Study On Land Use/Land Cover Change And Ecological Effects In Da'an City

Land use and land cover change (LUCC) is the most significant aspect inthe research field of globe changing. Affected by both of natural and artificialfactors, the global LUCC and land resour ces quality varied continually. As aresult, it demoted the quality of land productivity and potiential productivity andthe function of ecological service system. With the climatic anomaly andhuman's irrational activity in the past decades, the potential of fragile ecologicalenvironment brought about some real environmental calamity such as landdesertification, alkaline, grassland degeneration, lake atrophy, wetland landdegeneration and so on. Therefore, it seriously restricted the coordinateddevelopment of the regional economy, society and ecological environment. So,Da'an city where the zone has a typical feature of fragile ecological environmentwas selected as a case. The LUCC and its ecologic effects for regional scale,which is a hot issue in current research area of resources and ecologicalenvironment, were studied in this thesis.Firstly, the theories, methods and the latest advance of LUCC, landproductivity, land potiential productivity and the ecological service systemdomestic and foreign were comprehensively summarized in the thesis. Then,the author explain American TM Satellite dates of 1989 2000 and 2004 forDa'an city by means of RS-GIS integrative technique, and pick out theinformation. With that, the author further described and ana lyzed the researcharea's LUCC in both qualitative and quantitative ways. The result shows that themain land type of Da'an appears"three increases and three decrease"in quantity."three increase"means cultivated land, residential area and saline-alkaline landincrease,"three decrease"means the area of meadow, water and wetland(wetlanddecease very fast) decrease rapidly. There is an obviously mutual transformationamong saline-alkaline land, meadow, wetland, water and cultivated land from theangle of distribution, for example, most of the increased land is transformedfrom meadow, water and wetland, and the new cultivated land is from themeadow. The structure of land use has a really bad effect to the enviormont.This thesis establishes a target system of land productivity evaluation, landproductivity were evaluated respectively from two main aspects, i. e. , natural and society-economy-technique factors. Six single natural factors were selectedand synthetically evaluated by calculating their geomet rical average, whichproduced the natual evaluation index of land productivity, Four singlesociety-economy-technique factors were selected and their weights werecalculated by means of AHP(Analytic Hierarchy Process). Then, by summingthem up, the society-economy-technique evaluation index of land productivitywas got. Finally, the synthetic index of land productivity was calculated on thebases of the two index mentioned above. The methods of converse restricitivefactors modifications, accompanied with G IS (geographic informationsystem)tools, were utilized to calculate land potential productivity.Photosynthesis, light-temperature, light-temperature-water, land social potentialproductivity were estimated step by step. By means of rectifyinglight-temperature-water potential productivity with the natual evaluation index ofland productivitywas got. Data of land potiential productivity were preciselyexpressed by high precision maps.Natural capital and the ecosystem services, which flow from it, areobviously important in sustaining human life on earth. Never before havehuman actions so threatened their provision. Most of them are public goodsand not trades in markets, and thus resulted in the continuous decrease ofecosystem services and the deteriorati on of ecosystem functions that generatethem. In the past fifteen years, the valuation of ecosystem services has beenbecoming one of the focuses of sustainable development and one of the frontiersof ecological economics, environmental economics and ecolo gy. Variousattempts have been made to calculate the value of global and regional ecosystemservices. The valuation of ecosystem services is essential to the integratedaccounting of environment and economics. Based on the land coverage byinterpreting Landsat TM sensing images in Da'an city in 1989 and 2004. Theecosystem services of the Da'an city were evaluated by using Costanza'smethod., and then some modifications about unit value of forest, and grasslandsystem were made according to the real charact ers of ecosystem, climate, naturalconditions etc in there. The result shows that the ecosystems of Da'an city havebeen deteriorating continuously. The annual value of the ecosystem services was56.67×108 RMB /a in 1989, and 36.92×108 RMB /a in 2004. The totalannual lost value of the ecosystem services in Da'an city was 19.75×108RMB during the past 15a. The value of ecosystem services decreases 1.32×108RMB per year. The great decrease indicates that the ecosystems have beendeteriorating continuously. So it is urgent to protect the ecosystem in this area.