Influência de fatores edáficos na composição e estrutura de uma floresta seca no nordeste brasileiro

Abstract

The objective of this work was to investigate an influence of edaphic factors on a structure and composition of the tree community in a forest fragment in Brazilian Northeast. For this, 25 permanent plots with dimensions of 20 × 20 m were allocated, all the individual with CAP (circumference of chest height) > 15 cm being measured. From the field data, basal area, individual density, wood density, mean diameter and mean height. To characterize as chemical, physical and soil moisture variables, soil samples were collected inside each plot as well as accumulated litter samples. (PCA) in order to produce a plot order from the soil variables, a canonical correspondence analysis (CCA) to verify the relationship between a species distribution and as soil variables, as well as regression analysis to verify if there are correlations between the soil, structure and diversity of the fragment. The results indicate that the community structure is directly affected by the heterogeneous distribution of the environmental factors in the area, so that soils with low retention of one unit and high concentrations of phosphorus condition larger diameter of the individuals, while the highe st density of use is found in soils with higher moisture content and higher volumes of accumulated litter. The species composition also responded to the variation of the edaphic characteristics analyzed, so that two groups of species can be observed in the CCA, one related to sandy soil and another related to clayey soils. From this context, it is possible to see both physical and chemical properties of the soil as characteristics as important representatives of filtration, being a productivity and a distribution of the species affected by the variation of the characteristics edited without fragment studied. Thus, this study contributes to the advancement of the understanding of how environmental factors at local scales can influence any establishment and structure of plant species in forest fragments in the Brazilian northeast.