社会—生态脆弱性相互关系的计量推断方法

Quantitative inference method for the relationship between social and ecological vulnerabilities

本文在系统分析社会生态脆弱性综合方法研究进展后指出,综合指数法可作为代表某时期在社会和生态脆弱性两方面的指标,解释总体水平下的脆弱性等级,但无法反映指标间相互影响的程度和影响方向;相关系数分析能解释两指标间的相互关系,但无法解释其因果关系;由最小二乘法得到的解释指标变动系数,但由于解释指标和被解释指标选择的主观性,其相互作用的方向性仍无法判断。针对上述关系计量推断中存在的问题,本文探讨了工具变量估计参数的可行性,通过实例证实该方法能揭示社会脆弱性和生态系统脆弱性指标之间相互影响的方向。结果表明,社会脆弱性(So VI)对生态脆弱性(NPPI)的影响强度大于反方向的影响作用,从1980 s到2000 s,NPPI对So VI的作用由强减弱,其作用显著省区由5个减少至2个;而So VI对NPPI的作用由弱增强,其作用显著省区由1个增加为7个。定量且具备相互影响方向的推断方法有利于揭示社会系统和生态系统相互作用的机理。

This study systematically analyzed the results of current integrated method for social- ecological vulnerability research and found that the comprehensive index method can represent the overall level of social and ecological vulnerabilities using indicators of the two particular aspects of vulnerability in certain time period. But such method cannot reflect the degree of interaction and direction of influence of indicators.Correlation analysis can indicate a quantitative relationship between indicators, but is unable to identify causality. Least square method can generate variable coefficient of explanatory indicators when the indicators have changed, but due to the subjectivity in selecting indicators as explanatory variables or explained variables,the direction of influence between variables still cannot be determined. Given these problems, this article explores the feasibility of using instrumental variable（IV） method to reveal interactions between social and ecological vulnerabilities. By application in a case study at the country level in China, the result shows that the IV method can reveal the direction of influence between indicators of social vulnerability and ecological vulnerability, which overcomes the problem identified above. From 1980 s to 2000 s, the impact of ecological vulnerability on social vulnerability（NPPI→So VI） decreased, the corresponding significant impact provinces decreased from 5 to 2; the impact of social vulnerability on ecological vulnerability（So VI→NPPI） increased,and the corresponding significant impact provinces increased from 1 to 7. A quantitative method that indicates the direction of influence is expected to explain how social vulnerability and ecological vulnerability interact and affect one another.