南亚热带地区植被覆盖变化对系统水分输出分配的影响及其机制探究

Evapotranspiration (including evaporation and transpiration) and runoff (including surface runoff and underground runoff) are the two main forms and routes of terrestrial ecosystem water loss. Partitioning and quantifying the specific components of evapotranspiration and runoff is of importance for the proper understanding of the hydrological effects of forests, especially the relations between afforestation and water yield. Basically, the traditional time-trends studies and paired-watersheds experiments both have their natural limitation on the partitioning of the output water as the high variability in the generation of the various runoff components. For this reason, in the Dinghushan Forest Ecosystem Research Station, we have established the simulated forest ecosystem experimental platform, of which the liquid water processes were accurately controlled and monitored. Using both the traditional technique of small watershed and the fine controlled experimental platform together, combining qualitative and quantitative research methodologies, this project aims to: 1) determine the changes of ecosystem hydrologic processes in response to vegetation cover change; 2) explore the mechanisms of forest hydrological effects in response to vegetation cover change in lower subtropical zone. The results will contribute to revealing the effect and mechanism of forest on water cycles and providing scientific supports for assessing forest hydrological benefits in regional scale.

蒸散 (包括蒸发与植被蒸腾) 和径流 (包括地表与地下径流) 是陆地生态系统水分输出的两大主要途径。弄清生态系统水分输出过程中定量的组分分配及其随植被覆盖变化的去向规律，是正确认识森林与径流的关系以及科学评估森林的水文效应的关键所在。传统的流域/集水区实验在对水分输出的控制及其组分的分割、量化方面存在天然不足。本项目依托鼎湖山森林生态系统定位研究站已建成封闭式小集水区径流场与开顶箱式森林生态系统模拟精细控制实验平台，基于定性与定量研究相结合的指导思想，通过对生态系统水分的输入、运移与输出过程的严格控制与全面监测，探究南亚热带地区植被覆盖变化对系统水分的输出过程及其组分去向的影响，并结合气象因子、土壤因子以及植物生理因子等的监测，阐述本地区生态系统的水分过程受植被覆盖变化调控的内在机制。本研究有助于揭示南亚热带地区森林植被的水资源调蓄功能，为本区域森林的水文效益评估提供理论基础。

弄清生态系统水分输出过程中定量的组分分配及其随植被覆盖变化的去向规律，是正确认识森林与径流的关系以及科学评估森林的水文效应的关键所在。本项目依托鼎湖山森林生态系统定位研究站已建成封闭式小集水区径流场与开顶箱式森林生态系统模拟精细控制实验平台，基于定性与定量研究相结合的指导思想，揭示了湿润地区森林与径流关系的特定表征（即湿润地区森林覆盖变化对产水量的有限影响），阐述了湿润地区森林水分过程受植被变化调控的过程机制，整合综述了全球集水区试验研究的现状、进展、存在问题以及未来研究方向，系统回答了湿润地区森林植被与水资源关系问题。本研究有助于揭示南亚热带地区森林植被的水资源调蓄功能，为本区域森林的水文效益评估提供理论基础。