Ecological restoration of the land-sea interface: practices, challenges, and prospects in the Yellow River Delta

The ecological degradation of the Yellow River Delta is driven by the coupled effects of multiple land–river–sea stressors, including altered fluvial water and sediment regimes, seawater intrusion, biological invasions, and intensive human activities. However, existing restoration practices remain largely component-specific and therefore have limited capacity to address these interacting pressures. This review synthesizes multidisciplinary evidence to elucidate the major degradation processes, trace the evolution of restoration research, and characterize emerging synergistic restoration practices in the Yellow River Delta. The analysis reveals an increasing research emphasis on ecological connectivity, multi-objective coordination, and system-oriented restoration alongside earlier attention to water–sediment regulation and single-factor restoration. Based on representative practices, we further identify three complementary dimensions of synergistic restoration: elemental synergy, integrating hydrology, salinity, topography, and biological processes; spatial synergy, linking watershed, landscape, estuarine, and nearshore scales; and objective synergy, integrating invasive-species control with native habitat reconstruction. Building on these findings, we propose a resilience-oriented restoration framework that integrates Nature-based Solutions, Digital Twin technologies, and cross-scale adaptive management. This framework provides a systematic basis for coordinating ecological processes, restoration actions, and management institutions in the Yellow River Delta and offers transferable insights for other rapidly changing deltaic ecosystems.