Vegetation influences desert soil arthropods and their response to altered precipitation

Altered size and frequency of precipitation pulses will influence both plant and soil communities in water-limited systems such as the Sonoran Desert. Little is known about the response of desert soil fauna communities, particularly the mesofauna that are important components of the detrital food web. Further, while there is a well-documented impact of vegetation on soil fauna communities, the role of vegetation in buffering the soil community against such environmental changes is unclear. We conducted a short-term field study to (1) assess how the amount and frequency of monsoon season precipitation pulses influence soil arthropod communities and (2) explore the role of plant-soil linkages in the response of soil arthropod communities to altered precipitation. We experimentally altered the size (ambient and 50% increase) and frequency (ambient and 2X reduced frequency) of monsoon season precipitation for two dominant shrubs representing distinctly different functional types, as well as interplant spaces. We measured the resulting soil arthropod abundance, diversity, and composition, as well as key soil properties to characterize the soil habitat beneath each vegetation type.

降水脉冲的强度与频率变化，将对索诺兰沙漠（Sonoran Desert）这类水分受限生态系统中的植物与土壤群落产生显著影响。目前学界对荒漠土壤动物群落，尤其是作为腐食食物网重要组成类群的中型土壤动物（mesofauna）的响应机制仍缺乏深入认知。此外，尽管已有充分研究证实植被对土壤动物群落存在明确影响，但植被在缓冲土壤群落抵御此类环境变化中的作用仍未明确。本研究开展了一项短期野外实验，以实现两大研究目标：其一，评估季风季降水脉冲的强度与频率变化如何影响土壤节肢动物群落；其二，探究植物-土壤联系在土壤节肢动物群落响应降水变化过程中的调控作用。我们针对两种功能型显著迥异的优势灌木，以及植株间空地，对季风季降水的强度（设置自然对照与50%增幅两组）和频率（设置自然对照与降低2倍频率两组）进行了人工调控。随后我们测定了对应的土壤节肢动物丰度、多样性与群落组成，同时测定了关键土壤理化性质，以表征不同植被类型下的土壤生境特征。