mangrove(redirected from Mangroves)
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mangrove,large tropical evergreen tree, genus Rhizophora, that grows on muddy tidal flats and along protected ocean shorelines. Mangroves are most abundant in tropical Asia, Africa, and the islands of the SW Pacific. The American, or red, mangrove (Rhizophora mangle) is found along the muddy shores and in the everglades of the Florida peninsula and on other tropical American coast lines.
Many mangroves produce from their trunks aerial roots that become embedded in the mud and form a tangled network; this serves both as a prop for the tree and as a means of aerating the root system. Such roots also form a base for the deposit of silt and other material carried by the tides, and thus land is built up which is gradually invaded by other vegetation. Mangrove forests also can protect inland coastal areas by absorbing the effects of storm and some tsunami waves, but mangroves have been harvested destructively on a large scale in some areas, and their forests replaced in many cases by rice paddies, aquaculture facilities, and oil palm plantations. The bark is a rich source of tannins, and the wood is used for wharf pilings and other purposes.
Some mangrove species lack prop roots but have special pores on their branching root system for obtaining air. The mangrove fruit is a conical reddish brown berry. Its single seed germinates inside the fruit while it is still on the tree, forming a large, pointed primary root that quickly anchors the seedling in the mud when the fruit is dropped.
The name mangrove is also applied to other unrelated constituents of mangrove vegetation, such as Avicennia nitida, a bush of the vervain family, called black mangrove. True mangroves are classified in the division MagnoliophytaMagnoliophyta
, division of the plant kingdom consisting of those organisms commonly called the flowering plants, or angiosperms. The angiosperms have leaves, stems, and roots, and vascular, or conducting, tissue (xylem and phloem).
..... Click the link for more information. , class Magnoliopsida, order Rhizophorales, family Rhizophoraceae.
See P. B. Tomlinson, The Botany of Mangroves (1986).
A taxonomically diverse assemblage of trees and shrubs that form the dominant plant communities in tidal, saline wetlands along sheltered tropical and subtropical coasts. The development and composition of mangrove communities depend largely on temperature, soil type and salinity, duration and frequency of inundation, accretion of silt, tidal and wave energy, and cyclone or flood frequencies. Extensive mangrove communities seem to correlate with areas in which the water temperature of the warmest month exceeds 75°F (24°C), and they are absent from waters that never exceed 75°F (24°C) during the year. Intertidal, sheltered, low-energy, muddy sediments are the most suitable habitats for mangrove communities, and under optimal conditions, forests up to 148 ft (45 m) in height can develop. Where less favorable conditions are found, mangrove communities may reach maturity at heights of only 3 ft (1 m). See Ecosystem
At the generic level, Avicennia and Rhizophora are the dominant plants of mangrove communities throughout the world, with each genus having several closely related species in both hemispheres. At the species level, however, only a few species, such as the portia tree (Thespesia populnea), the mangrove fern (Acrostichum aureum), and the swamp hibiscus (Hibiscus tiliaceus), occur in both hemispheres.
Most plants of the mangrove community are halophytes, well adapted to salt water and fluctuations of tide level. Many species show modified root structures such as stilt or prop roots, which offer support on the semiliquid or shifting sediments, whereas others have erect root structures (pneumatophores) that facilitate oxygen penetration to the roots in a hypoxic environment. Salt glands, which allow excess salt to be extruded through the leaves, occur in several species; others show a range of physiological mechanisms that either exclude salt from the plants or minimize the damage excess salts can cause by separating the salt from the sensitive enzyme systems of the plant. Several species have well-developed vivipary of their seeds, whereby the hypocotyl develops while the fruit is still attached to the tree. The seedlings are generally buoyant, able to float over long distances in the sea and rapidly establish themselves once stranded in a suitable habitat. See Plants, saline environments of
A mangrove may be considered either a sheltered, muddy, intertidal habitat or a forest community. The sediment surface of mangrove communities abounds with species that have marine affinities, including brightly colored fiddler crabs, mound-building mud lobsters, and a variety of mollusks and worms, as well as specialized gobiid fish (mudskippers). The waterways among the mangroves are important feeding and nursery areas for a variety of juvenile finfish as well as crustaceans. Animals with forest affinities that are associated with mangroves include snakes, lizards, deer, tigers, crab-eating monkeys, bats, and many species of birds.
Economically, mangroves are a major source of timber, poles, thatch, and fuel. The bark of some trees is used for tanning materials, whereas other species have food or medicinal value. See Ecological communities, Forest management