基于突变级数法和主成分分析法的长沙市生态安全评价

On the ecological security evaluation of Changsha City via analyzing the catastrophe progression and the principal component analysis

基于P-S-R(压力-状态-响应)模型,构建长沙市生态安全评价的指标体系。同时结合突变级数法和主成分分析法,构建长沙市2008—2012年生态安全的突变模型,并对其进行评价。结果表明,2008—2012年,长沙市生态安全总隶属度值由2008年的0.68(V级)上升为2012年的0.94(Ⅲ级),表明长沙市生态安全状况呈上升趋势。在构成长沙市生态安全系统的3个子系统中,系统状态和系统响应两个子系统的安全隶属度呈上升趋势,且除2008年以外的其余年份均处于较安全等级;系统压力子系统的安全隶属度虽处在较安全等级以上,但呈下降趋势。这表明长沙市生态安全还存在生态隐患,需要降低环境压力。根据此评价结果,并结合长沙市当前存在的主要环境问题,得出长沙市生态安全建设的主要限制因子。

The paper is to present the author＇s study on the urban e- cological security. For the above research purpose, we would like to take Changsha City as our case study sample. As is known, ecologi- cal security used to be defined as the goal of the state in creating a condition where physical surroundings of a city or any other residential communities are supposed to be able to provide their residents with the condition without diminishing its natural stock. However the actu- al urban ecological security conditions have now been becoming a great challenge for the urban harmonious survival and development. With the fast pace of urbanization, Changsha is now confronted with a great stress in keeping its ecological balance. Though a lot of re- searchers are now engaged in the study of urban ecological security and presented their results and opinions, most of them expressed their concerns and feel discouraged on account of the limited methods. In order to change the situation and help to overcome the situation, this paper has brought about an evaluating indicator system for the urban ecological security based on P-S-R（Pressure-State-Response） frame- work, and established a catastrophe model for ecological security e- valuation of Changsha City from 2008 to 2012 along with our analysis of the catastrophe progression and principal component analysis. The results of our investigation and analysis indicate that, in the period from 2008 to 2012, the individual value of the ecological security has risen from 0.68（V） of 2008 to 0.94（III） of 2009, whereas the eco- logical security state tends to get improved, too. For example, in the three subsystems, the individual value of ecosystem state and ecosys- tem response proves to be in a safer level except for 2008. Although the individual value of ecosystem pressure turns to be in a safer level or above, the downward trend shows that the ecological security risks of the City still remain. Therefore, the evaluation results and the main environment problems we have found in the City for the time be- ing may all help to find the main inadequacies in the city＇s ecological security construction. Thus, our work can be taken as a reference to the promotion of establishing a scientific strategy for further develop- ment of the City＇s ecological security.