Freshwater swamp forests, or flooded forests, are

forest A forest is an ecosystem characterized by a dense ecological community, community of trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, ...

s which are inundated with

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

, either permanently or seasonally. They normally occur along the lower reaches of

river A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...

s and around freshwater

lake A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from ...

s. Freshwater

swamp A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...

forests are found in a range of climate zones, from boreal through

temperate In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ran ...

and

subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones immediately to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Ge ...

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

Appearance

A freshwater swamp forest is a type of

wetland A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...

ecosystem An ecosystem (or ecological system) is a system formed by Organism, organisms in interaction with their Biophysical environment, environment. The Biotic material, biotic and abiotic components are linked together through nutrient cycles and en ...

characterized by its unique

hydrology Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and drainage basin sustainability. A practitioner of hydrology is called a hydro ...

and vegetation. These forests are typically found in low-lying areas, riverbanks, and

floodplains A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high discharge.Goudie, ...

where there is a consistent supply of

. A forest that is frequently flooded with relatively fresh water rich in minerals is referred to as a freshwater swamp forest. Since tropical freshwater swamp forests are a subset of tropical rainforests, they share a number of environmental traits with other tropical rainforest formations. Beyond these shared characteristics, however, the environment in freshwater swamp forests and other tropical rain forest formations can vary greatly. In inland, freshwater swamp forests, flooding is typically sporadic, irregular, or seasonal. The depth of the water also varies greatly, from a few centimeters to several meters. These physical factors affect the ecology of freshwater swamp forests, either singly or in combination. Rain, rivers, and groundwater are all sources of water for freshwater swamp forests, whereas rain is the only source of water for peat swamp forests. The hue of the water in the freshwater swamp forest is typically an indication of the quantities of plant materials present in the water and soil. Contrary to ombrotrophic swamp forests, which only absorb nutrients from rain, freshwater swamp forest soils are relatively nutrient-rich. In freshwater swamp forests, rain and changes in the water table result in the following deposition of nutrients and alluvial soils. Due to the nutrient-rich soils of freshwater swamp forests, wetland rice farming and oil palm plantations have become very prevalent in agriculture.

Hydrology

Within aquatic ecosystems, geomorphological, biological, and biogeomorphological processes and functions are significantly influenced by the flow of water. Flow significantly affects the geomorphology, affecting the spatial and temporal benthic community structure. Freshwater swamp forests are permanently or seasonally inundated by

, with water levels that fluctuate throughout the year. They are often associated with slow-moving or meandering rivers,

oxbow lake An oxbow lake is a U-shaped lake or stream pool, pool that forms when a wide meander of a river is meander cutoff, cut off, creating a free-standing body of water. The word "oxbow" can also refer to a U-shaped bend in a river or stream, whether ...

s, and other water bodies. Macroinvertebrate assemblages were significantly influenced by hydrological connectivity, with highly connected water bodies exhibiting more macroinvertebrate diversity than isolated water bodies, which tended to have less diverse assemblages and were predominated by a small number of taxa. Similar impacts have been seen in tropical ecosystems where flooding during the wet or monsoon season has led to an increase in migratory species proportions and changes in community assemblages. On a smaller scale, modifications to the flow regime that result in changes to the physical environment can boost habitat variety and, as a result, boost species diversity. Additionally, a highly varied environment might provide as a haven for species during times of stress like flooding or drought. Freshwater swamp forests contain soft, unstable, and anoxic soil due to their waterlogged condition, which may have influenced the evolution of unique root adaptations in these trees that resemble those seen in a real mangrove forest.

Flora

The vegetation in freshwater swamp forests is adapted to survive in waterlogged conditions. Common tree species include various types of

mangrove A mangrove is a shrub or tree that grows mainly in coastal saline water, saline or brackish water. Mangroves grow in an equatorial climate, typically along coastlines and tidal rivers. They have particular adaptations to take in extra oxygen a ...

s, palms, and

hardwood Hardwood is wood from Flowering plant, angiosperm trees. These are usually found in broad-leaved temperate and tropical forests. In temperate and boreal ecosystem, boreal latitudes they are mostly deciduous, but in tropics and subtropics mostl ...

trees like

mahogany Mahogany is a straight- grained, reddish-brown timber of three tropical hardwood species of the genus ''Swietenia'', indigenous to the AmericasBridgewater, Samuel (2012). ''A Natural History of Belize: Inside the Maya Forest''. Austin: Universit ...

and

ebony Ebony is a dense black/brown hardwood, coming from several species in the genus '' Diospyros'', which also includes the persimmon tree. A few ''Diospyros'' species, such as macassar and mun ebony, are dense enough to sink in water. Ebony is fin ...

