Valuation of wetland ecosystem services:Progress and perspectives

As a form of natural assets,wetland ecosystem generate multiple ecosystem services that contribute to human welfare.However,along with urbanization and development of economy,excessive exploitation and usage have caused potential imbalance with undesirable consequences.Ecosystem services of wetland have been declined rapidly.In order to prevent the trend of wetland degenerate,the whole society should realize the huge beneficial of ecosystem services and recognize values of wetland assets.In this context,valuation of wetland ecosystem services is one of the most important issues in the study of wetland,and scientific evaluation is instrumental in determining whether wetland environments should be protected or restored as natural capital.In this paper,different definitions and characteristics of wetland were first introduced,then the biological,chemical,and physical processes of wetland were discussed.Based on an overview of the wide range of literatures,a framework of wetland ecosystem services valuation was proposed and the main valuing methods are illustrated,which include the outcome parameter method,market-based approach,surrogate market approach and simulated market.After that,different approaches for economic valuation of main ecosystem services of wetland are suggested,and some problems are found,which involve in valuing wetland ecosystem services:(1) The object is not clear;(2) Ignore the research background;(3) Methods of classify and sum dissever the relations among ecosystem services;(4) Data acquisition is difficult.In the end,it is looked forwards that researches of wetland ecosystem services valuation will need to define the object scientifically,take the background and purpose into account,and establish evaluation criteria and a data network platform,together with more inter-disciplinary research collaboration.The aim of this paper is sorting out the research systems of economic valuation of wetland ecosystem services and providing reference to correlative works.