| Poyang Lake Region is located at the north of Jiangxi Province, which includes11counties/cities/districts around Poyang Lake such as Nanchang county, Xinjian county, Jinxian county, Hukou county, Yongxiu county, De’an county, Poyang county, Xingzi county, Douchang county, Yugan county and Jiujiang city and so on, covers an area of19761.5km2. Over the last50years, Poyang Lake Rigion suffered high pressure from regional population, economic and resource, facing a series of eco-environment problems such as water and soil erosion, soil degradation, water pollution, flood and drought disasters which occurred frequently, biological diversity decreasing and some other problems.The regional land use/land cover changed obviously because of the changes of natural conditions and increasing intensity of human activity. So, researches were necessary to be implemented including spatial-temporal process of land use change in Poyang Lake Rigion over the past50years, analyzing the driving force and simulating land use change, quantitative evaluating the intensity which land use changes influence on eco-environment and so on. There were great theoretical and realistic significances on how to promote regional land resource sustainable utilization and social sustainable development as well as economic.Document survey,3S technology, model simulation, mathematical statistics method and practice investigation were used in the thesis based on the mainline of spatial-temporal changes of land use and eco-environmental influences. Some main results had been got as following:1. The most changes in Poyang Lake Region over the past50years were cultivated land, water land and construction land. Six kinds of land utilization had different spatial rules.①Quantitative changes:Construction land changed mostly in latest50years especially the area in2008was6.3times more than in1971.Cultivated land almost kept same total area as before though increased some first then decreased some later. Water land area decreased some first then increased some later then decreased a little while, but its total area almost did not have much changes. Both grass land and forestry land area lost about20%from1971to2008.②Spatial changes:Spatial Lorenz curve and Gini coefficient were adopted to analyze the spatial change processes of main land utilization in Poyang Lake Region. Cultivated land, forestry land and water land area were distributed balanced and did not have much annual fluctuating. Grass land, construction land and unused land were distributed unbalanced and had a trend of gathering, especially unused land converging in Xinjian county, Poyang county, Xingzi county and Yugan county.③landscape pattern changes of land use:General land utilizations were converging, and diversity were decreasing, e.g. from1985to2005, the Number of Patches (NP) decreased from18040to17571, the Largest Patch Index (LPI) increased from13.3985to15.8938, the Shannon’s Diversity Index (SHDI) decreased from1.6143to1.6091, and the Aggregation Index (AI) increased from94.7527to94.9168.2. The main driving force of land use changes in Poyang Lake Region was policy; secondary driving force was social economical factors.11indexes were chosen to be on behalf of4kinds of factors including economic, population, input and income from1954to2008. F1and F2were left after dimension reduction by principal components analysis. Main land utilization data which includes cultivated land, construction land and water land from1954to2008were standard transacted first, and then analyzed by multi-variation linear regression model as well as land use policies’ changes. The results showed:Both cultivated land and water land did not have obvious correlation with principal component F1and F2and main driving force were land use policy. The changes of construction land had positive correlation with principal component F1and negative correlation with principal component F2. So that its main driving force was social economical factors.3. Simulation of land use changes in Poyang Lake Region got an accuracy result, but mechanism of land use change was required to consummate in next step.100m×100m grid net technology were used in the research. Ten factors, which included gross domestic product at current price (GDP, million Yuan), population density (persons/km2), mean elevation (m), mean slope (based on90m DEM), direct distance to nearest city (m), direct distance to nearest major river (m), direct distance to nearest main road (m), average yearly precipitation (mm), average yearly temperature (℃) and soil fertility class (1to6class) were selected to simulate the land use pattern in2020in CLUE-S model on the basis of land use changes from1995to2005.The KAPPA index was0.879, which showed general accuracy was believable. But simulating accuracy of construction land distribution was not exact. The shortages of CLUE-S model mechanism were covered by extending the theory of ecology niche.Land use niche expansion-reduction model in global scale and Land use niche breadth model in micro scale were used to interpret construction land spatial changes in Poyang Lake Region.4. The quality of eco-environment in Poyang Lake Region had a trend of decreasing, and the key factor of which was water land area. As a case study of Poyang Lake Region from1985to2008, synthesis evaluation model of quality in Poyang Lake Region was build based on grid net30m X30m. The results showed:Eco-environment in Poyang Lake Region was still good, but average quality index of eco-environment decreased from50.03in1985to48.73in2008. Coupling analysis had been done for the spatial-temporal process of land use changes combined with Sensitivity assessment of eco-environment in Poyang Lake Region. The results showed:The dominant factors of eco-environment sensitivity in surrounding areas of Poyang Lake were water land area changes. On one hand, policy of "reclaiming the lake from farmland" was carried out well, meanwhile the water area enlarged, so the quality of regional eco-environment became well. On the other hand, policy of "make cultivated land from lake area" was the reason, that regional eco-environment became better than before. The negative effects of new construction land were more than the positive effect to regional eco-environment. The changes of forestry land area had obvious influences to regional eco-environment.5. Measures on land resources sustainable utilization in Poyang Lake Region must implement with multi-way with the basis of the regional resource character and innovating concepts. Land resources in Poyang Lake Region were different with each other obviously. In order to protect the eco-environment and to enhance the sustainable development of regional social and economic, function zoning should be implemented by dividing function zone, rational distributing Agricultural land area, eco-forestry land area, city and industry land area, wetland reserve land area. Innovating drainage basin management conception and implementing new urbanization style as well as developing eco-tourism were all put forward too. On the basis of relating researches on Poyang Lake Region by many scholars, deeper researches had been done on the land use changes of Poyang Lake Region by enlarging time limit, refreshing research methods, enriching theories of research and so on. The main innovations of the thesis are as following:1. Land use database were constructed from1954to2008which extended a longer time series in Poyang Lake Region. Spatial Lorenz curve and Gini coefficient were adopted to analyze the spatial change processes of main land utilization in Poyang Lake Region. Theory of ecology niche was expanded. Land use niche model was adopted to explain land use spatial changes.2. Basement were build for simulating the spatial-temporal land use changes by integrating3S technology, fine grid net and CLUE-S model simulating technology together. Most important was100m×100m grid which could analyze driving forces of land use changes in CLUE-S model more accurate. Researches on effects of land use changes on eco-environment based on grid30m X30m analyzed how different kinds of land utilization contributed to the quality changes of regional eco-environment.3. With the basis of land use changes simulating and eco-environment status,4kinds of function zones were divided, and measures on land resources sustainable utilization in Poyang Lake Region were put forward. |
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