Abundância e diversidade de artrópodes da superfície do solo em diferentes agroecossistemas em Canãa dos Carajás, PA

Abstract

The soil surface fauna has been widely used as a bioindicator of soil quality in agroecosystems because it responds rapidly to changes arising from use and management in agricultural systems. When changes occur in a natural system due to anthropic activities, for agricultural, forestry or any other purposes, there are numerous impacts on the soil environment and on populations and faunal communities, which can lead to various ecological impacts on the ecosystem or agroecosystem. The objective of this study is to evaluate the abundance and diversity of the soil surface fauna in four different agroecosystems and to identify the taxonomic groups that occur most, seeking to understand ecological environmental conditions based on these indicators. The systems studied were a corn crop, an agroforestry system, a secondary forest and an abandoned pasture. Six fall traps were installed in each area to capture soil fauna organisms, and six sampling points were set in the center of each agro-ecosystem, totaling 24 traps. A total of 2,546 individuals were collected, distributed in 19 taxa, being the orders Coleoptera, Hymenoptera, Diptera and Orthoptera the most abundant in the agro-ecosystems. The individuals represented by the families Bostrichidae, Staphylinidae, Formicidae, Drosophilidaee Gryllidae. The agroforestry system, the corn crop and the pasture showed higher abundance of individuals. The richness of morphospecies was higher in the SAF, pasture and secondary forest, respectively. These areas presented more uniformity in the distribution of arthropod organisms, except for the pasture. Among the four agroecosystems studied, the agroforestry system, the secondary forest and the cultivated crop presented the greatest diversity of arthropods. It is inferred that, by offering better conditions for survival and perpetuation of species, the more complex agroecosystems, such as the secondary forest and the SAF, have greater diversity. The study showed that the composition and abundance of the entomofauna in the four agroecosystems were influenced by the different land uses and the proximity to the forest, which favors the recolonization of the areas after anthropic disturbances. The more complex agroecosystems, such as secondary forests and the SAF, have greater diversity and demonstrated better conditions for survival and perpetuation of species by the analysis of ecological indices. Faunal communities in cropping systems near environmentally diverse sites suffer great influence/ interference in the composition and distribution of their communities.