长江上游土地利用/覆被变化特征及其驱动力分析

利用1970,1980,1990和2000年4个时相卫星遥感数据,阐述了长江上游近30年来土地利用/覆被在数量、结构和空间上的变化特征,明确了土地利用变化的主要类型和变化趋势,并进一步分析了长江上游土地利用/覆被变化的驱动因子.结果表明,研究区土地利用类型以耕地、林地和草地为主,此特征决定了该区以农牧业生产为主.1970-2000年耕地面积大幅减少,其余土地利用类型都得到一定程度上的增加,研究区土地利用类型转移的主要方向是林地转变为草地,草地转变为荒地和水域,耕地转变为林地、草地和城乡建设用地.研究区特殊的地形和气候条件是制约土地利用水平和结构的基本要素,而人类开发活动和宏观政策的制订对土地利用变化的影响更为显著.

AN ANALYSIS ON THE LAND USE/COVER CHANGE CHARACTERISTICS AND DRIVING FORCES IN THE UPPER REACHES OF YANGTZE RIVER

On the basis of the documentary data and the remote sensing data of 1970, 1980, 1990 and 2000, this paper focuses on the characteristics of the quantities, inner structure and spatial distribution of land use/cover changes in the upper reaches of Yangtze River during the past 30 years, reveals the major patterns and trends of the LUCC. Furthermore, the driving forces of the LUCC are analyzed in detail. The results show that the major land covers in the study areas are infield, forest and grassland; these decide the major producing processes in these areas, they are agriculture and stockbreeding. During the period of 1970 to 2000, the infield decreases markedly and other land use types are increased in different degrees. The major patterns of land use change are the conversions of forest to grassland, grassland to wasteland and water area and infield to forest, grassland and rural-urban construction land. LUCC is a complex process, which is affected by many comprehensive factors including both socioeconomic and natural and environment. The special topographical and climatic conditions of the studied areas restrict the degree and structure of land use. However, human activities and adjustment of the macro policy have influenced the land use changes more significantly.