城市内河生态系统服务的意愿价值评估

【作者】 张翼飞；

【导师】 戴星翼；

【作者基本信息】 复旦大学 ， 人口资源与环境经济学， 2008， 博士

【摘要】 生态资产的经济价值评估是生态环境经济学研究的前沿领域。意愿价值评估法(CVM)作为该领域迄今唯一能获知与环境物品有关的全部使用价值和非使用价值的方法,在西方已有40余年的研究历史,并获得了广泛的成功应用,研究成果在环境公共政策和治理决策的制定过程中发挥着巨大的作用。其独特的假想市场的方法学特征既使其受到研究者和政策制定者的青睐,同时也是该方法有效性和可靠性广受争议的根源。我国正处于经济转型的特殊发展阶段,生态(环境)与经济发展的矛盾日益凸现。生态环境政策和相关治理决策的科学制定,离不开生态(环境)物品的价值评估。CVM作为重要的评估技术之一,对其在我国应用的理论和实证研究,是增进以此为基础的环境公共政策和治理决策有效性和科学性,促进我国建设资源节约、生态友好社会的重要科学问题。受经济发展水平和市场成熟度等条件所限,CVM在我国的研究明显滞后。与国际上对其有效性的争议相一致,CVM在我国应用的可行性、结果的有效性和可靠性一直是我国生态经济学领域争议的焦点。而我国与发达国家在社会结构、制度安排、经济水平等方面的差异又增加了其应用的特殊性。那么CVM在我国是否能揭示出人们对生态(环境)物品的偏好?被调查者的真实偏好与CVM模拟的支付意愿之间的差异分布如何?如何有效应用从而减少差异?对上述问题的思考形成本文的研究动机,本文在借鉴国际、国内相关研究成果基础上,以上海市城市内河—漕河泾为研究对象,构建该河流生态恢复的假想市场,进行意愿价值评估的研究。从2006年2月到2008年3月共进行6次CVM的情景调查,共约2700份调查问卷,以此为基础,采用理论分析、问卷调查与计量分析相结合的方法,探讨CVM有效性可靠性的三个关键性问题:支付意愿的中国特殊影响因素、CVM研究成果的“内容依赖性”和时间稳定性。主要内容如下:本文在对国际国内CVM有效性与可靠性理论争议的系统输理和应用案例回顾的基础上,开展了以下研究:首先应用CVM方法评估上海市内河-漕河泾生态恢复的价值,经过预调查,由第一阶段496份支付卡正式调查问卷进行非参数估计:平均支付意愿是168.12元/年·户,3年总价值约21.4×10~6元。然后在实例分析基础上,进行支付意愿的中国特殊影响因素研究。在理论分析的基础上,创新性选取反映我国经济转型阶段特殊性质和研究区域特征的变量:收入差距、户籍安排、收入与户籍的交互影响、居住期差异、对管理部门的信任度。应用对数线性模型和二值响应的Logit概率模型对支付意愿和支付意愿为正的概率进行回归。回归结果显示:收入的差距加大,总支付意愿降低;非户籍人口支付意愿偏低,而同时随着收入的提高,户籍带来的影响降低;对政府信任程度越低,支付意愿越低;居住年限显著负相关。同时,调查显示居民支付意愿为零的主要原因是“应由政府负责”,低收入、非沪户籍、较长的居住期、对相关管理部门的不信任等因素同样增加零WTP的概率。结果验证了一般经济理论预期和生态(环境)的自然属性,也充分反映了我国和研究区域特殊的社会结构、制度安排和经济发展路径特征。再者,设计四重方案平行调查,在720份问卷基础上,验证了CVM研究中WTP“范围不敏感”、“顺序效应”“部分一整体效应”、“嵌入效应”等在本案研究中的存在。