The world has lost 20 percent of its wetland mangrove forests since 1980 according to a United Nations report. Mangroves are salttolerant evergreen forests found along coastlines, lagoons, rivers or deltas in 124 tropical and subtropical countries and areas.

Environmental and economic damages caused by the "alarming" loss of mangroves in many countries should be urgently addressed, said the UN Food and Agriculture Organization (FAO), calling for better mangrove protection and management programs.

"Mangroves are important forested wetlands," said Wulf Killmann, director of FAO’s Forest Products and Industry Division. "If deforestation of mangroves continues, it can lead to severe losses of biodiversity and livelihoods, in addition to salt intrusion in coastal areas and siltation of coral reefs, ports and shipping lanes. Tourism would also suffer."

"Countries need to engage in a more effective conservation and sustainable management of the world’s mangroves and other wetland ecosystems," Killmann said.

Mangrove ecosystems serve to protect coastal areas against erosion, cyclones and wind. They provide wood, food, fodder, medicine and honey. They are also habitats for many animals like crocodiles and snakes, tigers, deer, otters, dolphins and birds. Many fish and shellfish species also depend on these coastal forests and mangroves help to protect coral reefs against siltation from upland erosion.

Indonesia, Australia, Brazil, Nigeria and Mexico together account for around 50 percent of the total global mangrove area. Most countries have now banned the conversion of mangroves for aquaculture and they assess the impact on the environment before using mangrove areas for other purposes.

"This has led to better protection and management of mangroves in some countries," Killmann said. "But overall, the loss of these coastal forests remains alarming. The rate of mangrove loss is significantly higher than the loss of any other types of forests."

The world has lost around 3.6 million hectares of mangroves since 1980, equivalent to a 20 percent loss of total mangrove area, according to FAO’s recent mangrove assessment study, entitled, "The world’s mangroves 1980-2005."

The total mangrove area has declined from 18.8 million hectares in 1980 to 15.2 million hectares in 2005, according to the report. Since 2000, there has been a slowdown in the rate of mangrove loss, the report shows, reflecting an increased awareness of the value of mangrove ecosystems.

"On a positive note, a number of countries have had an increase in mangrove area over time, including Bangladesh," said FAO Senior Forestry Officer Mette Wilkie. "Part of the largest mangrove area in the world, the Sundarbans Reserved Forest in Bangladesh, is well protected and no major changes in the extent of the area have occurred during the last few decades, although some damage to the mangroves was reported after the recent cyclone in 2007," she said.

"In Ecuador, the abandoning of ponds and structures for shrimp and salt production led to a rebuilding of various mangrove sites," she added.

The FAO report cited high population pressure, the large-scale conversion of mangrove areas for shrimp and fish farming, agriculture, infrastructure and tourism, as well as pollution and natural disasters as the major causes for the destruction of mangroves.

The assessment of the world’s mangroves was prepared in collaboration with mangrove specialists throughout the world and was co-funded by the International Tropical Timber Organization (ITTO). FAO and ITTO are currently working with the nonprofit International Society for Mangrove Ecosystems and other partner organizations to produce a World Atlas of Mangroves to be published later this year.

The atlas will give GIS-based distribution maps and describe recent status of mangrove forests around the world, with detailed estimates of changes in mangrove forests worldwide and at regional and national levels. (Wildlife Extra)