October 18, 2018 Biodiversity Written by Greentumble
As unappealing as the term “wetlands” sounds,

wetlands should be celebrated for their multiple services they deliver which help keep our planet and society going as well as for their extraordinarily beautiful landscapes.

Luckily, in the past years, attitudes toward wetlands have changed from the view that wetlands are wasted areas to be dredged and filled for development to a recognition that they are indeed very valuable productive ecosystems, integral to the health and sustainability of earth’s biosphere.

What is a wetland and where are wetlands located?

Wetlands can be anywhere.  Internationally, the Ramsar Convention, an international treaty governing the protection of wetlands worldwide, defines wetlands very broadly to include all lakes and rivers, underground aquifers and even coral reefs.

A more common view of wetlands is the transition zone linking land and water, where water covers the soil, if only seasonally.

This includes:

  • saltwater coastal wetlands, such as estuaries and mango swamps;
  • the freshwater wetlands found along lakes and rivers;
  • the inland swamps;
  • marshes;
  • fens and bogs, both those that remain saturated and those depressions that fill only seasonally with water.

Wetlands are present all over the world, varying in location due to geologic history.

For example, many depressions in the earth were made during the retreat of glaciers at the end of the Ice Age and have filled with water.  Marine estuaries are where the sea meets the land and wetlands along rivers and streams are often the result of periodic heavy rains and flooding.

Peat bog in Venn

Different types of wetlands have formed as a result of the type of soil present and the type that has evolved from the cycling of decomposing plant life.

For example, a bog has a substrate of peat and supports only acid-loving plants.  Conversely, marshes support herbaceous plants like cattails and pickerelweed, with stems partly in and out of the water and swamps are best known for the tall trees and woody shrubs growing out of them.

The latter both have floors of black mucky soil rich in organic material as distinguished from the nutrient-deficient peat environment where decomposition is a very, very slow process.

In fact, it is believed that the corpse of the Tollund Man, discovered in a Danish bog in the 1950s, so well preserved that his fingernails and facial features including whiskers are visible, is 2,000 years old.


Why are wetlands important?

Wetlands are indeed nature’s liquid assets.

#1 Prevention of flooding

As the world has been warming, we are experiencing more severe weather and devastating flooding.  Wetlands are being looked to as significant moderators of the damage flooding can cause.

Wetlands operate as natural tubs storing overflowing water and then slowly releasing it.  Numerous studies by the EPA and The Wetlands Initiative, a nonprofit organization corroborate findings of dramatic flooding consequences that would not have occurred had wetlands not been drained and findings of savings where wetlands can be restored.

The US Army Corps of Engineers estimates that protecting wetlands along Boston’s Charles River will save $17 million in potential flood damage [1].

Findings by the Federal Emergency Management Agency corroborate this position that flood waters can be contained by natural ecosystems.

#2 Reduction of agricultural runoff

Additionally, wetland sinks absorb fertilizer runoff during periods of heavy rain, a significant asset in agricultural areas like those along the Mississippi River that account for eutrophication of the Louisiana delta and a dead zone that spreads across the Gulf of Mexico every summer [2].

In 2017, the dead zone expanded over 8,776 miles [3]

#3 Natural water purification

Wetlands not only filter excess nitrogen from fertilizer and manure primarily through uptake by plants, but they also filter residues from heavy metals, herbicides and other toxins that enter the water supply through the layers of sediment as the rainwater carrying these pollutants percolates down through the soil to groundwater where it becomes available for drinking water or makes its way to an open waterway.

Because of its effectiveness and the lower costs involved, municipalities are now considering the value of existing natural wetlands, as well as projects to create wetlands to supplement their wastewater treatment plants for water purification [4].

Constructed wetlands

Wetlands treatment systems can also create a wildlife habitat.  In a nod to the filtration abilities of the earth, one role a wetland fulfills, subsurface flow systems are designed to treat the water below the surface in order to avoid odors and other nuisance aspects.  These systems create a subsurface flow through a permeable medium such as soil, sand or gravelly rock.  Free water systems incorporate the advantage of providing wildlife habitat as natural wetlands do [5].

