Some overlap of species can be found within the different wetland types on the Gulf coast. Saline marsh is characterized by a monotypic stand of smooth cordgrass. Other plants present may include blackrush, saline marsh aster, saltwort, glasswort and sea-lavender. Brackish marsh communities, the most extensive communities in the Galveston Bay system, are transitional between saline and intermediate marshes. Dominant species include marshhay cordgrass, saltgrass, saltmarsh bulrush, marsh hemp and hairypod cowpea.
Intermediate marshes reflect greater plant diversity than the saline or brackish marsh assemblages.
Species found in this environment include seashore paspalum, marshhay cordgrass, Olney bulrush, Colorado River hemp, common reedgrass, coastal water-hyssop, bearded sprangletop, and cattail. Fresh marshes support the greatest diversity in plant species of all marsh types. Dominants include paillefine, giant cutgrass, American lotus, white water-lily, smartweed, marsh millet, arrowhead, seedbox, cattail, alligator weed, and many others. Coastal wetlands in Texas provide one of the most important wintering and migration areas in North America for waterfowl using the Central and Mississippi flyways. The bald eagle, peregrine falcon, brown pelican and whooping crane all depend on the marshes and estuaries for food, as do otter, alligator and swamp rabbit.