Spatiotemporal heterogeneity and synergy driving mechanisms of county ecological resilience in optimized urban agglomerations: integrated geographical detector-Bayesian spatiotemporal model

Accelerated urbanization intensifies ecological pressure on urban agglomerations. We construct a county-level ecological resilience index for the Guanzhong Plain Urban Agglomeration (2000–2020) under a resistance–recovery–adaptability framework and disentangle its spatiotemporal drivers by coupling an optimized-parameter geographical detector with an INLA-based Bayesian spatiotemporal model. Three patterns emerge. First, resilience exhibits a polarized spatial structure: high–high clusters persist in the southern Qinling foothills and northern Loess Plateau margin, a Baoji-anchored western high–high cluster expands westward and northwestward, and a low–low cluster occupies the central Wei River valley. Temporally, resilience follows a decline-then-rise trajectory with an inflection around 2010–2015, anchored by the post-Qinling rectification institutional dividend. Second, the western expansion is underpinned by synchronous positive growth across all three dimensions, whereas southern counties sustain high resilience despite a declining adaptability dimension. Third, elevation exerts the strongest positive effect, forest coverage and economic agglomeration exert significant positive effects, and cultivated land coverage exerts a negative effect; the cultivated-land × forest-coverage interaction produces the strongest positive synergy, whereas the forest × urbanization interaction exerts significant negative moderation. Local effects are spatially heterogeneous and scale-dependent—only forest coverage and local fiscal expenditure produce coherent county-level patterns, while globally significant interactions emerge only in isolated counties. Core findings survive three sensitivity checks. A three-zone differentiated governance framework—southern connectivity restoration, central cultivated-land–forest mosaic optimization, and western forest-barrier consolidation—is proposed to halt the central corridor’s resilience loss and convert the expanding western cluster into a regional ecological security asset.