Meso- and macrofauna in the soil and litter of leguminous trees in a degraded pasture in Brazil

Soil organisms comprise a large number of species that play a role in various ecosystem functions and provide valuable ecosystem services that sustain soil quality. The objective of this study was to characterize the meso- and macrofauna in soil and litter with different types of plant cover (Acacia auriculiformis A. Cunn. ex Benth., Mimosa caesalpiniifolia Benth., pasture and secondary forest) at different sampling times (dry season: June and September and rainy season: February). The faunal communities were sampled over during 15 days with a Berlese-Tullgren apparatus. The density of the total fauna ranged from 822 to 6,368 individuals m(-2) in the litter and 99 to 1,222 individuals m(-2) in the soil. The richness ranged from 9.4 to 12 in the litter and 6.4 to 8.8 in the soil. In all, 12,596 individual organisms were recovered from the soil and litter samples, and 8,012 individuals were found in the litter. Seasonal variation influenced the density and richness of the total fauna and the occurrence of functional groups, particularly the populations of microbial grazers, predators and herbivores, but this influence depended on the plant cover. Most groups that were found during the three sampling periods and in all types of plant cover belonged to two functional groups: social insects (Formicidae) and microbial grazers (Collembola). The plant cover types showed homogeneity in the distribution of the soil-litter fauna, and the development of a litter layer by leguminous tree plantations in a degraded pasture produced a higher abundance and diversity of soil fauna.