Mark Kinver Science and nature reporter, BBC News
July 2008
"Mangroves are a very dense vegetation type that grows
along the shore," explained Jeffrey McNeely, chief scientist for IUCN.
"Where the saltwater and freshwater meet, that is where the mangroves grow;
they often extend from several hundred metres to a few kilometers inland.
Mangrove loss 'put Burma at risk'
Destruction of mangrove forests in Burma left coastal areas exposed to
the devastating force of the weekend's cyclone, a top politician suggests.
ASEAN secretary-general Surin Pitsuwan said coastal developments had
resulted in mangroves, which act as a natural defence against storms, being
lost.
At least 22,000 people have died in the disaster, say state officials.
A study of the 2004 Asian tsunami found that areas near healthy mangroves
suffered less damage and fewer deaths.
Mr Surin, speaking at a high-level meeting of the Association of South-East
Asian Nations (ASEAN) in Singapore, said the combination of more people
living in coastal areas and the loss of mangroves had exacerbated the
tragedy.
MANGROVES - NATURAL DEFENSES
Mangroves are salt-tolerant evergreens that grow along coastlines, rivers
and deltas
"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," the AFP news agency reported him as
saying.
"Human beings are now direct victims of such natural forces."
His comments follow a news conference by Burma's minister for relief and
resettlement, Maung Maung Swe, who said more deaths were caused by the
cyclone's storm surge rather than the winds which reached 190km/h (120mph).
"The wave was up to 12ft (3.5m) high and it swept away and inundated half
the houses in low-lying villages," the minister said. "They did not have
anywhere to flee."
Storm shelter
Mangroves have been long considered as "bio-guards" for coastal settlements.
A study published in December 2005 said healthy mangrove forests helped save
Sri Lankan villagers during the Asian tsunami disaster, which claimed the
lives of more than 200,000 people.
Researchers from IUCN, formerly known as the World Conservation Union,
compared the death toll from two villages in Sri Lanka that were hit by the
devastating giant waves.
Monk planting mangrove saplings outside a temple (Getty Images) The 2004
tsunami prompted a series of mangrove replanting projects
While two people died in the settlement with dense mangrove and scrub
forest, up to 6,000 people lost their lives in a nearby village without
similar vegetation.
"Mangroves are a very dense vegetation type that grows along the shore,"
explained Jeffrey McNeely, chief scientist for IUCN.
"Where the saltwater and freshwater meet, that is where the mangroves grow;
they often extend from several hundred metres 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."
Lowering defenses
A recent global assessment found that 3.6 million hectares of mangrove
forests had disappeared since 1980.
The study carried out by the UN Food and Agriculture Organization (FAO) said
that Asia had suffered the greatest loss, with 1.9 million hectares being
destroyed, primarily as a result of land use change.
Map showing location of Irrawaddy region in Burma (Image: BBC)
It found that large-scale conversion of mangroves into shrimp and fish farms
were among the main destructive drivers.
Other pressures included new development to accommodate the growth in the
tourism sector and rising populations.
Mette Wilkie, a senior forestry officer for the FAO, said most of the
mangroves in Burma 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 region
of Burma where Cyclone Nagris first made 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."
Growing awareness
However, the global picture is not entirely bleak. The FAO assessment showed
that the annual rate of destruction had slowed from 187,000 hectares during
the 1980s to 102,000 hectares during the early 2000s.
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