Multi-scale transformation and evolutionary factors of ecological security patterns in the Yangtze River Economic Belt.

Ecological security is vital for ecosystem sustainability and varies across scales. Macro-scale assessments often miss local details, whereas micro-scale evaluations may overlook broader patterns. Multi-scale analysis of ecological security patterns (ESPs) offers key insights into ecosystem characteristics and interactions within nested systems. However, most studies focus on a single scale, limiting a systematic understanding of the multi-scale evolution of ESPs and their driving factors. Consequently, this study investigated the spatiotemporal dynamics, scale transformations, and key drivers of ESPs from a multi-scale perspective. We developed an integrated "structure-function" framework and applied it to the Yangtze River Economic Belt using grid- and urban-scale analyses across six benchmark years (1995-2020). This framework was supported by spatial analysis and machine learning models. ESPs showed scale-dependent spatiotemporal variations. The mean ESPs at the grid scale (0.91) exceeded those at the urban scale (0.88), reflecting greater variability and clustering at finer scales. Additionally, deviations emerged during scale transformations. The grid scale better captured localised advantages (0.88, 1.28) and exerted a stronger bottom-up influence on the urban scale, which showed a weaker top-down effect (0.30, 0.54). Dominant drivers also varied across scales, shifting from social to ecological at the grid scale, whereas social structural inertia remained dominant at the urban scale. We identified three-dimensional evolutionary mechanisms of ESPs: response divergence, transformation deviation, and factor differentiation. These findings offer insights into enhancing ecosystem resilience and regional ecological security.