Huge areas of mangrove have been lost, especially in southeast Asia and most parts of southern Africa, due to wood extraction, conversion to agriculture, (cash crops), coastal aquaculture and salt production, coastal industrialization and urbanization. Shrimp farming has caused large scale losses of mangrove habitats. In Papua New Guinea, Thailand and Malaysia the mangroves are destroyed for mining for tin and other minerals. Illegal dumping, beach re-nourishment, oil spill, agricultural run-off that contains herbicides, pesticides, and sugar cane wastes. Man-made canal systems alter fresh water run-off changing salinity levels and lowering the water table. Mangroves are destroyed as rivers are damned and their waters diverted. Fuelwood and charcoal production for domestic cooking and fish curing remains the most extensively used mangrove wood commodity.
Mangrove forests grow in the swampy, intertidal margin between sea and shore and are often considered part of the rain forest complex. The roots of mangrove trees help stabilize the shoreline and trap sediment and decaying vegetation that contribute to ecosystem productivity. Mangroves can be classified in to two broad categories: The old world mangroves occurring in the Indo-Pacific region extending from the east coast of Africa to Samoa in the South Pacific. The second group, the new world mangroves, occurs along the west coast of Africa between Mauritania and Angola, in the Americas on the east coast between Barbados and Brazil and on the west coast between Mexico and northern Peru. Plant species from true mangroves belong to at least 17 different families. About 80 species of true mangrove trees/shrubs are recognized. Species diversity is much higher in the southeast Asian region, where approximately two-thirds of all species are found while approximately 15 species occur in Africa and 10 in the Americas. Indonesia has the largest total area of mangrove forest while the Sundarbans swamp region in Bangladesh and India is the largest single area of mangrove forest in the world.
Approximately one-fourth of the world's tropical coastline is dominated by mangroves and they extend over 15.5 million ha world-wide. Indo-Pacific – 6.9m ha; Americas – 4.1m ha; Africa =–3.5m ha.
Hurricane Donna, in 1960, damaged an area of 100,000 acres of the Mangrove zone of South Florida. 60 percent of shallow water open mangroves in the Upper Keys, Florida were lost between 1965 and 1985. 40 percent of that was due to dredging and filling of Mangroves. A total of 430,000 - 500,000 acres of mangrove were lost during this period in all of Florida.
In most areas of the world, mangrove formations have simply been exploited with little or no attempt to manage the resource on a sustainable basis. The development of aquaculture represents a major threat to mangrove ecosystems.