Economics model of no net loss policy in wetland compensation mechanism

濕地生態系作為三大生態系之一，儘管面積不到全球陸地面積的6%，卻具有多樣的生態價值和功能。2012年所正式頒行的《濕地保育法》，於2015年始正式上路，各界皆期盼將兼顧「明智利用」與「濕地生態保育」之立法原意。其中，《濕地保育法》第五章即提綱挈領規範有關濕地開發迴避、衝擊減輕及生態補償等原則。唯進一步施行的標準與細則由於濕地本身的複雜性始終莫衷一是。 本文透過經濟理論模型的建構，針對《濕地保育法》有關濕地補償零淨損(no net loss)相關規範進行探討。透過經濟學最佳化理論及利用靜態分析方法，首先以部分均衡框架，討論濕地補償使用金錢或實質補償的機制分析，再以一般均衡框架討論濕地補償具空間異質性下補償的範圍分析。 結果顯示，當濕地開發影響人數極廣時，應以實質補償取代金錢補償成為最適的補償方式；另外，在評價時若僅考慮「效用」而未考量濕地「直接的環境價值」，將低估濕地的生態價值。最後，當濕地存在空間異質性時，若「補償濕地」的生態隔離效果大於「原生濕地」，則濕地生態品質將隨著距補償濕地中心距離增加而上升。Wetland ecosystems, being one of the three main ecosystems, possess multiple ecological values and functions, although they cover less than 6% of all the terrestrial area on Earth. “Wetland Conservation Act,” promulgated in 2012, came in force in 2015, with people of all walks of life anticipating that this Act will retain its legislative intent- “wise use” and “wetland ecological conservation.” Chapter Five in the Act focuses on the vital principles of wetland development avoidance, impact mitigation, ecological compensation, et cetera, except that criteria for further operations and detailed enforcement rules are still far from reaching a consensus due to the intricacies of wetlands. This paper conducts further research on regulations pertaining to “no net loss” concept in “Wetland Conservation Act” by constructing a model based on economic theories. Based on optimization in economic theory and static analysis, it first covers the analysis on utilizing pecuniary or substantial compensation of wetland mitigation through partial equilibrium analysis. It then discusses wetland mitigation coverage under spatial heterogeneity through general equilibrium analysis. As the result indicates, when the number of people influenced by wetland development is extremely large, substantial compensation should be the most suitable method, surpassing pecuniary compensation. Additionally, if “utility” is the only thing considered and “direct environmental value” is omitted during evaluation, the ecological value of a wetland will be underestimated. Finally, when spatial heterogeneity exists in a wetland, supposing the effects of ecological isolation in the mitigation wetland are more than those of the native wetland, the wetland ecological quality will consequently enhanced as its distance with the center of mitigation wetland increases