Wetlands Protect Coast, Plants, Animals, People
Hurricanes Katrina and Ike Illustrate Consequences of Marshland Loss
Sep 15, 2008
The coastal population of the United States has grown rapidly since the mid-twentieth century. This growth has meant that many acres of wetland habitat, also called marshes (no trees) and swamps (trees), have been lost. The wet, low-lying areas near the coast have been drained, channeled, and eroded by human activities and wave action. Famously, the coastal wetlands of the Gulf of Mexico, along the edge of Texas, Louisiana, Mississippi, Alabama, and Florida, have suffered.
What is a Coastal Wetland?
While some of the edge of the United States landmass is rocky and blunted against the oceans, there is a range of wetland habitat pooling behind juts of land and expanding into large open water areas like the Chesapeake Bay and Puget Sound. The lengthy edge habitat between the oceans and landmass is pocketed by many sizes and shapes of estuaries, or areas where saltwater meets fresh water in bays, rivers, and creeks and behind barrier peninsulas and islands.
There are three factors that define the presence of a wetland: 1) the presence of water all or most of the time, 2) the presence of plants that have evolved to tolerate inundation by water, and 3) the presence of gray to black soils that indicate lack of oxygen and minerals.
On the Atlantic, Gulf, and Pacific coasts, the water has a salt content from none to 30 parts per thousand. When saltier water inundates trees and plants unused to salt, they die. However, there are many other plants that have adapted to the range of saltiness and know how to use it or eliminate it. Likewise, wetlands plants have adapted themselves to low oxygen in soils that the water has dissolved and reduced. Certain plants thrive in the wetland habitat.
Why are Wetlands Important?
Like a sponge, wetlands are particularly adapted to soaking up water. This role of wetlands is most obvious to those who live on the hurricane ravaged Gulf Coast. Hurricanes are dramatic illustrations that wetlands are most important because they buffer the land and all that is on it from washing away. Draining and channeling wetlands leads to loss of this natural function. Natural wetland barriers in specific locations cannot be mitigated by manufacturing wetlands in another location, as is allowed as an option to developers in many states.
Wetlands are also important for the roles they play in improving water quality. Water that inundates wetlands with the tide or during heavy rain eventually soaks into the land to refill underground aquifers or is slowed down as it runs off to an open body of water like a river or bay. Water that is polluted is filtered when particles are grabbed on their way past the coffee filter-like net of plants, roots, and soil. Wetlands prevent erosion of sediment from land into the sea.
Plants have adapted to the wetlands habitat and they in turn provide habitat for animals. One-third of fish species on the East Coast use wetlands as their spawning ground. The young of crabs play in the wetlands nursery until old enough to brave the open water. Migrating birds use coastal wetlands as a stopover for rest and refueling. They fill up on seeds, berries, and baby fish and crabs before journeying onward.
Human kayakers and canoeists, wildlife watchers, hunters, and fishermen also thrive in wetland habitats!
Estuarine Wetlands Preservation
As scientists and citizens have become more knowledgeable of the role of wetlands as habitat for plants and animals that improve our quality of life, regulations have been established to prevent their destruction by human activities. Scientists delineate wetlands resource protection areas by testing soils and identifying plants. The protection of wetlands resources is critical in the large Chesapeake Bay estuarine area due to the decline of aquatic plants, oysters, and Blue Crabs; the observation of diseased fish; and the importance of Chesapeake Bay-related industry, recreation, and tourism to the area’s economic health. Nutrient pollution from farms and sewage treatment plants as well as runoff from paved area has lead to a campaign to Save the Bay.
At a network of protected coastal estuarine areas from Alaska and California, along the Gulf Coast, and up the East Coast from Florida to Maine, scientists are researching, monitoring, and educating. The National Estuarine Research Reserve System program brings an understanding of coastal wetlands to local communities in order to foster stewardship of estuarine wetlands as vital natural resources.
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