说明评估物品数量、种类、排列顺序等提供给被访者可以选择的集合不同,支付意愿确实存在显著性差异;在同一份问卷中同时调查居民的受偿意愿与支付意愿,结果显示,差异比例均值为10.4,相比于国际调查结果,平均比值偏大,影响因素呈现中国特殊性;以二分法和支付卡不同诱导技术进行评估,二分法呈现高估,二分法与支付卡法比例为4.69～6.02,与国内研究成果较为相符,在西方文献报道的范围中。再者,对CVM时间稳定性进行实证研究,以时间间隔为一个月的两次CVM结果比较显示:支付意愿分布相符,均值仅相差0.1元,中位数相同。收入、教育、对政府信任程度对支付意愿及其概率的影响因素重现性较好;混合数据时间虚拟变量统计上不显著。表明本案CVM结果在一个月时间间隔基本保持良好的时间稳定性。根据实证研究结果,我们得出以下结论:CVM在本案中的研究结果在一定的时间尺度内保持稳定,而WTP的数值随问卷的内容、诱导技术和测度指标的不同,呈现一定差异,同时与西方国家相比,我国经济转型期的特殊阶段性特征将导致CVM的研究成果偏离居民的真实偏好。因此结合实证研究的结果,对我国CVM的应用提出以下建议:1)我国经济转型阶段的特殊因素,如户籍、收入差距、发展模式、政府相关管理模式都会使得调查中的支付意愿偏离居民对生态环境物品的真实偏好,故在制定政策或决策时应予以充分考虑以纠正这种扭曲;2) CVM研究成果呈现显著的“内容依赖性”,因此政策制定者在应用CVM结果时,必须考虑CVM研究的特定方案和实施场景;CVM的时间稳定性检验说明,该方法可以在一定时间尺度上保持结果的稳定性。因此,经济发达地区可以审慎使用CVM的数值结果,经济相对落后地区可以应用CVM研究中获得的对环境物品重要程度的排序信息,支付意愿大于零的定性信息可以用以充分识别公众关注点,为相关公共政策制定和实施提供重要门槛条件;3) CVM通过个体调查获得消费者对生态(环境)物品的支付意愿和受偿意愿,两个指标互为补充,以揭示消费者的偏好信息。该方法为在消费者微观需求信息和宏观环境政策之间构建了科学的桥梁,是我国研究社会经济系统和生态系统相互之间作用机理,确定政策干预的过程变量和关键因素,实现生态系统有效管理的必要技术手段。综上所述,与现有文献相比:在以下几个方面做了一点创新性的工作:第一、在国内结合实例应用,系统地对CVM在我国应用的有效性可靠性的三个关键性问题:支付意愿的中国特殊影响因素分析、CVM“问卷内容依赖性”和CVM时间稳定性进行了研究。与现有文献相比,更为全面和深入。尤其是借鉴国际经验,设计四组平行问卷进行CVM“内容依赖性”的实验性研究,填补国内该领域的文献空白;对时间稳定性检验方面,借鉴国际经验,构造跨时混合数据,设置时间虚拟变量,在国内较好地从统计意义上验证了时间稳定性。第二、在对支付意愿影响因素的分析中,创新性地引入户籍、收入平方、收入与户籍的交互项、沿河居住期、对政府信任程度等变量,揭示了收入差距、户籍安排、环境污染的发展路径(以沿河居住期表征)、政府相关管理模式等我国经济转型阶段特殊社会结构、制度安排对CVM中居民支付意愿的影响。与现有国内该领域的经验研究相比,更为科学地剖析了我国特殊的影响因素。研究指出这几项特殊影响因素使得支付意愿偏离真实偏好;并且在国内对“零支付意愿”的原因分布和影响因素首次进行了专门的问卷调查。第三、根据上述实证研究的结果,提出在应用CVM结果时,必须考虑CVM研究的特定方案和实施场景;针对我国地区差异和发展特征提出了CVM绝对数值、相对大小和大于零的信息在经济发达与不发达地区间的应用原则。更多还原