In addition to purifying water for drinking, wetlands help to cleanse storm water runoff.  The expansion of development has not only eliminated the many wetlands that operated as basins to hold excess rainwater, but has caused the additional problem of water, polluted from the streets and overflow of municipalities running directly into nearby lakes and streams.

Urban planners are looking to small vegetative basins between roadways and sidewalks where possible to absorb some of this runoff, permeable pavements and more green infrastructure like green roofs and rain gardens to serve purposes wetlands accomplish [6].

#4 Sustainable cultivation of food crops

Rice, a staple in half of the world’s population, grows exclusively in wetlands [7].  Cranberries and high mountain blueberries grow in bogs.

Wetlands are being looked at for other agricultural possibilities, with an eye toward low-intensity agriculture, foregoing the use of fertilizers and pesticides and considering both biodiversity and flood detention [8].


#5 Important natural habitat

The US Environmental Protection Agency estimates that wetlands are vital in the life cycle, whether for breeding, laying eggs or as a food source and habitat of two thirds of fish worldwide, including shellfish, commercially harvested in the United States [11]. Because wetlands provide an abundance of food that attract many animal species.

The small particles of organic material from dead plant leaves and stems breaking down provide rich nutrients that make their way up the food chain from insects to mammals.

Beaver, ducks, and muskrats all depend upon wetlands as a habitat. In fact, 150 different kinds of birds need wetlands in order to survive.

Other animals that routinely forage in wetlands include:

  • deer
  • bear
  • raccoon
  • elk
  • moose
  • snowshoe hares
  • bobcats

Wetlands are also a critical habitat for many species of reptiles and amphibians. Most amphibians lay eggs under water, though some lay them on moist land. Once hatched, the babies live in the water until grown enough to leave the water. Wetlands provide a rich and diverse menu of insects, spiders, snail and worms and small fish for amphibians.

Wetlands are one of the most biologically diverse and productive of earth’s ecosystems.

An example: wetlands cover only five percent of the mainland US but are home to a full one-third of threatened and endangered species. And an additional 20 percent of threatened and endangered species use wetlands during some point of their life cycle.

The Ramsar Convention Global Wetland Outlook recently published and to be used as a working document for discussion at their meeting this October 2018 has found that over 19,500 plant and animal species depend upon wetlands globally [13].

#6 High recreational and economical value

Wetlands are critical for the existence of up to 90 percent of recreational fish catch [9]. Recreational fishing is popular in the US with an estimated annual economic impact of $115 billion [10].

They are also home to many beautiful migratory birds and as such are visited both by birdwatchers and hunters.

Beautiful wetland landscape in the fall

Fishing, hunting and birdwatching are all popular in the US, adding approximately $157 million in 2016 alone, hunters of migratory birds spent over $81 million of this spent on hunting expeditions of migratory birds, exclusive of costs to lease land [12].

Not surprisingly, all of these services add up.

The Ramsar Convention cites wetlands as the most valuable ecosystem economically.

#7 Education

As such, not only do wetlands provide recreational opportunities to take in their aesthetic beauty, but those that are protected as sanctuaries serve the educational purpose of helping visitors understand the web of life supporting the earth’s biosphere.

Not only can visitors view the diverse species of animals and plants, but they can sometimes see them in action: carnivorous plants like the hooded pitcher plant and the yellow butterwort attracting insects, snakes devouring frogs, bear eating fish, a graceful heron seemingly studying its reflection in the water.

White heron hunting

Oftentimes too, wildlife sanctuaries will have signage explaining the important role of the microorganisms, plants and wildlife in the global cycles for water, nitrogen and sulfur.

And expressing the increasingly important role of wetlands in regulating climate change by storing carbon within their plant communities and soil [14].

The Ramsar Convention which also includes rivers and lakes in its definition points out that wetlands provide all of the earth’s fresh water [15].

