Thinning profoundly affects soil microbial communities and carbon (C) cycling through altering soil microclimate, plant growth, C inputs and allocations. However, these effects are uncertain and may change with thinning intensity, recovery stage, forest type, and climate. Here, we conducted a global meta-analysis, based on 337 observations from 49 studies, to quantify the responses of soil properties, microbial biomass and community structure, and extracellular enzyme activities (EEAs) to thinning. We found that thinning did not change the total microbial biomass, but significantly shifted the soil microbial community structure and EEAs. Thinning stimulated both C-oxidase and C-hydrolase, but decreased the ratio of oligotrophic to copiotrophic microbes (i.e. fungi to bacteria ratio and Gram-positive bacteria to Gram-negative bacteria ratio) in the early recovery stage. In contrast, in the mid recovery stage, thinning enhanced C-oxidase but reduced C-hydrolase, and increased the ratio of oligotrophic to copiotrophic microbes. In the late recovery stage, neither community structure nor EEAs differed significantly between thinned and control stands. Such recovery dynamics reflect shifts of the resource-utilization strategies of microbes that are associated with community reorganization. Besides, the distinct litter quality between coniferous and broadleaf forests explained their different microbial responses. Overall, the current meta-analysis suggested that microbes can adapt the thinning-induced biotic and abiotic changes by adjustment of community structure rather than their biomass. The global patterns of how soil microbial community structure and EEAs respond to thinning deepen the understanding of the mechanisms underlying the thinning impacts on the soil C cycling.

稀疏通过改变土壤微气候，植物生长，碳输入和分配而深刻影响土壤微生物群落和碳（C）循环。但是，这些影响尚不确定，并且可能随着间伐强度，恢复阶段，森林类型和气候的变化而变化。在这里，我们基于49项研究的337项观测值进行了一项全球荟萃分析，以量化土壤性质，微生物生物量和群落结构以及细胞外酶活性（EEA）对稀化的响应。我们发现间伐不会改变微生物的总生物量，但会显着改变土壤微生物群落结构和EEAs。稀化刺激C-氧化酶和C-水解酶，但降低了贫营养微生物和营养营养微生物的比例（即 真菌和细菌的比率以及革兰氏阳性菌与革兰氏阴性菌的比率）。相反，在恢复中期，稀化增强了C-氧化酶但降低了C-水解酶，并增加了贫营养微生物与嗜营养微生物的比例。在恢复后期，间伐林分和对照林分之间的群落结构和EEA均无显着差异。这种恢复动态反映了与社区重组相关的微生物资源利用策略的变化。此外，针叶林和阔叶林之间不同的凋落物质量解释了它们不同的微生物反应。总体而言，当前的荟萃分析表明，微生物可以通过调节群落结构而不是生物量来适应稀疏引起的生物和非生物变化。