Used by U.S. Fish and Wildlife Service

One commonly provided classification device for wetlands was emerged by Cowardin and is explained in Group of Wetlands and Deepwater Habitats of the United States. The Cowardin system is supplied by the U.S. Fish and Wildlife Service for the National Wetlands Inventory. In this mechanism, wetlands are classified by landscape place, vegetation cover and also hydrologic regimen. The Cowardin device contains 5 major wetland also types: marine, tidal, lacustrine, palustrine and riverine.

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Used by U.S. Army Corps of Engineers

Another prevalent wetland classification mechanism, supplied by the U.S. Military Corps of Engineers, was emerged by Brinson and also is explained in A Hydrogeomorphic Category for Wetlands. As the title indicates, wetlands are classified by their geomorphic setting, leading water resource (e.g. precipitation, groundwater or surface water) and hydrodynamics. The hydrogeomorphic (HGM) has five major wetland types: riverine, slope depressional, level and also fringe.

Types of Wetlands


Non-Tidal Marshes

Tidal marsh along the Edisto River, South Carolina.

Common Cattail (Typha latifolia) is a freshwater and estuarine marsh species.
Description of Marshes

Marshes are defined as wetlands generally or continually inundated via water, identified by emergent soft-stemmed vegetation adapted to saturated soil problems. There are many various kinds of marshes, varying from the prairie potholes to the Everglades, coastal to inland also, freshwater to saltwater. All forms obtain a lot of of their water from surconfront water, and also many type of marshes are also fed by groundwater. Nutrients are numerous and also the pH is commonly neutral bring about an abundance of plant and also pet life. We have divided marshes into 2 primary categories: non-tidal and also tidal.

Functions & Values of Marshes

Marshes recharge groundwater offers and moderate streamflow by giving water to streams. This is an especially important feature during durations of drought. The presence of marshes in a waterburned helps to minimize damages caused by floods by slowing and also storing flood water. As water moves progressively via a marsh, sediment and other pollutants resolve to the substrate or floor of the marsh. Marsh vegetation and microorganisms additionally use excess nutrients for development that can otherwise pollute surconfront water such as nitrogen and also phosphorus from fertilizer.

Non-Tidal Marshes


Non-tidal marshes are the a lot of widespread and extensively dispersed wetlands in The United States and Canada. They are greatly freshwater marshes, although some are brackish or alkaline. They frequently occur alengthy streams in poorly drained depressions and in the shpermit water alengthy the limits of lakes, ponds and rivers. Water levels in these wetlands mainly vary from a few inches to two or 3 feet, and some marshes, like prairie potholes, might periodically dry out completely.

Highly organic, mineral wealthy soils of sand, silt, and clay underlie these wetlands, while lily pads, cattails (view photo), reeds and also bulrushes carry out wonderful habitat for waterfowl and also various other little mammals, such as Red-winged Blackbirds, Great Blue Herons, otters and muskrats. Examples 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 many fertile ecounits on earth. They can sustain a substantial array of plant areas that consequently support a wide range of wildlife within this necessary wetland also ecomechanism. As an outcome, marshes sustain a diversity of life that is disproportionate with their dimension. In enhancement to their substantial habitat worth, non-tidal marshes serve to reduce flood damages and filter excess nutrients from surconfront runoff.




Unfortunately, prefer many kind of other wetland ecosystems, freshwater marshes have endured major acreage losses to human development. Some have been degraded by extreme deposits of nutrients and also sediment from building and also farming. Severe flooding and nutrient deplace to downstream waters have actually often complied with marsh destruction and deterioration. Such environmental problems prove the vital duties these wetlands play. This realization has actually spurred amplified security and restoration of marsh ecosystems, such as the prairie potholes and also the Everglades.

Tidal Marshes

Tidal marshes deserve to be uncovered alengthy safeguarded coasts in middle and also high latitudes worldwide. They are the majority of prevalent in the United States on the eastern coast from Maine to Florida and proceeding on to Louisiana and Texas along the Gulf of Mexico. Some are freshwater marshes, others are brackish (somewhat salty), and also still others are saline (salty), however they are all influenced by the movement of sea tides. Tidal marshes are generally categorized into two unique areas, the lower or intertidal marsh and the upper or high marsh.

