南水北调中线工程核心水源区土地利用空间格局动态变化研究

Study on Land Use Change in the Water Supplying Core Area of Middle Route of South-to-North Water Transfer Project

掌握南水北调工程水源区土地利用变化情况对于改善水源区生态环境,确保足量、优质的清水进京入津具有重要意义。本文基于第一次地理国情普查、历史基础测绘等数据,借助RS和GIS技术,对2009—2015年南水北调中线工程核心水源区土地利用时空变化进行了分析,结论如下:1)区域以林地为主,约占全区总面积的80%,植被覆盖情况良好; 2009—2015年,土地利用减量以耕地为主,增量以草地为主,林草总覆盖率略有增加,耕地、林地、草地总量基本保持平衡。2)土地利用类型相互转化主要发生在耕地、林地、草地三者之间,集中发生在海拔1 000 m以下、坡度15°以上的区域。3)政府实施的生态工程建设、库区移民政策等取得了明显效果,53.47%的坡耕地(5°以上)转化为林地、草地,但仍有相当一部分林地、草地转化为坡耕地,政府应重点加强保护海拔1 000 m以下、15°—25°坡度带内的林地和草地,减少人为活动对水源区生态环境的破坏。

Investigating the characteristics of dynamic changes of land use in the water source area of South-to-North Water Transfer Project is of great significance to ameliorate the environmental quality to guarantee adequate,high quality water diverted into Beijing and Tianjin.The spatial and temporal characteristics of land use in the water source core area of middle route of South-to-North Water Transfer Project from 2009 to 2015 were analyzed by RS and GIS technologies based on national geoinformation survey data and basic surveying and mapping data,the results as follow:1)the land was mainly covered with forest,which was accounting for about 80%of the total area.The area of cropland was reduced obviously,contrarily,the area of grassland increased prominently during the period from 2009 to 2015.The total coverage of wood and grass land rose lightly.2)the land use transforming mainly occurred among cropland,woodland and grassland.Cropland was mainly changed to woodland and grassland,distributed in the altitude below 1 000 m and the slope above 15°.3)the ecological engineering construction and reservoir resettlement policy had provided an effective backdrop for above changes.53.47%of slope cropland was changed to woodland and grassland.However,there was still a considerable area of woodland,grassland transformation into slope cropland.The government should strengthen the protection of ecological environment,especially in the altitude bellow 1 000 m and the slope between 15°to 25°,in order to reduce the man-made environment destruction to the water supplying area.