疏勒河中游土地利用与景观格局动态

Dynamic changes of land use and landscape patterns in middle reaches of Shule River,Northwest China

利用1976年Landsat MSS、1989年Landsat TM、2000年Landsat ETM+和2010年TM遥感影像,运用GIS和景观生态学方法,分析了1976—2010年疏勒河中游玉门市土地利用/覆被和景观格局的变化.结果表明:1976—2010年间,玉门市土地利用类型转移的主要方向是草地和戈壁转化为耕地、耕地转化为建设用地、草地转化为戈壁;土地利用变化经历了"缓慢变化-急剧变化-显著变化"的过程,景观密度持续增大,最大斑块指数先增大后减小,面积加权形状指数增大,形状趋于不规则;斑块间的最邻近距离减小,景观逐渐向具有多种要素的密集格局演变,更加破碎;不同斑块间的分离度减小;景观的多样性和均匀度先减小后增加.农业人口增长和经济发展是研究区土地利用/覆被变化的最直接驱动力,气候和政策因素也是重要的影响因素.

By using the MSS images in 1976,TM images in 1989 and 2010,and ETM＋ images in 2000,in combining with GIS and landscape ecological methods,this paper analyzed the changes of land use/cover and landscape patterns in Yumen County at the middle reaches of Shule River from 1976 to 2010.In the study period,the major patterns of land use change in the County were the conversions from grassland and Gobi to farmland,from farmland to construction land,and from grassland to Gobi.Such a land use change underwent a process of ＇slow-tremendous-obvious＇,during which,the landscape density increased,the largest path index decreased after an initial increase,the weighted area index increased,and the landscape shape became irregular.In the meantime,the nearest distances between patches and the separation among different patches decreased,the patches became more complex,and the landscape diversity and evenness increased after an initial decrease.The increased landscape diversity and fragmentation also showed that the land uses became more complex.The growth of agricultural population and the development of economy were the most direct driving forces of the land use/cover change in Yumen City,whereas the climatic and policy factors also had important effects on the land use change in the study area.