Mangroves uses


The next generation of mangroves exposed at low tide.

The uses of mangroves falls into two categories, firstly the use of the mangrove ecosystem as a whole or its conversion to other uses, and secondly, the use of products from the mangrove ecosystem.

Ecologically mangroves are important in maintaining and building the soil, as a reservoir in the tertiary assimilation of waste, and in the global cycle of carbon dioxide, nitrogen, and sulfur. The protection against: cyclones is a "free" benefit. Yet hidden benefits from mangroves, specially in marginal areas, may even be more important than the obvious ones. They play a significant role in coastal stabilization and promoting land accretion, fixation of mud banks, dissipation of winds, tidal and wave energy.


They play a significant role in coastal stabilization and promoting land accretion, fixation of mud banks, dissipation of winds, tidal and wave energy


Transplanting saltmarsh vegetation is an alternative erosion control method which is relatively inexpensive and proven to be effective on some shorelines. The aerial plant parts dissipate waves, act as a living groyne by accumulating sediment and the tough mat of roots and rhizomes stabilizes the substrate (Broom et al., 1981). They trap sediments and thus contribute to land building and prevent excessive shifting of coastline sand. A relatively recent commercial use of recreation and ecotourism.

The uses of mangroves are many and varied. A fundamental function of all forests has been to supply timber for cooking, heating and constructing dwellings, and mangrove forests are no exception (Watson, 1929; FAO, 1982). Traditionally, people have used mangroves for the benefit of the local community, but increasing populations have led to an increasing non-sustainable abuse of the resources.


Traditionally, people have used mangroves for the benefit of the local community, but increasing populations have led to an increasing non-sustainable abuse of the resources


Mangroves have been exploited for timber for building dwellings and boats and fuel-wood for cooking and heating. Palm species are used, especially in Southeast Asia and Brazil, to construct jetties and other submerged structures because they are resistant to rot and to attack by fungi and borers.Rhizophoraand, to a lesser extent,Avicenniawoods have a high calorific value and are excellent fuels for the boilers of trains in Pakistan. In Indonesia, commercial exploitation of mangroves for charcoal is reported from 1887. In Central America, the direct use for charcoal production and the extraction of tannin has been responsible for large-scale mangrove removal and degradation. Large-scale conversion of mangroves for wood chip production began in East Malaysia and Indonesia during the 1970s. Mangrove wood chips are still a major export from Kalimantan.


Mangroves are used in flavouring agents, textiles, mats, paper, housing, baskets, boats and tapa cloth and also used as staple food


 

In Malaysia, where mangroves occur in profusion, an important cottage industry is the manufacture of shingles for roof thatching from the fronds of Nypa fruticans. Basketry, corks and floats are obtained from the pneumatophores. Rhizophora apiculata has been exported from the Philippines to various parts of the world for utilization in the textile industry and extracts of stilt roots exhibited mosquito larvicidal activity. In Sri Lanka, Cerebera manghas is used in making masks for many traditional cultural activities. Pulp for paper, matchsticks, household utensils, agricultural implements and toys are some other products produced from mangroves. In Japan, propagules of Rhizophora and Bruguiera are planted in pots and make good decorations when germinated.

The tender leaves of Acrostichum, the hypocotyls of Bruguiera, are the staple food of some Papua New Guineans. Leaves of Osbornia octodonata are flavouring agents. Fibres, mats, paper and tapa cloth are products of Hibiscus tiliaceus, Thespesia populnea and Pandanus spp.

A local industry in the Sundarbans of Bangladesh and India is the production of honey and, in Bangladesh, a large number of people including wood and thatch cutters, honey and wax collectors and fishermen are directly dependent on the mangroves. Fruits of Avicennia marina are universally used as vegetables. The fruits of Kandelia candel and Bruguiera gymnorrhiza contain starch and if sliced, soaked in water to rinse out tannins and then ground to a paste can make excellent cakes or sweetened stuffing for pastry.

A scene depicting many traditional uses of mangroves.

"Sagu" is taken from the mangrove palm treeMetroxylon sagufound in Southeast Asia where the hypocotyts ofBruguieraare also an accepted food item. Intoxicating drinks are made from the sap of the "coconut" ofNypaandBorassus.The commonNypaplant, in addition to sugar, provides a diversity of products, including thatch from the leaves and alcohol and vinegar obtained by distillation of the fermented sugary phloem sap. Cooking oil and cigarette wrappers are also products obtained from many species of mangroves. Extracts of the heartwood ofAvicennia albaandA. officinalishave tonic properties. It is reported that some mangrove plants and extracts are used as incense, perfumes, hair preservatives, condiments and aphrodisiacs. Edible jelly and a kind of salt are made from the ashed leaflets.

Among the coastal lagoons along the west coast of Africa, the villagers produce salt by using a technique of boiling brackish water placed in a clay bowl over a fire made from Avicennia. On the west coast of Sri Lanka twigs and branches, mainly of Rhizophora mucronata, R. apiculata and Lumnitzera racemosa, are used to form "brush piles" or "brush parks" in a specially devised fishing method. The gathering of mangrove leaves (e.g. Suaeda and Porteresia) for animal fodder remains widespread in the Near East and South Asia, and for feeding camels in Iran and India.


The indigenous people of Australia and Sri Lanka use extracts from mangrove plants as valuable sources of dyes


 

The importance of bark tannins has declined in many Asian countries, but mangrove tannin is still used in India and Bangladesh for leather curing and in Sri Lanka tannin is used traditionally in curing fishnets. The tannins comprise two groups of phenolic constituents, hydrolysable and condensed, which are important economically as agents for the synthesis of certain medicines.

Their potential value as cytotoxic and/or antineoplastic agents and as antimicrobial agents has been demonstrated.


The exploitation and value of aquatic products from mangrove ecosystems is of great significance today


 

Mangrove plants are rich sources of saponins, alkaloids and flavonoids. Plant saponins have been shown to have interesting biological activities such as spermicidal and molluscicidal activity.

The extraction of natural chemical compounds, in addition to those already known to the pharmacopoeia of the people, continues to this day and among the latest additions are an array of substances from glues to alkaloids and saponins and many other substances of interest to modern industry and medicine.

An alternative source of wealth in the mangroves is the exploitation of the fish, molluscs and crustaceans that abound in the mangrove areas. In Vietnam, farmers complement their income by collecting and sorting shells from the mangrove mud flats. The exploitation and value of aquatic products from mangrove ecosystems is of great significance today.


A relatively recent commercial use of mangroves is for recreation and ecotourism


 

Use of mangroves as natural sewage-treatment plants has been considered. Mangroves trap sediments and so contribute to land building, preventing erosion and excessive shifting of coastlines.

A relatively recent commercial use of mangroves is for recreation and ecotourism. In Australia, mangrove habitats play a significant role in programs of conservation, recreation and researching methods of establishing nature reserves, sanctuaries, national parks and biosphere reserves.

A non-governmental organization, the International Society for Mangrove Ecosystem (ISME), which was established in 1990, aims to promote the study of mangroves with the purpose of enhancing their conservation, rational management and sustainable utilization.