Hamdallah Zedan, executive secretary of the UN's Convention on Biological Diversity (CBD), said the amplified toll from the December 26 calamity -- more than 227,000 dead -- was due in part to the destruction of natural buffers against killer waves.

"Once the immediate humanitarian needs are accommodated, it is time to rehabilite impacted ecosystems and to look at lessons learned," said Zedan.

"Early reports indicate that areas with healthier ecosystems, such as dense, intact mangrove forests and coral reefs, have been less affected than areas that have been disturbed or degraded," he said.

"We have to use this knowledge in the reconstruction," said Klaus Toepfer, executive director of the UN Environment Programme (UNEP). "When we strip away these natural forms of protection, we place ourselves in harm's way."

The conference, taking place at the headquarters of the UN Educational, Scientific and Cultural Organisation (UNESCO), gathers 1,200 experts from some 30 countries.

Their task is to focus on action on combating the planet's alarming loss of biodiversity, as wild species are battered by habitat loss and climate change.

The graphic opinion of some scientists is that the world is facing its biggest mass extinction in 65 million years, when the dinosaurs were wiped out by climate change inflicted by an asteroid impact.

French President Jacques Chirac, who proposed the forum at the G8 summit in Evian, France, in June 2003, cited figures from the World Conservation Union (IUCN), which estimates that nearly 16,000 of identified species are close to being wiped out.

"The destruction of this heritage, bequeathed by thousands of years of evolution, is a terrible loss and a grave threat for the future," he said.

Chirac threw his weight behind a proposal for setting up a world panel of biodiversity experts, who would deliver neutral, informed and timely advice on species loss.

France will push the idea at the CBD, the treaty set up under the 1992 Earth Summit in Rio, Chirac pledged.

A similar scientific panel for climate change exists under UN auspices, and its findings have helped shaped the political agenda for reducing greenhouse gases blamed for global warming.

Of the estimated 10-30 million species on Earth, only around 1.7 million have been identified and described. Each year, between 25,000 and 50,000 species die out, the vast majority of which have not even been identified, according to scientists' estimates.

The loss is likely to accelerate this century under the impact of habitat loss and rising global temperatures, stoked by fossil-fuel gases which trap the Sun's heat.

As with so many problems involving the environment, resolving the biodiversity crisis will not be simple, for it raises questions that are tangled, not separate.

Population pressure and poverty are often interlinked with deforestation, overfishing, pollution and other perils to habitat.

The 2003 Nobel Peace Prize laureate, Wangari Maathai, who is also Kenya's deputy minister for the environment, said it was senseless to ignore the connection between the environment and poverty.

Malaysian Prime Minister Abdullah Ahmad Badawi said the tsunami provided an "opportunity to take a hard look at what we are doing to protect the environment.

"The tsunami and its aftermath underscored not only the overwhelming power of nature, but also the fragility of our own existence."

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