| Nowdays, in China the human activities brought by the urbanization makes differences on the ecosystem structure, processes and functions. Those phenomenon, including population growth, rapid socio-economic development, land use change, ect, caused the destruction of the regional ecological system structure, leading to unnormal work of the ecosystem service function and restricted the coordinated development of the regional social economy and environment. At present, the ecosystem services evaluation is a hotspot of ecology research. The wuhan city circle is selected as the research object in this paper, the author analyzed the impact of urbanization on. the regional water conservation function. This paper applied InVEST model to estimating the wuhan city circle water conservation content quality, and used ArcGIS spatial analysis comparing the space and time differences of the water conservation function between2000to2010. It revealed the mechanisms, which drivie the changes of regional water conservation function causing by the urbanization, and puts forward measures to improving the wuhan city circle water conservation function. The main conclusions are as follows:(1) In Wuhan city circle, the urbanization developed rapidly, the changes magnitude in land types was much larger, the urban construction land area nearly doubled, and1.2%of the land cover changed to the artificial surface types between2000to2010. Additionally, regional land ecological quality had trended down, but the forest ecosystems increased slightly owing to less human activities.(2) On the time scale, the water conservation function in Wuhan City Circle decreased after an initial increase. The total amount of water conservation is2.78x108mm,3.26x108mm,2.52x108mm respectively in2000,2005and2010, the average amount of water conservation changes from194.31mm in2000to227.82mm in2005, and then reduced to176.09mm in2010. In the spatial scales, the area of the highest water conservation function mainly distributed in the northeast of metropolitan and the southeast of mountain foothills; some areas in the north of Xiaogan City were less high; while water conservation function of HanJiang Plain and the eastern of the Hubei plain along water were relatively low; the focus of urban construction area was the lowest.(3) The change in the water conservation function was influenced not only by natural factors but also by human activities. Among the natural factors, the vegetation cover, rainfall, the topography index, the soil depth and the available water content played a positive role on the water conservation function; while potential evapotranspiration had a side effect on it. Among the human factors, the population and its density growth put pressure on the water conservation function; and the impact of socio-economic development also had some negative interactions in the short-term; but the implementing of the rational policy can improve the water conservation-function by changing human activities; while the change in land cover types would directly alter the water conservation function, and water conservation function in Wuhan city circle were waning.(4) Wuhan City Circle is one of the major water conservation functionl areas over China, and it is of important ecological significance to restore its water conservation function. According to the research results, we can propose the following specific measures:①The water conservation forests should be plant and tended, then the vegetation cover would increase and precipitation losses reduced.②It should be prohibited reclaiming the land, and should encourage people to return the farmland to the lake and to protect and restore the existing lakes and wetlands.③Protecting the land resources and the implementation of ecological compensation policy will promote the arable production capacity.④It will increase the water conservation functions in the city to carry out the construction of urban green space system. |
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