SWAMP: CHARACTERISTICS, TYPES, FLORA, FAUNA, EXAMPLES - ENVIRONMENT - 2025

A swamp is a flat, poorly drained area with a shallow, permanent or temporary stagnant sheet of water covered by vegetation. The sheet of water is formed either by waterlogging due to rains, by flooding when rivers or lakes overflow, or by the action of tides.

Freshwater swamps are known as swamps or marshes and marshes if they are coastal saltwater areas. These ecosystems are considered wetlands, which is why they are within the RAMSAR agreement, due to their importance in the water cycle.

Pantano de Aznalcollar (Seville, Spain). Source: Wwal / CC BY-SA (https://creativecommons.org/licenses/by-sa/2.5)

The swamp is characterized by a cycle of periodic flooding or waterlogging and a low content of dissolved oxygen in the water. The soils tend to be heavy, with poor drainage and a predominance of reductive processes with the presence of ferrous iron.

The vegetation is made up of rooted and floating aquatic plants, including trees tolerant to excess water. The flora that makes up this vegetation is highly variable, depending on the type of swamp and the latitude at which it develops.

The fauna of the swamp includes various species of amphibians (frogs, toads), reptiles among which the alligator species and different species of mammals stand out. Furthermore, the swamp, like other wetlands, has a great diversity of birds.

Worldwide there are numerous swamp areas forming an extended and varied biome. Among them is the extensive South American swampy area between Brazil, Argentina and Paraguay, called the Gran Pantanal in Brazil and estuaries in the other two countries.

In North America the swamps of the Everglades in Florida (USA) are known. And in Europe there is the Sjaunja swamp in Sweden.

Features of the swamps

- Relief and hydrology

The swamps occur in low, flat or concave areas with poor drainage characterized by the presence of a shallow sheet of water and abundant vegetation. This sheet of water can be present permanently or for long periods of time.

Relief of a swamp. Source: by Manjeet Bawa / CC BY (https://creativecommons.org/licenses/by/2.0)

The water comes from the overflow of rivers or lakes (flooding) or from rain, combined with poorly drained soils and little infiltration (waterlogging).

Water

Due to the shallow water depth in the swamp and the abundant aquatic and marsh vegetation, dissolved oxygen is scarce. Furthermore, the amount of suspended organic matter and dissolved organic acids in water is high and therefore the pH is acidic.

- Floor

As they are soils subject to permanent or almost permanent flooding, they are anoxic (absence of pure oxygen), with difficulty for gas exchange. The structure of the soil is also affected by the disaggregation of the particles due to the water that makes cementing difficult.

These soils are subjected to reduction processes such as denitrification (conversion of nitrates into nitrogen). They are generally heavy soils, that is, with a high content of clays in their texture.

There are layers of gray soil with a greenish-gray color, due to the presence of ferrous iron due to the reduction processes.

Peat

Due to the excess of water, the acidic pH and the bacterial action, there is a partial decomposition of the organic matter. A process of loss of hydrogen is generated and under these conditions a compact carbonated matter called peat is formed.

- Microbiological processes

The combination of aerobic areas (with free oxygen) and other anaerobic (without oxygen), provoke the development of various processes. In the swamps there is an increase in the activity of decomposing organisms.

In these areas, there are sulfide production processes by sulfate reduction under good lighting conditions. Whereas in shaded and anaerobic areas methanogenic bacteria form methane (methanogenesis).

- Weather

The climate is very variable, since swamps are located both in tropical areas and in temperate and cold areas.

Types of swamps

The swamps are classified according to different criteria, either by the salinity of the water that composes it or by the type of vegetation that inhabits it.

Salt water swamp

It corresponds to the so-called marshes that are coastal swamps generally associated with estuaries. These swamps are formed in depressions near estuaries due to overflowing rivers.

They occur in sandy soils, but flooded by the high level of the water table (underground water fed by a nearby river). The type of vegetation that appears is the marsh grassland with a predominance of reeds, sedges and grasses, as well as algae and other aquatic plants.

Freshwater swamp

This type of swamp occurs in inland depressions as a result of waterlogging by rain or overflowing bodies of water. The soil is generally clayey and the vegetation can reach greater complexity, with trees and shrubs as well as herbs.

Flora

The plant species that inhabit the swamps have to be adapted to the permanent presence of water. In those cases of salt water marshes, the limiting factor of salinity is added.

Bora (Eichornia crassipes). Source: NickLubushko / CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0)

The swamp ecosystem is not uniform, presenting diverse areas of emergent land alternated with large flooded areas. This determines a distribution of the species according to their ability to withstand waterlogging (excess water).

In such a way that they are found from submerged, rooted and floating aquatic species, to others that do not withstand a long flood time.

- Herbs and shrubs

Bottom-rooted grasses in flooded areas include reeds (Juncaceae). While among the floating is the bora (Eichhornia spp.) And various species of Nymphaea.

Halophytic species predominate in marsh areas, that is, resistant to saline substrates. Among these are the saladillo (Sporobolus virginicus) and the salted chard (Limonium vulgare).

Other halophytes are Atriplex (called salt plants) and wiregrass (Spartina spp.). In addition, in many marshy areas of the world there are reeds or cattails (Typha latifolia) and shrubs such as the marsh rose (Rosa palustris) in North America.

- Trees

Tropical zone

In wooded swamps there are various species capable of withstanding periods of permanent flooding. Among these is the Guiana chestnut (Pachira aquatica), a tree up to 18 m tall whose seeds are edible.

Other species are the labón or palo cruz tree (Tabebuia nodosa), the curupí (Sapium haematospermum) and palms such as the pindó (Syagrus romanzoffiana).

