Abstract The complex interplay between soil moisture and salinity governs vegetation dynamics in estuarine salt marshes, yet a quantitative understanding of these relationships remains limited. This study introduces an integrated modeling framework coupling water‐salt transport with a spatially explicit vegetation model to investigate community responses to hydrological fluctuations in a typical estuary salt marsh in China. The model simulates spatial patterns, biomass dynamics, and interspecific competition for four dominant species from 2013 to 2021. In response to soil moisture and salinity fluctuations driven by interannual variations in Yellow River discharge, the results revealed distinct species‐specific responses. Phragmites australis exhibited a biomass decline (from 8.951 to 8.182 × 10 7 kg) with a stable distribution, indicating physiological stress. Tamarix chinensis maintained a stable biomass (about 1.94 × 10 7 kg) despite a shrinking distribution, suggesting concentration into optimal microsites. Suaeda salsa showed resilience, with its biomass fluctuating before recovering to 11.802 × 10 7 kg in 2021. The invasive Spartina alterniflora demonstrated a biomass increase (from 9.682 to 10.139 × 10 7 kg) even as its range contracted post‐2018, likely due to increased density in remaining patches. The model identified a community shift from stability (2013–2017) to restructuring (2018–2021), driven by increased freshwater input. Across all species, biomass changes preceded distributional shifts, highlighting biomass as a more sensitive indicator of environmental stress. These findings suggest that moderate freshwater inputs can enhance native species' competitiveness and provide quantitative insights for managing salt marsh ecosystems under changing hydrological regimes.
Song et al. (Fri,) studied this question.