The Research On Urban Wetland Ecosystem Service Functions In Changsha City

The wetland, forest and ocean bear the most strongest biological function among all of the biology systems and provide the important living environment for human's life and work.And the wetland is one of the important living environment with the most richest biodiversity.Urban wetland which plays an important role in urban ecosysterms, has lots of ecological and social service functions and it also has lots of economic benefits, social benefits and ecological benefits.This article based on field survey, using the methods of RS combined with GIS, analyzes the changes of Changsha urban wetland of the years 1998 and 2007, and assesses the service values of the ecosysterm, and provides some reasonable measures to protect and use sustainably the ueban wetland resource.The main results are as follows:(1) Laying down the scope of selecting the urban wetland.(2) Based on the feature of Changsha urban wetland and wetland classification analyzed, we divide the Changsha urban wetland into permanent river, warter storage area, ponds, paddy fields and drainage.(3) The areas of Changsha urban wetland(not including paddy fiels area) have reducted from 5 734.28 hm2 to 5 212.47 hm2 last ten years, averagely reducted 52.18 hm2 every year.(4) Based on thelocation of Changsha city and ecosysterm service analyzed, the results showed that there are three main types of ecosystem services value, including use-value and non-use value. Each type of ecosystem services can also be further classified. Use-value was fractionized as food supply value, water supply value, tour value, scientific research value, water conservation value, fixing carbon and releasing oxygen value, soil conservation value, climate regulation value, biodiversity conservation value.Non-use value was fractionized as heritage value, existence value and choice value. Moreover, each value of Changsha urban wetland was depicted particularly in this article.(5) The value of ecosystem services of Changsha urban wetland was assessed through many methods, and the resule shows that total value of Changsha urban wetland eosysterm service are 1 595.758 million RMB per year, direct value are 1 250.260 6 million per year, indirect value are 160.959 5 millionRMB per year, and non-use value are 182.267 9 milion RMB per year.The idiografic value are as follows:food supply value(110.336 milion RMB per year), water supply value(849.937 6 milion RMB per year), tour value(291.65 milion RMB per year), scientific research value(0.58 milion RMB per year), water conservation value(3.911 4 milion RMB per year), carbon fixed and oxygen released value(102.395 milion RMB per year), soil conservation value(3.519 milion RMB per year), climate regulation value(8.39 2 milion RMB per year), biodiversity conservation value(42.734 9 milion RMB per year), heritage value(37.106 milion RMB per year), existence value(41.591 3 milion RMB per year) and choice value(103.570 6 milion RMB per year)(6) Show the measures that protecting and utilizing the Changsha urban wetland.