Exploring the human-nature relationships on the Qinghai-Tibet Plateau through interactive analysis of ecosystem services and human activities over a 20-year period.

Identifying human-nature relationships is essential for supporting regional ecological security and sustainable development. However, limitations persist due to insufficiently comprehensive indicators for characterizing human and natural attributes, as well as a lack of localized analysis in exploring their interactions, hindering targeted conservation policymaking. To address these gaps, this study developed an ecosystem services integrated benefits (ESIB) index to more holistically express natural attributes. Combined with a human activity index (HAI), we employed the median slope estimator, local clustering method, and a four-quadrant diagrammatic model to analyze the spatiotemporal evolution and local interaction characteristics of human-nature relationships on the Qinghai-Tibet Plateau (QTP) from 2000 to 2020. Results show that 59.16% of the QTP experienced ESIB decline (with 4.89% statistically significant), while HAI increased more than it decreased, indicating ongoing anthropogenic pressure. Spatially, ESIB improved in the east, whereas HAI rose in central and western regions. Significant relationships between ESIB change rate and HAI change rate were concentrated around urban peripheries and along roads. Along roadsides, 38.80% of areas exhibited conflict relationships, and this proportion reached 49.60% along national roads. The Xining metropolitan area showed more harmonious human-nature relations than the Yarlung Tsangpo-Nyangchu-Lhasa region, where human-nature relationships in urban areas were largely depended on development and conservation policies. Among various ecological project combinations, grassland protection combined with forestland protection yielded the most favorable outcomes, with coordination and restoration zones accounting for 53.06% of its significant area. The proposed framework advances understanding of human-nature interactions on the QTP and offers a practical reference for future research.