Freshwater marsh

A freshwater marsh is a marsh that contains fresh water. Freshwater marshes are usually found near the mouths of rivers and are present in areas with low drainage.[1] It is the counterpart to the salt marsh, an upper coastal intertidal zone of bio-habitat which is regularly flushed with sea water.

Freshwater marshes are non-tidal biomes containing little or no peat (unlike bogs and fens, both a kind of mire and mires consisting heavily of moist, biologically active peat). They are most common in the Gulf Coast region, specifically in Florida. They can be one of two principal types: either fresh water mineralized marshes, which derive their water from groundwater, streams and surface runoff; or poorly mineralized fresh water marshes whose moisture comes mostly from regular direct precipitation. Freshwater marshes support an independent pH-neutral ecosystem which encourages biodiversity. Common species include ducks, geese, swans, songbirds, swallows, coots, and black ducks. Although shallow marshes do not tend to support many fish, deeper ones are home to many species, including such large fish as the northern pike and carp. Some of the most common plants in these areas are cattails, water lilies, arrowheads, and rushes.[2]

The Florida Everglades represent the largest contiguous freshwater marsh in the entire world.[3] This immense marsh covers 4,200 square miles (11,000 km2) and is located in the southern tip of Florida. Continued human development, including drainage for development and polluted agriculture runoff, as well as alterations in the water cycle threaten the existence of the Everglades. The remaining parts of the Everglades are grasses, sedges and other emergent hydrophytes.[4]

Naselle River seen from US 101
Freshwater marsh, Naselle River, Washington

See also


  1. ^ "Freshwater Marshes - NatureWorks". Retrieved April 30, 2010.
  2. ^ "Florida Wetlands: Freshwater Marshes". Retrieved April 30, 2010.
  3. ^ Laura Riley; William Riley (1 January 2005). Nature's Strongholds: The World's Great Wildlife Reserves. Princeton University. p. 491. ISBN 978-0-691-12219-9. Retrieved 8 September 2013.
  4. ^ "Freshwater Marsh Habitat". Retrieved April 30, 2010.

Aunu'u is a small volcanic island off the southeastern shore of Tutuila in American Samoa. It has a land area of 374.83 acres (0.59 sq mi; 1.52 km2) and a 2000 census population of 476 persons. Politically it is a part of the Eastern District, one of the primary divisions of American Samoa.

Faimulivai Marsh is a freshwater marsh in Aunu'u Crater and the largest such wetland in American Samoa. It was formed from drainage of the low-lying crater. It is part of a protected National Natural Landmark on Aunu'u which was designated in 1972. The Pacific black duck was seen in the marsh in 1976, but it may now be extinct in the region; another significant local bird is the purple swamphen. This marsh is the only place in American Samoa that has Chinese water chestnut.[1]The main sources of economic activity for the Aunu’u people since the 1960s have been taro and production of faausi.

Ballona Wetlands

The Ballona Wetlands are located in Southern California, United States south of Marina del Rey and east of Playa del Rey. The wetlands once included the areas now taken up by Marina del Rey, Venice, and Playa Vista, extending north to about present-day Washington Blvd. in Venice.It is one of the last significant wetlands areas in the Los Angeles basin, and is named for Port Ballona and Ballona Creek which now runs through the area as a flood control channel. In the 1930s the Ballona Creek corridor was channelized in concrete, thus greatly reducing the inflow of salt water to the marsh, and eliminating spring floods, which brought freshwater to the wetlands. Among the many groups dedicated to protecting the wetlands are the Friends of Ballona Wetlands, the Ballona Wetlands Land Trust, Grassroots Coalition, Ballona Ecosystem Education Project, and the Sierra Club Airport Marina Group.

Capel Sound, Victoria

Capel Sound (formerly Rosebud West) is a suburb located on the Mornington Peninsula in Victoria, Australia. Its local government area is the Shire of Mornington Peninsula.

A distinguishing landmark feature of Capel Sound is the Tootgarook Swamp, the largest example left of a shallow freshwater marsh in the Port Phillip bay region. The swamp is also described by Melbourne water as a ground water dependent ecosystem. The 381 hectare swamp is found on the lower section of the Mornington Peninsula, called the Nepean Peninsula in Victoria, Australia. A large portion of the Tootgarook Swamp is zoned as residential and industrial, with roughly half of the actual swamp inside the green wedge and half within the urban growth boundary.Rosebud West Post Office opened on 12 January 1938 and closed around 1996.On 15 September 2016 Mornington Peninsula Shire Council officially changed the name from Rosebud West to Capel Sound.

