流域植被结构动态的水文学机制及其模拟研究

气候变化影响下，流域生态系统面临着水文变异引起的植被结构变化，以及由此产生的水文过程调节功能降低等系列生态环境问题。本项目强调水文过程在驱动植被结构动态中的关键作用，围绕水分胁迫影响下植被结构特征响应机制与阈值的关键科学问题，以“水分变化胁迫-植被结构响应-系统模拟与反馈”为总体研究思路，通过定位监测、实验与模拟相结合的方法，研究多尺度植被动态特征及其对水文过程的响应，辨识影响植被结构动态以及空间分布变化的关键水文指标阈值；构建耦合生态水文过程的植被结构动态模型，分析多要素驱动下植被结构动态响应规律及其对径流过程的影响，权衡产流、蒸散和生态需水的动态响应关系，筛选维护健康流域产流过程的生态情景。成果将从内涵和机制上丰富和发展生态水文学基础理论，为发展应对气候变化的流域保护和解决产流问题的生态学方法提供技术指导。

Influenced by the climate changes, responses of vegetation structure to hydrological processes variation have altered its regulation for streamflow. This project highlights the role of hydrological changes in forcing and keeping vegetation structure and focuses on changes in response and threshold of vegetation structure to water stress. According to the thought “influences resulted from water stress – response of vegetation structure – ecohydrological processes simulation and feedback” and using methods of in-situ monitoring, experiment and modeling, objectives of this project are: to study vegetation structure and its response to hydrological change on multi-scale; to identify hydrological thresholds which impact on vegetation structure and vegetation spatial distribution; to set up a dynamic vegetation structure model incorporated ecohydrological processes; to analyze response of vegetation structure forced by multi-variable and its feedback to runoff; and to obtain ecological scenarios to maintain catchments integrity using the trade-off between evapotranspiration, runoff and ecological water requirement. Results of this project will enrich and develop ecohydrology theory, and is significant to catchments conservation and resolving problems in runoff generation under climate change.