Dwarf smooth cordgrass forms extensive stands just above the low marsh. Above the dwarf smooth cordgrass zone, common reed, saltmeadow cordgrass, and saltgrass predominate. Common reed forms pure or mixed stands, saltmeadow cordgrass forms nearly pure stands, and saltgrass is commonly intermixed with other species. Smooth cordgrass and saltmeadow cordgrass are often intermixed with patches of big cordgrass and common reed. Tidal salt marshes are highly productive ecosystems.
Consumers living in tidal saltmarshes are either grazers or alga-detritus feeders.
Some interesting relationships have been reported, however. Through their burrowing activities, fiddler crabs increase soil drainage, decomposition of belowground debris, and the oxygen content of the soil, all of which benefit smooth cordgrass. Ribbed mussels attach to smooth cordgrass in the low salt marsh and buffer it from physical disturbance.