国外湿地补偿率的确定方法及对中国的启示

Methods of Determining Wetland Compensation Ratio and the Enlightenment to China

湿地补偿率是湿地占用补偿制度实施的重要依据。回顾了国外湿地补偿率的确定依据和方法,为中国湿地补偿制度的建立和湿地补偿率的制定提供借鉴。湿地补偿率的确定,主要依据补偿措施、湿地类型、湿地功能和价值、地理位置、时间、湿地补偿的成功率或失败率等因素。湿地补偿率的确定方法主要包括King D M和Bohlen C B提出的湿地补偿率模型及King D M和Price E W提出的改进的湿地补偿率模型、选择实验法和失败率法。在中国,目前湿地补偿率的确定需要制度保障、实践经验的积累和技术方法的支持。

Wetland compensation ratios are fundamental principles of the implementation of wetland compensation system. This paper reviews the basis and methods of determining wetland compensation ratios in the United States, Canada and Australia, and provides reference for the formulation of wetland compensation ratio and the establishment of wetland compensation system in China. Wetland compensation ratios are determined by multiple factors, including compensatory mitigation, wetland types, wetland functions and values, the location of wetlands, whether there is delay of compensatory mitigation, the time an artificial wetland needs to achieve wetland values and functions, and the failure rate of compensatory compensation. Existing methods to determine wetland compensation ratios include the wetland compensation ratio model defined by King D M and Bohlen C B, the improved wetland compensation ratio model by King D M and Price E W on the basis of King and Bohlen＇s model, choice experiment method, and failure rate method. Firstly, the wetland mitigation ratio model defined by King D M and Bohlen C B use factors reflecting existing wetland functions and values, wetland restoration limits, compensation delay, time to achieve target function, failure rates, and discount rate. The method requires a large amount of data in several aspects of wetlands, and the result varies according to different discount rates. Secondly, the wetland compensation ratio model improved by King and Price adds landscape context of the compensation site（compared to the impacted wetland） to the model. The result is higher than the previous model when the landscape context is less ideal, and lower when the landscape context is enhanced, as the conditions are more rigorous. Thirdly, the choice experiment method is different from the above two in that it does not require data directly related to wetland conditions. Instead, it collects data by questionnaires, which is based on consumers＇ utilities. This is practical when there lacks historical research and experience in an area. Fourthly, the failure rate method is the simplest one because it only considers the failure rates as the factor associated with wetland compensation ratios, but as well the most adverse method for wetland protection. All the four methods have their pros and cons, and the paper compares the four methods by applying them in a wetland mitigation case. The results showed that as the discount rate increases, wetland compensation ratio increases except under the failure rate method, which does not consider discount rate;within the same discount rate, failure rate method gives the lowest wetland compensation ratio which is 2︰1,while the improved model by King and Price under a less ideal landscape context（-0.3） derives the highest outcome 62.52 ︰ 1. Given various wetland compensation ratios in different countries, states and provinces,there are no fixed wetland compensation ratios for all wetlands. Usually in practice, wetland compensation ratios are set between 1︰1 and 10︰1. At present, China needs a comprehensive wetland compensatory mitigation system in favor of‘No Net Loss＇ principle as the prerequisite for the establishment of wetland compensation ratios. In order to determine the ratios in Chinese context, efforts should be made to gain experience from wetland mitigation practice, and develop data collection and processing techniques related to wetland compensation.