Analysis On Land Use And Land Cover Change And Its Driving Mechanism In The Ordos Plateau

Data of this text are Ordos plateau TM remote sensing images of Summer in 1990, 2000 and 2005s rainfall, temperature, population data from 1990-2005 and social and economic data. On the basis of field investigation, making use of remote sensing technique and geography information system image processing technique, under introduction of correlative analysis and stepwise analysis method, carry through qualitative and quantitative analysis on land use and land coverage dynamic changes and driving forces; And build up 1990-2000 and 2000-2005 land use dynamic change diversion matrix with the help of Visual FoxPro6.0 software and calculate relative index among dense of population, social economic factors and all kinds of land use type changes. The following conclusions are arrived at:(1) As is seen from the actual land use of 2005, areas of grassland and unused land in the study region separately account for 61.14% and 27.12% of the total area, other types of land account for 11.74% of the total area.(2) The main changes of land use in the study region from 1900-2000 are conversion from high coverage grassland to middle and low coverage grassland and conversion from middle and low coverage grassland to high coverage grassland, areas of conversion are separately 13800.02hm2, 93441.80hm2, 204055.05hm2 and 140311.48hm2. Area of forest increases, mainly area of shrubbery increases, area of increase is 27732.33hm2. Area of town and farm land increases, but extent of increase is not big.(3) The main changes of land use in the study region from 2000-2005 are mutual conversion among all kinds of grassland and conversion from desert to grassland, area of conversion from high and middle coverage grassland to low coverage grassland is 64439.94hm2, area of conversion from low coverage grassland to high and middle coverage grassland is 152444.1hm2,area of conversion from desert to grassland is 10459.11hm2 .Area of town, factory and mine and residential area has increased largely; ratio of increase is 16.88%.(4) Change of land use and land coverage in the study region is closely related to changes of rainfall and air temperature and population and social economical development. For example, area of farm land, high coverage grassland, forest and water area obviously decreases in the study area during 1990—2000, and area of shrubbery and sparse woodland and middle and low coverage grassland increases accordingly. This is closely related to elevation of air temperature and reduction of rainfall. On one hand, area of farmland, forest, middle and low coverage grassland and river in the study region has obviously increased during 2000-2005, on the other hand area of desert and low coverage grassland reduced accordingly. This is coincident with air temperature reduction and rainfall increase. At the same time study area catches up to chance of implement some national forestry key project and develop sand industry, process farmer and herder population transfer, develop modern stockbreeding.