生态恢复背景下无定河流域土地利用时空变化

以恢复林灌草植被为核心的黄土高原生态建设的直接结果就是引起了土地利用格局变化。选取黄河中游区无定河流域为对象,以1985,1995,2000和2008年土地利用数据为基础,综合运用GIS分析技术、土地利用动态分析方法与模型,系统研究了生态恢复背景下流域土地利用时空变化过程。结果表明,草地始终是该流域优势土地利用类型,生态恢复以大规模治理沙荒及未利用地,恢复林草地景观为主要形式;随着退耕还林还草工程实施与推进,耕地转出明显,林、草地新增明显;1995年前后,流域土地利用类型相互频繁流转,土地利用总动态度在2000年达到了最高水平;在植被恢复因素驱动下,流域土地利用重心空间漂移明显,主要表现为耕地重心均向流域东部下游地区偏移,林、草地重心向西北方向偏移。

Spatial-temporal Changes of Land Use in Wuding River Basin Under Ecological Restoration

In the Loess Plateau, restoring vegetation(grass, shrub, or tree), as the core of the ecological construction, directly caused the changes of the land use patterns. Based on the land use data of 1985, 1995, 2000 and 2008, using GIS and statistical methods, the authors analyzed the spatial-temporal changes of land use of Wuding River basin located in the middle reach of the Yellow River. The results showed that grassland had always been the dominant landscape, and recovering forest and grassland were the main form of ecological restoration through combating desertification and restoring vegetation. With the implementation of the grain for green project, forest and grassland expanded significantly, while the farmland area had been declining. Around 1995, the mutual transformation between land use types was more obvious, and the land-use comprehensive dynamic change rate was reached maximum level. Droven by the vegetation restoring, the gravity center of land use types moved significantly. The main features of the migration was that the core of farmland moved towards east of the downstream area, while the core of forest and grassland moved northwest on the whole.