With the further study of wetland, the service of wetland ecosystem is becoming more and more important. The wetland system is considered to play a great role in the whole global circle and is called the kidney of the land. It controls the flood and purifies the wastewater efficiently. At the same time, people begin to pay more attentions on the services provided by the ecosystem that has been ignored for many years and begin to use the measurable methods to express the values of ecosystem service, so the v...