Quantifying land use and land use changes of loess hilly semi-arid region-A case of Dingxi County, China

摘要

The study area of this paper is Dingxi County, a typical loess gully-hilly region of the semi-arid regions. The land use maps in 1990 and 2000 were compiled from the Landsat TM images and other data resources. There are 9 kinds of land use types. The slope data derived of contour lines. Referring to some metrics of the landscape ecology, 10 metrics were selected or developed for quantifying the land use characteristic, monitoring the land use changes and analyzing the relationships between land use, land use changes and the topographical condition, governmental policies of the Dingxi County. Some conclusions were obtained. The selected metrics can quantify the land use and land use change in typical loess gully-hilly region, Dingxi County. The land use and land use change have good spatial distribution regularities in the slope grades. The governmental policies are the primary driving factors for the land use changes in our study area. The policies are reclaiming the slope farmlands and grassland into terraces, rainfall-collection works, and reforesting and regressing some sloping cultivated lands.