基于CVM的海涂湿地生态服务价值的模糊评估模型

正确评估海涂湿地生态服务价值有助于加强人们保护海涂湿地的意识,为海涂湿地围垦生态补偿标准的制定提供依据。视价格"便宜"、"适中"和"昂贵"为模糊集,基于CVM法区间型数据建立了传统模糊统计模型、赋权模糊统计模型和三相划分模型,并以此评价了杭州湾国家湿地公园单位面积年生态系统服务价值。结果显示:3种方法得到的单价分别为10.28、10.38、9.76元m~(-2)a~(-1),三者一致程度较高,与国内沿海湿地价值比较接近。分析了"生态价值"概念客观上的"模糊性"引致模糊数学模型的合理性;采用"橄榄球"式赋权建立赋权模糊统计模型以克服传统模糊统计模型中对区间数据均匀赋权的不合理性,结果在隶属度函数的光滑性和拟合度上好于后者;第三,三相划分模型拟合出3个模糊集的隶属度函数,可以比较相同价格在不同模糊集中隶属度差异。建立的模型对于基于CVM法的生态资源价值评估具有借鉴意义。

The fuzzy evaluation model of beach wetland ecosystem service value based on the contingent value method

Properly evaluating the beach wetland ecological services value will contribute to the awareness of beach wetland protection for people, and provide basis for the planning of beach wetland reclamation ecological compensation criterion. The scientific nature of traditional classification calculation method of ecological services value is disputing, and the common CVM data handling techniques have some limits on the recognition of investigation results analysis. This research establishes a fuzzy evaluation model for beach wetland ecological services value based on CVM method. The prices "cheap", "moderate" and "expensive" are three fuzzy subsets for specific domains of discourse. This paper highlights the comparison of different membership grades for different prices on different fuzzy subsets, establishes a traditional fuzzy statistical model, weighted fuzzy statistical model and three-phase model according to non-uniform discrete membership grades, weighted discrete membership grades and successive membership grades based on the interval data of CVM, and evaluates the annual ecological services value per unit area of Hangzhou Bay National Wetland Park. The results showed that:the unit prices obtained through 3 methods are 10.28 Yuan/m², 10.38 Yuan/m² and 9.76 Yuan/m², which have high uniform degree and similar with domestic beach wetland values. The interval of moderate price for wetland ecological services is5.46,15.33] which is obtained when dividing the model through three phases and the subordinate function values of each "moderate" price in the moderate price interval are higher than the subordinate function values of "cheap" and "expensive". Innovations of this study are as follows. First, the innovation value is the rationality of fuzzy mathematical model analyzed through the conceptual "fuzziness" of "ecological value", and find the representative price from the maximal onset principle of membership grade, which is different with the data central tendency principle of traditional CVM data processing; second, the "rugby" type weighted statistical model established can overcome the irrationality of the uniform weighting to interval data of the traditional fuzzy statistical model, and the results of smoothness and degree of fitting on the membership function are better than the traditional model; third, three-phase model fits the membership functions for three subsets which could compare the membership grades difference of different fuzzy subsets with same prices. The established model is reference significance for the evaluation of ecological resources value based on CVM.