Temperate zones

Even in temperate zones there is a swamp conifer, the swamp cypress (Taxodium distichum), typical of the swamps of Louisiana (USA). Also a species of the genus Quercus, the American marsh oak or swamp oak (Quercus palustris).

Similarly, the aquatic tupelo (Nyssa aquatica) is an angiosperm characteristic of the swampy areas of the southeastern United States.

Fauna

Tropical zone

Marsh crocodile (Crocodylus moreletii). Source: Alfonsobouchot / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0)

The tropical swamps are home to the capybara (Hydrochoerus hydrochaeris), the swamp deer (Hippocamelus antisensis) and birds such as the soldier heron (Jabiru mycteria). There are also species of crocodiles (Caiman crocodilus, Caiman yacare. Crocodylus moreletii) and the anaconda (Eunectes murinus).

Temperate zone

Large reptiles such as the Alligator mississippiensis and Crocodylus acutus are found in subtropical or temperate swamps. And mammals like the Canadian otter (Lontra canadensis), as well as birds like the flamingo (Phoenicopterus ruber).

Examples of swamps in the world

- The Great Pantanal (Brazil)

This swampy area is located in the Brazilian states of Mato Grosso and Mato Grosso do Sul. It is the largest wetland in the world with about 140,000 km ². The swamp is a flooded savanna, with herbaceous vegetation both submerged and floating and rooted, and some emerging areas where tree vegetation grows.

The Pantanal (Brazil). Source: Alicia Yo at the English language Wikipedia / CC BY-SA (http://creativecommons.org/licenses/by-sa/3.0/)

The Great Pantanal is home to around 1,600 species of plants. This region of South America is continued with the Iberá estuaries in Argentina and the Ñeembucú estuaries in Paraguay.

From a biogeographic point of view, this area is influenced by the Amazon rainforest, the Brazilian Cerrado and the water system of the Paraguay River.

Weather

It has a seasonal tropical climate with abundant rainfall in the rainy season and high average temperatures.

Fauna

This biome has the influence of the Amazon, therefore the fauna is very diverse. About 260 species of fish, 700 birds, 90 mammals, 160 reptiles, 45 amphibians and 1,000 butterflies have been inventoried.

Various species of felines live here, such as the jaguar (Panthera onca) and the jaguarundi (Herpailurus yagouaroundi). As well as a great diversity of primates, reptiles, amphibians, birds and the Caribbean manatee (Trichechus manatus).

- Everglades

Everglades (Florida, USA). Marc Ryckaert / CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0)

This region is the world's largest rainfed grassland swamp, with a great diversity of flora and fauna. It is located at the southern tip of the Florida peninsula in the United States.

The meaning of its name translated into Spanish is "eternal light green", being its name in the Spanish colony "Cañaveral de la Florida".

The Everglades extend to Lake Okeechobee to the north, connecting with the Big Cypress Swamp. This whole set of swamps contains about 11,000 species of plants, including 25 species of orchids.

Nymphaea species (Nymphaea spp.) Abound in water bodies. While in the islands of trees there are tropical species such as red bay (Persea borbonia) and the bagá de Cuba or pond apple (Annona glabra).

Weather

It has a subtropical climate with two seasons, one rainy and the other dry, with high rainfall and very hot temperatures in summer and cool in winter.

Fauna

The Everglades swamp contains an important diversity of birds with about 300 species, as well as fish with 150 species. There are also 17 species of mammals such as the manatee (Trichechus manatus) as well as 30 species of reptiles and 14 of amphibians.

- Pantanos de Centla Biosphere Reserve

«Pantanos de Centla» Biosphere Reserve. Alfonsobouchot / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0)

This swamp is located in the state of Tabasco (Mexico) south of the Gulf of Mexico. It is a biosphere reserve, which constitutes the largest wetland in North America with more than 300,000 Ha.

It is formed by the contributions of the Grijalva and Usumacinta rivers, which are the largest in Mexico. In this wetland there is an important diversity of aquatic vascular plants, with 569 species.

The reserve includes mangrove areas, semi-deciduous forests and various marsh and aquatic communities. Among the trees are the cedars (Cedrela), mahogany (Swietenia) and ceibas (Ceiba).

Floating plants such as mouse ear (Lemna minor) and nymphae (Nymphaea odorata and N. ampli) occur in water bodies.

Weather

It is a hot and humid tropical climate, with abundant rainfall in the astronomical summer and two dry periods.

Fauna

You can find the manatee (Trichechus manatus), as well as a great diversity of birds with about 255 species. The diversity of species of terrestrial and aquatic turtles also stands out, with species such as the guao (Staurotypus triporcatus).

References

1. Calow P (Ed.) (1998). The encyclopedia of ecology and environmental management.
2. Cole, S. (1998). The Emergence of Treatment Wetlands. Environmental Science & Technology.
3. RAMSAR Agreement (Seen on September 21, 2019). ramsar.org/es
4. Cowardin, LM, Carter, V., Golet, FC & LaRoe, ET (1979). Classification wetlands and deepwater habitats of the United States.
5. Mereles, MF (Coord. Genl.). (2000). Cross-border initiative for the Pantanal (Paraguay). The Nature Conservancy-Foundation for the Sustainable Development of Chaco. USAID.
6. Richardson, CJ (2010). The Everglades: North America's subtropical wetland. Wetlands Ecology and Management.
7. Ramsar Convention Secretariat (2016). Introduction to the Convention on Wetlands.
8. World Wild Life (Viewed on March 26, 2020). worldwildlife.org ›ecoregions