环境与生态系统服务价值的WTA/WTP不对称

支付意愿(WTP)和受偿意愿(WTA)是条件价值法(CVM)研究中环境与生态系统服务价值的两类不同表征尺度,对同一环境物品的WTP和WTA往往存在显著不对称性.以上海某城市河流生态系统服务评价为例,基于CVM研究方法,对WTP和WTA进行了对比分析和探讨.研究表明:(1)WTP和WTA的不对称性在案例研究中得到反映,WTA/WTP的平均值比值为7.02,中点值比值为6.18,两个比例与国际已有研究的一般范围较为接近;(2)WTA不受收入等变量约束,但受学历、家庭人口等变量的影响,尤其与WTP呈显著正向关联,显示WTA作为环境资源价值的表征尺度亦可能具有一定有效性;(3)WTA/WTP不对称的主要决定因素为收入和学历.WTA/WTP不对称的一个重要环境管理学含义在于,破坏或污染相同质量或数量的环境资源所引起的福利损失,将远大于保护和改善环境资源所引起的福利改进,而不是两者相等.

The WTA/WTP disparity in environmental and ecosystem services valuation

Willingness to pay (WTP) and Willingness to accept (WTA) are the main two measures when using contingent valuation method (CVM) for valuation of environmental goods and ecosystem services, however, in most CVM cases there does exist a significant disparity between the two measures. Taking an urban river in Shanghai as a case, this paper using CVM values the ecosystem services of the river in both WTP and WTA measures. The comparative study of the two measures shows that, (1)There clearly exists a disparity between WTA and WTP, with a WTA/WTP ratio of 7.02, which is very consistent with some lastly international study results; (2)There is no significantly relationship between WTA and some important social-economic variables of respondents such as income, but WTA clearly related with population of respondents family, and education level, especially there is a remarkable relationship between WTA and WTP, all this indicates that the WTA may be a appropriate measure to value environmental change; (3)The WTA/WTP disparity may be caused by respondents income and education level, the WTA/WTP ratio is positively related with education level while negatively related with income of respondents. One important environmental management implication for the WTA/WTP disparity is that, when the same degree of quality or quantity of environment or ecosystem is changed, the welfare loss caused by damage or pollution will be many times greater than the welfare gain brought by protection or restoration.