May 8, 2008

Loss of Mangrove Forests Increased Cyclone Damage

ASEAN secretary-general Surin Pitsuwan said Burma's coastal areas were left exposed to last weekend's catastrophic cyclone as a result of destruction of the country's mangrove forests.  

Officials say at least 100,000 people perished in the catastrophe.

Both the large numbers of people living in coastal areas and the loss of mangroves had contributed to the tragedy, Pitsuwan said while speaking at a high-level ASEAN (Association of South-East Asian Nations) meeting in Singapore.

"Encroachment into mangrove forests, which used to serve as a buffer between the rising tide, between big waves and storms and residential areas; all those lands have been destroyed," he said, according to an AFP news agency report.

"Human beings are now direct victims of such natural forces."

Pitsuwan made his comments after a news conference by Maung Maung Swe, Burma's minister for relief and resettlement, who said the cyclone's storm surge had caused more deaths than the 120mph (190km/h) winds.

"The wave was up to 12ft (3.5m) high and it swept away and inundated half the houses in low-lying villages," he said. "They did not have anywhere to flee."

Mangroves have been long been known to act as "bio-guards" for coastal developments.  A study published in late 2005 of the Asian tsunami that claimed the lives of more than 200,000 found that healthy mangrove forests helped save the lives of Sri Lankan villagers.

Scientists from IUCN, formerly known as the World Conservation Union, compared the death toll from two villages in Sri Lanka that were hit by the giant waves.  The researchers found that only two people died in the settlement with dense mangrove and scrub forest, whereas 6,000 people were killed in a nearby village without similar vegetation.

"Mangroves are a very dense vegetation type that grows along the shore," Jeffrey McNeely, chief scientist for IUCN, told BBC News.

"Where the saltwater and freshwater meet, that is where the mangroves grow; they often extend from several hundred meters to a few kilometers inland.

"Especially in river deltas, mangroves prevent waves from damaging the more productive land that are further inland from the sea."

A recent review of the world's mangrove forests by the UN Food and Agriculture Organization (FAO) determined that 3.6 million hectares had disappeared since 1980. The study said the greatest destruction had occurred in Asia, with 1.9 million hectares having been lost, primarily due to land use change such as the large-scale conversion of mangroves into shrimp and fish farms.

Other pressures included new development to accommodate the growth in the tourism and increasing populations.

Mette Wilkie, a senior forestry officer for the FAO, told BBC News most of Burma's mangroves had suffered as a result of being overexploited.

"There are very limited areas that you would describe as pristine or densely covered mangrove in the Irrawaddy area," she said, referring to the area where Cyclone Nagris made initial landfall.

"There are some efforts in place to try to rehabilitate and replant mangroves, but we do know that the loss rate is quite substantial still.

"During the 1990s, they lost something like 2,000 hectares each year, which is about 0.3% being lost annually.

"But that does not give you the whole picture because the majority of these tidal habitats are being degraded, even if they are not being completely destroyed."

From a global perspective, however, the situation looks better. The FAO study found that the annual rate of destruction had slowed from 187,000 hectares during the 1980s to 102,000 hectares during the early 2000s.

And some areas, such as Bangladesh, actually experienced an increase in mangrove forests, the report said, due to the county's recognition of the role the mangroves play in reducing damage caused by extreme weather events.  

"This has been allowed to grow, or in part at least, because Bangladesh was really hammered by a typhoon that killed something like 300,000 people a couple of decades ago," Dr McNeely said, referring to the Sundarbans, 100,000 hectares of mangrove forest habitat located in the delta of the Ganges and Brahmaputra rivers.  

"They realized that if they did not have that mangrove buffer, another typhoon heading up the Bay of Bengal would cause even worse damage because the population is even more dense than it was then."


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