. The tree canopy tends to be dense and can create a shaded environment beneath.

Biodiversity

Freshwater swamp forests are rich in

biodiversity Biodiversity is the variability of life, life on Earth. It can be measured on various levels. There is for example genetic variability, species diversity, ecosystem diversity and Phylogenetics, phylogenetic diversity. Diversity is not distribut ...

and provide habitat for a wide range of plant and animal species. They support numerous aquatic species,

amphibian Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excl ...

s, reptiles, and mammals. Birds are also abundant in these ecosystems. The flooded conditions can make these areas particularly important for fish breeding and

spawning Spawn is the Egg cell, eggs and Spermatozoa, sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of freely releasing eggs and sperm into a body of water (fresh or marine); the physical act is ...

. Fires of various intensities were used in southern Sumatra to burn down the swamp forest to make way for agriculture. There, a rich and complex environment was reduced to a habitat made up of uniform stands of fire-resistant Melaleuca L. species thickets as a result of widespread and frequent fires. Furthermore, improper management of these ecosystems through massive logging and agricultural conversion has resulted in serious deterioration and loss of ecological and biological diversity.

Adaptations

Many plants in freshwater swamp forests have special adaptations to cope with waterlogged soils, such as pneumatophores (aerial roots) in mangroves for oxygen exchange. Some animals have adapted to life in these wet environments, like

s with permeable skin that can absorb oxygen from water.

Ecosystem services

Freshwater swamp forests offer a variety of

ecosystem service Ecosystem services are the various benefits that humans derive from ecosystems. The interconnected living and non-living components of the natural environment offer benefits such as pollination of crops, clean air and water, decomposition of wast ...

s. They act as natural buffers against flooding by absorbing excess water during heavy rains. They also filter water, helping to improve

water quality Water quality refers to the chemical, physical, and biological characteristics of water based on the standards of its usage. It is most frequently used by reference to a set of standards against which compliance, generally achieved through tr ...

by trapping sediments and pollutants. These forests are crucial for

carbon sequestration Carbon sequestration is the process of storing carbon in a carbon pool. It plays a crucial role in Climate change mitigation, limiting climate change by reducing the amount of Carbon dioxide in Earth's atmosphere, carbon dioxide in the atmosphe ...

, playing a role in mitigating

climate change Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...

Human use

Local communities often rely on freshwater swamp forests for resources such as

timber Lumber is wood that has been processed into uniform and useful sizes (dimensional lumber), including beams and planks or boards. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, window frames). ...

non-timber forest product Non-timber forest products (NTFPs) are useful foods, substances, materials and/or commodities obtained from forests other than timber. Harvest ranges from wild collection to farming. They typically include game animals, fur-bearers, nuts, see ...

s (e.g., fruits, honey), and fish. Traditional agriculture may take place in the drier, elevated areas around the swamp forest. However, unsustainable

logging Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidder, skidding, on-site processing, and loading of trees or trunk (botany), logs onto logging truck, trucksecosystem An ecosystem (or ecological system) is a system formed by Organism, organisms in interaction with their Biophysical environment, environment. The Biotic material, biotic and abiotic components are linked together through nutrient cycles and en ...

Conservation

Freshwater swamp forests are globally important and often designated as protected areas or Ramsar wetlands due to their ecological significance. Conservation efforts aim to protect these

s from degradation and promote sustainable land use practices.

Threats

Freshwater swamp forests are vulnerable to

habitat destruction Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

and degradation due to

urbanization Urbanization (or urbanisation in British English) is the population shift from Rural area, rural to urban areas, the corresponding decrease in the proportion of people living in rural areas, and the ways in which societies adapt to this change. ...

agriculture Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created ...

logging Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidder, skidding, on-site processing, and loading of trees or trunk (botany), logs onto logging truck, trucksdrainage Drainage is the natural or artificial removal of a surface's water and sub-surface water from an area with excess water. The internal drainage of most agricultural soils can prevent severe waterlogging (anaerobic conditions that harm root gro ...

for development.

Climate change Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...

, including rising sea levels, can further threaten these

s by altering water levels and

salinity Salinity () is the saltiness or amount of salt (chemistry), salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensio ...

Freshwater swamp forest ecoregions

Globally, freshwater swamp forests are found in

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

tropical Africa The Afrotropical realm is one of the Earth's eight biogeographic realms. It includes Sub-Saharan Africa, the southern Arabian Peninsula, the island of Madagascar, and the islands of the western Indian Ocean. It was formerly known as the Ethiopi ...

, and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

, with the largest areas being part of the

Amazon basin The Amazon basin is the part of South America drained by the Amazon River and its tributary, tributaries. The Amazon drainage basin covers an area of about , or about 35.5 percent of the South American continent. It is located in the countries ...

