Valuation of ecosystem services and natural capital

Ecological systems provide a wide range of essential goods and services to humanity. They are the life\|support system for all of life on the Earth,and are the key natural capital of humanity.Ecosystem services or nature's services refer to the ecosystem goods and services,which represent the benefits that human population derive,directly or in directly,from ecosystem functions. In the past ten years, the valuation of ecosystem services has become a frontier of ecological economics, environmental economics and resources economics,various attempts have been made to calculate the value of global and regional ecosystem services.All estimations showed that the value of ecosystem services is very large.In the paper,the concept and connotation and their classification of ecosystem services are introduced briefly,the present value theories and valuation methods of ecosystem services are generalized.The progress in the case studies on the ecosystem services valuation at various levels at home and abroad are summarized and compared.This paper also points out the difficulties and main problems existed in ecosystem services valuation.Finally,the authors put forward the research trend of the valuation of ecosystem services.