TROPHIC GROUPS OF SOIL FAUNA IN SEMIARID: IMPACTS OF LAND USE CHANGE, CLIMATIC SEASONALITY AND ENVIRONMENTAL VARIABLES

Abstract Soil fauna performs several functions in native and anthropized ecosystems, being affected by spatiotemporal variation and by environmental resource availability. However, there is still a gap in knowledge of how land use change, climatic seasonality, and soil and climate variables impact trophic groups of soil fauna in semiarid environments. We investigated the abundance of detritivores, herbivores, microbivores and predators in three land uses (native forest, pasture and irrigated agriculture), during the dry and wet season, using two collection methods (manually separated soil monoliths and pitfalls) and the effects of soil and climate variables on soil fauna. Detritivore and predator activity was predominant in the 0−20 cm layer (monoliths), while herbivores and microbivores abundance were greater on the soil surface (pitfalls). Irrigated agricultural areas had higher abundance of soil fauna and a different community structure from native forest and pasture, due to continuous water availability. Climatic seasonal variables (temperature, air humidity, solar radiation and wind speed), soil characteristics (Macronutrients, C, C:N ratio, pH and CEC) and land use change impacted all trophic groups. Irrigated agriculture in semiarid regions can serve as a refuge for soil fauna, bringing light to a new community structure that can be shaped to shelter the highest possible biodiversity.