Responses of soil microarthropods to warming and increased precipitation in a semiarid temperate steppe

• Increased precipitation has stronger effects on soil microarthropods than elevated temperature.
• Functional group-specific responses result in changes in community structure.
• Food resource availability is more important than abiotic factors (temperature and water availability) in regulating soil microarhtropods in response to climate change.

Soil microarthropods are an important component in soil food webs and their responses to climate change could have profound impacts on ecosystem functions. As part of a long-term manipulative experiment, with increased temperature and precipitation in a semiarid temperate steppe in the Mongolian Plateau which started in 2005, this study was conducted to examine effects of climate change on the abundance of soil microarthropods. Experimental warming had slightly negative but insignificant effects on the abundance of mites (−14.6%) and Collembola (−11.7%). Increased precipitation greatly enhanced the abundance of mites and Collembola by 117 and 45.3%, respectively. The response direction and magnitude of mites to warming and increased precipitation varied with suborder, leading to shifts in community structure. The positive relationships of mite abundance with plant cover, plant species richness, and soil microbial biomass nitrogen suggest that the responses of soil microarthropods to climate change are largely regulated by food resource availability. The findings of positive dependence of soil respiration upon mite abundance indicate that the potential contribution of soil fauna to soil CO2 efflux should be considered when assessing carbon cycling of semiarid grassland ecosystems under climate change scenarios.