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Freshwater swamp forests, or flooded forests, are forests which are inundated with freshwater, either permanently or seasonally. They normally occur along the lower reaches of rivers and around freshwater lakes. Freshwater swamp forests are found in a range of climate zones, from boreal through temperate [1] and subtropical to tropical. [2]
A freshwater swamp forest is a type of wetland ecosystem characterized by its unique hydrology and vegetation. These forests are typically found in low-lying areas, riverbanks, and floodplains where there is a consistent supply of freshwater. [3] 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. [4]
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. [5]
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. [6] 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. [7] Contrary to ombrotrophic swamp forests, which only absorb nutrients from rain, freshwater swamp forest soils are relatively nutrient-rich. [8] 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. [9]
Within aquatic ecosystems, geomorphological, biological, and biogeomorphological processes and functions are significantly influenced by the flow of water. [10] [11] Flow significantly affects the geomorphology, affecting the spatial and temporal benthic community structure. [12] [13] Freshwater swamp forests are permanently or seasonally inundated by freshwater, with water levels that fluctuate throughout the year. They are often associated with slow-moving or meandering rivers, oxbow lakes, and other water bodies. [14] 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. [15] 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. [16] 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. [17] [18]
The vegetation in freshwater swamp forests is adapted to survive in waterlogged conditions. Common tree species include various types of mangroves, palms, and hardwood trees like mahogany and ebony. The tree canopy tends to be dense and can create a shaded environment beneath. [19]
Freshwater swamp forests are rich in biodiversity and provide habitat for a wide range of plant and animal species. They support numerous aquatic species, amphibians, reptiles, and mammals. Birds are also abundant in these ecosystems. The flooded conditions can make these areas particularly important for fish breeding and spawning. [20] 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. [21] Furthermore, improper management of these ecosystems through massive logging and agricultural conversion has resulted in serious deterioration and loss of ecological and biological diversity. [22]
Many plants in freshwater swamp forests have special adaptations to cope with waterlogged soils, such as pneumatophores (aerial roots) in mangroves for oxygen exchange. [23] [24] Some animals have adapted to life in these wet environments, like amphibians with permeable skin that can absorb oxygen from water. [25]
Freshwater swamp forests offer a variety of ecosystem services. They act as natural buffers against flooding by absorbing excess water during heavy rains. They also filter water, helping to improve water quality by trapping sediments and pollutants. [26] These forests are crucial for carbon sequestration, playing a role in mitigating climate change. [27] [28]
Local communities often rely on freshwater swamp forests for resources such as timber, non-timber forest products (e.g., fruits, honey), and fish. Traditional agriculture may take place in the drier, elevated areas around the swamp forest. However, unsustainable logging and land conversion can threaten these ecosystems. [29]
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 ecosystems from degradation and promote sustainable land use practices. [30] [31]
Freshwater swamp forests are vulnerable to habitat destruction and degradation due to urbanization, agriculture, logging, and drainage for development. Climate change, including rising sea levels, can further threaten these ecosystems by altering water levels and salinity. [32]
Globally, freshwater swamp forests are found in Southeast Asia, tropical Africa, and South America, with the largest areas being part of the Amazon basin. In Southeast Asia, they are found all over the region, frequently close to major rivers like the Mekong, Chao Phraya, and Irrawaddy in Thailand and Myanmar, as well as numerous smaller systems like the Sedili rivers in Johor. [33] 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 and east Java. [34]
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 mosquitoes. [35] In the Amazon Basin of Brazil, a seasonally flooded forest is known as a várzea, and refers to a whitewater-inundated forest. Igapó refers to blackwater-inundated forest. [36] [37] Mangrove and peat swamp forests, for example, have a tendency to draw more attention than other wetland habitats. [38] 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. [39]
A biome is a distinct geographical region with specific climate, vegetation, and animal life. It consists of a biological community that has formed in response to its physical environment and regional climate. Biomes may span more than one continent. A biome encompasses multiple ecosystems within its boundaries. It can also comprise a variety of habitats.
An ecoregion is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural communities and species. The biodiversity of flora, fauna and ecosystems that characterise an ecoregion tends to be distinct from that of other ecoregions. In theory, biodiversity or conservation ecoregions are relatively large areas of land or water where the probability of encountering different species and communities at any given point remains relatively constant, within an acceptable range of variation . Ecoregions are also known as "ecozones", although that term may also refer to biogeographic realms.
