长江上游土地利用／覆被变化及区域分异研究

Study on the Regional Differentiation of Land Use/Land Cover Change in the Upper Reaches of Yangtze River

在遥感技术和GIS技术的支持下,对长江上游地区1980、1990和2000年3个不同时期土地利用的时空动态特征进行了定量分析.通过数学建模,利用土地利用变化率和相对变化率指数、土地利用动态度模型以及土地利用程度模型等对土地利用的空间分布特征及动态变化的区域分异进行了分析.研究结果表明:近20年来该地区主要的土地利用变化类型为草地、林地、建设用地和耕地,其中建设用地面积增长迅速.西藏主要的土地利用/覆被类型为草地、林地和未利用地,土地利用/覆被最不稳定,但土地利用程度增幅非常小.青海以草地和未利用地为主,虽然期间土地利用动态度较高,但土地利用程度有所下降.其余地区主要的土地利用/覆被类型都为耕地、林地和草地,四川土地利用动态度和利用程度的变化幅度不大,云南、陕西和贵州的土地利用动态度和利用程度变化的趋势和幅度都基本相似.虽然湖北、甘肃和重庆的土地利用动态度变化幅度不大,但土地利用程度却有明显地提高.

Research on land use/cover change is a key to understanding global changes. Also the study on the regional differentiation of land use/cover change is significantly important for better understanding land use/cover change and environmental management for sustainable development. The upper reaches of Yangtze River is an ecological sensitive and vulnerable area in China. It is of great significance for the ecological pattern safety of the Yangtze Basin and China. By using the technologies of remote sensing and geographical information system, the spatial-temporal dynamical features of land use among 1980, 1990 and 2000 in the upper reaches of Yangtze River were quantitatively analyzed. In order to study the regional differentiation of spatial distribution and dynamical features of land use/cover change, this research focused on the using of several mathematical methodologies, such as dynamic velocity, land use degree, and so on. The results revealed that, the dominating types of land use/cover change were grassland, forest, construction land and farmland during recent 20 years, and the area of construction land increased rapidly. The spatial distributions of land use/cover in nine regions of the upper reaches of Yangtze River were quite different. In Sichuan, the main land use/cover types were farmland, forest and grassland. Because it is the biggest region in the upper reaches of Yangtze River, its dynamic velocity and land use degree change were small. In Xizang, the main land use/cover types were grassland and forest. There was a big instability of land use in this region, but the land use degree increased slowly, because the most conversion were among forest, grassland and water area. The main land use/ cover types in Yunan, Shanxi and Guizhou were forest, farmland and grassland, and these regions have the similar direction and extent of dynamic velocity and land use degree change. In Qinghai,where grassland and unused land were the main land use/cover types, has a high dynamic velocity, but the land use degree decreased obviously, because there was a big proportion of conversion among unused land and other types. The main land use/cover types in Hubei, Gansu and Chongqing were farmland, forest and grasslan velocity were moderate, because of the conversion from forest and d. Although their dynamic grassland to farmland and construction land, the land use degree in these regions increased dramatically.