function of the edge were not proven. Similarity analyzes distinguished the interior from the edge and measured the distance covered in the studied fragments, demonstrating that the composition of the first 40 meters of forest can be considered edges.

Keywords
Anthropization; Dendrogram of similarity; Edge distance; Forest fragmentation