Studies On LUCC Of Yanchi County In Ningxia Based On Remote Sensing And GIS

Yanchi County in Ningxia Hui Autonomous Region is a typical farming pasture ecotonal area in China. To study the process, features and driving forces of LUCC in this area is theoretically and practically significant in rehabilitation of the eco-system in arid and semi-arid areas in China. Based on the integrated techniques of Remote Sensing (RS) and Geographic Information System (GIS), this paper applies Landsat/TM image in 1991 and Landsat/ETM image in 2000 to dynamically monitor LUCC of Yanchi County between 1991-2000. After extracting the location and quantities of land use/cover, land use/cover Conversion Matrix model, Dynamic Change Degree model, Utilization Degree model and landscape model were applied to analyze the process, features, trends and landscape pattern of LUCC in Yanchi County. The driving forces of LUCC were analyzed finally. The studying findings were: from 1991 to 2000, the farming land decreased by 39,853 hm2, the proportion accounting for total land areas decreased from 24.09% to 18.18%; the forest land and pasture increased by 27,055 hm2 and 13,251 hm2 respectively, the proportion increased from 5.48% and 66.64% to 9.49% and 66.60% respectively; and desert decreased by 4659 hm2; while pasture degraded considerably, the proportion of the high and medium-covered pasture accounting for total land areas decreased from 51.21% to 17.29%; by contrast, the proportion of the lower-covered and the lowest covered pasture increased from 4.09% and 9.34% to 36.40% and 12.91% respectively; the land use now is on the unstable and adjusting stage; the main driving forces of LUCC of Yanchi County are environmental rehabilitation projects, less and uneven rainfall, unreasonable human activities and self-contradiction land tenure polices.