基于ISODATA法的三峡库区生态区划

在可持续发展思想的指导下，以生态学理论为基本依据，探讨了生态区划的原则、指标和方法。采用ISODATA法结合SPSS100中的层次聚类分析软件包，选择生态环境指标、社会发展指标和经济发展指标等20个定性、定量指标，利用数量化评分标准将三峡库区划分为4个生态类型区，并对各生态类型区的主要特征进行分析，应用ArcGIS绘制出三峡库区生态区划图，结果表明第I区生态类型较好。研究指出三峡地区生活在生态安全质量较高的人口约有28万多人，只占库区总人口的17%；此外通过对各区生态经济特征的综合评价结果，可以看出各区主要以山地、丘陵地为主，而且水土流失面积占60%左右，三峡库区生态安全形势十分严峻。旨在为生态分区评价以及三峡库区生态安全建设提供参考，提出加强山地丘陵的综合治理、控制水土流失及降低污染是优化三峡库区生态状况的关键。

ON THE ECOLOGICAL REGIONALIZATION BASED ON THE ISODATA METHOD IN THE THREE GORGES RESERVOIR AREA

As a significant symbol of regional ecological environment health, ecological security is an important component of social stability and national security. In this paper, a new index system was established for ecological security construction in the Three Gorges Reservoir area according to the local natural and economic conditions, and the principles, indices and methods for ecological security regionalization were discussed based on ecological theory. The whole Three Gorges Reservoir area was then divided into 4 regions with different degrees of ecological security, using fuzzy cluster analysis of ISODATA and the tools for analytic hierarchy process of SPSS. The characteristics of the 4 regions were analyzed, and the distribution map of them was drawn using ArcGIS. It is showed that there were about 2 852 thousand people, accounting for 17% of the total population of the area, living in regions with better situation of ecological security, occupying 15% of the total reservoir area; whereas, 57 percent of the total population living in regions of type III and IV with fragile environment, accounting for 55% of the total area. Soil erosion rates in these regions exceeded 4 600 t/km2〖DK1〗·a.Therefore, the situation of ecological security in the Three Gorges Reservoir area was serious. The results can be of reference significance for ecological security evaluation and the construction of ecological security in the reservoir area. It was also proposed that comprehensive management of hilly areas, controlling soil erosion and decreasing pollution are key points to improve the ecological situation of the Three Gorges Reservoir area.