LUCC in farming pasture ecotonal areas based on RS and GIS-A case study of Yanchi County in Ningxia

Based on the integrated techniques of Remote Sensing (RS) and Geographic Information System (GIS), this paper extracted the location, quantities and types of LUCC(land use and land cover change) of Yanchi County in Ningxia Hui Autonomous Region from 1991 to 2000, and applied conversion matrix model to further analyze the process, features and drives of LUCC in this area. The studying findings were as following:from 1991 to 2000, the farming land decreased by 39 853 hm²,the forest land and pasture increased by 27 055 hm² and 13 251 hm² respectively, and desert decreased by 4 659 hm². The pasture degraded considerably, the proportion of the high and medium-covered pasture accounting for total land areas decreased from 51.21% to 17.29%. In 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 ecological environment in the county improved partially, yet got worse wholly. The land use was in the unstable and adjusting stage. The decrease in farming land and the increase in forestry and grass land resulted from adjustment of agricultural structure and the implementation of Three North Shelter Belt and other anti-desertification projects, while the degradation of pasture resulted from unreasonable human being activities and pasture tenure.