Nonlinear trade-off relationship and critical threshold between ecosystem services and climate resilience for sustainable urban development

Metropolitan areas are faced with ecosystem degradation driven by rapid urbanization and climate change. Synergizing ecosystem services (ES) and ecosystem climate resilience (ECR) in ecological restoration programs is essential for sustainable urban and social development. However, it remains unclear whether there is a trade-off relationship between ECR and ES, particularly nonlinear relationships. Here, the Wuhan metropolitan area (WMA) was selected as the study area. First, the entropy theory was used to quantify ECR on multiple timescales using GPP time -series data. Then, the critical ECR timescales of different ES were detected using the GeoDetector model. Finally, restricted cubic spline regression was performed to reveal the nonlinear trade-off relationship and threshold effect between ECR and ES. The results showed that: (1) The critical ECR timescale is 20 years for water yield and grain production services, while one year for habitat quality, water purification, air purification, carbon sequestration, soil retention, and recreational services; (2) The short- and long-term ECR thresholds to ensure the synergistic growth of ECR with multiple ES are 0.38-0.47 and 0.445, respectively; (3) ESB dynamics and ECR thresholds can be integrated as a tool for climate -adaptation ecological restoration zoning.