Variations in the Value and Trade-Offs/Synergies of Ecosystem Services on Topographic Gradients in Qinghai Province, China

Qinghai Province is an important part of the Qinghai-Tibet Plateau. It is the birthplace of the Yangtze, Yellow, and Lancang (Mekong) Rivers, the recharge area for China's freshwater resources. With different terrains, the temperature, daylight, and precipitation of Qinghai Province are widely variable. Consequently, the topography largely determines the spatial distribution of ecosystem services (ESs) and affects their interaction. Studying the impact of topography on the spatial-temporal evolution of ESs and their interaction is of great significance for land-use planning and the ecological civilization in Qinghai Province. To explore the spatial distribution and evolution characteristics of ESV and trade-offs/synergies among ESs in Qinghai Province, we considered topography (elevation, slope, RDLS, and terrain niche index) in 1980, 1990, 2000, 2010, and 2020 using the ArcGIS software and the equivalent factor method. The results were then corrected using various parameters. The results showed that the ESV of Qinghai Province decreased from 129,573.99 million USD in 1980 to 129,155.85 million USD in 2000, and then increased rapidly to 142,682.97 million USD in 2020. The spatial distribution of ESV is characterized by high in the south and east and low in the northwest. The geographical distribution and temporal variation of ESV and trade-offs/synergies of ES pairs show distinct vertical zonality, and the relationship between ESs showed different patterns on different topographic gradients. Hence, priority should be given to the ecological protection of high-altitude areas, and the implementation of ecological migration continued. The implementation of protection measures considering the ecological conditions under different topographic gradients can ensure more appropriate ecosystem management and more sensible decision-making.