[Land use change and its driving force on the southern slope of Qilian Mountains from 1980 to 2018].

Qilian Mountains is the boundary of the first and second steps of China's terrain, with fragile ecological environment. There is great ecological significance to study land use change and driving force in transitional areas. In this study, we investigated the spatial and temporal characte-ristic of land use and its driving force in the south slope of Qilian Mountains, based on RS image data from 1980 to 2018, with the spatial autocorrelation method, ArcGIS spatial analysis method and principal component analysis. The results showed that, from 1980 to 2018, grassland was the main land use type, and the proportion of construction land was the smallest. Water area and grassland showed a declining trend, while unused land, construction land and farmland showed an increasing trend. There was smaller change for the woodland. The single dynamic degree of different land types decreased following an order of construction land, water, farmland, unused land, woodland and grassland. The comprehensive dynamic degree of land use was 0.9%. The spatial distribution of different land use types showed the characteristics of spatial agglomeration. The increased areas of farmland and the decreased areas of woodland and grassland were mainly distributed in the northwest of the Datong River valley of Menyuan County, while in the upper reaches of Datong River in the northeast of Tianjun County, grassland was occupied by construction land. The driving force of land use was population, science and technology, urbanization, level of economic development, and policies. Our results would support the government to reasonably plan and utilize land resources, which is of significance to the protection of ecological environment and the sustainable development of society and economy on the southern slope of Qilian Mountains.