城市生态环境安全评价研究

城市作为一种典型的复合生态系统。其生态环境具有相当的脆弱性，因此如何改善生态质量和维护生态安全已成为城市发展要解决的主要问题之一。本文从生态环境状况和生态安全2个方面对张家港市生态环境安全进行评价和研究，计算了生物丰度指数、植被覆盖指数、水网密度指数、土地退化指数、污染负荷指数等5个指标，计权确定该市生态环境质量指数为48．7，评价等级为一般；同时选择了资源安全评价、环境安全评价、生物安全评价和灾害安全评价等4个要素，确定该市生态系统安全指数为0．44。

Ecological Environmental Security Assessment Zhangjiagang in City

As one typical compound ecosystem,urban ecological environmental has comparative frangibility,so how to improve ecological quality and maintain ecological security have become to one of primary problems for city development.This study assesses ecological environment in Zhangjiagang in two aspects,ecological environmental status and ecological security.Five indexes(biology plentiful degree,vegetation revetment,water net density,soil degradation and pollute burthen) are counted to confirm ecological quality index with a value of 48.7,and assess grade as common,meanwhile,four factors(resource, environment,biological security and disasters) are chosen to calculate the ecological security index with a value of 0.44.