. In Southeast Asia, they are found all over the region, frequently close to major rivers like the

Mekong The Mekong or Mekong River ( , ) is a transboundary river in East Asia and Southeast Asia. It is the world's twelfth-longest river and the third-longest in Asia with an estimated length of and a drainage area of , discharging of wat ...

Chao Phraya The Chao Phraya River is the major river in Thailand, with its low alluvial plain forming the centre of the country. It flows through Bangkok and then into the Gulf of Thailand. Etymology Written evidence of the river being referred to by the ...

, and Irrawaddy in

Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

and

Myanmar Myanmar, officially the Republic of the Union of Myanmar; and also referred to as Burma (the official English name until 1989), is a country in northwest Southeast Asia. It is the largest country by area in Mainland Southeast Asia and has ...

, as well as numerous smaller systems like the Sedili rivers in

Johor Johor, also spelled Johore,'' is a States and federal territories of Malaysia, state of Malaysia in the south of the Malay Peninsula. It borders with Pahang, Malacca and Negeri Sembilan to the north. Johor has maritime borders with Singapore ...

. Although freshwater swamp forests are frequently found in wet climates, they can also be found in areas that are seasonally drier, such as west

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; , fossilized , also known as Papua or historically ) is the List of islands by area, world's second-largest island, with an area of . Located in Melanesia in the southwestern Pacific Ocean, the island is ...

and

east Java East Java (, , ) is a Provinces of Indonesia, province of Indonesia located in the easternmost third of Java island. It has a land border only with the province of Central Java to the west; the Java Sea and the Indian Ocean border its northern ...

. Freshwater swamp forests are a relatively understudied forest type in Southeast Asia, primarily because they are difficult to access and can harbor diseases spread by insects, such as

mosquito Mosquitoes, the Culicidae, are a Family (biology), family of small Diptera, flies consisting of 3,600 species. The word ''mosquito'' (formed by ''Musca (fly), mosca'' and diminutive ''-ito'') is Spanish and Portuguese for ''little fly''. Mos ...

es. In the

Amazon Basin The Amazon basin is the part of South America drained by the Amazon River and its tributary, tributaries. The Amazon drainage basin covers an area of about , or about 35.5 percent of the South American continent. It is located in the countries ...

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

, a seasonally flooded forest is known as a ''várzea'', and refers to a

whitewater Whitewater forms in the context of rapids, in particular, when a river's Stream gradient, gradient changes enough to generate so much turbulence that air is trapped within the water. This forms an unstable current that foam, froths, making t ...

-inundated forest. '' Igapó'' refers to blackwater-inundated forest.

Mangrove A mangrove is a shrub or tree that grows mainly in coastal saline water, saline or brackish water. Mangroves grow in an equatorial climate, typically along coastlines and tidal rivers. They have particular adaptations to take in extra oxygen a ...

and

peat swamp forest Peat swamp forests are tropical and subtropical moist broadleaf forests, tropical moist forests where waterlogged soil prevents dead leaves and wood from fully decomposing. Over time, this creates a thick layer of acidic peat. Large areas of th ...

s, for example, have a tendency to draw more attention than other

habitats. Peat swamp forests are swamp forests where waterlogged soils prevent woody debris from fully decomposing, which over time creates a thick layer of acidic

peat Peat is an accumulation of partially Decomposition, decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, Moorland, moors, or muskegs. ''Sphagnum'' moss, also called peat moss, is one of the most ...

Afrotropic

* Eastern Congolian swamp forests (

Democratic Republic of the Congo The Democratic Republic of the Congo (DRC), also known as the DR Congo, Congo-Kinshasa, or simply the Congo (the last ambiguously also referring to the neighbouring Republic of the Congo), is a country in Central Africa. By land area, it is t ...

) * Niger Delta swamp forests (

Nigeria Nigeria, officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf of Guinea in the Atlantic Ocean to the south. It covers an area of . With Demographics of Nigeria, ...

) *

Western Congolian swamp forests The Western Congolian swamp forests ( French: ''Forêts marécageuses de l'ouest du Congo'') are an ecoregion of the Republic of the Congo, Democratic Republic of the Congo and adjoining Central African Republic. Together with the adjacent Easter ...

(

Republic of the Congo The Republic of the Congo, also known as Congo-Brazzaville, the Congo Republic or simply the Congo (the last ambiguously also referring to the neighbouring Democratic Republic of the Congo), is a country located on the western coast of Central ...

, Democratic Republic of the Congo).

Australasia

* Northern New Guinea lowland rain and freshwater swamp forests (

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

Papua New Guinea Papua New Guinea, officially the Independent State of Papua New Guinea, is an island country in Oceania that comprises the eastern half of the island of New Guinea and offshore islands in Melanesia, a region of the southwestern Pacific Ocean n ...