【Abstract】 Contingent valuation method adopts hypothetical market to measure the efficiency of large-scale change of eco-product or environmental product by investigating consumer’s WTP(willingness to pay).It has been extensively used in western developed countries.However,large amount of case studies revealed quite a few economic "anomalies" phenomena,i.e.,WTP is content dependent,which shows that CVM can’t reflect the interviewees’ stable preferences to environmental product. It is against the core assumption of the neo-classis economics,which dues to the wide questioning of CVM’s validity and reliability.China has had case studies using CVM around 2000,but the studies on the validity and reliability are in bad shortage.Based on theoretical expectation and current case results,the empirical research in China has appeared to be much complicated because of sharp distinction of social structures between China and developed countries.Learning from the related research achievements home and abroad,the dissertation studies Caohejing,the urban inner river in Shanghai,and tends to construct the hypothetical market of its ecological restoration based on CVM.Six CVM situational investigations have been made from Feb.2006 to Mar.2008, collecting 2700 questionnaires.Relied on the questionnaires,theoretical analysis, questionnaire investigation and quantitative analysis are employed to study the issues including China’s special influential factors on WTP,the content dependency and temporal reliability of CVM’s research results,both from the perspective of the validity and reliability of CVM’s application.Based on the systematic review of the domestic and international case studies and theoretical controversy on the validity and reliability of CVM,the dissertation carries out the following research:Firstly,CVM was applied to evaluate the ecological restoration value of Caohejing port,a landscape inner river in Shanghai.After the pre-investigation,the non-parameter estimation was made by 496 paying cards’ formal questionnaires in the first phase.The average WTP is 168.12 Yuan per household per year,and totals 21.4×10~6 Yuan in three years.Secondly,Chinese special influential factors of WTP are studied on the basis of case analysis.Founded on theoretical analysis,variables of special features at the stage of economic transformation are innovatively selected.They are income gap, Huji arrangement,interaction of income and Huji,differences of residential period, trust for the management offices.Applying linear logarithm model and probability model of Logit to regress WTP and positive probability of WTP with influential factors,the results indicate that the more the income gap,the lower the WTP;WTP of non-Huji resident is low,but with the growth of the income,the influence of Huji drops;the lower the trust for the government,the lower the WTP;living duration has negative effect to the demand.The study also tells the main reason for zero WTP is that it is considered as a "governmental responsibility",the factors such as low income,non-Shanghai Huji,long residential duration and distrust to the related government departments also add points to the probability.The result proves the expectancy of general economic theories and the nature of ecosystem or environment. It is as well in accordance with the social structure,system arrangement and characteristics of economic development pattern in China,which illustrates that CVM has validity in the present case study.Thirdly,four optional schemes and parallel questionnaire investigations are designed.Based on 720 questionnaires,the existence of scope insensitivity, sequencing effects,part-whole effect,embedding effect of WTP in CVM studies is proved.WTP differs greatly according to the amount,range and sequence of the public goods provided to the interviewees.The same questionnaire is to investigate their WTP and WTA(willingness to accept) which suggests that average differential ratio is 10.4.Compared to the result of the international investigation,it is higher.The influential factors reveal Chinese particularities.Compared with the results obtained by method of dichotomy and payment-card,the result of dichotomy method is higher than that of payment-card method.The ratio between two methods is about 4.69-6.02, which matches with domestic research achievements and falls within the data reported in western literatures.Fourthly,the empirical study on the temporal reliability of CVM is carried out by comparing two CVM investigations accomplished in two sequent months.The results indicate that the distributions of the two WTP match with each other,the difference of average value between two investigations is only 0.1Yuan,and the median value is same.The influence of income,education,trust for the government on WTP and its probability of the two investigations repeat well.The pool data is not of statistic significance on the dummy variable of time.It demonstrates that the CVM result of the case primarily keeps good temporal reliability in the one month interval.Lastly,the application of CVM in China combined with empirical study has come to conclusions as follows: The special factors at the economic transformation stage in China makes the statement of WTP badly deviate from the true preference.It should be fully considered to convert such a deviation when making decisions or policies;the apparent CVM’s content dependency directs that policy makers should take the CVM study’s specific solution and practical situation into consideration when putting its results into application;it should be careful for developed areas to use the data of CVM;less developed areas could apply the sequence information on the significance degree of the environmental goods achieved from CVM.The qualitative information of whose WTP is more than zero could be recognized as focal points of the public, providing important necessities for the correspondent public policy making and applying;the demand information on ecosystem service gained from individual investigation constructs a scientific bridge in realizing micro demand information and macro environmental policy,which a must technical technique to study the interaction between socioeconomic system and ecosystem,define the process variables and key factors in policy intervening,and manage the ecosystem service efficiently.The dissertation has made initiative discussions on the following aspects.First of all,it systematically studies the key issues of CVM’s validity and reliability in China’s application,complete with domestic case.Learnt from the overseas experiences,the four parallel questionnaires employed to carry out the pilot study of CVM’s "content dependency" is the first of its kind in China.Second,the analysis of influential factors on WTP discovers the apparent influence on CVM sourcing from the social structure elements such as income gap,Huji arrangement,interactions between income and Huji,development pattern of environment pollution(manifested by the riverside residential duration) and the trust for the government,esp.at China’s economic transformation phase.Questionnaires are made to expose the reason and influential factors of zero WTP.Third,in terms of temporal reliability,the temporal pool data is constructed,temporal dummy variable is set up,and temporal reliability thus is proved statistically.Lastly,with the consideration of regional differences and development characteristics of China,applicable principles of CVM’s absolute value, relative magnitude and data above zero in different regions are proposed.更多还原