强烈人类活动扰动下毛乌素沙地浅层地下水与植被演变规律研究

The natural vegetation of the water-limited area plays a key role in maintaining regional ecological stability, retaining biodiversity and decelerating desertification. The stability and structure of natural vegetation community and its evolution are closely related to groundwater, especially the shallow groundwater. Study on the interactive relationship between the natural vegetation evolution and the shallow groundwater regime under intensive disturbance by human activities has an important significance in keeping the regional economic sustainable development and ecosystem preservation. Mu Us Sandland was selected as the study area in this proposal. Firstly, the spatial coverage and temporal dynamic variation of natural vegetation and its driving forces will be analyzed by using quantitative remote sensing and GIS technology. Secondly, a quantitative relationship between the shallow groundwater regime and natural vegetation changes will be established by using geostatistics principle and methods, combined with field groundwater level observations data, and a coupled model of the mechanism of interaction between the natural vegetation and the shallow groundwater will be built. Thirdly, the trends of the natural vegetation evaluation and shallow groundwater regime under the various planning scenery of the study area will be simulated and predicted. A practical paradigm of the study results can be introduced to evaluate and preserve the shallow groundwater resources and ecological environment of water limited area in the Northwest China, and to provide the scientific basis for decision making for industrial planning and protection of ecological environment in the development process of the energy base in Shaanxi and Inner Mongolia can be suggested.

缺水地区天然植被在维护区域生态稳定、保护生物多样性及抑制荒漠化等方面具有重要意义。由于降雨少，天然植被群落稳定性、结构及演变与地下水，尤其是与浅层地下水之间存在非常密切的关系。采矿等人类活动强烈扰动了地下水的天然流场，进而影响天然植被的演变，研究两者之间的规律，对保护区域生态环境，促进地区资源可持续开发利用具有重要现实意义。本项目选取毛乌素沙地为研究区，首先采用定量遥感方法分析天然植被时空变化规律，并利用地理信息系统技术进行驱动力分析。然后结合野外地下水观测资料，应用地质统计学原理建立浅层地下水位动态与天然植被演变之间的定量关系，构建两者相互作用规律的耦合模型，进而对不同规划方案扰动条件下研究区内浅层地下水位和植被变化趋势进行模拟预测。研究成果可为陕蒙能源基地开发过程中产业规划与生态环境保护方案提供科学决策依据，并为类似地区地下水资源及生态环境保护的研究与评价提供一套切实可行的方法体系。

毛乌素沙地地处我国西北干旱半干旱地区，天然植被的演变和地下水有密切的关系，强烈的人类活动通过影响区域水文过程，间接影响了天然植被的演变。本项目在充分收集整理现场资料后，编制了研究区浅表层地下水位埋深图。采用遥感方法反演了研究区地面温度及地表覆盖类型，重点研究了区内最大的水体-红碱淖的水面面积变化。结合野外调查结果，研究了毛乌素沙地南缘不同类型植被生态与潜水埋深的关系，尝试建立浅层地下水位动态与天然植被演变之间的定量关系。项目主要取得如下主要成果：1）建立了毛乌素沙地气象、水文、遥感、水文地质等基础信息数据库，为后续继续开展该地区相关研究工作奠定了坚实的基础；2）基于ESTARFM算法，利用MODIS数据填补了Landsat数据的缺失，构建了1987-2018年红碱淖水面面积变化的高精度时间序列数据；3）通过调查，初步查明了毛乌素沙地南缘植被类型、根系、长势等与浅表层地下水的关系。研究成果可为毛乌素沙地区域产业规划与生态环境保护方案提供部分科学决策依据。