Ecosystem Service Assessment of Grasslands in the Sanjiangyuan Region

Grassland ecosystem in the Sanjiangyuan Region(Three-River Headwater Region) plays an important role in maintaining ecological balance and guaranteeing sustainable development of social-economic system.By using multiple methods,we assessed the value of nine types of ecosystem services in the Sanjiangyuan region based on the ecosystem services classification system of MA.The results showed that the total value of grassland ecosystem in the Sanjiangyuan Region was 56.26 billion RMB yuan in 2000.The top two values of ecosystem services were climate regulation and food production,which were 11.17 billion RMB yuan and 2.59 billion RMB yuan,with the contribution rate of 46.05% and 19.85% respectively.With respect to different grassland types,alpine meadow and alpine grassland have the values of 49.10 billion RMB yuan and 6.47 billion RMB yuan,contributing 87.42% and 11.52% to the whole value.Swamp has the highest value of 4230.77 RMB yuan per hm2,but its area is small,thus a relatively low value in total.The results of this study provide the scientific support for policy making in ecosystem protection and the practice of ecological compensation.