The Azimuth Project
Wetland (Rev #3)


A wetland is an ecosystem type that arises when inundation by water produces soils that are dominated by anaerobic processes, and the plant life is forced to adapt to standing water. Wetlands may be the most biologically diverse of all ecosystems. Wetlands provide ecosystem services such as flood control and the cleaning of water pollution. However, many wetlands have been eliminated either by large-scale draining efforts for real estate development, or flooding for use as recreational lakes. By 1993 half the world’s wetlands had been drained.

A simple classification includes six basic kinds of wetlands:

  • Swamp - a wetland that is dominated by trees that are rooted in soils, but not in peat. Examples include tropical mangrove swamps (mangal) of Bangladesh and bottomland forests in floodplains of the Mississippi river valleys.

  • Marsh - a wetland that is dominated by herbaceous plants that usually emerge through water and rooted in hydric soils, but not in peat.

  • Bog - a wetland dominated by Sphagnum moss, sedges, ericaceous shrubs or evergreen trees rooted in deep peat with a pH less than 5.

  • Fen - a wetland that is usually dominated by sedges and grasses rooted in shallow peat, often with considerable groundwater movement, and with pH greater than 6.

  • Wet meadow - A wetland dominated by herbaceous plants rooted in occasionally flooded soils.

  • Shallow water - A wetland community dominated by truly aquatic plants growing in at least 25 centimeters of water.


An excellent reference is:

  • Paul A. Keddy, Wetland Ecology: Principles and Conservation, second edition, Cambridge U. Press, Cambridge, 2000.

Online, one can start with:

See also Peatland.

category: ecology