In saline tidal marshes, the lower marsh is usually spanned and exposed day-to-day by the tide. It is mostly extended by the tall develop of Smooth Cordgrass (Spartina alterniflora). The saline marsh is covered by water just sporadically and also is identified by Quick Smooth Cordgrass, Spike Grass and also Saltmeadow Rush (Juncus gerardii). Saline marshes assistance a very specialized collection of life adjusted for saline conditions.

Functions & Values

Tidal marshes serve many type of crucial attributes. They buffer stormy seas, slow-moving coast erosion and are able to absorb excess nutrients prior to they reach seas and also estuaries. Tidal marshes also administer vital food and also habitat for clams, crabs and juvenile fish, and also offering shelter and nesting sites for several species of migratory waterfowl.


Prescertain to fill in these wetlands for seaside advance has led to substantial and continuing losses of tidal marshes, especially along the Atlantic coastline. Pollution, particularly near metropolitan locations, also continues to be a severe risk to these ecounits. Fortunately, many says have enacted special legislations to protect tidal marshes, but diligence is necessary to ascertain that these protective measures are proactively implemented.

Skunk Cabbage (Symplocarpus foetidus) sprouts incredibly early on in the spring, melting the neighboring scurrently. The insects that pollinate it are attracted by its odor, which resembles decaying flesh.
Description of Swamps

A swamp is any kind of wetland conquered by woody plants. Tbelow are many different kinds of swamps, ranging from the forested Red Maple, (Acer rubrum), swamps of the Northeastern to the substantial bottomland hardhardwood woodlands discovered along the sluggish rivers of the Southeast. Swamps are identified by saturated soils during the prospering seakid and standing water throughout certain times of the year. The highly organic soils of swamps develop a thick, black, nutrient-affluent atmosphere for the expansion of water-tolerant trees such as Cypress (Taxodium spp.), Atlantic White Cedar (Chamaecyparis thyoides), and also Tupelo (Nyssa aquatica). Some swamps are conquered by shrubs, such as Buttonbush or Smooth Alder. Plants, birds, fish, and invertebrates such as freshwater shrimp, crayfish, and clams need the habitats provided by swamps. Many type of rare species, such as the endangered American Crocodile, depfinish on these ecounits as well. Swamps might be divided right into 2 significant classes, depending on the type of vegetation present: shrub swamps and forested swamps.

Functions & Values of Swamps

Swamps serve necessary roles in flood protection and nutrient removal. Floodordinary woodlands are specifically high in performance and also species diversity because of the affluent deposits of alluvial soil from floods. Many upland creatures depfinish on the abundance of food discovered in the lowland also swamps, and handy timber deserve to be sustainably harvested to provide structure products for people.


Due to the nutrient-wealthy soils present in swamps, many kind of of these fertile woodlands have actually been drained and cleared for farming and also other development. Historically, swamps have actually been portrayed as frightening no-man"s-lands. This perception resulted in the substantial devaterminal of tremendous tracts of swampland also over the past 200 years, such as the destruction of more than fifty percent of the legendary Great Dismal Swamp of southeastern Virginia.

Swamps typically support highly diverse vegetation because of the many layers of vegetation present: shrubs, saplings, and herbaceous plants.

Forested swamps are uncovered throughout the USA. They are regularly inundated via floodwater from surrounding rivers and also streams. Sometimes, they are spanned by many feet of exceptionally slowly relocating or standing water. In exceptionally dry years they may represent the only shenable water for miles and their existence is instrumental to the survival of wetland-dependent species prefer Wood Ducks (Aix sponsa), River Otters (Lutra canadensis) and also Cottonmouth Snakes (Agkistrodon piscivorus). Some of the common species of trees discovered in these wetlands are Red Maple and also Pin Oak (Quercus palustris) in the Northern USA, Overcup Oak (Quercus lyrata) and Cypush in the South, and Willows (Salix spp.) and also Western Hemlock (Tsuga sp.) in the Northwest. Bottomland hardlumber swamp is a name typically offered to forested swamps in the southern central USA.

