生态系统服务弹性敏感性系数的合理性与决策属性探讨

Rationality and Decision-making Attributes of Sensitivity Coefficient of Ecosystem Services Based on Elastic Model

在经济学弹性基本概念的基础之上,采用数学推导的方式重点探讨3种生态系统服务弹性敏感性评价模型的合理性与决策属性。研究结果表明:①Kreuter敏感性系数大小始终为0~1;在极限形式下,生态系统服务价值变率函数与Kreuter敏感性系数具有相同的数学表达式与值域;所以这两种敏感性评价模型把1作为是否敏感的评价标准并不合适。生态系统服务交叉敏感性系数不符合一般意义上的"交叉敏感性"的概念,并且其计算公式不符合弹性的基本定义。②弹性敏感性计算方式适用于随机变量间的研究,不适用于具有确定性关系的变量;生态系统服务框架下的3种弹性敏感性系数均建立在具有确定性关系的生态系统服务价值计算公式的基础之上,导致其敏感性计算结果缺乏深层次的决策属性。

It’s not suitable for 1 to be regard as criterion to judge the sensitivity of ecosystem services because the Kreuter sensitivity coefficient always ranges from 0 to 1, which means, it can only be regarded as the land ecological importance to ecosystem service value under the existing ecosystem service value evaluation system. In addition, the variability function of ecosystem service value has the same mathematical expression and range as Kreuter sensitivity coefficient in the limit form. However, sometimes it can get a little different or approximate calculation results using the inaccurate arc elasticity calculation method, so that it mistakenly leads us to believing that the two models get two kinds of results. Although the impact of the transformation between different categories on the value of ecosystem services is taken into the cross-sensitivity coefficient, the calculation formula does not meet the basic definition of elasticity, and so the calculation results are difficult to express the meaning of elasticity. The calculation method of elastic sensitivity is generally suitable for random variables, but not for variables with deterministic relations. Whether Kreuter sensitivity coefficient, variability function of ecosystem service value or ecosystem service cross-sensitivity coefficient are all based on the ecosystem services value formula. As a result, the elastic calculation results lack of deep decision-making attributes. According to the elasticity(sensitivity) in economics, the relationship between the supply or demand of ecosystem services and prices should be the research focus rather than the deterministic relationship between the ecosystem services value and the coefficient of ecological value. The price elasticity(sensitivity) of supply or demand of ecosystem services is inherent in the attributes of goods. It may be of greater practical significance to study the sensitivity of ecosystem services to price changes according to the attributes of goods. In ecosystem services, private goods are generally the necessities with the characteristics of low elastic demand and high elastic supply, while public goods are characterized by high elastic demand and low elastic supply. Although the existing studies have used Pearl growth curve to adjust the ecological value coefficient, they do not distinguish between private goods and public goods in ecosystem services, and uniformly regard ecosystem services as public goods.