金沙江流域生态脆弱性评价

Assessment of ecological vulnerability in Jinsha river basin

以自然环境复杂且生态功能重要的金沙江流域为研究区,从自然环境和人类活动2个方面构建评价指标体系,采用空间主成分分析模型定量评价2005—2015年金沙江流域的生态脆弱性并对评价结果进行分级和统计,进而得出其生态脆弱性分布特征和变化趋势。结果表明,金沙江流域内生态脆弱性地区差异显著,上游生态环境较好,中游次之,下游较脆弱,河流流经地区比河谷两岸脆弱性低;流域内生态环境整体处于中等水平,各脆弱性等级占比由高到低依次为轻度、中度、潜在、重度和极度;2005、2010、2015年的3个研究时段内,金沙江流域的生态脆弱性综合指数(EVSI)分别为2.53、2.55、2.38,先略增长后减小,再加上极度脆弱面积持续减少,可见生态环境总体上有所改善。

Taking the Jinsha river basin with a complex natural environment and important ecological functions as a research area,an evaluation index system was constructed from two aspects of natural environment and human activities,and a spatial principal component analysis model was used to quantitatively evaluate the ecological vulnerability of the Jinsha river basin from 2005 to 2015.The evaluation results were graded and counted,and then the distribution characteristics and change trends of its ecological vulnerability were obtained.The results showed that the ecological fragility in the Jinsha river basin was significantly different,the upstream ecological environment was better,the middle reaches was second,the downstream was more fragile,and the areas river flow was less vulnerable than the two banks of the valley;The overall ecological environment in the river basin was at a medium level,and the proportions of vulnerability levels from high to low were mild fragile,moderate fragile,potential fragile,severe fragile,and extreme fragile;During the three study periods from 2005 to 2015,the comprehensive index of ecological vulnerability(EVSI)of the Jinsha river basin were 2.53,2.55 and 2.38,respectively,which firstly increased slightly and then decreased,coupled with the continuous reduction of extremely vulnerable areas,and the overall ecological environment had improved.