Shrub Swamps

Shrub swamps are comparable to forested swamps other than that shrubby vegetation such as Buttonbush, Willow, Dogwood (Cornus sp.) and Swamp Rose (Rosa palustris) predominates. In truth, forested and shrub swamps are frequently discovered nearby to one an additional. The soil is regularly water logged for much of the year and also covered at times by as a lot as a couple of feet of water bereason this form of swamp is uncovered along slow relocating streams and in floodlevels. Mangrove swamps are a kind of shrub swamp dominated by mangroves that covers vast expanses of southern Florida.

This Eastern Mud Salamander (Pseudotriton montanus) is resting on sphagnum moss. Sphagnum creates bogs by holding water and also creating acidic conditions. Sphagnum itself may be up to 70 percent water.
Description of Bogs

Bogs are one of North America"s a lot of distinctive kinds of wetlands. They are defined by spongy peat deposits, acidic waters and also a floor spanned by a thick carpet of sphagnum moss. Bogs get all or the majority of of their water from precipitation fairly than from runoff, groundwater or streams. As a result, bogs are low in the nutrients needed for plant growth, a problem that is intensified by acid developing peat mosses.

There are two primary methods that a bog deserve to develop: bogs have the right to develop as sphagnum moss grows over a lake or pond and also progressively fills it (terrestrialization), or bogs have the right to develop as sphagnum moss blankets dry land and stays clear of water from leaving the surchallenge (paludification). With time, many type of feet of acidic peat deposits construct up in bogs of either beginning. The distinct and also demanding physical and also chemical qualities of bogs cause the presence of plant and also animal neighborhoods that demonstrate many type of distinct adaptations to low nutrient levels, waterlogged problems, and also acidic waters, such as carnivorous plants.

Carlisle Bog in Alaska. Unlike the rest of the United States, Alaska still has actually most of its wetlands. Functions & Values of Bogs

Bogs serve a crucial eco-friendly function in staying clear of downstream flooding by absorbing precipitation. Bogs assistance some of the the majority of amazing plants in the United States (favor the carnivorous Sundew) and also carry out habitat to animals endangered by human encroachment.

Status of Bogs

Bogs in the USA are mostly uncovered in the glaciated northeast and also Great Lakes areas (northern bogs) yet also in the southeastern (pocosins). Their acreage decreased historically as they were drained to be used as cropland and also mined for their peat, which was offered as a fuel and also a soil conditioner. Recently, bogs have actually been known for their role in regulating the worldwide climate by storing big amounts of carbon in peat deposits. Bogs are unique areas that can be damaged in a issue of days however require hundreds, if not thousands, of years to form normally.

Nothern Bogs
This bog in Nova Scotia, Canada is overcame by ericaceous dwarf-shrubs, a widespread household of plants in the peat bogs of the Northeastern.
The Northern Pitcher Plant (Sarracenia purpurea) overcomes the nutrient deficiencies of bog life by capturing insects in pools of water in its leaves and also digesting them with the aid of some neighborhood bacteria. The Northern Pitcher Plant"s flower looks a lot favor the Sweet Pitcher Plant"s (watch below).

Northern bogs are primarily associated through low temperatures and also brief thriving periods wbelow ample precipitation and high humidity cause extreme moisture to accumulate. Because of this, the majority of bogs in the USA are discovered in the northern states. Northern bogs frequently develop in old glacial lakes. They might have either significant amounts of open water surrounded by floating vegetation or vegetation might have entirely filled the lake (terrestrialization).

The sphagnum peats of north bogs reason especially acidic waters. The result is a wetland ecodevice via a very specialized and also distinct flora and also fauna that can thrive in these problems called acidophiles. Nevertheless, bogs assistance a variety of species of plants in addition to the characteristic Sphagnum Moss, consisting of Cotton Grass, Cranberry, Blueberry, Pine, Labrador Tea and Tamarack. Moose, deer, and also lynx are a few of the pets that can be found in north bogs. The Greater Sandhill Crane, the Sora Rail, and also the Great Gray Owl depfinish on bogs for survival.


Pocosins are densely vegetated with trees and also shrubs. They are based on fire about eexceptionally 10 to 30 years (Picture by Dr. Curtis Richardson/Duke Wetland also Center).


