Wetlands, apart from hindering some walks in the woods, serve a variety of purposes, both quantifiable and abstract.There are many different kinds of wetlands, each its own unique ecosystem.
Marshes are characterized as a type of wetland that is “frequently inundated with water,” according to the U.S. Environmental Protection Agency’s (EPA) website. Most of this water comes from surface water but, in many cases, marshes also receive ground water. Marshes have a relatively neutral pH which, when coupled with the abundance of nutrients, makes excellent conditions for plant and animal growth. Within the grouping of marshes, two sub-categories can be delineated: tidal and non-tidal marshes.
A perfect example of tidal marshes are the salt marshes that exist along much of the North Shore’s coastline. Covered in cord grass, these marshes have a distinct look to them. Marshes of the non-tidal variety include the most prevalent wetlands in North America. Vernal pools are seasonal marshes, depressions in the land where water collects; they are critical to species in need of a breeding ground safe from predators. An example of one species found often in vernal pools is the marbled salamander which, in its infancy, would be devoured by fish if it did not have these safer wet areas.
Bogs are a type of wetland characterized by the formation of peat moss. They have relatively acidic soils which are covered in sphagnum moss. Most of the water for a bog comes from precipitation which results in a low amount of nutrients for plants and animals. Because of the unique makeup of bogs, some interesting species inhabit them. For example, pitcher plants get around the nutrient deficiency of bogs by eating insects. Northern bogs are often the remains of glacial lakes and may have standing water (if the vegetation has not completely taken over). Pocosins are a type of bog that occur mostly from Virginia to northern Florida, a southern bog, if you will. The word pocosin comes from the Algonquin “swamp on a hill.” Due to periodic biodiversity-increasing fires, charcoal can be found in the peat.
Fens are similar to bogs. These also form peat but, unlike bogs, most of a fen’s water comes from sources other than precipitation, usually runoff. Because of this, fens are less acidic than bogs and also have higher amounts of nutrients. As the amount of peat increases, the groundwater supply of a fen may be cut off and the fen could become a bog due to the reduction in nutrients it will receive. Also true of bogs, fens occur most often in the Northern Hemisphere.
The fourth type of wetland is the swamp, characterized as being “dominated by woody plants.” They have standing water at times and saturated soils too. Swamps are very productive; their soils are rich in nutrients and look blackish. They support a myriad of species, including many rare ones, and can be divided into two main groups with a couple special examples. The first type is the forested swamp. These are most often covered in shallow water and in droughts can be the only such water around, giving them monumental importance in the support of plants and animals in need of this environment. They are found throughout the United States.
Forested swamps farther south usually occur along rivers and are called bottomland hardwood forests. They provide flood protection when the rivers overflow their banks and, as the name says, are comprised of deciduous trees which can handle the inundation of water. In many cases the trees in these swamps have developed aerated roots and flared trunks to help cope with the saturated environment they live in.
The second kind of swamp is the shrub swamp, very similar to forested swamps, the difference being the dominance of shrubs as opposed to trees. Shrub swamps often occur next to other types of swamps. A special example of shrub swamps occurs in coastal, tropical to sub-tropical regions. The mangrove swamp is home to plants that are salt loving and often grow right in the intertidal zone. Because of the flow of nutrients from runoff and the exchange of water from the tides, mangrove swamps support a plethora of species, especially bacteria and worms. The mangroves themselves create maze-like tunnels through which one can explore by kayak.
Wetlands serve many functions and have untold values. Wetlands are huge producers of food for many organisms. The large accumulations of detritus that can be seen in most swamps and bogs are a clear example of the food available to bacteria and other decomposers. From here the food chain continues up and the organisms get larger and larger. With the great amount of food for the base species in the food pyramid, wetlands are easily demonstrated to support a large amount of organisms. Because of this abundance of food, many animals have adapted to living directly in/on the wetlands. Examples of these species include the beaver, otter, great blue heron, and countless detritevores. According to the U.S. Fish and Wildlife Service, almost half of America’s threatened and endangered species directly or indirectly need wetlands for survival. In addition, many of the organisms that do not live in/on the wetlands were born there or spent some critical phase of their life cycle there.
Wetlands also serve to maintain the earth’s biogeochemical cycles. Many bodies of water suffer because of eutrophication, an inundation of nutrients. Wetlands often serve the purpose of removing excess nutrients, mainly nitrogen and phosphorus, from the water. This keeps the water cleaner and more oxygenated, which supports greater biodiversity and greatly improves the aesthetics of the body of water by preventing algal blooms. Wetlands also store up vast amounts of carbon which would otherwise be released as carbon dioxide. In peat-forming bogs and fens, huge “sinks” of carbon are contained in the peat which blankets the wetland. This serves to reduce the greenhouse effect, caused largely by the excess amounts of carbon dioxide being released into the atmosphere, which is to say that wetlands help in the fight against global warming.
The third important service wetlands provide is that of maintaining the hydrologic cycle. They keep waters clean by working against eutrophication, as was previously mentioned, and by filtering out sediments and suspended particles. This sedimentation could lead to the blocking of sunlight from bottom dwelling plants, effectively killing them. By filtering surface runoff, wetlands remove much of the wastes that come from industry and agriculture. Many wetlands act like sponges; they soak up water in times of excess, which prevents flooding, and in times of drought they release this stored up water to maintain flow in the river. By acting as flood control, wetlands also help to prevent downstream erosion, which itself is a large cause of sedimentation and the destruction of human-made structures. Coastal wetlands prevent erosion from waves.
Economically, wetlands are viable marketplaces. Tens of millions of acres of wetlands support timber industry trees and many other crops, such as blueberries, cranberries, and even some medicinal varieties of plants. The fish and shellfish industry are supported by a fish population that is 75% reliant on wetlands, putting a large portion of that market in direct dependence on wetlands. Muskrats and alligators, both animals hunted and sold commercially, live and are dependent on wetlands.
In addition to hunting, many people enjoy wetlands for their recreational importance. They are home to many birds sought after by birders, a growing percentage of the recreation-enjoying population. Also, there exist opportunities for hiking, canoeing, and camping in and along many wetlands. In addition to all the textbook-fun to be found in wetlands, they also serve as excellent classrooms to teach about ecosystems or biogeochemical cycling or many other topics.
Wetlands serve many uses even beyond what humans have conventionally put dollar figures on. Wetlands comprise a rich assortment of different ecosystems which are vital to the well being of our planet. Preserving pieces of the environment is important globally and wetlands especially need protection against developers who have historically viewed them as vacant lots. The great amount of environmental functions they serve make them that much more important in aiding the environment as a whole.
Sipple, William S. Wetland Functions and Values. US Environmental Protection Agency. 1 Dec. 2002 http://www.epa.gov/watertrain/wetlands.
Wetland Types. US Environmental Protection Agency. 29, Nov. 2002 http://www.epa.gov/owow/wetlands/types/.