Spatiotemporal Evolution of Ecosystem Service Supply–Demand Shaped by Nonlinear Thresholds in Socio-ecological Drivers

Improving the zonal management of the ecosystem service (ES) supply–demand balance requires a thorough understanding of its spatiotemporal variability and the nonlinear characteristics of the driving mechanisms. Coordinated social–ecological development at the regional level depends on this understanding. Consequently, we delineated bundles of the ES supply–demand relationship within the Harbin–Changchun urban agglomeration, examined interactions between ES supply and demand across these bundles, and investigated the mechanisms by which social–ecological drivers shape the spatial pattern of this relationship over an extended time series. The findings show that deficit areas for the 5 ESs are concentrated in construction zones and have expanded annually; synergies outweigh trade-offs among the 5 bundles, and the trade-off relationship intensifies markedly over time. Social drivers dominate bundles 1 (key synergetic bundle), 2 (carbon fixation–water yield–crop production synergetic bundle), and 5 (carbon fixation–crop production–habitat quality synergetic bundle), whereas ecological drivers prevail in bundles 3 (water yield bundle) and 4 (ecological transition bundle). The ES supply–demand relationship is increasingly strained by social disturbances over time. A normalized value near 0.5 emerges as a recurrent threshold at which the effects of several metrics such as digital elevation model, average precipitation, and normalized difference vegetation index shift over a 20-year period. Implementing precise optimization and rational planning for bundle-level ecological management benefits sustainable development and human well-being.