Positive plant diversity effects on soil microbial drought resistance are linked to variation in labile carbon and microbial community structure

Biodiversity loss and drought are substantially altering both above-and belowground terrestrial ecosystem functioning, but mechanistic understanding of plant diversity effects on the drought resistance of soil microbial biomass remains limited. We designed a mesocosm experiment to examine drought resistance of soil microbial biomass along a plant species richness gradient (five plant species richness levels based on old-field communities). We calculated resistance of microbial biomass to drought and recorded key belowground properties which may influence microbial resistance to drought (i.e., microbial diversity, microbial community structure, soil carbon stocks and root biomass). Plant species richness had a positive effect on microbial resistance to drought. Variation in microbial resistance to drought was linked to properties of the fungal community in ambient soil (Shannon diversity, arbuscular mycorrhizal fungal richness and abundance) but not soil bacterial diversity. Moreover, ..., ,生物多样性丧失与干旱正显著改变陆地生态系统的地上与地下生态系统功能，但当前对植物多样性如何影响土壤微生物生物量干旱抗性的机制性认知仍较为匮乏。 本研究设计了中型生态系统实验，以探究沿植物物种丰富度梯度（基于弃耕地群落设置5个植物物种丰富度水平）的土壤微生物生物量干旱抗性。我们计算得到微生物生物量的干旱抗性，并记录了可能影响微生物干旱抗性的关键地下属性，即微生物多样性、微生物群落结构、土壤碳库与根系生物量。 植物物种丰富度对微生物干旱抗性具有正向作用。微生物干旱抗性的变异与原位土壤真菌群落属性（香农多样性指数、丛枝菌根真菌丰富度与多度）相关，但与土壤细菌多样性无关。此外，,