Hydrological regulation of tidal creek morphology promotes salt marsh restoration

The ecological functions of estuarine wetlands strongly depend on tidal creek network morphology and associated hydrological processes. The Liao Estuarine wetland has experienced long-term human disturbance and shoreline change, which has degraded the tidal creek network and limited the recovery of saltmarsh vegetation habitats. This study focuses on the Liao Estuarine wetland, home to China’s largest single aquaculture-to-wetland restoration project, and uses remote sensing, statistical modeling, and process-based simulation to analyze changes in the tidal creek network and vegetation before and after restoration, identify the key tidal creek morphological features that control vegetation distribution and their suitable ranges, and test whether tidal creek morphology can move toward these ranges under different hydrodynamic scenarios. After pond removal, the tidal creek network showed smaller area but more branches and higher structural complexity, and Suaeda salsa expanded and became more concentrated near tidal creeks. Tidal creek area and tidal creek sinuosity were the two key factors controlling habitat suitability for Suaeda salsa, with suitable thresholds of tidal creek area at 0.035–0.245 km2/km2 and sinuosity between 1.0 and 1.5. Scenario simulations show that moderately narrowing the inflow cross-section of the main tidal creek can move the tidal creek area toward the suitable range while keeping sinuosity stable. The results support a restoration path that uses small interventions to guide natural processes and strengthen the system’s self-recovery, and they provide quantitative design targets and scientific support for ecological restoration based on hydro-geomorphic optimization in estuarine wetlands.