Evaluation of Regional Ecological Security Based on Dynamic Factors——A Case Study of Wanquan County, Hebei Province
基于动态因子的区域生态安全评价 ——以河北省万全县为例

At the beginning of the new century,the issue of ecological security has been put on the agenda of the government in many countries owing to increasingly deteriorating environment of the world.Because regional ecological security serves as the basis of sustainable regional and national development,it comes to be the focus of ecological security.The aim of this study was to develop a comprehensive evaluation system for regional ecological security.Wanquan County of Hebei Province,located in a transitional zone between the farming and pastoral regions,was taken as a case study area.It serves as one of major channels of sandstorm transportation from Inner Mongolia to Beijing.After processing of basic data and in accordance with the principle that evaluating indicators should be dynamic,principal and operable,3 types of evaluating indicators,including vegetation changes,LUCC and soil erosion,were selected.By the comprehensive index method,the dynamic evaluation model was built with the three types of indices based on ecological degradation,and their weights were worked out by introducing least squares solution.And then,the evaluation image for ecological security was generated in ArcGIS9.0/Spatial Analyst module and the model was realized.The final results show that the situation was better in the river area and insecure areas distributed in north part and middle part mainly.An average score of 2.3 in a 4-grade range would not only tell the ecological condition for the entire study area,but also remind the local government to pay more attention to ecology protection.It was proved that dynamic evaluation indicators were superior to static ones for ecological security evaluation,and the least squares solution was a practical and scientific method to balance the weights for evaluation indicators.In addition,the evaluation system was proved to be qualified and synthetically corrected also by applying it to other counties around Beijing.