长江源区植物水分来源及其对冻土退化的响应机制研究

植物水是维系寒区生态环境稳定的主要因素。全球变暖背景下，多年冻土区的持续退化对寒区植物水分来源产生显著的影响，但目前对寒区植物水分来源的量化解析尚不清晰，限制了预测未来寒区生态环境变化的准确性。本项目以长江源区为研究区，应用稳定同位素示踪技术和混合模型，拟开展如下研究工作：（1）构建观测采样网络，探究长江源区各水体稳定同位素指示的植物水分来源；（2）应用混合模型，阐释各潜在水分来源与植物水分稳定同位素之间的关联机制，确定其与植物水分之间的水力联系，量化长江源区植物水分来源；（3）辨识各补给源对长江源区植物水分来源的作用机制，剖析长江源区植物水分来源对冻土退化的响应机制。研究结果将为全面认知气候变暖背景下多年冻土的水文效应和寒区水循环模拟研究提供数据支撑与理论支持，为区域水资源管理、生态保护和植被修复提供科学依据。

Plant water is the main factor to maintain the stability of ecological environment in cold regions. Under global warming, the continuous degradation of permafrost has a significant impact on the sources of plant water in cold regions. However, the quantitative analysis of plant water source is not clear, which limits the accuracy of predicting the future changes of ecological environment in cold regions. Therefore, this project takes the source region of the Yangtze River as the study area, and applies the stable isotope tracer technology and mixed model to carry out: (1) To construct the observation and sampling network to explore the plant water sources indicated by the stable isotope of plant water and other water bodies in the source region of the Yangtze River; (2) To explain the correlation mechanism between potential water sources and plant water stable isotopes by the mixed model, to determine the hydraulic relationship between potential water sources and plant water, and to quantify plant water sources in the source region of the Yangtze River; (3) To identify the mechanism of each recharge source on plant water sources and to analyze the response mechanism of plant water sources to the permafrost degradation in the source region of the Yangtze River. The research results will provide parameter support and theoretical support for the comprehensive understanding of the hydrological effect of permafrost under climate warming and the simulation of water cycle in cold regions, and provide scientific basis for regional water resources management, ecological protection and restoration.