Used by U.S. Fish and Wildlife Service

One typically used group system because that wetlands was arisen by Cowardin and also is explained in Classification that Wetlands and Deepwater Habitats that the united States. The Cowardin system is provided by the U.S. Fish and Wildlife company for the national Wetlands Inventory. In this system, wetlands room classified by see position, vegetation cover and hydrologic regime. The Cowardin system consists of five significant wetland types: marine, tidal, lacustrine, palustrine and also riverine.

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Used by U.S. Army Corps that Engineers

Another usual wetland group system, provided by the U.S. Military Corps of Engineers, was emerged by Brinson and also is defined in A Hydrogeomorphic classification for Wetlands. As the title implies, wetlands are classified by their geomorphic setting, dominant water resource (e.g. Precipitation, groundwater or surface ar water) and hydrodynamics. The hydrogeomorphic (HGM) contains five significant wetland types: riverine, slope depressional, flat and also fringe.

Types that Wetlands


Description that Marshes

Marshes are identified as wetlands frequently or continually inundated through water, identified by emergent soft-stemmed vegetation adapted to saturated floor conditions. There are many different type of marshes, varying from the prairie potholes to the Everglades, seaside to inland, freshwater come saltwater. All varieties receive many of your water from surface ar water, and many marshes are additionally fed by groundwater. Nutrients space plentiful and also the pH is generally neutral top to an abundance of plant and animal life. Us have divided marshes right into two primary categories: non-tidal and tidal.


Functions & worths of Marshes

Marshes recharge groundwater supplies and moderate streamflow by providing water to streams. This is particularly important role during periods of drought. The existence of marshes in a watershed help to reduce damage caused by floods by slowing and storing flood water. As water moves slowly through a marsh, sediment and other pollutants work out to the substrate or floor the the marsh. Wetland vegetation and also microorganisms additionally use excess nutrient for expansion that deserve to otherwise pollute surface water such together nitrogen and phosphorus indigenous fertilizer.

Non-Tidal Marshes



Non-tidal marshes are the many prevalent and widely distributed wetlands in north America. Lock are greatly freshwater marshes, although some room brackish or alkaline. They typically occur follow me streams in poorly drained depressions and also in the shallow water follow me the borders of lakes, ponds and rivers. Water levels in this wetlands typically vary indigenous a few inches to two or 3 feet, and some marshes, favor prairie potholes, may periodically dry out completely.

Highly organic, mineral well-off soils that sand, silt, and also clay underlie these wetlands, while lily pads, cattails (see photo), reeds and bulrushes provide excellent habitat because that waterfowl and also other small mammals, such together Red-winged Blackbirds, good Blue Herons, otters and also muskrats. Instances of non-tidal marshes are: Prairie potholes, playa lakes, vernal pools and wet meadows.

Functions & Values

Due to their high levels of nutrients, freshwater marshes are among the most abundant ecosystems top top earth. They deserve to sustain a large array of plant neighborhoods that subsequently support a wide range of wildlife in ~ this an essential wetland ecosystem. As a result, marshes sustain a diversity of life the is disproportionate with their size. In enhancement to their considerable habitat value, non-tidal marshes offer to reduce flood damage and filter excess nutrients from surface runoff.



Pickerelweed (Pontederia cordata). Status

Unfortunately, like numerous other wetland ecosystems, freshwater marshes have actually suffered major acreage casualty to person development. Some have been degraded by extreme deposits of nutrients and also sediment indigenous construction and also farming. Major flooding and also nutrient deposition come downstream waters have actually often complied with marsh destruction and also degradation. Such environmental difficulties prove the vital roles these wetlands play. This realization has spurred intensified protection and also restoration of swamp ecosystems, such together the prairie potholes and the Everglades.

Tidal Marshes


Tidal marshes can be found along protected coasts in middle and high latitudes worldwide. Castle are many prevalent in the United says on the eastern coast from Maine come Florida and continuing on to Louisiana and Texas along the Gulf that Mexico. Some room freshwater marshes, others are brackish (somewhat salty), and still others room saline (salty), but they room all influenced by the movement of ocean tides. Tidal marshes are normally categorized into two distinct zones, the reduced or intertidal marsh and also the upper or high marsh.

