近25年三峡库区土地覆被变化及驱动力分析

基于1990、2000、2005、2010和2015年五期30 m空间分辨率土地覆被遥感数据，利用动态度模型和转移矩阵，综合分析了近25 a三峡库区土地覆被的时空格局、变化特征及驱动力。研究结果表明：2015年三峡库区土地覆被以森林和耕地为主，分别占总面积的41.45%和24.58%；1990~2015年三峡库区人工表面、湿地、森林和其他用地的面积增长明显，耕地、灌丛和草地的面积整体减少，区域综合土地覆被动态度呈先增加后稳定的变化趋势，人工表面是最为活跃的土地覆被类型，其次是湿地和耕地；前10 a三峡库区人工表面占用耕地较为突出，后15 a土地覆被类型转换主要为森林、灌丛和耕地转为人工表面和湿地；三峡工程建设、移民安置与迁建、经济发展与城镇化导致人工表面不断扩张，水库蓄水导致湿地面积迅速增加，农业结构调整促使园地面积扩张。三峡库区近25 a来，在退耕还林等生态保护政策影响下，生态环境状况趋于改善，库区森林面积显著增加，坡耕地面积持续减少，但人地矛盾日益突出，研究结果可为后三峡时代库区生态环境保护与社会经济的协调发展提供数据支撑。

Land Cover Changes and Drivers in the Three Gorges Reservoir Area During 1990-2015

Based on land cover database of the Three Gorges Reservoir area in 1990, 2000, 2005, 2010 and 2015, we analyze the spatial temporal patterns, changing characteristics, and the main drivers. Results show that:(1) the main land cover types in 2015 are forest(41.45%) and arable land(24.58%).(2) From 1990 to 2015, the acreage of artificial surface, wetland, forest and other land increased significantly, while cultivated land, shrub and grassland decreased.(3) The regional comprehensive dynamic degree of land cover increased and then tended to be stable. Artificial surface changed mostly, followed by wetland and cultivated land. The prominent changes in the first ten years were cultivated land occupied by the artificial surface, and in the last fifteen years were forest, shrub and cultivated land turned to artificial surface and wetland.(4) The construction of the Three Gorges Project, resettlement, economic development and urbanization led to the continuous expansion of the artificial surface. The storage of reservoir contributed to the rapid increase of wetland, and the adjustment of agricultural structure promoted the expansion of garden. In summary, the eco environment of this area tended to be improving, under Grain for Green ecological policy in the past 25 years, and the acreage of forest increasing significantly. Meanwhile, the acreage of sloping cultivated land continuously decreased, resulting in the contradiction between human and land. These results will support the eco environmental protection and coordinated development of social economy in the Three Gorges Reservoir area.