Distribution of and changes in natural resources between 1990 and 2020 in the Lanzhou Basin analyzed using remote sensing

Ecological protection and high-quality development in the Yellow River Basin are the fundamental national policies of China. In the face of global climate change, the change patterns and interaction mechanisms of natural resources, such as glaciers, water, forests, land, and grassland, are important research topics. The present study focused on the Lanzhou Basin, located in the upper reaches of the Yellow River, and analyzed the spatial distribution characteristics of and changes in natural resources from 1990 to 2020 using remote sensing. In 2019, natural resources in the Lanzhou Basin primarily included croplands, orchards, grasslands, forests, shrubs, urban green spaces, rivers, lakes, bare land, and saline alkali land. The grassland area was the largest in 2019, accounting for 45.36% of the study area, followed by cultivated land (24.29%), forest land (6.84%), and shrubland (6.31%). Lake area spanned 0.22 ha. Extensive bare land was reclaimed as cultivated land in the Lanzhou Basin between 1990 and 2000. Simultaneously, construction land was extended, and forests were converted to grasslands in Xinglongshan. From 2000 to 2010, land development progressed further into the Lanzhou Basin, occupying cultivated land and grassland resources. Additionally, most of the bare land was transformed into grassland in the northern part of the basin, whereas part of the forest land was transformed into grassland and shrubland in Xinglongshan. From 2010 to 2020, construction land expanded further, and urban construction intensity increased in the Yuzhong Basin. A large area of bare land in the northern part of the basin was transformed into grassland. During this period, the shrubland area increased significantly, primarily via transformation from forest land and grassland, in the northern part of the Lanzhou Basin and Xinglongshan. Our conclusions and data will contribute to the unified management of natural resources, land-space ecological monitoring, and theoretical research.