陇南地区脆弱生态环境动态评价

分析了陇南山区生态环境的特点，认为其是以干旱河谷为基带的较为特殊的山地生态系统，具有较明显的过渡性和敏感性．选取自然、社会和经济等人文因素建立了陇南脆弱地域生态系统的评价指标体系，对该地域生态脆弱程度进行动态评价，结果表明，陇南地区生态系统脆弱度为0．18，属轻度脆弱区．14年来该地区生态环境的变化可划分为两个阶段，1992年以前为重度脆弱性，脆弱指数大于0．30；1992年以后，为轻度脆弱性，脆弱指数小于0．30，且逐年下降．说明该地区生态环境正在向良性方向转化．其中农民收入的增加、人口素质的提高以及环保政策的有力支持，是该地区生态环境向良性转化的重要因素，也是区域可持续发展的有力保障．

A dynamic evaluation fragile environment in Longnan District

The article analyses the features of the eco-environment in Longnan District,which is considered to be the rather special mountain ecological system on the basis of dry valley with the characteristic of transition and tenderness. We established the fragile ecosystem appraisal target system,which including the nature fragile factor,society and economic fragile factor.According to the dynamic change of fragile index,the environment change in Longnan District can be divided into two stages,its fragile index is 0.18.In the last fourteen years,its represents as moderated fragility with index of above 0.30 before 1992,and after that it does as light fragility with index of below 0.30,especially is tending to decrease continuously,which proves the environment in the Longnan District is getting better.As for the reasons,some factors are influential,such as the increase of peasants' income,improvement of population quantity,support of environment protection policies,which are the important guarantee of regional sustainable development