In saline tidal marshes, the lower marsh is normally covered and also exposed everyday by the tide. It is mostly covered by the tall type of Smooth Cordgrass (Spartina alterniflora). The saline marsh is extended by water only sporadically and is characterized by short Smooth Cordgrass, Spike Grass and also Saltmeadow rush (Juncus gerardii). Saline marshes support a highly dedicated set of life adapted for saline conditions.

Functions & Values

Tidal marshes serve many important functions. Castle buffer stormy seas, slow coastline erosion and are able come absorb excess nutrients before they reach oceans and also estuaries. Tidal marshes additionally provide vital food and habitat because that clams, crabs and juvenile fish, and offering shelter and also nesting sites because that several varieties of migratory waterfowl.


Pressure to to fill in these wetlands for coastal development has actually led to significant and continuing losses of tidal marshes, especially along the Atlantic coast. Pollution, especially near metropolitan areas, likewise remains a significant threat to these ecosystems. Fortunately, many states have enacted special legislations to safeguard tidal marshes, however diligence is required to guarantee that this protective measures are actively enforced.


Skunk Cabbage (Symplocarpus foetidus) sprouts very early in the spring, melting the surrounding snow. The insects the pollinate it space attracted by its odor, which each other decaying flesh.

Description the Swamps

A swamp is any wetland dominated by woody plants. Over there are countless different type of swamps, varying from the forested Red Maple, (Acer rubrum), swamps the the Northeast to the comprehensive bottomland hardwood forests found along the sluggish rivers that the Southeast. Swamps are identified by saturated soils during the cultivation season and also standing water during specific times that the year. The highly organic soils that swamps form a thick, black, nutrient-rich atmosphere for the growth of water-tolerant tree such together Cypress (Taxodium spp.), Atlantic White Cedar (Chamaecyparis thyoides), and Tupelo (Nyssa aquatica). Some swamps are dominated by shrubs, such as Buttonbush or Smooth Alder. Plants, birds, fish, and also invertebrates such together freshwater shrimp, crayfish, and also clams need the habitats noted by swamps. Plenty of rare species, such as the intimidated American Crocodile, depend on this ecosystems as well. Swamps may be divided into two major classes, depending upon the kind of vegetation present: shrub swamps and forested swamps.

Functions & worths of Swamps

Swamps serve critical roles in overwhelming protection and also nutrient removal. Floodplain woodlands are particularly high in productivity and types diversity since of the well-off deposits that alluvial floor from floods. Numerous upland creatures count on the abundance of food discovered in the lowland swamps, and an useful timber have the right to be sustainably harvested to carry out building materials for people.


Due to the nutrient-rich soils existing in swamps, many of these fertile woodlands have been drained and also cleared for agriculture and other development. Historically, swamps have actually been portrayed as frightening no-man"s-lands. This perception brought about the large devastation of tremendous tracts that swampland end the previous 200 years, such as the devastation of more than fifty percent of the legendary great Dismal Swamp that southeastern Virginia.

Swamps typically support highly diverse vegetation since of the plenty of layers that vegetation present: shrubs, saplings, and also herbaceous plants.

Forested swamps are found throughout the joined States. They are frequently inundated through floodwater from surrounding rivers and also streams. Sometimes, they room covered by countless feet of an extremely slowly relocating or stand water. In really dry years they may represent the only shallow water because that miles and their existence is crucial to the survive of wetland-dependent varieties like hardwood Ducks (Aix sponsa), river Otters (Lutra canadensis) and Cottonmouth snake (Agkistrodon piscivorus). Few of the common varieties of trees discovered in these wetlands space Red Maple and Pin Oak (Quercus palustris) in the north United States, Overcup Oak (Quercus lyrata) and also Cypress in the South, and Willows (Salix spp.) and Western Hemlock (Tsuga sp.) in the Northwest. Bottomland hardwood swamp is a name frequently given to forested swamps in the south central United States.

