在分析青藏高原高寒生态系统形成机制的基础上,构筑了3个层次、10个指标的脆弱性评价指标体系,系统评估了青藏高原生态脆弱性及其区域差异。研究结果表明:青藏高原中、重度以上脆弱区的面积较大,占区域总面积的74.79%。微度、轻度脆弱区主要分布在雅鲁藏布江大拐弯处、藏东南海拔3000m以下的山地、祁连山南坡的西北段和昆仑山北坡、塔里木盆地南缘地带。重度和极度脆弱区集中分布的趋势明显,占全区面积的49.46%,主要分布在黄河源区、柴达木盆地和阿里高原往东32°N附近的带状区域(78°E～92°E)。研究结果有助于全面掌握青藏高原生态系统的脆弱程度及其空间分异特征,对识别高寒区关键脆弱环境因子、提高生态环境治理的针对性有重要意义。
Unstable natural factors and pressures from human activities determine the ecological vulnerability of the Tibetan Plateau.This paper analyzed the factors and mechanism of ecological vulnerability,and developed an index system comprising 3 levels and 10 indicators for the vulnerability assessment.Using multi-source data and ArcGIS spatial analysis tools,this study quantitatively evaluated the degree and its spatial variation of ecological vulnerability on the Tibetan Plateau,based on the above index system.The results show that most parts of the Tibetan Plateau is ecologically fragile,with 74.79% of the area belonging to moderate to extreme-level vulnerability.The map and data of vulnerability classification indicate that the slight and light-level vulnerability area covers 8.33%,which are mainly distributed in the relatively low mountain areas below 3000 m in southeastern Tibet,the northwestern part of the Qilian Mountains,the northern slope of the Kunlun Mountains and the southern margin of the Tarim Basin;the moderate-level vulnerability area occupies more than 25.33%,mainly on the north and central Tibetan Plateau and the source region of the Yangtze,Lancang and Yellow rivers;while the heavy and extreme-level vulnerability area covers 49.46%,mainly concentrated in the source region of Yellow River,Qaidam Basin and the zone along 32°N(from 78°E to 92°E).The results contribute to understanding the extent of ecological vulnerability and its spatial difference on the Tibetan Plateau,and help to identify environmental problems,the key fragile factors and measures for ecological protection and rehabilitation in this region.
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