Distribution of Wetlands in the World

Wetlands are complex and sensitive ecosystems, characterized by a water table at or near the land surface for some part of the year, by soil conditions that differ from adjacent uplands, and by vegetation adapted to wet conditions. Wetlands are usually classified on the basis of their morphology and vegetation and, to a lesser extent, their hydrology. Though definitions vary, the following types are widely recognized: coastal salt and freshwater marshes; swamps (mangrove, shrub and wooded); wet grasslands, meadows and prairies; and peat lands (landforms in which organic sediments have accumulated to depths in excess of 30-50 cm, including mires, moors, muskeg, bogs and fens), including areas of marine water the depth of which at low tide does not exceed six meters.…