Atributos do solo como indicadores da distribuição de espécies florestais

Abstract

Soil is an important constituent of forest ecosystems. However, there are few studies that aim to understand the influence of the variability of its attributes on the distribution of forest species. These studies are necessary because they provide information for a better understanding of the complex soil-forest relationship, aiming at the adoption of appropriate strategies for the conservation of biodiversity and forest restoration. Therefore, this work aimed to evaluate correlations between the distribution of tree forest species and soil attributes in a fragment of Atlantic Forest type Dense Ombrophilous Forest of the Lowlands, Recife, Pernambuco, Brazil. The study was carried out in a forest fragment located in the Botanical Garden of Recife. The phytosociological survey was carried out using the plots method, with 40 plots of 10 m x 25 m being allocated, systematically distributed, where all living individuals who had a circumference at 1.30 m above the ground ≥ 15 cm were identified and georeferenced. The physical and chemical attributes of the soil were determined in each plot, collecting 4 samples of non-deformed soil at the depth of 0-5 cm and 18 simple samples deformed at the depth 0-20 cm, forming a sample composed by plot. Among the physical attributes of the soil, the contents of sand, silt and clay, density of the soil, resistance of the soil to penetration, total porosity, macro and microporosity were determined. The chemical characterization of the soil was carried out by determining the levels of total organic carbon (TOC), available P, exchangeable bases (Ca+2, Mg+2 and K+), exchangeable acidity (Al+3) and potential acidity (H+Al). In addition, base sum, base saturation, Al+3 saturation, effective cation exchange capacity and potential cation exchange capacity were calculated. Soil characteristics were evaluated using descriptive statistics and to evaluate the influence of soil attributes on the distribution of forest species, multivariate and geostatistical analysis was used. The soil of the forest fragment was characterized as Sandy-Clay-Loam, acid, non-alic and eutrophic. Possibly, because it is a forest in an advanced successional stage, the decomposition and mineralization of the litter layer deposited on the surface contribute to the forest nutrition and act in the increase of soil fertility levels. The distribution of forest species is related to the physical and chemical attributes of the soil. Brosimum guianense, Miconia affinis, Bactris ferruginea and Dialium guianense show preference for areas with higher clay contents. Parkia pendula, Pouteria durlandii and Schefflera morototoni, predominated in areas with increased density and resistance to soil penetration. Artocarpus heterophyllus, Eriotheca gracilipes, Hevea brasiliensis, Luehea ochrophylla and Mabea piriri were more prevalent in places with better fertility conditions. While Brosimum rubescens, Helicostylis tomentosa and Thyrsodium spruceanum predominated in places with more acidic soils and higher levels of exchangeable and potential acidity. Because they are complex and specific interactions, patterns on the influence of soil attributes on the distribution of forest species should only be generalized after repetitions of the same pattern in different areas.