A wetland is a land area that is saturated with water, either permanently or seasonally, such that it takes on the characteristics of a distinct ecosystem.[2] Primarily, the factor that distinguishes wetlands from other land forms or water bodies is the characteristic vegetation that is adapted to its unique soil conditions: Wetlands consist primarily of hydric soil, which supports aquatic plants.[3][4]
The water found in wetlands can be saltwater, freshwater, or brackish.[4] Main wetland types include swamps,marshes, bogs and fens.[5] Sub-types include mangrove, carr, pocosin, and varzea.
Wetlands play a number of roles in the environment, principally water purification, flood control, and shoreline stability. Wetlands are also considered the most biologically diverse of all ecosystems, serving as home to a wide range of plant and animal life.[6]
Wetlands occur naturally on every continent except Antarctica.[7] They can also be constructed artificially as a water management tool, which may play a role in the developing field of water-sensitive urban design.
The largest wetlands in the world include the Amazon River basin and the West Siberian Plain.[8] Another large wetland is the Pantanal, which straddles Brazil, Bolivia, and Paraguay in South America
Ramsar international wetland conservation treaty, wetlands are defined as follows:[15]
- Article 1.1: "...wetlands are areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six metres."
- Article 2.1: "[Wetlands] may incorporate riparian and coastal zones adjacent to the wetlands, and islands or bodies of marine water deeper than six metres at low tide lying within the wetlands
WHEN AN AREA SUPPORTS HYDROPHILIC VEGETATION
WHEN AN AREA HAS HYDRIC SOIL THT ARE SATURATED OR FLOODED FOR SUFFICIENTLY LONG PERIOD TO BECOME ANAEROBIC IN THE UPPER LAYER.
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