Conscience Point National Wildlife Refuge

The Conscience Point National Wildlife Refuge was established July 20, 1971 as a land gift from Stanley Howard. The 60-acre (24 ha) refuge is located in the hamlet of North Sea on the north shore of Long Island's south fork. The refuge protects grasslands, oak-beech forest, shrub habitats, kettle holes, freshwater marsh and salt marsh.

The refuge grasslands are a habitat model for maritime grasslands, a disappearing habitat type on Long Island due to development. Maritime grasslands are native grasslands composed of little bluestem (Schizachyrium scoparium), switchgrass (Panicum virgatum), poverty grass (Danthonia spicata), hairgrass (Deschampsia flexuosa), and prickly pear cactus (Opuntia humifusa).

Wildlife on the refuge is as diverse as its habitats. Waterfowl are primarily American black ducks and bufflehead. The grasslands are being managed and enlarged specifically to attract grassland dependent birds such as grasshopper sparrow, eastern meadowlark, Savannah sparrow and bobolink. Due to its coastal location, the refuge is heavily used by migratory songbirds, shorebirds and raptors. The refuge also supports endangered and threatened species.

Elizabeth A. Morton National Wildlife Refuge

The Elizabeth A. Morton National Wildlife Refuge is a 187-acre (76 ha) National Wildlife Refuge in Noyack, New York. Much of the refuge is situated on a peninsula surrounded by Noyack and Little Peconic bays. The refuge is managed by the United States Fish and Wildlife Service as part of the Long Island National Wildlife Refuge Complex.

The refuge was established December 27, 1954, through a donation by the Morton family. It encompasses diverse habitats including bay beach, a brackish pond, a freshwater pond, kettle holes, tidal flats, salt marsh, freshwater marsh, shrub, grasslands, maritime oak forest, and red cedar. The refuge's diversity is critical to Long Island wildlife.

The north/south orientation of the refuge's peninsula creates important habitat for shorebirds, raptors and songbirds as they navigate the coastline during migration. Habitats along the beach attract nesting piping plovers, roseate terns, least terns, common terns, and shorebirds. The waters surrounding the refuge are considered critical habitat for juvenile Kemp's ridley sea turtles and are occasionally used by loggerhead sea turtles. Waterfowl use of the refuge peaks during the colder months. Long-tailed ducks, white-winged scoter, goldeneye and black ducks will most likely be spotted during winter.

Elizabeth Hartwell Mason Neck National Wildlife Refuge

Elizabeth Hartwell Mason Neck National Wildlife Refuge is a National Wildlife Refuge of the United States located in Virginia. It is part of the Potomac River National Wildlife Refuge Complex. It is on Mason Neck, a peninsula in the Potomac River that forms part of the shoreline of Belmont Bay. The refuge is adjacent to Mason Neck State Park.

Established in 1969 and managed by the United States Fish and Wildlife Service, it was the first federal refuge created specifically for the protection of the bald eagle. It is 2,277 acres (9.21 km2) in size, with 4.4 miles (7.1 km) of shoreline. It is covered with oak and hickory forest and it includes the largest freshwater marsh in northern Virginia.

Since its founding, the refuge has been renamed for Elizabeth Hartwell, a local activist who fought to keep Mason Neck free of development.

Farlington Marshes

Farlington Marshes is an area of reclaimed land in Langstone harbour. It was reclaimed from the harbour in 1771 and includes a larger part of what was formerly Binner's Island (the remainder of the island is now referred to as North Binness Island). Farlington Marshes is about 120 hectares in size and features both freshwater marsh and brackish marsh. It is a Local Nature Reserve and is a feeding ground for overwintering Brent geese. During World War 2 it was used as a starfish site acting as a decoy for Portsea Island. The control blockhouses remain on the marshes.

Florida scrub

Florida sand pine scrub is an endangered subtropical forest ecoregion found throughout Florida in the United States. It is found on coastal and inland sand ridges and is characterized by an evergreen xeromorphic plant community dominated by shrubs and dwarf oaks. Because the low-nutrient sandy soils do not retain moisture, the ecosystem is effectively an arid one. Wildfires infrequently occur in the Florida scrub. Most of the annual rainfall (about 135 cm or 53 in) falls in summer. It is endangered by residential, commercial and agricultural development, with the largest remaining block in and around the Ocala National Forest. Lake Wales Ridge National Wildlife Refuge also holds a high proportion of remaining scrub habitat, while the Archbold Biological Station near Lake Placid contains about 20 km2 (7.7 sq mi) of scrub habitat and sponsors biological research on it.