A mangrove is a shrub or tree that grows mainly in coastal saline or brackish water. Mangroves grow in an equatorial climate, typically along coastlines and tidal rivers. They have special adaptations to take in extra oxygen and to remove salt, which allow them to tolerate conditions that would kill most plants. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evolution in several plant families. They occur worldwide in the tropics and subtropics and even some temperate coastal areas, mainly between latitudes 30° N and 30° S, with the greatest mangrove area within 5° of the equator. Mangrove plant families first appeared during the Late Cretaceous to Paleocene epochs, and became widely distributed in part due to the movement of tectonic plates. The oldest known fossils of mangrove palm date to 75 million years ago.
A swamp is a forested wetland. Swamps are considered to be transition zones because both land and water play a role in creating this environment. Swamps vary in size and are located all around the world. The water of a swamp may be fresh water, brackish water, or seawater. Freshwater swamps form along large rivers or lakes where they are critically dependent upon rainwater and seasonal flooding to maintain natural water level fluctuations. Saltwater swamps are found along tropical and subtropical coastlines. Some swamps have hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodic inundation or soil saturation. The two main types of swamp are "true" or swamp forests and "transitional" or shrub swamps. In the boreal regions of Canada, the word swamp is colloquially used for what is more formally termed a bog, fen, or muskeg. Some of the world's largest swamps are found along major rivers such as the Amazon, the Mississippi, and the Congo.
A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently for years or decades or seasonally for a shorter periods. Flooding results in oxygen-free anoxic processes prevailing, especially in the soils. The primary factor that distinguishes wetlands from terrestrial land forms or water bodies is the characteristic vegetation of aquatic plants, adapted to the unique anoxic hydric soils. Wetlands are considered among the most biologically diverse of all ecosystems, serving as home to a wide range of plant and animal species. Methods for assessing wetland functions, wetland ecological health, and general wetland condition have been developed for many regions of the world. These methods have contributed to wetland conservation partly by raising public awareness of the functions some wetlands provide. Constructed wetlands are designed and built to treat municipal and industrial wastewater as well as to divert stormwater runoff. Constructed wetlands may also play a role in water-sensitive urban design.
A marsh is — according to ecological definitions — a wetland that is dominated by herbaceous rather than woody plant species. More in general, the word can be used for any low-lying and seasonally waterlogged terrain. In Europe and in agricultural literature low-lying meadows that require draining and embanked polderlands are also referred to as marshes or marshland.
This glossary of ecology is a list of definitions of terms and concepts in ecology and related fields. For more specific definitions from other glossaries related to ecology, see Glossary of biology, Glossary of evolutionary biology, and Glossary of environmental science.
Freshwater ecosystems are a subset of Earth's aquatic ecosystems. They include lakes, ponds, rivers, streams, springs, bogs, and wetlands. They can be contrasted with marine ecosystems, which have a larger salt content. Freshwater habitats can be classified by different factors, including temperature, light penetration, nutrients, and vegetation. There are three basic types of freshwater ecosystems: Lentic, lotic and wetlands. Freshwater ecosystems contain 41% of the world's known fish species.
Sundarbans is a mangrove area in the delta formed by the confluence of the Ganges, Brahmaputra and Meghna Rivers in the Bay of Bengal. Sundarban Reserve Forest (SRF) of Bangladesh is the largest mangrove forest in the world. It spans the area from the Baleswar River in Bangladesh's division of Khulna to the Hooghly River in India's state of West Bengal. It comprises closed and open mangrove forests, land used for agricultural purpose, mudflats and barren land, and is intersected by multiple tidal streams and channels. Sundarbans is home to the world's largest area of mangrove forests. Four protected areas in the Sundarbans are enlisted as UNESCO World Heritage Sites, viz. Sundarbans West (Bangladesh), Sundarbans South (Bangladesh), Sundarbans East (Bangladesh) and Sundarbans National Park (India).
The Nature Society (Singapore) (NSS) is a non-government, non-profit organisation centered towards the preservation and appreciation of Singapore's natural heritage, as well as that of the surrounding region. Run by volunteers, the NSS depends financially on its members' contributions as well as companies, institutions and individuals.
