Zoning policy performance in China: Network insights from 77 Yellow River counties in Shandong, China

In response to the global call for sustainable development, China launched the "Three Lines and One List" zoning policy in 2022, designating land into preferred conservation, key control, and general management units. However, current tools remain insufficient for systematic evaluation and science-based policy refinement. This study assesses the performance of 67 ecological, economic, social, and water-related indicators-compiled from multi-source datasets-across 77 districts in Shandong Province, a key region at the Yellow River estuary. The results show notable ecological improvement from 2013 to 2020. Moreover, using 47 representative indicators, we construct a complex network grounded in the "product space" method from development economics to reveal synergistic relationships among indicators and identify structurally important indicators and strategic counties for policy guidance. Key "bridge" indicators-such as Vegetation carbon sequestration (VCS), Pesticide use tonnage (PUT), and water consumption-and critical regions like Boxing county exhibit high centrality and connectivity, underscoring their potential to influence system-wide outcomes. Aligned with other conservation policies, findings suggest differentiated strategies: preferred conservation zones should strengthen carbon monitoring, key control zones should promote water-carbon synergies, and general management units should adopt green technologies to enhance agricultural productivity. Taking Boxing as a case study, we offer a scalable framework for robust, long-term evaluation of zoning policies and integrated river basin governance.