Value Study On Service Function Of Ecosystem Wetlands In Changsha

With the development of science and technology, more and more attention has been paid to the research on service function of ecosystem by academic circles in recent years, which makes it become research frontier of environment science, ecology, environment economic and other subjects. Wetlands ecosystem in Changsha is comparatively comprehensive ecosystem, playing decisive role both in Yangtze River valley and economic development of Changsha city, and possessing ecological functions like regulating and storing floods, degrading contaminant, and regulating climate, etc. Comprehensive value measuring of service function of ecosystem in Changsha is carried out and thus provides theoretical basis for some departments in the processing of related project construction and planning decision and is of important realistic significance.On the basis of investigation in wetland ecosystem of Changsha in this paper, the function characteristic of wetland ecology in Changsha is analyzed by using correlated theories of subjects like environment science, ecology and ecology economic, etc. And it is the first time to conduct comparatively comprehensive value estimation and assessment in ecology service function, on the basis of which quality assessment and function regionalization of wetland ecology in Changsha are carried out. The study results indicate: (1) By investigation with statistics and related analysis, the wetland in Changsha can be divided into 4 main categories:river wetland, lake wetland, marsh wetland and constructed wetland. Further, it can be divided into 9 subclasses:permanent river, freshwater lake, herbaceous swamp, reservoir (barrage, hydroelectric dams), freshwater culture pond, agricultural pond (small pond), wastewater treatment place, water for urban landscape and entertainment, ditch for irrigation. According to the practical situation of Changsha and the related theory, it can be analyzed that the wetland in Changsha possesses 8 main functions: function value of material production, function value of tourism and leisure, storing and supplying water, culture and science research, climate regulation, maintenance of species diversity, pollutant degradation and regulating and storing floods.(2) The whole value of service function of wetland ecology in Changsha is high, up to 9.091 billion yuan, equal to 2.1% of GDP (45.47 billion yuan) in 2010. The order of each function value amount of wetland in Changsha is:material production (4.713 billion/a)> storing and supplying water (2.178 billion/a)> pollutant degradation (1.086 billion/a)> tourism and leisure (0.427 billion/a)> climate regulation (0.261 billion/a)> regulating and storing floods (0.223 billion/a)> culture and science research (0.119 billion/a)> maintenance of species diversity (0.084 billion/a), among of which the value of material production is highest, accounting for51.84% of the total value amount, next storing and supplying water, accounting for 23.96%, and the value of maintenance of species diversity is least, only 0.08% of the total value, indicating that the main function of wetland ecosystem in this area is material production and regulating and storing and supplying water. It has new requirement for protection and rational utilization of marsh and constructed wetland that provides function of material production, meanwhile, the maintenance and standardized administration of storing and supplying function of wetland cannot be ignored.(3) According to 6 index of species diversity, representation, rareness, naturality, suitability and survival threat, the index system is established to evaluate the ecology quality of wetland in Changsha. The results show that the wetland quality in Changsha is bad and the wet ecosystem is unstable.(4) Based on the above study, the wetland ecology in Changsha is divided as ecology function. There are 5 function areas:wetland material production area, wetland water storing and supplying area, demonstration area of pollutant degradation, ecology tourism and leisure area and ecology balance maintenance and protection area. The related protection measures should be proposed according to ecology function in the same divided area.