Effects of Tidal Creek Order on <i>Suaeda salsa</i> Growth in the Liaohe Estuary Wetland: Mechanisms and Implications for Restoration

Tidal creeks serve as key channels for hydrological connectivity in coastal wetlands, but the mechanisms through which tidal creeks affect the growth of coastal wetland plants remain unclear. We measured the growth of Suaeda salsa , plot elevations, tidal creek morphologies, and soil properties at 3 levels (e.g., first, second, and third order) of tidal creeks in the Liaohe Estuary wetland, northeastern China. We found that the morphology of second-order tidal creeks was more favorable for the growth of S. salsa . Partial least squares structural equation modeling revealed that elevation significantly affects the morphological development of tidal creeks and indirectly affected the growth of S. salsa by regulating hydrological conditions and soil properties. Soil total nitrogen and organic matter were key factors directly promoting aboveground biomass accumulation, whereas salinity had a negative effect on nutrient availability. Our findings suggest that tidal creeks can alleviate salt stress by affecting the efficiency of hydrological exchange, and prioritizing the design of tidal creek networks with moderate connectivity to optimize the habitat of S. salsa for restoration is advisable. These findings provide a theoretical basis for ecological restoration based on hydrogeomorphic design in coastal wetlands.