The value of wetlands
Loading reeds onto a boat which will transport them to one of the paper mills along the shore of the Dongting Lake. Hunan Province, China.
© WWF-Canon / Edward PARKER
© WWF-Canon / Edward PARKER
A source of life for people and wildlife
Nature's water filter
Wetlands help clean the water in various ways:
From the WWF Baltic Bulletin
- Nitrogen in water is transformed to harmless nitrogen gas
Bacteria in the water transform the nitrogen (nitrit and nitrate) to harmless nitrogen gas (N2) which goes back into the air. This process is called denitrification. - Nutrients are taken up by wetland plants in the water
Through mowing and grazing, plants – with their content of nutrients – are removed from wetlands. - Wetlands act as filters
Phosphorous, heavy metals and certain toxic compounds get trapped in the sediments of the wetlands. - Peat forming
During the formation of peat coal, nitrogen and heavy metals are incorporated into the peat.
From the WWF Baltic Bulletin
Wetland ecosystems are often mistakenly undervalued. Few people realise the range of products derived from freshwater habitats like wetlands: food such as fish, rice and cranberries; medicinal plants; peat for fuel and gardens; poles for building materials; and grasses and reeds for making mats and baskets and thatching houses.
These complex habitats act as giant sponges, soaking up rainfall and slowly releasing it over time. Wetlands are like highly efficient sewage treatment works, absorbing chemicals, filtering pollutants and sediments, breaking down suspended solids and neutralising harmful bacteria.
They are also the most biologically diverse ecosystems on Earth.
Wetlands provide...
* Flood control
The most significant social and economic benefit that wetlands provide is flood control. For example, the economic benefit of the Charles River Basin wetlands in the US state of Massachusetts is estimated at over USD$95 million per year, 41% of which is flood damage prevention.
* Clean water
New York City found that it could avoid spending USD$3-8 billion on new waste water treatment plants by investing USD$1.5 billion in the purchase of land around the reservoirs upstate. This land purifies the water supply for free.
* Food supply
Rice is the staple diet of nearly 3 billion people - half the world's population. It is grown in wetlands across Asia and west Africa, and in the United States. Almost as important is sago palm, which provides starch from which sago flour is made. And palms from the wetlands of Africa yield valuable oils for cooking and soap making.
* Cultural value
Throughout history humans have gathered around wetlands and these areas have played an important part in human development and are of significant religious, historical or archeological value to many cultures around the world. For example, on the Coburg Peninsula (the world’s first Ramsar site), traditional Aboriginal owners still conduct an active ceremonial life and undertake semi-traditional hunting and gathering in this coastal wetland.
* Other services
Wetlands yield fuelwood for cooking, thatch for roofing, fibres for textiles and paper making, and timber for building. Medicines are extracted from their bark, leaves, and fruits, and they also provide tannins and dyes, used extensively in the treatment of leather.
* Recreation areas
Wetlands everywhere provide important leisure facilities - canoeing and fishing, shell collecting and bird watching, swimming and snorkelling, hunting and sailing.
Home to many species
It has been estimated that freshwater wetlands hold more than 40% of all the world’s species and 12% of all animal species. Individual wetlands can be extremely important in supporting high numbers of endemic species. For example, Lake Tanganyika in Central Africa supports 632 endemic animal species.
Wetlands provide a nursery habitat for many commercially important fish species that are harvested outside the wetland. The Varzea Flooded Forest in Brazil is a breeding ground for more than 200 species of fish.
A refuge for migrating birds
When winter sets in across the northern hemisphere, it triggers the most extraordinary mass movement of any living creature on Earth - the annual migration of countless birds over vast distances.
Many nations are now aware of the negative impact of destroying wetland areas and are attempting to restore the ecological processes provided by wetlands. These projects are very costly and are rarely able to match the ecological processes provided by the original or natural wetland systems.
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