Wetlands ecosystem facts

If you want to change your mind completely about what a swamp, a marsh or a bog actually look like or do, then continue reading to find out some astonishing facts about wetlands!

    • Private wetlands

99 percent of the wetlands is privately owned.

    • Mosquito factories? Not really…

Healthy wetlands are not home to uncontrolled mosquito populations as they sustain many species of mosquito-eating fish, amphibians and other insects and birds, all which help to curb mosquito populations.

    • Insect divers

Many insects in wetlands have developed ways of breathing under water by coming to the surface periodically and taking a bubble of air back down under the water with them much like divers with air tanks.

Common whirligig beetle is adapted to swimming.

    • The world’s largest wetland

The largest wetlands in the world is the Plantanal extending over somewhere between 54,000 and 75,000 square miles (140,000 to 195,000 square kilometers) in Brazil, Bolivia and Paraguay. The Pantanal is a vast, gently-sloped basin that receives runoff form the highlands and slowly releases the water into the Paraguay River and its tributaries.

    • 17 million acres of extraordinary biodiversity

The world’s largest protected wetland is the Llanos de Moxos, 17 million acres near the borders of Bolivia, Peru and Brazil. It is primarily tropical savannah, with cyclical flooding and droughts.

It is home to a rich natural diversity including at least 131 species, 568 different birds, 102 reptiles, 62 amphibians, 625 fish and at least 1,000 plant species [16].


    • Global distribution

Wetlands appear on every continent except for one: Antarctica. They can be made of freshwater, saltwater, or a combination of the two. Some wetlands are actually dry at certain times of the year. Depending on the type of wetland, the area may be filled with trees, grasses, shrubs or moss; to be called a wetland it must be filled or soaked with water for at least part of each year.

    • Incredible capacity to contain impurities and pollutants

You will be amazed to find out that they can remove up to 60 percent of metals contained in the water, trap and retain up to 90 percent of sediment from runoff and eliminate up to 90 percent of nitrogen. Pretty impressive, right?

New York City found that it could save $3 billion to $8 billion in new wastewater treatments plants by purchasing and preserving $1.5 billion in wetlands around its upstate reservoirs to filter the water naturally.

    • The best flood control

An acre of wetland can store up to 1.5 million gallons of floodwater. This is because wetlands are able to store excess water from rainfall and release it water back into the ground where it becomes a source of drinking water for people.

Wetlands flood prevention

Most of other types of landscapes cannot absorb excess rainwater and runoff like wetlands can. Wetlands are one of our environment’s great successes when it comes to natural flood prevention mechanisms.

    • The main breeding ground for America’s birds

Bottomland hardwood swamps are found predominantly in the southern US. It is believed that 80 percent of the nation’s breeding bird population require these swamps and the extinction of America’s largest woodpecker, the ivory-billed woodpecker is attributed to the over-logging of the hardwood trees found there.

    • Mysterious lights

The ghostly light seen wavering in dark, dank swamps across the world and over millennia, nicknamed will-o-the-wisp or Jack-o-lantern, the lamp carried by stingy Jack, cursed by the Devil and barred even from Hell for his shenanigans.

The ethereal light that retreats as the trembling traveler approaches, mesmerized, but still aware of the slithering of snakes, the croak of the bullfrog, the dragonfly flitting by, aware that a panther could be lurking, aware of the thick odor of the deep muck he is wading through, of the heavy fragrant flowers but still plodding forward toward the light…

Scientists believe these lights of varying colors are caused by combustion when the methane from decomposition comes into contact with oxygen.

Wetland climate facts

    • Key carbon sinks

If you thought that it is trees and forests that can mainly capture carbon from the atmosphere, you are forgetting the great work that peat wetlands are doing. More specifically, peat wetlands alone store more carbon in their soil than rainforests do.

This means that they store a third of the world’s total carbon but only take up three percent of the world’s surface [1]. Pretty effective biomes!

