Identifying priority areas for ecological restoration in metropolitan areas through resilience threshold of...

Intensive human disturbances in metropolitan areas have profoundly reshaped ecological spatial networks (ESNs), undermining their resilience and long-term sustainability. Identifying priority areas for ecological restoration is therefore crucial for enhancing network resilience and guiding spatial governance. However, existing studies rarely incorporate the concept of resilience thresholds into restoration planning. Focusing on the Changsha-Zhuzhou-Xiangtan metropolitan area (CZXMA), this study combines circuit theory with gravity models to construct ESNs and employs network attack simulations to quantify their structural and functional resilience. By linking patch-level resilience contribution with human activity intensity, we determined the critical resilience threshold and delineated priority areas for eco-restoration. The results indicate that the ESNs exhibit trends toward increased fragmentation and reduced habitat quality. The ESNs are highly sensitive to the loss of high-centrality nodes, with the failure of just 1%-2% of nodes triggering structural collapse and precipitous declines in functional resilience. The priority of patch nodes was ranked based on their resilience contribution and human activity intensity, and the top 22% of nodes were identified as keystone patches. Within this subset, 60 degraded patches were determined as priority restoration targets, accounting for 1.6% of the total metropolitan area. Restoring these degraded keystone patches would substantially enhance the ESNs' resilience. Overall, this study develops a novel analytical framework that integrates resilience thresholds into spatial network analysis, offering practical guidance for ecological restoration and sustainable land management in rapidly urbanizing regions worldwide.