Dynamic changes and key drivers of ecosystem service values in populous zones on the Tibetan Plateau: A 35-Year analysis

• In 35 years, value rose by 20.36 billion; grasslands, climate led. • Human activity, elevation, temperature drive with complex links. • Mid-to-high altitudes, urban areas face human, temperature’s adverse impact. • Above specific altitude, temperature, precipitation impact shifts positively. Understanding the value of ecosystem services (ESV) and the mechanisms that influence it is pivotal for upholding ecological equilibrium and fostering sustainable development in the densely populated regions of the Tibetan Plateau. In this study, we used several improved ESV calculation methods to describe the dynamic changes of ESV, and investigated the individual effects, synergistic effects, local spatial clustering patterns and spatial correlations of each factor using Geodetector and Geoda. The results reveal: (1) Over the past 35 years, ESV in the study area exhibited an overall increasing trend, with a total increase of 20.36 billion Chinese yuan. Grassland accounted for the largest proportion, approximately 60 %, playing a vital role in maintaining ecological balance. Climate regulation services had the highest share at around 24 %, with hydrological regulation and soil conservation services dominating. (2) Human activity, elevation, and temperature had the most significant impact on ESV in the Tibetan Plateau human activity intensive area, followed by Fractional Vegetation Cover (FVC) and precipitation. The synergistic effects of two factors indicated that the interaction between elevation and FVC exhibited a decreasing influence on ESV, while the interaction between human activity and temperature showed an increasing impact. (3) In medium to high-altitude areas and urban agglomeration zones, human activity and temperature had the most pronounced negative impact on ESV, highlighting the need for more effective land management and sustainable development plans. Elevation and annual precipitation showed a positive correlation with ESV, but beyond a certain elevation threshold, elevation and precipitation had an adverse effect on ESV. Similarly, in extremely high-altitude regions and water source areas like the Yellow River, ESV exhibited a positive correlation with temperature.