Soil fauna in subtropical landscapes: Response to environmental, spatial, and land use systems changes

Soil fauna plays an important role in the stabilization of ecosystems in agricultural landscapes, due to their morphological and functional variety and for directly or indirectly participating in biological processes. This study aimed to evaluate the effect of landscape fragmentation on soil fauna communities and their relationship with environmental and spatial variables in Southern Brazil. The heterogeneity of land use systems in rural landscapes of three municipalities was considered. A sampling grid was established in a window with a 1 km diameter in each landscape in two sampling periods. The increase in landscape complexity and efficiency followed the fragmentation gradient (High < Intermediate < Low). The environmental variables related to the fauna were land uses, altitude, litter dry weight, litter carbon to nitrogen ratio, soil nitrogen, potassium, pH, biopores, aeration space, saturated hydraulic conductivity, and penetration resistance. Thus, the environmental variables explained the soil fauna composition more than the spatial variables. Furthermore, pasture and native forest were the most important land use systems as refuge and source of soil fauna in the landscape. The heterogeneity of the subtropical landscapes influenced the structure of soil fauna communities, and the more fragmented landscape was less favourable to maintaining complex interconnections.