Study on the Surface Landscape Changes in Fenhe River Basin of the Loess Plateau

The Loess Plateau is one of the most ecologically fragile regions in China.A case study was conducted in an independent basin unit in the eco-fragile region of the Fenhe River basin on the Loess Plateau based on Landsat-TM image respectively made in 2000 and 2008 and integrated by the means of the technology of RS and GIS as well as the theory of landscape ecology,the change tendency of landscape pattern was analyzed,and digital elevation model（DEM） was used to discuss the spatial distribution of the major landscape change types to provided valuable information for studying the driving force of the landscape changes.The results showed:（1） farmland,forest and grass were the main landscape types all along.Moreover,although the farmland element had the absolute superiority over the other two,it sharply decreased during the study period;（2） by analyzing the landscape pattern of the whole area,we found that the shape became more regular,the connectedness rose,diversity index increased and contagion decreased,which suggested the disturbance due to human activities on the landscape change were more and more strong;（3） the changes from farmland grassland,forestland and settlement was the main landscape change types and had constituted in this river basin from 2000 to 2008;（4） the landscape change from farmland to settlement usually occurred in the central basin with lower altitude and flat terrain,while but most of the landscape changes from farmland to grassland and forestland had been found in the upstream area with higher altitude and large slope,in the southern area of middle reaches and in the mountain area of the peripheral middle and lower reaches.