Floridian highlands freshwater marsh

The Floridian highlands freshwater marsh is a wetland community found on the Florida peninsula. These are upland marshes occurring in shallow peat-filled valleys, the basins of dried lakes, and the borders of existing lakes. The vegetation mosaic includes a range of mostly herbaceous plant communities, varying based on water depth. Deep water supports various submerged and floating plants. Approximately meter-deep supports emergent herbaceous perennials, typically in dense, monospecific stands; species include bulrush (Typha latifolia), pickerelweed (Pontederia cordata), American lotus (Nelumbo lutea). Shallow areas only submerged during wet season support more graminoid vegetation, including maidencane (Panicum hemitomon) and southern cutgrass (Leersia hexandra). Subsurface subsidence and changing drainage patterns make these habitats shift and change over time. Soils can be mucky, loamy, or sandy, but they are generally above permeable subsoils that create standing water much of the year. These marshes may also be called meadows or prairies.Examples include Paynes Prairie and the marshes along the Kissimmee and St. Johns River.

Hopper Mountain National Wildlife Refuge

Hopper Mountain National Wildlife Refuge is located in the Topatopa Mountains of Ventura County, in southern California. It is bordered by the Los Padres National Forest and the Sespe Condor Sanctuary to the north. The 2,471-acre (10.00 km2) refuge was established in 1974 to protect the endangered California condor, its habitat, and other wildlife resources.

The refuge is in rugged, mountainous terrain. Primary habitats include annual grasslands, interspersed with oak and California black walnut groves, with chaparral on the steeper slopes, natural water springs and riparian habitat, and a freshwater marsh. The California black walnut community is considered to be a unique habitat in California, and is recorded in the State Natural Heritage Database.

The refuge provides habitat for more than 130 species of birds, mammals, and reptiles, including the southwestern pond turtle—a California species of special concern--black bear, bobcat, mule deer, golden eagle, and California tree frog. More than 200 plant species have also been documented on the refuge.

Hopper Mountain National Wildlife Refuge plays an integral part in the California Condor Recovery Program, providing foraging and roosting habitat for the bird. The refuge shares information about the Condor Recovery Program through an outreach program that extends to local, national and international publics.

The refuge is closed to public use to protect habitat for the endangered California condor and to support ongoing efforts to reintroduce California condors to the wild. The road to the refuge runs through private lands, and the road itself is inaccessible to the general public. The U.S. Forest Service maintains two observation points in Los Padres National Forest.

As of July 2014, there is a total population of 437 condors living in sites in California, Baja California and Arizona. This includes a wild population of 232 and a captive population of 205. 68 free-flying condors are managed by the US Fish & Wildlife Service in Southern California.

Ingrebourne Marshes

Ingrebourne Marshes are a 74.8 hectare biological Site of Special Scientific Interest in Hornchurch in the London Borough of Havering. Ingrebourne Valley Local Nature Reserve includes a small part of the SSSI west of the River Ingrebourne. The site is managed by the Essex Wildlife TrustThe Marshes run along both sides of the river, the northern portion next to Hornchurch Country Park and stretching south to Rainham. This is almost all closed to the public, but part of it can be viewed from the Park. A long narrow strip stretches east from the river to Berwick Pond Road, incorporating Berwick Pond, a reservoir which is used for fishing. This is open to the public. The site also includes an irrigation reservoir east of Berwick Pond Road.The site is the largest area of freshwater marsh in Greater London. It is very diverse, with large areas of reed sweet-grass, common reed swamp, wet neutral grassland and tall fen. These habitats have a wide variety of invertebrates and breeding birds. Invertebrates include sixteen nationally scarce fly, beetle dragonfly and cricket species. There are two nationally rare Red Data Book species, the hoverfly Anasimyia interpuncta and the scarce emerald damselfly Lestes dryas. 61 species of bird regularly breed on the site, such as the common redshank and the northern lapwing. Common cuckoos exploit the nests of reed warblers and sedge warblers. Havering Council has raised the water level and reintroduced grazing to protect the wetland.Access to the site is from Hornchurch Country Park and Berwick Pond Road.

Louis C. Clark Sanctuary

The Louis C. Clark Sanctuary is located on Valentine's Road in Old Brookville in Nassau County, New York on Long Island.

The eight-acre (3.2 ha) sanctuary was once a part of Valentine Farm. It was donated by Frances S. Weeks to The Nature Conservancy in 1965 in memory of her son, Louis C. Clark. In 2012, the property was transferred to the North Shore Land Alliance.The sanctuary protects a freshwater marsh and swamp that is part of the Cedar Swamp Creek watershed. The swamp is characterized by cattail, buttonbush, red maple and tupelo; in addition, over 150 species of wildflowers and 25 species of shrubs and vines are found within the preserve. A total of 0.75 miles (1.21 km) of trails are maintained on the property, which is open to the public. The James Preserve is located across Valentine's Road from the property.


