沿海城市生态安全系统结构及稳定性研究

论文以传统DPSIR,概念模型为基础,构建中国沿海城市生态安全系统评价指标体系,提出5个因素间的7组因果关系假设.通过结构方程模型(SEM)对假设进行检验,辨识中国沿海城市生态安全系统的结构框架.运用生态网络分析法(ENA)建立信息传递方程,对生态安全系统稳定性进行测度.研究发现:传统DPSIR概念模型的因果关系假设不具有普适性,在中国沿海城市生态安全系统结构中,“响应R”对“状态S”正向作用的因果假设被拒绝.进而本文根据其他6组因果关系构建了独具特色的沿海城市生态安全系统结构.生态网络分析结果显示,中国沿海城市生态安全系统信道容量为2.1065,聚合度为1.7254,表明沿海城市生态安全系统稳定性较高,系统内要素间相互依赖程度强.同时由于系统空闲率(0.1809)较低,导致系统对外部冲击的抵御能力较差.沿海城市应进一步增加系统的弹性空间,提高生态安全系统稳定性.

The framework structure and stability analysis of coastal urban ecological security system

Based on the original conceptual model of "driver-pressure-state-impact-response" (DPSIR), this study develops an assessment index system of coastal urban ecological security system, proposing 7 causal hypotheses among 5 elements in pairs. By means of structural equation model (SEM), this study verifies the causal relationship and causal coefficients among the five elements in pairs, and identifies the framework structure of the ecological security system. The stability level of the ecological security system of Chinese coastal cities is then measured by an ecological information delivering equation established from ecological network analysis (ENA). The results indicate that: the original causal hypotheses of DPSIR model are not universal. In the Chinese coastal urban ecological security system, the hypothesis that "the response (R) has a positive influence on the state (S)" is rejected. A coastal urban DPSIR model is further developed according to the other 6 groups of causal relationships. The ENA analysis results present that the channel capacity and degree of polymerization in the system are 2.1065 and 1.7254 respectively, which shows that the coastal urban ecological security system has a strong stability, with high dependence on the elements within the system. With low vacancy rate (0.1809), the system is poor at resisting shockwaves from external system. It is imperative for coastal cities to broaden their flexible space so as to guarantee their sustainable development.