Comunidades da fauna edáfica invertebrada em ecossistemas preservados e cultivos de banana irrigada no domínio caatinga em Minas Gerais

Abstract

Northern Minas Gerais includes areas of the Caatinga, a semi-arid biome. Banana cultivation is a prominent agricultural activity in northern Minas Gerais and is made possible by irrigation systems, which exert a significant influence on this biome. Despite its environmental and economic importance, the soil invertebrate fauna has been little studied in this region. This study aimed to evaluate the influence of irrigated banana cultivation on soil invertebrate communities by comparing them with those found in preserved Caatinga areas in the municipalities of Jaíba and Matias Cardoso, Minas Gerais, Brazil. Sampling was carried out using pitfall traps baited with human feces. Soil samples were also collected for physical and chemical analyses, which were used as explanatory variables in the analysis of community composition. The collected material was sorted and identified to the lowest possible taxonomic level. The separation between land uses was associated with a gradient of physical and chemical attributes, with cultivated areas related to higher Na, Mg, Zn, and B contents, whereas preserved areas showed higher H+Al values. A total of 62,257 soil invertebrates were collected, of which 37,701 were recorded in preserved areas and 24,556 in cultivated areas, with predominance of Collembola, Acari, Coleoptera, and Formicidae. For the overall soil fauna, total abundance did not differ between land uses; however, richness was significantly higher in preserved areas. Variance Partitioning Analysis (VPA) indicated that land use exerted a greater influence on community structuring than the physical and chemical soil attributes. Faunal composition differed between environments, with a clear separation between preserved areas and irrigated cultivation (PERMANOVA R² = 0.496; p = 0.006). Indicator taxa analysis revealed the association of Blattaria, Pseudoscorpiones, and Isoptera with preserved caatinga areas, whereas Dermaptera was associated with banana cultivated areas. For Araneae, 216 individuals distributed across 24 families were recorded, with higher abundance and diversity (q0, q1, and q2) in preserved areas, in addition to indicator families restricted to these areas. For Coleoptera, 15 families (8,991 individuals) were recorded, with higher abundance and richness (q0) in preserved areas, as well as indicator families found only in these areas. For Scarabaeinae beetles, 7,797 individuals belonging to 49 species were recorded. Preserved areas contained almost the entire community, with 7,656 individuals and 46 species, whereas the cultivated area had 141 individuals and 20 species. Abundance and diversity (q0, q1, and q2) were higher in preserved areas (p < 0.001). Indicator taxa analysis identified 16 taxa/species as indicators of preserved Caatinga areas and only one as an indicator of banana cultivation (Canthon quinquemaculatus). The results demonstrate that irrigated banana cultivation promotes a reduction in richness and consistent changes in the structure and, especially, the composition of soil communities when compared with preserved Caatinga. These findings indicate that soil fauna is an important indicator of land-use changes in the semi-arid region and reinforce the need for management practices that conserve soil attributes and microhabitats in agricultural landscapes, although the preserved areas existing in the region and adjacent to these crops play this role.