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. Coastal development poses a severe threat to coastal wetlands, through conversion to other habitats, groundwater withdrawal, erosion, sedimentation, decreased water quality and impacts to wildlife and waterfowl. Playas are ephemeral wetlands characterized by Randall or Ness clays, and are very similar to potholes, but have a different geologic origin.
Saline lakes are generally larger than playas, are very saline, and are influenced by groundwater.
A few playas and playa-like basins with connections to groundwater occur in the Rolling Plains. Riparian wetlands include main channels of creeks and rivers and associated wet meadow, bog and beaver pond habitats. Abandoned creek or river channels may continue to hold water and are wetlands called oxbows . Oxbows found in the Lower Rio Grande Valley are called resacas . The playa lakes region of the United States includes portions of Colorado, Kansas, New Mexico, Oklahoma and northwestern Texas.