Dynamic Change Of Changsha Urban Wetland Ecosystem Services Value And Its Driving Force

Changsha urban wetland is rich in resources with various kinds of rivers, lakes, pools, marshes for breeding and with farmlands widely distributed. The paper classified remote sensing image date of Changsha city in 2000, 2008 and 2013 which is under the support of GIS and remote sensing technique. The landscape of wetland ecosystem service that was evaluated in the paper, the driving force of the reduction of wetland area and ecological function degradation was attributed to several reasons in Changsha city.The contents of the result include:1) The classifying system of wetland landscape which was established in the article is distributed into 5 classes, such as rivers, lakes, pools, marshes, farmlands. The area changes of wetland landscape types was counted. The value evaluation method used for constructing an assessment system of wetland eco-services functions that was based the basics of rearch results on ecosystem profitability and combined with the features of ecosystem and environment in the light of Changsha city.2) The total wetland area is 22046.44 hectares in 2000, in 2008 it is 19600.43 hectares, but it dropped to 12720.41 hectares in 2013. It was affected greatly by the artificial factors in the city central. The farmlands hold dominant position in Changsha urban wetland which is also the biggest reduction in recent ten years. The area of farmland reduce 51.29% from 2000 to 2013, The degree of fragmentation of wetland landscape was increased, the advantage of the landscape was reduced, the landscape tends to be complex with the diversity of landscape has increased accordingly.3) The total service value of wetland ecosystem in Changsha city is 0.654 billion yuan in 2000, in 2008 it is 0.967 billion yuan. An increase of over 0.313 billion yuan in service value of wetland ecosystem since 2000. In 2013, the total service value of wetland ecosystem in Changsha city is 0.967 billion yuan, it has dropped by 0.18 billion yuan since 2008, which was ascend in first and descend at last.4) The service of tourism and leisure was increased from 0.026 billion yuan in 2000 to 0.247 billion yuan in 2013 that is the fastest growing in the value of wetland ecosystem services in Changsha which has slowed down the reduction trend of the total service value of wetland ecosystem. The highest ecosystem service value is the value of material production of wetland. In 2000,2008 and 2013, the value is 0.217 billion yuan, 0.357 billoin yuan and 3.21 billion yuan respectively with the rate of 33.18%、36.92%、33.83%. The service value of purification of wetland was ascend in first and descend at last. The service value of providing water resources and habit function is quite stable.5) The paper analyzed the dynamic evolution of landscape pattern and its driving forces that is mainly influenced by the natural and economic factors, the natural driving force factors include annual precipitation, annual average temperature,cultivated land area and so on. Social factors include built-up area, GDP, gross industrial output value, gross agricultural output value, total urban population and agricultural population.