高山苔原是受全球气候变化威胁最大的生物群系之一。在高山苔原，大部分植物生物量都存在于地下，植物根系在土壤中的分布模式、周转率、根凋落物的分解速率对土壤碳库和养分循环都有重要的影响，因此植物根系在高山苔原的生态系统功能中占据着重要的地位。但是目前国内外关于气候变化对高山苔原植被根系影响的研究依然较少。本项目拟通过位于青藏高原高寒草甸的人工控制实验，模拟气候变化造成的温度、降水和土壤养分的变化，并通过连续采样和微根窗对植被根系的分布模式和生长动态进行研究、通过凋落物袋对根凋落物的分解及丛枝菌根真菌在分解中的作用进行研究，来了解气候变化对高寒草甸根系的生长和分解动态的影响，以及通过植物去除实验来研究气候变化引起的植物多样性改变对这两个过程的影响。研究结果将有助于我们更深入地了解全球变化背景下高山苔原土壤碳动态和养分循环的变化机制，将为评估高山苔原对全球变化的响应和反馈提供科学依据。

Alpine tundra is one of the biomes that are most sensitive to climate change. In alpine tundra, the major part of plant biomass occurs belowground. Soil carbon pools and nutrient cycling can be profoundly influenced by the distribution patterns of plant roots, root turnover rates, and decomposition rates of root litter. Therefore, plant roots play a key role in ecosystem functions of alpine tundra. However, studies on the effects of climate change on the belowground part of alpine tundra vegetation are still limited. This project aims to investigate climate change effects on root growth and decomposition dynamics of alpine meadow, and influences of biodiversity change induced by climate change on the two processes. On the basis of a field manipulation experiment in an alpine meadow in Qinghai-Tibet Plateau simulating changes in temperature, precipitation and soil nutrient availability caused by climate change, root distribution pattern and growth dynamics will be investigated through consecutive sampling and minirhizotron observation; decomposition dynamics of root litter and the role of arbuscular mycorrhizal fungi in the decomposition will be investigated through litter bag incubation. Furthermore, impacts of changes in plant diversity on these two processes will be investigated through a plant removal experiment. The results will improve our understanding of the mechanisms of changes in carbon dynamics and nutrient cycling in alpine tundra soils in the context of global change, and enable us to better estimate responses and feedbacks of alpine tundra to climate change.