Integrating Climate Connectivity and Network Resilience for Protected Area Network Optimization in the Yangtze River Delta

Intensifying climate change poses a major challenge to biodiversity conservation by weakening the ability of protected area systems to support species movement and ecological processes. However, protected area network planning has paid limited attention to the integration of climate connectivity and network resilience. Taking the highly urbanized Yangtze River Delta (YRD) as a case study, this study developed an integrated framework for climate-connected protected area network optimization. Specifically, climate refugia potential and species distribution probability were integrated to identify source areas, climate connectivity corridors were delineated by coupling landscape resistance with temperature gradients, and complex-network-based resilience analysis was applied to evaluate network responses under multiple disturbance and recovery scenarios. The results showed that: (1) climate stability, climate heterogeneity, and species distribution probability generally exhibited a south-to-north decreasing pattern, and 205 source areas were identified, mainly concentrated in the western and southern mountainous regions; (2) 459 climate connectivity corridors were extracted, forming a network backbone in the western and southern mountains, whereas corridors were relatively sparse in the plains and highly urbanized coastal areas; and (3) the network was highly vulnerable under critical-node-targeted, human-pressure-oriented, and climate-risk-oriented attack scenarios, while critical-node-priority recovery was the most effective strategy for restoring network function. These findings provide scientific support for cross-regional coordination, restoration prioritization, and long-term adaptive management in climate-connected protected area network planning.