    • Flood and pollution control

The Smithsonian Research Environmental Research Center is conducting an experiment in the tidal marshes of Chesapeake Bay to determine the effects of water pollution and climate change on wetlands.

Wetlands will play an increasingly important role in buffering the effects of flooding from the tempestuous storms that are already devastating the world due to the increased greenhouse gas emissions in our atmosphere, so we need to understand what their condition will be in 100 years.

Researchers are using models predicting agricultural runoff and the increased carbon dioxide emissions predicted from the continued burning of fossil fuel and entering a third variable: an invasive species of tall, feathery grass introduced from Europe, the European Phragmite, which is madly overtaking the marshes.

Invasive phragmite plants

This grass species is aggressively displacing native vegetation and thrives in water and air pollution, unfortunately, the researchers are foreseeing an unwelcome future; with a cascading effect on the food web and biodiversity of wildlife and plants [17].

Wetland destruction facts

    • Quick disappearance

Half of the world’s wetlands have disappeared since 1900 [19]. A recent report by the Ramsar Convention on Wetlands warns that wetlands are disappearing today three times faster than forests [20].

    • Land cultivation: bad news for wetlands

The United States has lost half of its wetlands since the late 1700s.  This has been due to the historic view boosted by federal legislation in 1850 granting many of the states ‘swamp and overflowed land unfit for cultivation’ to be drained [18].

The tide turned in the late 19th century when federal, state and private organizations began acquiring wetlands as waterfowl sanctuaries, recognizing that many migratory birds rely upon them for habitat at some point of their life cycle–to rest on long flights or to nest.

Species dependent on wetlands

As a matter of fact, wetlands have become known in recent years as “nurseries of life” because they provide habitat for thousands of species of aquatic and terrestrial plants, waterfowl, fish, reptiles amphibians and mammals.

    • Many serious threats

Wetlands face threats from pollution, climate change, dams, agriculture, and development. While wetlands are natural filters of pollutants, if the polluted water exceeds the carrying capacity of the ecosystem, its entire ecology will break down.

    • Leading cause of species extinction

Habitat ruin since the 1970s has been a leading cause of species extinction in wetlands [21].
To this end, planning at the outset is essential before dams or other infrastructure are built, agricultural lands expanded that would require loss of wetlands or other development is approved.  A system of permitting where careful consideration is given to the foreseeable consequences needs to be implemented.


The Ramsar Convention on Wetlands

Natural wetlands are critical ecosystems and are vanishing. However, governments are making efforts to curb their destruction and are artificially creating wetlands that may well provide habitat and ecological services similar to the habitat that has been lost.

It is difficult to know without a comprehensive assessment of the type of flora and fauna being displaced and those that can readily acclimate to these manmade wetlands.  Many scientific groups are focusing on the problem and working hard to address it.

The good news at the international level is that 170 countries are members of the Ramsar Convention on Wetlands, signaling a worldwide acceptance of the vital role wetlands play to the sustainability of the planet.  The member countries agree to implement goals set forth for the protection of wetlands.

Ramsar also collaborates with six other conventions focusing on biodiversity issues:

  • The Convention on Biological Diversity;
  • The Convention on the Conservation of Migratory Species of Wild Animals (CMS);
  • The Convention on the International Trade in Endangered Species of Wild Flora and Fauna, (CITES);
  • The International Treaty on Plant Genetic Resource for Food and Agriculture (ITPGRFA);
  • The International Plant Protection Convention (IPPC);
  • The World Heritage Convention (WHC)

In an ongoing effort to develop and share increased understanding of wetlands ecosystems, Ramsar provides scientific research support to the Scientific Advisory Bodies of the Biodiversity-related Conventions (CSAB) and the Chair of Ramsar’s Scientific and Technical Review Panel (STRP) observes the Multidisciplinary Expert Panel of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES).