An aquatic ecosystem is an ecosystem found in and around a body of water, in contrast to land-based terrestrial ecosystems. Aquatic ecosystems contain communities of organisms—aquatic life—that are dependent on each other and on their environment. The two main types of aquatic ecosystems are marine ecosystems and freshwater ecosystems. Freshwater ecosystems may be lentic ; lotic ; and wetlands.
Mangrove forests, also called mangrove swamps, mangrove thickets or mangals, are productive wetlands that occur in coastal intertidal zones. Mangrove forests grow mainly at tropical and subtropical latitudes because mangroves cannot withstand freezing temperatures. There are about 80 different species of mangroves, all of which grow in areas with low-oxygen soil, where slow-moving waters allow fine sediments to accumulate.
A riparian zone or riparian area is the interface between land and a river or stream. In some regions, the terms riparian woodland, riparian forest, riparian buffer zone, riparian corridor, and riparian strip are used to characterize a riparian zone. The word riparian is derived from Latin ripa, meaning "river bank".
Igapó is a word used in Brazil for blackwater-flooded forests in the Amazon biome. These forests and similar swamp forests are seasonally inundated with freshwater. They typically occur along the lower reaches of rivers and around freshwater lakes. Freshwater swamp forests are found in a range of climate zones, from boreal through temperate and subtropical to tropical. In the Amazon Basin of Brazil, a seasonally whitewater-flooded forest is known as a várzea, which is similar to igapó in many regards; the key difference between the two habitats is in the type of water that floods the forest.
Mangrove ecosystems represent natural capital capable of producing a wide range of goods and services for coastal environments and communities and society as a whole. Some of these outputs, such as timber, are freely exchanged in formal markets. Value is determined in these markets through exchange and quantified in terms of price. Mangroves are important for aquatic life and home for many species of fish.
Mangrove restoration is the regeneration of mangrove forest ecosystems in areas where they have previously existed. Restoration can be defined as "the process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed." Mangroves can be found throughout coastal wetlands of tropical and subtropical environments. Mangroves provide essential ecosystem services such as water filtration, aquatic nurseries, medicinal materials, food, and lumber. Additionally, mangroves play a vital role in climate change mitigation through carbon sequestration and protection from coastal erosion, sea level rise, and storm surges. Mangrove habitat is declining due to human activities such as clearing land for industry and climate change. Mangrove restoration is critical as mangrove habitat continues to rapidly decline. Different methods have been used to restore mangrove habitat, such as looking at historical topography, or mass seed dispersal. Fostering the long-term success of mangrove restoration is attainable by involving local communities through stakeholder engagement.
A várzea forest is a seasonal floodplain forest inundated by whitewater rivers that occurs in the Amazon biome. Until the late 1970s, the definition was less clear and várzea was often used for all periodically flooded Amazonian forests.
Nigeria has extensive mangrove forests in the coastal region of the Niger Delta. Considered one of the most ecologically sensitive regions in the world, the Niger Delta mangrove forest is situated within a deltaic depositional environment. These mangrove forests serve a critical role in regional ecological and landscape composition, and support subsistence gathering practices, and market-based income opportunities. Anthropogenic development threatens the survival of Niger Delta mangrove populations.
Katherine Carter Ewel is a Professor Emeritus at the University of Florida's School of Forest Resources and Conservation. She is an ecosystem, forest, and wetlands ecologist who has worked in Florida for much of her career, focusing much of it on cypress swamps, pine plantations, and mangrove forests in the Pacific. Ewel served as the vice-president of the Society of Wetland Scientists in 2003, becoming president in 2004 and now since 2005, a past president. She has now retired and lives near Gainesville, Florida.
The Niger Delta swamp forests is a tropical moist forest ecoregion in southern Nigeria. It consists of freshwater swamp forests in the Niger Delta of the Niger River. This swamp forest is the second largest in Africa after the Congolian swamp forests. Although there are large cities just outside the ecoregion, the area has been relatively isolated by the difficulty of building roads across the swamps, although this is changing with development of oil and logging industries. Scientific surveys have only begun in recent years, and new species were being identified into the 1990s. Crude oil exploration and pollution has been a threat to forests in the Niger Delta region.