Words pocosin originates from the Algonquin Native Amerihave the right to word for "swamp on a hill." These evergreen shrub and also tree overcame landscapes are uncovered on the Atlantic Coastal Plain from Virginia to northern Florida; though, a lot of are uncovered in North Carolina. Typically, there is no standing water present in pocosins, yet a shpermit water table leaves the soil saturated for much of the year.They selection in size from less than an acre to numerous thousand also acres located between and isolated from old or existing stream devices in many instances.

Because pocosins are found in broad, flat, upland also locations much from huge streams, they are ombrotrophic prefer northern bogs, meaning rain gives the majority of of their water. Also prefer the bogs of the much north, pocosins are uncovered on waterlogged, nutrient bad and acid soils. The soil itself is a mixture of peat and also sand containing big quantities of charcoal from regular burnings. These natural fires take place bereason pocosins periodically come to be incredibly dry in the spring or summer. The fires are ecologically important because they boost the diversity of shrub forms in pocosins.

Pocosins carry out huge tracks of undisturbed land also necessary by Babsence Bears (Ursus americanus).
Sweet Bay (Magnolia virginiana.)
Zenobia (Zenobia pulverulenta).

The most widespread plants are evergreen trees (Loblolly Bay, Red Bay and also Sweet Bay), and also evergreen shrubs (titi, fetterbush and also zenobia). Pocosins carry out crucial habitat for many animals, including some threatened species prefer the red-cockaded woodpecker. They are specifically vital as the last refuge for Babsence Bears in coastal Virginia and North Carolina and also the Red Wolf has recently been represented in North Carolina pocosins.

Functions & Values

Habitat is the the majority of valuable function of Pocosins. Some pocosins are very big and hard to build, and so they reprimary mainly undisturbed. As a result, they are a haven for species adapted to living in untransformed woodlands. As even more and more land also is developed in the Eastern United States, pocosins are coming to be ever before even more helpful refuges for wildlife.
The Sweet Pitcher Plant (Sarracenia rubra) is among the carnivorous plants uncovered in pocosins.

The slow motion of water with the dense organic matter in pocosins gets rid of excess nutrients deposited by rainwater. The exact same organic issue additionally acidifies the water. This extremely pure water is progressively released to estuaries, wright here it helps to preserve the proper salinity, nutrients and acidity. This process is important to assist preserve healthy and balanced fish populations vital to both business and reproduction. Pocosins are additionally resources of helpful wood and also fuel, yet these uses have the right to damage or ruin pocosins if they are not carried out responsibly.


Historically, pocosins were greatly endangered by farming. Today, lumber harvesting, peat mining, and also phosphate mining join farming as the biggest threats to the staying undisturbed pocosins.


Description of Fens

Fens, are peat-developing wetlands that get nutrients from resources other than precipitation: commonly from upslope resources via drainage from neighboring mineral soils and also from groundwater activity. Fens differ from bogs bereason they are less acidic and also have greater nutrient levels. Therefore, they are able to assistance an extra varied plant and also pet neighborhood. These units are often spanned by grasses, sedges, rushes and also wildflowers. Some fens are defined by parallel ridges of vegetation ssteustatiushistory.orgrated by much less abundant hollows. The ridges of these patterned fens develop perpendicular to the downslope direction of water movement. Over time, peat might develop up and also ssteustatiushistory.orgprice the fen from its groundwater supply. When this happens, the fen receives fewer nutrients and may end up being a bog.

Like bogs, fens are greatly a northern hemispbelow phenomenon -- developing in the northeastern United States, the Great Lakes area, the Rocky Mountains and also much of Canada -- and also are mainly associated via low temperatures and also brief growing periods, wbelow ample precipitation and also high humidity cause excessive moisture to accumulate.

Functions & Values of Fens

Fens, prefer bogs, carry out crucial benefits in a waterburned, consisting of avoiding or reducing the danger of floods, boosting water quality and also giving habitat for unique plant and also pet areas.

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

Like the majority of peatlands, fens knowledgeable a decrease in acreage at a rate of around eight percent from 1950 to 1970, greatly from mining and draining for cropland, fuel and also fertilizer. Because of the large historical loss of this ecomechanism type, continuing to be fens are that much even more rare, and it is important to safeguard them. It is crucial to identify that while mining and also draining these ecosystems carry out resources for human being, up to 10,000 years are required to develop a fen naturally.

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