Response of Soil Fauna to Simulated Global Change Factors Depends on Ambient Climate Conditions

Abstract Soils systems provide essential ecosystem functions and services performed by a hyperdiverse array of fauna, but how soil communities respond to climate change remains an understudied topic. Although previous long-term studies have found variable effects of climate change manipulations on soil communities, precipitation often yields strong responses from fauna. In this study we used a field-based experiment to test how soil communities respond to active warming (+4 °C) and elevated atmospheric CO2 concentrations (800 ppm) in the boreal forest over two consecutive years in a full factorial experimental design. We sampled and identified soil fauna across multiple taxonomic groups to determine how species abundance, richness, diversity, evenness, and community composition were affected by these simulated global climate change factors. Fauna were minimally affected by experimental treatments in the first year of sampling. However, in the second year of treatment, richness and diversity increased and soil community composition shifted as oribatid mites responded to both warming and elevated CO2 and springtails responded to warming treatments. We propose that the enhanced response of soil communities in the second year of experimental treatment was due to greater than normal precipitation, suggesting that annual variability in weather conditions can influence soil fauna response to climate change.