Biomat Mulching Enhances Saltmarsh Restoration: Impacts on the Growth and Physiology of Suaeda salsa

Following the removal of invasive species Spartina alterniflora , extensive exposed sandbars have formed in the coastal wetlands of the Yellow River Delta. The growth of native halophyte Suaeda salsa is critically constrained by multiple factors, including wave erosion and periodic flooding, thereby impeding ecological restoration progress. Conventional restoration methods face inherent limitations. To address these issues, this study conducted a controlled experiment in the laboratory using a wave-generating device. Various wave frequencies of 20 and 40 r/min were applied to simulate different tidal regimes. Biomats were constructed with dried reed stems in 1 cm × 1 cm, 2 cm × 2 cm, and 3 cm × 3 cm grid sizes. Each pot was sown with 120 seeds of S. salsa , with 3 replicates established for the experimental treatments. S. salsa growth parameters and biomechanical traits were measured under different grid sizes of cover methods. Results showed that under no wave conditions, the 3-cm grid biomat markedly promoted S. salsa height and biomass accumulation, but as wave frequency increased, it instead exerted an inhibitory effect ( P < 0.01). The 2-cm grid enhanced rhizome tensile and flexural strength ( P < 0.05). This research proposes a “minimally invasive–self-healing” restoration technique. By utilizing wetland resources like reeds without altering the wetland natural topography, the technique offers a low-intervention, cost-effective, and eco-friendly strategy for coastal wetland recovery. These findings provide experimental evidence for the effectiveness of biomat mulching in regulating S. salsa growth, biomechanical performance, and hydrological connectivity under wave disturbance, offering practical guidance for coastal wetland restoration.