There are four main kinds of wetlands — marsh, swamp, bog and fen bogs and fens being types of mires. Some experts also recognize wet meadows and aquatic ecosystems as additional wetland types. Wetlands go by many names, such as swamps, peatlands, sloughs, marshes, muskegs, bogs, fens, potholes, and mires.
Most scientists consider swamps, marshes, and bogs to be the three major kinds of wetlands. In A Nutshell Marshes are nutrient-rich wetlands that support a variety of reeds and grasses, while swamps are defined by their ability to support woody plants and trees.
Bogs are characterized by their poor soil and high peat content, while fens have less peat and more plant life than a bog. They typically have acidic and nutrient poor organic soil that has accumulated over time on top of mineral soils.
Pocosins are characterized by dense waxy shrub and woody vine vegetation. In some cases, trees like loblolly bay, swamp bay, sweet bay and pond pine are scattered throughout. Dense vegetation can quickly turn a pocosin hike into a crawling expedition. A hiker should never venture far into a pocosin without a GPS unit or compass. Pocosins also provide food for migrating birds and black bears — the latter of which being another reason to take precautions during a pocosin hike.
Due to their inaccessibility to people, pocosins provide good wildlife habitat. Pine Savannas are now rare and found scattered throughout the Coastal Plain ecoregion of the southeast, in the wide flat areas between streams and rivers interstream flats.
They have mineral soils that are poorly drained and remain wet for part of the year. They typically do not flood. Pine Savannas generally have a more open canopy and shrub layer. The canopy is composed of longleaf and pond pine trees.
Scattered shrubs include gallberry, blueberry, wax-myrtle, and dangleberry. The ground layer is a diverse combination of grasses, sedges, and wild flowers. Pine Savannas also provide habitat for the red-cockaded woodpecker, a federally endangered species that nests in the cavities of mature longleaf pine trees.
Frequent ground fires maintain the open grass and herb covered understory. Historically, lightning strikes and Native Americans would start these fires. Pine Flats are primarily found in the wide interstream flats of the Coastal Plain ecoregion. Pine Flats usually occur in mineral soils that are saturated part of the year. The tree canopy is generally composed of pine, as the name suggests. These wetlands exist due to changes in the landscape caused by human activity.
Natural wetlands with similar hydrology found on interstream flats e. Basin Wetlands are natural depressions in the earth that are surrounded by uplands, or occur on the edges of small lakes or ponds. They tend to be wet for only part of the year, and can dry up during the warmer months. Basin Wetlands are fed by groundwater, overland runoff, and rain.
These wetlands generally have sandy to fine clay based soils. Some Basin Wetlands have an underground clay layer that acts as a natural seal, and can hold water above ground for months at a time. Basin Wetlands provide important breeding habitat for amphibians, such as frogs and salamanders, because these wetlands often do not contain fish that eat these amphibians. Because Basin Wetlands exist in many forms with variable hydrology, their vegetation can vary widely, ranging from tree species to herbaceous sedges and floating wetland plants e.
A bog can be found on either floodplains or lowlands in the western part of the state, typically within the Blue Ridge Mountains and western Piedmont foothills. Bogs are formed by a poorly understood combination of groundwater seepage and blocked overland runoff. This kind of wetland is moist but not flooded, and is found over organic or mineral acidic soils. Bogs exist in many forms, from forested to tree-less, from mossy to near bare earth.
Common names for wetlands include marshes, estuaries, mangroves, mudflats, mires, ponds, fens, swamps, deltas, coral reefs, billabongs, lagoons, shallow seas, bogs, lakes, and floodplains, to name just a few! Often found alongside waterways and in floodplains, wetlands vary widely due to differences in soil, topography, climate, water chemistry, and vegetation.
Large wetland areas may also be comprised of several smaller wetland types. Wetland habitats serve essential functions in an ecosystem, including acting as water filters, providing flood and erosion control, and furnishing food and homes for fish and wildlife.
They do more than sustain plants and animals in the watershed, however. Swamps may be divided into two major classes, depending on the type of vegetation present: shrub swamps and forested swamps. Swamps serve vital roles in flood protection and nutrient removal. Floodplain forests are especially high in productivity and species diversity because of the rich deposits of alluvial soil from floods.
Many upland creatures depend on the abundance of food found in the lowland swamps, and valuable timber can be sustainably harvested to provide building materials for people.
Due to the nutrient-rich soils present in swamps, many of these fertile woodlands have been drained and cleared for agriculture and other development. Historically, swamps have been portrayed as frightening no-man's-lands. This perception led to the vast devastation of immense tracts of swampland over the past years, such as the destruction of more than half of the legendary Great Dismal Swamp of southeastern Virginia.
Forested swamps are found throughout the United States. They are often inundated with floodwater from nearby rivers and streams. Sometimes, they are covered by many feet of very slowly moving or standing water. In very dry years they may represent the only shallow water for miles and their presence is critical to the survival of wetland-dependent species like Wood Ducks Aix sponsa , River Otters Lutra canadensis and Cottonmouth Snakes Agkistrodon piscivorus.
Bottomland hardwood swamp is a name commonly given to forested swamps in the south central United States. Shrub swamps are similar to forested swamps except that shrubby vegetation such as Buttonbush, Willow, Dogwood Cornus sp. In fact, forested and shrub swamps are often found adjacent to one another. The soil is often water logged for much of the year and covered at times by as much as a few feet of water because this type of swamp is found along slow moving streams and in floodplains.
Mangrove swamps are a type of shrub swamp dominated by mangroves that covers vast expanses of southern Florida. Bogs are one of North America's most distinctive kinds of wetlands. They are characterized by spongy peat deposits, acidic waters and a floor covered by a thick carpet of sphagnum moss.
Bogs receive all or most of their water from precipitation rather than from runoff, groundwater or streams. As a result, bogs are low in the nutrients needed for plant growth, a condition that is enhanced by acid forming peat mosses. There are two primary ways that a bog can develop: bogs can form as sphagnum moss grows over a lake or pond and slowly fills it terrestrialization , or bogs can form as sphagnum moss blankets dry land and prevents water from leaving the surface paludification.
Over time, many feet of acidic peat deposits build up in bogs of either origin. The unique and demanding physical and chemical characteristics of bogs result in the presence of plant and animal communities that demonstrate many special adaptations to low nutrient levels, waterlogged conditions, and acidic waters, such as carnivorous plants. Bogs serve an important ecological function in preventing downstream flooding by absorbing precipitation.
Bogs support some of the most interesting plants in the United States like the carnivorous Sundew and provide habitat to animals threatened by human encroachment. Bogs in the United States are mostly found in the glaciated northeast and Great Lakes regions northern bogs but also in the southeast pocosins. Their acreage declined historically as they were drained to be used as cropland and mined for their peat, which was used as a fuel and a soil conditioner.
Recently, bogs have been recognized for their role in regulating the global climate by storing large amounts of carbon in peat deposits. Bogs are unique communities that can be destroyed in a matter of days but require hundreds, if not thousands, of years to form naturally. Northern bogs are generally associated with low temperatures and short growing seasons where ample precipitation and high humidity cause excessive moisture to accumulate. Therefore, most bogs in the United States are found in the northern states.
Northern bogs often form in old glacial lakes. They may have either considerable amounts of open water surrounded by floating vegetation or vegetation may have completely filled the lake terrestrialization. The sphagnum peats of northern bogs cause especially acidic waters.
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