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East Chidham salt marsh, southern England
Wetland in Marshall County, Indiana, USA

A wetland or wetland biotope is an area that lies in the transition area from dry to permanently moist ecosystems . The term wetland includes various types of flora and fauna such as floodplain , quarry forest , wet meadow , bog , reed , swamp and marshland , which are adapted to the year-round surplus of water .

Wetlands are of great importance for ecology , climate protection and flood protection . The Ramsar Convention initiated by UNESCO is intended to ensure international cooperation in the protection of wetlands. Significant still existing wetlands are for example the Pantanal , the flood plains of the Bhar Aouk and Salamat , the Everglades and the Wadden Sea .


There is no generally accepted definition of the term “wetland”. The term or its counterparts in other languages ​​(e.g. the English "wetland") are interpreted differently in European countries, depending on national tradition.

The definition in the Ramsar Convention reads: “Wetlands within the meaning of this Convention are wet meadows, moorland and marshland or bodies of water that are natural or artificial, permanent or temporary, standing or flowing, fresh, brackish or salt water, including such marine areas that do not exceed a depth of six meters at low tide. "

In the German-speaking world, the definition is traditionally narrower. Usually marine habitats are not counted among the wetlands here. Linguistic usage is inconsistent with regard to the Wadden Sea. However, the Wadden Sea is usually designated as a wetland within the framework of the Ramsar Convention.

The term is generally not used in vegetation science. The term does not appear in the recognized standard textbooks (e.g. Ellenberg).

Definitions of the term can be made from three angles:

  1. Hydrology : saturation of the terrain up to the land surface with water over a longer period of the year
  2. Substrate / Soil: Area with hydric soil types (e.g. gley )
  3. Vegetation: area with wet vegetation types, e.g. B. moors, reed beds, wet grassland / wet meadows .

Whether open waters represent "wetlands" is also handled differently depending on the author. They are included in the broad definition of the Ramsar Convention. Most German-speaking authors only calculate transition areas between open waters and land habitats to the wetlands. However, smaller bodies of water such as ponds and ponds or temporary and periodic bodies of water are usually included. Lakes or rivers and streams are generally not considered to be part of the wetlands, although it is recognized that there are significant interactions here and these bodies of water are often enclosed by wetlands.

Significance for ecology and climate protection

Wetlands are of great ecological importance as they serve as resting and wintering areas for water birds and waders . Wetlands cover around six percent of the earth's surface and generate 24 percent of the net primary production - they are therefore highly productive ecosystems. They also serve as groundwater filters and flood protection. Wetlands of international importance (for example for bird protection ) are therefore placed under protection under the Ramsar Convention.

Wetlands are of particular importance for climate protection, as they act as a carbon sink and store large amounts of carbon worldwide . You can thus help reduce the greenhouse effect . Since many wetlands are also net emitters of the strong greenhouse gas methane , their actual contribution depends on the individual case and can be difficult to determine. When peatlands are drained , they emit part of the stored carbon in the form of carbon dioxide and nitrous oxide , which increases the greenhouse effect.

Importance as a water reservoir

Another importance of the wetlands is their function as a water reservoir. Bogs and swamps can absorb large amounts of water and release it again slowly and with a delay. In doing so, they help to reduce the risk of flooding in underlying areas. On the other hand, they can support the low water runoff and thus prevent dehydration phases.

In addition, wetlands serve as a sink for pollutants and nutrient inputs and can thus relieve underlying areas and waters. Because of the nutrient sink function, many wetlands are exceptionally productive.

See also


  • Claus-Peter Hutter (eds.), Alois Kapfer, Peter Poschlod: Swamps and Moore. Recognize, define and protect biotopes. Weitbrecht Verlag, Stuttgart / Vienna / Bern 1997, ISBN 3-522-72060-1 .

Web links

Commons : Wetlands  - Collection of images, videos and audio files

Individual evidence

  1. chap. 2.1: What is a wetland? ( Memento of January 30, 2012 in the Internet Archive ) in the EU Wetlands Guide to the Water Framework Directive (PDF; 442 kB).
  2. Article 1.1 of the Ramsar Convention. See the text of the Convention in the 1987 version: PDF download of the German translation www.ramsar.org.
  3. Example: Wadden Sea is a World Heritage Site, press release by the German Commission for UNESCO, June 26, 2009.
  4. Heinz Ellenberg : Vegetation of Central Europe with the Alps in an ecological, dynamic and historical perspective. 5th, heavily changed and improved edition. Ulmer, Stuttgart 1996, ISBN 3-8001-2696-6 .
  5. Hannes Müller Schmied: Integrative derivation of hydrological functions of wetlands using the example of the "Wipfragrund", upper Gera catchment area, Thuringia . Diploma thesis at the Institute for Geography of the Friedrich Schiller University Jena, 2008.
  6. ^ Coastal Wetland Protection. In: Project Drawdown. February 6, 2020, accessed on September 13, 2020 .
  7. ^ William J. Mitsch et al .: Wetlands, carbon, and climate change . Landscape Ecology 2013; 28 (4), pp. 583-597. doi : 10.1007 / s10980-012-9758-8 .
  8. J. Hommeltenberg, HP Schmid, M. Drösler, P. Werle: Can a bog drained for forestry be a stronger carbon sink than a natural bog forest? Biogeosciences 2014; 11, pp. 3477-3493. doi : 10.5194 / bg-11-3477-2014 .
  9. Kenneth A. Byrne et al .: EU Peatlands: Current Carbon Stocks and Trace Gas Fluxes . Carboeurope GHG, Report 4/2004. PDF .
  10. Michael Trepel (2008): On the importance of moors in the climate debate. Annual reports of the State Office for Nature and the Environment of Schleswig-Holstein 2007/08, 12: pp. 61–74.
  11. Environment in class: Wetlands and moors are valuable Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety, February 1, 2012.
  12. If the bogs are gone, it's bad for the climate Interview with Gert Michael Steiner, Scientific Advisory Board of the Ramsar Convention, in: derstandard.at, June 25, 2007.