岷江上游生态脆弱性评价

岷江上游流域是我国典型的生态脆弱区之一，由于地质变化频繁、高差显著、气候干旱，加上人为活动影响，生态脆弱性的表现十分明显。通过对其生态环境脆弱性因素及成因机制的分析，构建了由土地生产力、地表起伏度、干燥度指数、土壤侵蚀强度、草场退化荒漠化率、物种消失率等14个指标组成的岷江上游生态脆弱性的评价指标体系；根据本地区生态环境现状、全国和四川省情况及奋斗目标，建立了Ⅰ到Ⅲ级的评价标准体系；利用模糊数学聚类方法对评价指标进行分析计算，得出了岷江上游生态环境为第Ⅲ级，即生态环境非常脆弱的结论。评价结果符合岷江上游地区的生态环境状况。

ASSESSMENT OF ECOLOGICAL VULNERABILITY IN UPPER REACHES OF MINGJIANG RIVER

This paper was mainly delt with the assessment on ecologyical vulnerability in the upper reaches of Mingjiang River. The upper reaches of the Mingjiang River is one of the typical vulnerable ecotones in our country. Its vulnerability is quite evident on account of the variable geography remarkably differentin height and dry climate,added up by the effect of human actions. In the light of the analysis which involves the factors and mechanisms of the ecological vulnerability,14 indexes including productivity of land,dryness index, soil errosion rate and grassland degeneration rate,etc,were chosen in order to set up an assessment index system. The system consists of three grades:1st ,2nd and 3rd grades. According to the \{analysis\} and calculations by the fuzzy mathematics method,we have drawn a conclusion that the ecological vulnerability of the upper reaches of the Mingjing River belongs to the 3rd grade of the system,namely the most vulnerable grade among the three grades. The conclusion conformed to the present condition of this regional ecological environment. At the same time,it is important to guide the river basin's economical development and ecological environment construction.