) * Southern New Guinea freshwater swamp forests (Indonesia, Papua New Guinea)

South and SE Asia

Borneo peat swamp forests The Borneo peat swamp forests ecoregion, within the tropical and subtropical moist broadleaf forests biome, are on the island of Borneo, which is divided between Brunei, Indonesia and Malaysia. Location and description Peat swamp forests occur ...

(

Brunei Brunei, officially Brunei Darussalam, is a country in Southeast Asia, situated on the northern coast of the island of Borneo. Apart from its coastline on the South China Sea, it is completely surrounded by the Malaysian state of Sarawak, with ...

, Indonesia,

Malaysia Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...

) * Chao Phraya freshwater swamp forests (

) * Irrawaddy freshwater swamp forests (

) * Peninsular Malaysian peat swamp forests (Malaysia, Thailand) * Ratargul Swamp Forest (

Bangladesh Bangladesh, officially the People's Republic of Bangladesh, is a country in South Asia. It is the List of countries and dependencies by population, eighth-most populous country in the world and among the List of countries and dependencies by ...

) *

Sundarbans Sundarbans (; pronounced ) is a mangrove forest area in the Ganges Delta formed by the confluence of the Ganges, Brahmaputra and Meghna Rivers in the Bay of Bengal. It spans the area from the Hooghly River in India's state of West Bengal ...

freshwater swamp forests in Bangladesh and India * Red River freshwater swamp forests (

Vietnam Vietnam, officially the Socialist Republic of Vietnam (SRV), is a country at the eastern edge of mainland Southeast Asia, with an area of about and a population of over 100 million, making it the world's List of countries and depende ...

) * Southwest Borneo freshwater swamp forests (Indonesia) * Tonle Sap-Mekong peat swamp forests (

Cambodia Cambodia, officially the Kingdom of Cambodia, is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. It is bordered by Thailand to the northwest, Laos to the north, and Vietnam to the east, and has a coastline ...

, Vietnam) * Wathurana freshwater swamp forest (

Sri Lanka Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka, also known historically as Ceylon, is an island country in South Asia. It lies in the Indian Ocean, southwest of the Bay of Bengal, separated from the Indian subcontinent, ...

) *

Myristica swamp ''Myristica'' swamps are a type of freshwater swamp forest predominantly composed of species of ''Myristica''. These are found in three localities in India. ''Myristica'' swamps have adapted to inundation by way of stilt roots and knee roots. ''M ...

(

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

) * Nelapattu Bird Sanctuary (India)

Neotropic

Cantão Cantão is a tropical forest ecosystem located in the central Araguaia River, Araguaia river basin, the southeastern edge of the Amazon biome, in the Brazilian state of Tocantins. It is one of the biologically richest areas of the eastern Amazon, ...

igapó forest (

) * Gurupa várzea (Brazil) *

Iquitos várzea The Iquitos várzea (NT0128) is an ecoregion of flooded forest along rivers in Brazil, Peru and Bolivia in the west of the Amazon biome. The forest is seasonally flooded up to by whitewater rivers carrying nutrient-rich sediment from the Andes. T ...

(

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

, Brazil,

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

) *

Marajó várzea The Marajó várzea (NT0138) is an ecoregion of seasonally and tidally flooded várzea forest in the Amazon biome. It covers a region of sedimentary islands and floodplains at the mouth of the Amazon that is flooded twice daily as the ocean tides ...

(Brazil) * Monte Alegre várzea (Brazil) *

Orinoco Delta swamp forests The Orinoco Delta swamp forests (NT0147) is an ecoregion of eastern Venezuela and northern Guyana covering the large and shifting Orinoco Delta. The vegetation is mostly permanently flooded rainforest. The ecoregion is relatively intact apart fro ...

(

Guyana Guyana, officially the Co-operative Republic of Guyana, is a country on the northern coast of South America, part of the historic British West Indies. entry "Guyana" Georgetown, Guyana, Georgetown is the capital of Guyana and is also the co ...

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

) * Pantanos de Centla (

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

) *

Paramaribo swamp forests The Paramaribo swamp forests (NT0149) is an ecoregion in the coastal plain of Suriname covering a strip of land that is almost always flooded by fresh waters. It transitions into saline mangrove swamps towards the coast, and into submontane forests ...

(Guyana,

Suriname Suriname, officially the Republic of Suriname, is a country in northern South America, also considered as part of the Caribbean and the West Indies. It is a developing country with a Human Development Index, high level of human development; i ...

) * Purus várzea (Brazil)

References

{{aquatic ecosystem topics Swamps Tropical and subtropical moist broadleaf forests