|
In physical geography, a wetland is an
environment "at the interface between truly terrestrial ecosystems...and truly aquatic systems...making them different from each yet highly dependent on both" (Mitsch
& Gosselink, 1986). In essence, wetlands are ecotones. Wetlands are found under
a wide range of hydrological conditions, but at least some of the time water
saturates the soil. The result is a soil
type (called hydric soil) that is
unique to wetlands. The hydric soil supports plants (called hydrophytes) specifically adapted to these
conditions and excludes species intolerant of them.
Types of Wetlands
Functions of wetlands
By absorbing the force of strong winds and tides,
wetlands protect terrestrial areas adjoining them from storms, floods, and tidal damage. Fresh water marshes are often on river floodplains.
A temperate wetland in Britain, with shallow open water and reedbeds. Wetlands are often filled in to be used for everything from agriculture to
parking lots, in part because the economic value of wetlands has only been recognised recently: the shrimp and fish that breed in salt water marshes are generally harvested in
deeper water, for example. Wetlands support a wide variety of wildlife (bird, plants, fish, mammals etc) and therefore the
conservation of wetlands is of prime importance for the preservation of
many species of wildlife. In 1962, the idea of wetlands conservation was born with a "List of Wetlands of International
Importance". This was followed up in 1971 by the Ramsar Convention when conservationists from 23 countries met in the city of Ramsar, Iran on the shores of the Caspian Sea. There are now over 1,200 wetlands on the Ramsar
List.
See also
References
- Mitsch, William J., and James G. Gosselink, (1986). Wetlands, New York: Van Nostrand Reinhold, 1986, p. 539.
External links
|