Vegetation influences desert soil arthropods and their response to altered precipitation

Altered precipitation in the arid southwestern USA will influence both plant and soil communities, but relatively few studies explore its impact on soil arthropods who comprise an important component of soil food webs. Further, while vegetation has a well-documented influence on soil communities, it is unclear how the plant community might influence their response to altered precipitation. We altered both the size and frequency of monsoon season precipitation pulses in the Sonoran Desert and measured the resulting soil arthropod abundance, diversity, and composition. We manipulated the precipitation for two dominant shrubs representing distinctly different functional types compared to interplant spaces. Plant cover significantly influenced soil arthropods, with the deep-rooted evergreen Larrea tridentata increasing abundance and diversity over interplant spaces more strongly than the drought-deciduous Ambrosia deltoidea. Precipitation pattern altered arthropod diversity and evenness, particularly in interplant soils. While soil arthropod total abundance was resistant to altered precipitation, vegetation buffered Shannon diversity from the impacts of altered precipitation. Thus, climate-induced changes in the plant community could indirectly influence soil arthropod diversity. However, these plant-soil interactions may not be equally important under all scenarios of altered precipitation.