The world has lost around 3.6 million hectares (ha) of mangroves since 1980, equivalent to an alarming 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 ha in 1980 to 15.2 million ha in 2005, according to the report. There has, however, been a slowdown in the rate of mangrove loss: from some 187 000 ha destroyed annually in the 1980s to 102 000 ha a year between 2000 and 2005, reflecting an increased awareness of the value of mangrove ecosystems.
“Mangroves are important forested wetlands and 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,” said Wulf Killmann, Director of FAO’s Forest Products and Industry Division, on the occasion of World Wetlands Day (2 February 2008).
“This has lead to better protection and management of mangroves in some countries. 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. 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,” he added.
Asia suffered the largest net loss of mangroves since 1980, with more than 1.9 million ha destroyed, mainly due to changes in land use.
North and Central America and Africa also contributed significantly to the decrease in mangrove area, with losses of about 690 000 and 510 000 ha respectively over the last 25 years.
At the country level, Indonesia, Mexico, Pakistan, Papua New Guinea and Panama recorded the largest losses of mangroves during the 1980s. A total of some one million ha were lost in these five countries - a land area comparable to Jamaica. In the 1990s, Pakistan and Panama succeeded in reducing their rate of mangrove loss. Conversely, Viet Nam, Malaysia and Madagascar suffered increased clearing and moved into the top five countries with major area losses in the 1990s and 2000-2005.
FAO 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.
“On a positive note, a number of countries have had an increase in mangrove area over time, including Bangladesh,” said 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. In Ecuador, the abandoning of ponds and structures for shrimp and salt production led to a rebuilding of various mangrove sites,” she said.
Mangroves are salt-tolerant evergreen forests found along coastlines, lagoons, rivers or deltas in 124 tropical and subtropical countries and areas, protecting coastal areas against erosion, cyclones and wind.
Mangroves are important ecosystems providing wood, food, fodder, medicine and honey. They are also habitats for many animals like crocodiles and snakes, tigers, deer, otters, dolphins and birds. A wide range of fish and shellfish also depends 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.
The assessment of the world’s mangroves 1980-2005 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 International Society for Mangrove Ecosystems and other partner organizations to produce a World Atlas of Mangroves to be published later this year.