Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province & National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River & Rainy Area of West China Plantation Ecosystem Permanent Scientific Research Base & Institute of Ecology & Forestry, Sichuan Agricultural University, Chengdu 611130, China.
Global Ecology Unit CREAF-CSIC-UAB, CSIC, Barcelona, Catalonia, Spain.
Sci Total Environ. 2020 Nov 1;741:140454. doi: 10.1016/j.scitotenv.2020.140454. Epub 2020 Jun 23.
Winter snow cover is a major driver of soil microbial processes in high-latitude and high-altitude ecosystems. Warming-induced reduction in snow cover as predicted under future climate scenarios may shift soil bacterial communities with consequences for soil carbon and nutrient cycling. The underlying mechanisms, however, remain elusive. In the present study, we conducted a snow manipulation experiment in a Tibetan spruce forest to explore the immediate and intra-annual legacy effects of snow exclusion on soil bacterial communities. We analyzed bacterial diversity and community composition in the winter (i.e., the deep snow season), in the transitional thawing period, and in the middle of the growing season. Proteobacteria, Acidobacteria, and Actinobacteria were dominant phyla across the seasons and snow regimes. Bacterial diversity was generally not particularly sensitive to the absence of snow cover. However, snow exclusion positively affected Simpson diversity in the winter but not in the thawing period and the growing season. Bacterial diversity further tended to be higher in winter than in the growing season. In the winter, the taxonomic composition shifted in response to snow exclusion, while composition did not differ between exclusion and control plots in the thawing period and the growing season. Soil bacterial communities strongly varied across seasons, and the variations differed in specific groups. Both soil climatic factors (i.e., temperature and moisture) and soil biochemical variables partly accounted for the seasonal dynamics of bacterial communities. Taken together, our study indicates that soil bacterial communities in Tibetan forests are rather resilient to change in snow cover, at least at an intra-annual scale.
冬季积雪是高纬度和高海拔生态系统土壤微生物过程的主要驱动因素。未来气候情景预测的积雪减少可能会导致土壤细菌群落发生变化，从而影响土壤碳和养分循环。然而，潜在的机制仍然难以捉摸。在本研究中，我们在西藏云杉林中进行了一项雪操纵实验，以探讨雪去除对土壤细菌群落的即时和年内遗留效应。我们分析了冬季（即深雪季节）、过渡融雪期和生长季节中期土壤细菌多样性和群落组成。变形菌门、酸杆菌门和放线菌门是各季节和雪处理下的主要门。细菌多样性通常对缺乏雪覆盖并不特别敏感。然而，雪去除在冬季显著提高了 Simpson 多样性，但在融雪期和生长季则没有。细菌多样性在冬季通常高于生长季。在冬季，由于雪去除，分类组成发生了变化，而在融雪期和生长季，去除和对照样地之间的组成没有差异。土壤细菌群落随季节强烈变化，特定群体的变化方式不同。土壤气候因素（即温度和水分）和土壤生化变量共同解释了细菌群落的季节性动态。总的来说，我们的研究表明，西藏森林的土壤细菌群落对雪覆盖的变化具有相当的弹性，至少在年内尺度上是如此。
