Mangroves are various large and extensive types of trees (up to medium height) and shrubs that grow in saline coastal sediment habitats in the Tropics and Subtropics. Located mainly between latitudes 25°N and 25°S. Remaining mangrove forest areas of the world was estimated around 137,760 km² in 2000, and declining since then. Found in 118 countries and territories.
Mangroves frequently perceived at three different meanings: [a]most broadly to refer to the habitat, i.e. mangrove forest biome, mangrove swamp and mangrove forest; [b] to refer to all trees and large shrubs in the mangrove swamp; and [c] narrowly to refer to the mangrove within the family of Rhizophoraceae, or even more specifically just to trees of the genus Rhizophora.
Mangrove trees are salt tolerant (halophytes), adapted to live in harsh coastal conditions, characterized by: [a] A complex salt filtration system to cope with salt water immersion; [b] A complex root system to withstand wave action; and [c] Adaptable to the low oxygen (anoxic) conditions of waterlogged mud. About 110 species are considered ‘mangroves’, in the sense of being a tree that grows in such a saline swamp, though only a few are from the mangrove plant genus, Rhizophora.
A given mangrove swamp typically features only a small number of tree species. It is not uncommon for a mangrove forest to feature only three or four tree species.
The mangrove biome, or mangal, is a habitat characterized by depositional coastal environments, where fine sediments were accumulated in areas protected from high-energy wave action. The saline conditions tolerated by various mangrove species range from brackish water, through pure seawater (3.0 to 4.0%), to water concentrated by evaporation to over twice the salinity of ocean seawater (up to 9.0 %). The high salinity creates major limitations to number of species able to thrive in this habitat.
Complete slides on this topic can be downloaded here: Landscape Ecology 09-10