A marsh is a wetland that is dominated by herbaceous rather than woody plant species. Marshes can often be found at the edges of lakes and streams, where they form a transition between the aquatic and terrestrial ecosystems. They are often dominated by grasses, rushes or reeds. If woody plants are present they tend to be low-growing shrubs. This form of vegetation is what differentiates marshes from other types of wetland such as swamps, which are dominated by trees, and mires, which are wetlands that have accumulated deposits of acidic peat.

Moose Hill Wildlife Sanctuary

Moose Hill Wildlife Sanctuary is a 1,971 acres (798 ha) wildlife sanctuary located in Sharon, Massachusetts. The property is the oldest property of the Massachusetts Audubon Society, established in 1916. It is adjacent to Moose Hill Farm, which is owned by the Trustees of Reservations.

The Moose Hill parking area and nature center is located at 293 Moose Hill Street in Sharon. The nature center displays rotating exhibits throughout the year. The sanctuary consists of habitats including forest, freshwater marsh, meadow, eskers and kettle holes. Over 160 species of birds have been observed on the property. There is a bird checklist available

Niumi National Park

Niumi National Park is a national park in The Gambia. The occupies the coastal strip in the northern region of the country, in the southern tip of the Sine-Saloum Delta. It covers an area of approximately 4,940 ha (49.4 square km) and encompasses a range of types of wetlands and vegetation, from freshwater marsh to sand spits and brackish lagoons. Rhizophora mangrove forest is abundant in the park, and its swamp and mudflats are an important sheltering ground for birds, with over 200 species found here.


Orongo is a stone village and ceremonial center at the southwestern tip of Rapa Nui (Easter Island). It consists of a collection of low, sod-covered, windowless, round-walled buildings with even lower doors positioned on the high south-westerly tip of the large volcanic caldera called Rano Kau. Below Orongo on one side a 300-meter barren cliff face drops down to the ocean; on the other, a more-gentle but still very steep grassy slope leads down to a freshwater marsh inside the high caldera.

The first half of the ceremonial village's 53 stone masonry houses was investigated and restored in 1974, with the remainder completed in 1976 and subsequently investigated in 1985 and again in 1995. Orongo now has World Heritage status as part of the Rapa Nui National Park.

Otter River State Forest

Otter River State Forest is a publicly owned forest and recreational preserve located in the towns of Templeton, Winchendon, and Royalston in Massachusetts managed by the Massachusetts Department of Conservation and Recreation. The state forest encompasses the land surrounding the junction of the Otter and Millers rivers. Habitats include freshwater marsh, northern hardwood stands, and pine groves planted by the Civilian Conservation Corps to reforest former farmlands.

Pamet River

The Pamet River is a 4.2-mile-long (6.8 km) river in Truro, Massachusetts on Cape Cod. It is named for the Paomet tribe.

The river is primarily salt marsh, flows west nearly all the way across Cape Cod from its eastern beaches, and empties into Cape Cod Bay. It lies a few miles south of the Little Pamet River.

The upper Pamet River is made up of a freshwater marsh. The marsh occupies the broad floor of the upper Pamet River valley. Originally, 12,000–13,000 years ago, this was the glacial outwash channel that drained water away from the glacier westward, northward and finally eastward into the Atlantic some distance from where Provincetown now lies. Sea level was then 300 to 400 feet (91 to 122 m) lower than it is today. There was no Cape Cod Bay, and Stellwagen Bank and the Grand Banks were hills well above the ocean. The subsequent rise of the Atlantic Ocean, which continues to this day, nearly drowned the outer Cape, including the Pamet, which is now only four miles long, compared to 30 miles (48 km) long thousands of years ago. This upper freshwater marsh dates from the middle 19th century, when, to promote agriculture, the saltwater tides were prevented from entering by means of a dike that traverses the valley where Route 6A (Truro Center Road) now passes. A one-way clapper valve permitted fresh water to leave at low tide. The result is the meandering, slow-flowing stream that flows from the Atlantic dunes at Ballston Beach west to the bay, with low, flat banks that lie just above the water table. The entire valley, fresh and salt, is underlain by a thick mat of peat derived from the original salt marshes. All plant species growing in this upper portion were brought in as seeds, mostly by birds and mammals. All are indigenous, and virtually none is tolerant of seawater.MassWildlife has stocked the river with trout.

Tollesbury Wick

Tollesbury Wick is a 242.8 hectare nature reserve east of Tollesbury in Essex. It is managed by the Essex Wildlife Trust.This is coastal freshwater marsh which is grazed by sheep, and is worked by traditional methods which encourage wildlife. Areas of ungrazed rough pasture have badgers, and field voles and pygmy shrews are hunted by hen harriers and short-eared owls.There is access from the sea wall only to a footpath to a bird hide.

Aquatic ecosystems
Classification systems

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