Protected wooden path through wetland

Although it does not have a formal relationship with the water conventions, Ramsar has of late been engaging with the UN Convention on the Law of the Non-Navigational Uses of International Watercourses (the New York Convention) and the UNECE Convention on the Protection and Use of Transboundary Watercourses and International Lakes (the Helsinki Convention), as well as taking part in the UN Water, which is the United Nations Forum on all freshwater issues.

Ramsar counts as partners:

  • Birdlife International;
  • International Union for Conservation of Nature (IUCN);
  • Wetlands International;
  • the World Wildlife Fund (WWF);
  • the International Water Management Institute (IWMI)
  • the Wildfowl and Wetlands Trust (WWT)

The Convention also has numerous collaborations with different global multilateral environmental agreements, global intergovernmental organizations and processes, regional intergovernmental organizations and processes and a host of other international non-governmental organizations and processes.

The Ramsar Convention offers small grants to developing countries to help implement wetlands protection programs. Partnerships between the Ramsar Convention and private companies have also opened some opportunities for financial incentives and awards for protecting wetlands.

Additionally, the Ramsar Convention partners with a number of entities which may be more familiar to you, like Ducks Unlimited and The Nature Conservancy. 

How can we protect wetlands?

Encourage your local government to explicitly set forth the conservation of wetlands as part of the comprehensive plan for land use.

Governments can only go so far, especially where development projects do not require permitting or where private landowners do not know that their activities require permitting.

Tibet Lalu wetland

In this instance, it is important to educate people on the value of wetlands. The USEPA offers educational materials online at its website.

Some governments offer financial incentives to conserve wetlands.  In the US, the US Department of Agriculture administers these programs.

Not only can people make private donations to conservation groups focusing on wetlands, but the US government donates the proceeds of duck stamps to the acquisition of wetlands.

And don’t forget to celebrate World Wetlands Day which occurs each year on 2 February in honor of the day that the Ramsar Wetlands Convention was signed in 1971.



[1] https://nepis.epa.gov/Exe/ZyPDF.cgi/2000D2PB.PDF?Dockey=2000D2PB.PDF
[2] http://www.wetlands-initiative.org/nutrient-removal/
[3] https://news.nationalgeographic.com/2017/08/gulf-mexico-hypoxia-water-quality-dead-zone/
[4] https://www.epa.gov/sites/production/files/2015-10/documents/2004_10_25_wetlands_introduction.pdf
[5] https://www.epa.gov/sites/production/files/2015-10/documents/2004_10_25_wetlands_introduction.pdf
[6] https://theconversation.com/stormwater-innovations-mean-cities-dont-just-flush-rainwater-down-the-drain-40129
[7] https://www.worldwildlife.org/stories/what-is-a-wetland-and-8-other-wetland-facts
[8] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2794053/
[9] https://nepis.epa.gov/Exe/ZyPDF.cgi/2000D2PF.PDF?Dockey=2000D2PF.PDF
[10] https://www.sportfishingmag.com/recreational-fishing-economy-impact-2017
[11] https://nepis.epa.gov/Exe/ZyPDF.cgi/2000D2PF.PDF?Dockey=2000D2PF.PDF
[12] https://www2.census.gov/programs-surveys/fhwar/publications/2016/fhw16-nat.pdf
[13] https://www.ramsar.org/
[14] https://www.epa.gov/wetlands/how-do-wetlands-function-and-why-are-they-valuable
[15] https://www.ramsar.org/
[16] http://wwf.panda.org/knowledge_hub/where_we_work/amazon/species/key_species_for_conservation/
[17] https://www.smithsonianmag.com/science-nature/how-will-the-wetlands-respond-to-climate-change-164048534/
[18] https://www.gpo.gov/fdsys/pkg/USCODE-2010-title43/pdf/USCODE-2010-title43.pdf
[19] https://www.worldwildlife.org/stories/what-is-a-wetland-and-8-other-wetland-facts
[20] https://www.ramsar.org/
[21] https://www2.census.gov/programs-surveys/fhwar/publications/2016/fhw16-nat.pdf