LAND USE/LAND COVER CHANGE AND ENVIRONMENTAL EFFECTS IN THE NORTHEASTERN QINGHAI-TIBET PLATEAU FROM 1980 TO 2015

摘要

The Qinghai-Tibet Plateau ecosystem is sensitive and fragile, the grassland degradation and soil erosion in the plateau are still increasing. In this paper, we conducted a quantitative study to clarify the characteristics of land use/land cover change, the driving factors, and the environmental effects in the plateau. We focused on the northeastern Qinghai-Tibet Plateau as an example, and created land use change matrices and determined the relative change rate, vegetation cover, and environmental quality index using land use data and NDVI3g data from 1980 to 2015. The results show that there were significant differences in land use/land cover change in the study area around 2000, while the farmland did not increase significantly, and the water areas exhibited a decreasing trend initially followed by an increasing trend, the unused land first increased and then decreased, and residential areas increased significantly after 2000. The relative change rate of the grassland was the largest between 1980 and 2015, while most of the grassland was converted into farmland, residential land, and unused land. In addition, grassland degradation increased significantly. Considerable spatial heterogeneity in vegetation and land use/land cover was observed in the study area. The vegetation cover decreased in some areas due to the grassland degradation, however, the others areas showed improvements due to the influences of policies and climate change. The environmental index and ecological service value of the study area declined and the environment deteriorated during the study period.