Vegetation dynamics induced by groundwater fluctuations in the lower Heihe River Basin, northwestern China
Vegetation dynamics induced by groundwater fluctuations in the lower Heihe River Basin, northwestern China
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DOI：
10.1093/jpe/rtr002
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发表时间：
2011-03
影响因子：
2.7
通讯作者：
Ping Wang;Yi-chi Zhang;Jing-Jie Yu;G. Fu;Fei Ao
中科院分区：
文献类型：
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作者：
Ping Wang;Yi-chi Zhang;Jing-Jie Yu;G. Fu;Fei Ao
黑河流域是我国西北地区典型的干旱内陆河流域，自2000年起，在黑河下游实施环境流量控制工程，以恢复该地区日益恶化的生态环境。本研究的目的是探讨地下水波动对植被动态的影响。研究结果可作为干旱区水资源规划和管理的参考，以维持适当的环境流量。方法于2009年7 ~ 8月对各监测点的监测威尔斯井的位置、深度、地下水埋深和盐度进行现场监测。根据黑河下游环境流量控制工程实施后地下水埋深和矿化度的实测资料，分析了2001 - 2009年黑河下游地下水的变化规律。采用描述性统计和皮尔逊相关分析方法分析了植被变化与地下水位波动的关系。此外，地下水位埋深和盐度的空间分布插值使用简单的克里格方法。趋势分析应用于时间序列的综合中分辨率成像光谱仪归一化差异植被指数数据，以确定年际植被动态。通过时间序列和趋势分析比较，研究了不同空间尺度下植被状况与地下水环境的关系。主要研究结果（1）研究区大部分地区地下水位和矿化度显著上升，且空间异质性较强。平均而言，地下水位上升0.5和1.5米，在额济纳盆地的上部和下部，分别，和地下水盐度增加0- 4%，在整个研究区域。(ii)地下水位在1.8 ~ 3.5m之间变化时，植被状况与地下水位变化有显著的相关性，而地下水位在5-6 m之间变化时，植被状况对地下水位变化的响应不明显。(iii)植被恢复主要发生在距天然河流500-1 000 m范围内，地下水埋深2 ~ 4 m，矿化度<5%的河岸带，部分地下水环境恶化的地段出现植被退化。
Aims Since 2000, the environmental flow controls project has been implemented in the lower Heihe River Basin, a typical arid inland river basin in northwest China, to restore the deteriorated ecological environment in this region. The aim of this study was to explore the impacts of groundwater fluctuations on vegetation dynamics. Our results can be used as a reference for water resources planning and management to maintain proper environmental flows in arid areas. Methods The location (by Global Positioning System) and depth of the monitoring wells, as well as groundwater table depth and salinity were measured in situ at each site from July to August 2009. Based on the measurements of the groundwater table depth and salinity following the implementation of environmental flow controls project (EFCP) in the lower Heihe River Basin, the groundwater fluctuations during the period from 2001 to 2009 were analyzed. Descriptive statistics and Pearson’s correlation were used to analyze the relationship between vegetation changes and groundwater table fluctuations. Additionally, the spatial distributions of the groundwater table depth and salinity were interpolated using the simple kriging method. Trend analysis was applied to the time series of integrated Moderate Resolution Imaging Spectroradiometer normalized difference vegetation index data to identify interannual vegetation dynamics. The relationship between vegetation status and groundwater environment was investigated at different spatial scales by analyzing and comparing the time series and trends. Important Findings (i) The groundwater table and salinity increased significantly in most of the study area with spatial heterogeneity. On average, the groundwater table rose ;0.5 and 1.5 m in the upper and lower Ejina Basin, respectively, and the groundwater salinity increased across the study area by 0–4%. (ii) A notable correlation between the vegetation status and the groundwater table was revealed when the groundwater table depth fluctuated between 1.8 and 3.5 m, whereas the vegetation did not show an obvious response to groundwater table changes when the groundwater table depth was more than 5–6 m. (iii) Vegetation restoration mainly occurred in riparian areas within 500–1 000 m of from natural rivers, where the groundwater table depth varied from 2 to 4 m, and salinity was <5%, whereas vegetation degradation appeared at some locations where groundwater environment had deteriorated.