High latitude regions are experiencing considerable winter climate change, and reduced snowpack will likely affect soil microbial communities and their function, ultimately altering microbial-mediated biogeochemical cycles. However, the current knowledge on the responses of soil microorganisms to snow cover changes in permafrost ecosystems remains limited. Here, we conducted a 2-year (six periods) snow manipulation experiment comprising ambient snow and snow removal treatments with three replications of each treatment to explore the immediate and legacy effects of snow removal on soil bacterial community and enzyme activity in secondary Betula platyphylla forests in the permafrost region of the Daxing'an Mountains. Generally, bacterial community diversity was not particularly sensitive to the snow removal. Seasonal fluctuations in the relative abundance of dominated bacterial taxa were observed, but snow removal merely exerted a significant impact on the bacterial community structure during the snow melting period and early vegetation growing season within two consecutive years, with a reduction in the relative abundance of Chloroflexi and an increase in the relative abundance of Actinobacteria, and no evidence of cross-season legacy effects was found. Moreover, snow removal significantly altered the soil enzyme activities in the snow stabilization period and snow melting period, with an increase in soil acid phosphatase (ACP) activity of snow melting period and a decrease in polyphenol oxidase (PPO) activity of snow stabilization period as well as β-glucosidase (BG) activity of snow stabilization period and snow melting period, but this effect did not persist into the vegetation growing periods. The seasonal variations in bacterial community and enzyme activity were mostly driven by changes in soil nutrient availability. Overall, our results suggest that soil bacterial communities have rather high resilience and rapid adaptability to snow cover changes in the forest ecosystems in the cold region of the Daxing'an Mountains.

高纬度地区正在经历相当大的冬季气候变化，积雪减少可能会影响土壤微生物群落及其功能，最终改变微生物介导的生物地球化学循环。然而，目前关于土壤微生物对永久冻土生态系统积雪变化的反应的知识仍然有限。在这里，我们进行了为期 2 年（六个阶段）的造雪实验，包括环境积雪和除雪处理，每种处理重复 3 次，以探讨除雪对白桦次生林土壤细菌群落和酶活性的直接和遗留影响位于大兴安岭多年冻土区。一般来说，细菌群落多样性对除雪不是特别敏感。优势细菌类群相对丰度存在季节性波动，但除雪仅在连续两年的融雪期和植被生长季早期对细菌群落结构产生显着影响，Chloroflexi相对丰度减少放线菌相对丰度增加，并且没有发现跨季节遗留影响的证据。此外，除雪显着改变了积雪期和融雪期土壤酶活性，融雪期土壤酸性磷酸酶（ACP）活性增加，积雪期土壤多酚氧化酶（PPO）活性降低。积雪稳定期和融雪期的β-葡萄糖苷酶（BG）活性也受到影响，但这种影响并没有持续到植被生长期。细菌群落和酶活性的季节性变化主要是由土壤养分有效性的变化驱动的。总体而言，我们的研究结果表明，大兴安岭寒区森林生态系统土壤细菌群落对积雪变化具有较高的恢复能力和快速适应能力。