Land use change and its eco-environmental effects on vulnerable desert margin areas: A case study from Yanchi County in Ningxia

Based on Landsat remote sensing images from 2000, 2010, and 2017, this study quantitatively analyzed the land use change pattern and ecological environment quality of Yanchi County from 2000, using ENVI, ArcGIS, and other software. The results showed that grassland area, unused land, and cultivated land in Yanchi County shrunk, while forest land (mainly shrubs) and construction land continued to increase from 2000 to 2017. Land use change was frequent between woodland, grassland, cultivated land, and unused land, and most of them were distributed in the northeast of the region. The index of land use structure showed that the orderliness and stability of the land use system in Yanchi County increased, especially in large disturbed areas, and its stability was stronger than that in weakly disturbed areas. The environmental quality showed two main directions: improvement and deterioration, with improvement being the dominant trend; different townships (towns) showed obvious regional differentiation characteristics. The main factors leading to changes in the ecological environment were government policies, including the implementation of the policy of returning farmland to forestry and grassland, sand control and desertification control (2000), the construction of Haba Lake Reserve (2006), and the prohibition of grazing (2002). A large number of unused lands had been converted to grassland and woodland with a higher environmental quality index, which contributed to the improvement of the environment in the study area to as high as 6.5%.