Shrub Swamps

Shrub swamps are similar to forested swamps other than that shrubby vegetation such as Buttonbush, Willow, Dogwood (Cornus sp.) and also Swamp climbed (Rosa palustris) predominates. In fact, forested and also shrub swamps are often found adjacent to one another. The soil is regularly water logged for lot of the year and also covered at time by as lot as a few feet the water since this kind of swamp is discovered along slow relocating streams and also in floodplains. Mangrove swamps room a kind of shrub swamp overcame by mangroves that covers vast expanses of southern Florida.


This eastern Mud Salamander (Pseudotriton montanus) is resting on sphagnum moss. Sphagnum creates bogs by stop water and creating acidic conditions. Sphagnum itself may be approximately 70 percent water.

Description of Bogs

Bogs are one of North America"s many distinctive kinds of wetlands. Castle are characterized by spongy peat deposits, acidic waters and also a floor covered by a thick carpet of sphagnum moss. Bogs get all or most of your water from precipitation quite than from runoff, groundwater or streams. Together a result, bogs room low in the nutrients needed for tree growth, a problem that is enhanced by acid creating peat mosses.

There are two primary ways the a bog can develop: bogs can kind as sphagnum moss grows over a lake or pond and slowly fills it (terrestrialization), or bogs can kind as sphagnum moss blankets dried land and also prevents water native leaving the surface ar (paludification). End time, numerous feet the acidic peat deposits build up in bogs of either origin. The unique and demanding physical and also chemical attributes of bogs an outcome in the presence of plant and animal areas that demonstrate numerous special adaptations to low nutrient levels, waterlogged conditions, and acidic waters, such as carnivorous plants.

Carlisle Bog in Alaska. Uneven the rest of the unified States, Alaska still has actually most that its wetlands.

Functions & worths of Bogs

Bogs serve an essential ecological role in avoiding downstream flooding by absorbing precipitation. Bogs support some of the most exciting plants in the United says (like the carnivorous Sundew) and provide habitat to animals threatened by human being encroachment.

Status the Bogs

Bogs in the United states are mostly discovered in the glaciated northeast and great Lakes regions (northern bogs) but also in the southeast (pocosins). Your acreage declined historically together they were drained come be used as cropland and also mined for your peat, which was offered as a fuel and also a floor conditioner. Recently, bogs have actually been well-known for their role in regulating the worldwide climate by storing big amounts of carbon in peat deposits. Bogs are unique neighborhoods that deserve to be damaged in a issue of days but require hundreds, if not thousands, of years to form naturally.

Northern Bogs

This bog in Nova Scotia, Canada is conquered by ericaceous dwarf-shrubs, a usual family of tree in the peat bogs the the Northeast.
The northern Pitcher tree (Sarracenia purpurea) overcomes the nutrient deficiencies the bog life by catching insects in pools the water in its leaves and also digesting them through the aid of some neighborhood bacteria. The north Pitcher Plant"s flower looks much like the Sweet Pitcher Plant"s (see below).

Northern bogs room generally connected with low temperatures and short growing seasons where ample precipitation and high humidity reason excessive humidity to accumulate. Therefore, many bogs in the United states are found in the north states. Northern bogs often type in old glacial lakes. Castle may have either considerable amounts of open up water surrounding by floating vegetation or vegetation may have completely filled the lake (terrestrialization).

The sphagnum peats of northern bogs reason especially acidic waters. The result is a marsh ecosystem v a very specialized and unique flora and also fauna the can grow in these problems called acidophiles. Nevertheless, bogs assistance a variety of species of plants in enhancement to the characteristic Sphagnum Moss, including Cotton Grass, Cranberry, Blueberry, Pine, Labrador Tea and Tamarack. Moose, deer, and also lynx are a few of the animals that deserve to be uncovered in northern bogs. The greater Sandhill Crane, the Sora Rail, and the an excellent Gray Owl count on bogs for survival.


Pocosins space densely vegetated through trees and also shrubs. They space subjected come fire around every 10 come 30 years (Photo by Dr. Curtis Richardson/Duke marsh Center). Description

The indigenous pocosin comes from the Algonquin native American word for "swamp ~ above a hill." these evergreen shrub and tree dominated landscapes are found on the Atlantic coastal Plain from Virginia to northern Florida; though, most are found in phibìc Carolina. Usually, over there is no was standing water present in pocosins, yet a shallow water table leaves the soil saturated for much of the year.They range in size from much less than one acre to number of thousand acres situated between and also isolated native old or currently stream systems in many instances.

