| Because ecosystem services are not fully 'captured' in commercial markets or adequately quantified in terms comparable with economic services and manufactured capital, they are often given too little weight in policy decisions. This neglect may ultimately compromise the sustainability of humans in the biosphere. So, how to estimate the value of ecosystem service function effectively becomes the focus of present research and front subject. Numerous Chinese and foreign scholars are all trying to calculate the value of service function of ecosystem, But most of them estimate the economic worth of single ecosystem as static at present and studies on the space heterogeneity of ecological service are insufficient, so they are not enough to guide the formulation and implementation of ecological nursing measure. To solve the above problems, taking YUYANG District as an example, which belongs to wind drift sand region, the author has calculated the ecological service value of six major kinds of ecosystem functions about the woodland, grassland, garden plot and cultivated land of YUYANG District during 1988-2003 and analyzed the features of their spatial-temporal dynamic changes. The six categories of ecosystem functions are net primary productivity, CO2 regulation, O2 release, water conservation, soil retention and fixing drifting sand against wind. The research has done new exploration for the quantitative appraisal of the service function of ecosystem. The paper is divided into nine parts:First part: Progress in the study of ecosystem service function. The part summarized the research contents, research signification, quantitative appraisal methods, current situation and existing problem of ecosystem service function research.Second part: Overall thinking of the research and overview of the research district. This part described conceive, selection of research district, as well as natural conditions, social conditions and conditions about LUCC.The third part: Studies on the dynamic changes of net primary productivity function value of YUYANG District. In this part, the author calculated the net primary productivity of the woodland, grassland, garden plot and cultivated land of YUYANG District during 1988-2003 and analyzed the features of their spatial-temporal dynamicchanges.The fourth part: Studies on the dynamic changes of CO2 regulation and O2 release function value of ecosystem in YUYANG District. This part synthetically analyzed the features of the spatial-temporal dynamic changes of the ecosystem function value of CO2 regulation and O2 release about the woodland, grassland, garden plot and cultivated land of YUYANG District during 1988-2003.The fifth part: Studies on the dynamic changes of water conservation function value of vegetation ecosystem in YUYANG District during 1988-2003.The sixth part: Studies on the dynamic changes of soil retention function value of ecosystem in YUYANG District. Utilized ERDAS8. 5 to interpret the remote sensing image and get LUCC data and vegetation information of YUYANG District. Utilized R2V5. 5 to digitize administrative map, topographic map, vegetation picture, soil distribution map and meteorological website map. Utilized ARCINFOR8. 3 to change every digitization layer to the same projection, to generate Tyson polygon, to structure DEM and do vector polygon overlay. Utilized ARC VIE W3. 3 to obtain the grid data topographic slope and slope length from DEM data of YUYANG District, and then, turned every coverage layer into grid layer and do grid polygon overlay to gain data about dynamic changes of value of soil retention of ecosystem in YUYANG District, at last, the author analyzed the features of the spatial-temporal changes and its reason.The seventh part: Studies on the dynamic changes of fixing drifting sand against wind function value of ecosystem in YUYANG District. Utilized wind erosion models which were formulated according to the wind-tunnel experiment which was done in Maowusu desert to calculate the fixing drifting sand against wind function value of vegetation ecosystem in northern Wind Drift Sand Region of YUYANG District during 1988-2003.The eighth part: Comprehensive appraisal of dynamic change of the ecosystem service function value in YUYANG District during 1988-2003. In this part, the author made comprehensive dynamic analysis to the six kinds of ecosystem service function value that are considered in this research.The ninth part: Summary of the thesis. Through above-mentioned calculation and analysis, the paper got following meaningful conclusions:(1) The ecosystem service function value was on the rise generally in YUYANG District during 1988-2003. The annual ecosystem service function value increased from4.986 billion yuan in 1988 to 5.679 billion yuan in 2003, increasing degree was up to 13. 89% and annual increasing degree was 0.93%. The ascendant trend of annual ecosystem service function value in 1988-1996 year and in 2001-2003 were obvious but not rise and fall obviously during 1996-2001. In the same period, the GNP of YUYANG District increased from 0.234 billion yuan in 1988 to 2.138 billion yuan in 2003. Increasing degree was 813. 68%. The result of study shows: The implementation of ecological policy in YUYANG District made improvement in both ecology and economy. The direction of structural adjustment of land use pattern was correct in this period, and that made ecosystem service function here better.(2) There were heavy difference in ecosystem service function value and its changes of different region in YUYANG District. The major differences between northern wind drift sand region and southern loess hilly-gully region were as following: The average unit area value of net primary productivity of the northern was about 1.58 times as that of the southern, the average unit area value of CO2 regulation and unit O2 release of the northern was about 1.6 times as that of the southern, the average unit area value of water conservation of the northern was about 2 times as that of the southern and the average unit area value of fixing drifting sand against wind in the northern was much higher than in the southern, but the value of the average unit area soil retention in southern loess hilly-gully region was about 8.4 times as in northern wind drift sand region. During 1988-2001, the increasing degree of the total value of the six kinds of ecosystem service function was 10.56% in northern wind drift sand region, but only 3.24% in southern loess hilly-gully region. In this period, the average unit area value of the six kinds of ecosystem service function was about 8.4 thousand yuan / hni2.a in the northern, but 6.3 thousand yuan / hm2.a in the southern, the northern is nearly 30% more than the southern.The major differences among urban, suburb and outer suburb were as following: The average unit area value of the six kinds of ecosystem service function in the urban, the suburb and the outer suburb was about 7.7 thousand yuan / hni2.a, 9.6 thousand yuan / hni2.a and 7.5 thousand yuan / hm2.a. The average unit area value of the six kinds of ecosystem service function in the suburb was higher than in the urban area and outer suburb. During 198 8-2001,every above-mentioned ecosystem value in the suburb was reducing and the total value of ecosystem service function in the suburb nearby dropped by 3.16%, but the total value of ecosystem service function in the urban and in the outer...
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