Diversidade de invertebrados do solo em sistema agroflorestal e diferentes ambientes sucessionais em floresta ombrófila densa

Abstract

Studies on soil fertility and soil fauna diversity in agroforestry systems are of fundamental importance to prove the efficiency of these sustainable production models associated with the recovery of degraded areas. This work aims to evaluate correlations between soil fauna diversity and soil fertility in an agroforestry system and areas of native forest at initial and intermediate stages of forest succession. The study was conducted in the campus area of the Federal Rural University of Pernambuco, located in the Metropolitan Region of Recife, Pernambuco. Three sites with different land use histories were used: an area at an intermediate stage of forest succession (A1), a 3-year-old agroforestry system (A2), and an area at an initial stage of forest succession (A3). Pitfall traps were used to capture the soil invertebrate community. The captured organisms were identified, classified into taxa, and subsequently sent for analysis. Soil collection covered the 0-20 cm and 20-40 cm layers in each study area. The samples underwent chemical analysis. Data on soil meso- and macrofauna were used to calculate abundance, relative frequency, richness, Pielou's evenness indices, Shannon's diversity, and Simpson's diversity. Hill's true diversity components (qD) were estimated for each environment. Data analysis also included exploratory analysis with NMDS, permutational multivariate analysis of variance (PERMANOVA), Pearson correlation matrix, agglomerative hierarchical clustering analysis (HAC), principal component analysis (PCA), and Canonical Correlation Analysis (CCA). A total of 2,232 individuals distributed in 18 taxonomic groups were identified. Overall, regardless of land use, the most representative groups were Hymenoptera: Formicidae (37.46%), Acarina (21.10%), Collembola (15.86%), and Diptera (9.68%). Together, these groups represented 84% of the individuals collected in this study. The agroforestry area showed greater richness, the area of initial forest succession showed greater abundance in groups, and the area at an intermediate stage of succession showed greater diversity. Although the agroforestry area had greater richness, the estimated diversity was lower compared to the area of initial forest succession. Soil chemical analysis showed differences between the areas, influencing fauna distribution. Similarity in fauna composition was observed between the agroforestry area and the initial forest succession, highlighting the influence of soil chemical attributes on soil fauna. It is concluded that the study of soil fauna has the potential to be used as an indicator of soil quality, as it is sensitive to environmental interference.