Although waterfowl such as ducks and herons are commonly associated with marshes, other birds, such as songbirds and hawks, also feed on the life generated within wetlands. Southern deepwater swamps are riparian systems notable for the standing water present during much of the year. Other examples of riparian forested wetlands include maple swamps, bottomland hardwood forests, and cottonwood riparian areas. In hardwood swamps, a variety of shrubs and plants, such as skunk cabbage, grow beneath the forest canopy. Shrub swamps are dominated by willows, alders, shrubby dogwoods, and buttonbush.
Some shrub swamps are permanent, while others slowly transform themselves into true forested swamps.
Approximately half of the organic matter produced in these marshes is transported downstream to the estuary or the sea as detritus, forming the base of the food web. Black mangrove has hundreds of roots the size of pencils that grow up from the soil. Tall white mangrove and buttonwood usually grow upland of the red and black mangroves. For information on Texas wetlands refer to the Texas wetland conservation plan.