Studies On The Spatial-temporal Changes Of Ecological Service Value In Yulin City Based On 3S

Land use/land cover is material base of mankind's survival and development, which not only provides material for the humanity, but also forms and maintains a global life-support system—ecological system. The changes of land use/land cover can alter types, size and spatial patterns of ecosystems directly, moreover, they can affect the types and intensity of ecosystems' services. Over the years, however, the economic value of land's physical products has been taken as the only basis for the adjustment of land utilization structure, which results in deterioration of ecological environment. Hence, more and more researchers have realized that it's urgent to carry out the value analysis of ecological systems service and have explored methods for estimating the value of ecosystem services. However, the estimating methods and results vary in different regions because of the space heterogeneity of ecosystems' services. YuLin Area lies in the joint region of the Mu Us Desert and the Loess Plateau where the ecological environment is fragile and land use/ cover has been changing in recent 20 years, but current studies on the ecological service value under different land cover conditions in YuLin Area based on 3S are few. This paper estimated services values of ecosystem under different land use/cover conditions in different periods in YuLin Area , analyzed the features of the spatial, temporal, and structure changes of ecological service values according to different spatial scales, and revealed the land use/cover changes' ecological effects quantitatively, which explored quantitative evaluation of the regional ecosystem services.The methods used in this paper may be classified into two categories: the methods for study on land use/land cover changes, including the technology of RS,GIS; and the ecological economics analysis methods, including induction, the opportunity cost principle, various substitutions and so on.Firstly, this paper utilized R2V and GIS to digitalize, edit YuLin Area's district maps, soil type maps, vegetation maps, land use maps and other reference maps, to define their projection and to reproject them to form coverages with Lambert Azimuthal Equal-area projection system. Reference sample points coverage was formed so by GPS and GIS. Based on above coverages, supported by ERDAS and GIS, three different...