Pocosins provide large tracks that undisturbed land needed by black color Bears (Ursus americanus).

Because pocosins are found in broad, flat, upland locations far from big streams, they space ombrotrophic like north bogs, definition rain provides most of their water. Additionally like the bogs that the much north, pocosins are found on waterlogged, nutrient poor and acid soils. The floor itself is a mixture of peat and sand containing big amounts the charcoal from routine burnings. These herbal fires occur because pocosins periodically become very dry in the spring or summer. The fires space ecologically important due to the fact that they increase the diversity that shrub varieties in pocosins.

The most common plants space evergreen trees (Loblolly Bay, Red Bay and Sweet Bay), and evergreen shrubs (titi, fetterbush and zenobia). Pocosins administer important habitat for countless animals, including some endangered species like the red-cockaded woodpecker. Castle are specifically important together the last refuge for black color Bears in seaside Virginia and also North Carolina and the Red Wolf has actually recently to be reintroduced in north Carolina pocosins.

Functions & Values

Habitat is the most valuable duty of Pocosins. Part pocosins space very huge and difficult to develop, and so they remain mostly undisturbed. Together a result, they are a haven for varieties adapted to life in unaltered forests. As an ext and more land is arisen in the Eastern united States, pocosins are becoming ever an ext valuable refuges for wildlife.

The Sweet Pitcher tree (Sarracenia rubra) is one of the carnivorous plants discovered in pocosins.

The slow motion of water with the dense organic issue in pocosins removes excess nutrient deposited by rainwater. The same organic matter additionally acidifies the water. This an extremely pure water is progressively released to estuaries, wherein it help to maintain the suitable salinity, nutrients and also acidity. This process is necessary to assist maintain healthy and balanced fish populations vital to both commerce and also recreation. Pocosins are also sources of an important timber and fuel, but these offers can damage or destroy pocosins if they space not lugged out responsibly.


Historically, pocosins were greatly threatened by agriculture. Today, hardwood harvesting, peat mining, and also phosphate mining join agriculture as the biggest threats come the staying undisturbed pocosins.


Description of Fens

Fens, are peat-forming wetlands that receive nutrients indigenous sources various other than precipitation: normally from upslope resources through drainage from bordering mineral soils and from groundwater movement. Fens differ from bogs due to the fact that they are much less acidic and also have higher nutrient levels. Therefore, they are able to assistance a much much more diverse plant and also animal community. These equipment are often covered by grasses, sedges, rushes and wildflowers. Part fens are identified by parallel ridges the vegetation be skatifund.orgrate by less productive hollows. The ridges of these patterned fens kind perpendicular come the downslope direction that water movement. Over time, peat may build up and skatifund.orgrate the fen native its groundwater supply. When this happens, the fen receives under nutrients and may come to be a bog.

Like bogs, fens are mainly a north hemisphere phenomenon -- emerging in the northeastern united States, the good Lakes region, the Rocky Mountains and also much that Canada -- and also are generally connected with low temperatures and also short cultivation seasons, whereby ample precipitation and also high humidity reason excessive humidity to accumulate.

Functions & worths of Fens

Fens, favor bogs, provide important benefits in a watershed, including staying clear of or to reduce the hazard of floods, improving water quality and also providing habitat for distinctive plant and also animal communities.

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Fens might be conquered by woody or herbaceous vegetation. In this photograph, trees are invading an herbaceous fen.

Status that Fens

Like many peatlands, fens proficient a decline in acreage in ~ a rate of around eight percent indigenous 1950 come 1970, greatly from mining and draining for cropland, fuel and also fertilizer. Since of the big historical ns of this ecosystem type, continuing to be fens space that much much more rare, and it is vital to protect them. That is important to recognize that if mining and draining this ecosystems carry out resources for people, up to 10,000 years are required to kind a fen naturally.

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