A fifth of the world's mammals, birds, amphibians, reptiles and fishes are in imminent danger of going extinct, says this year's edition of the benchmark IUCN Red List. The percentages of threatened invertebrates and plants are similar.
Releasing the findings at the October 18-29 UN biodiversity summit, being attended by 192 countries, here on Wednesday, Simon Stuart, chair of the Species Survival Commission of the International Union for Conservation of Nature (IUCN), said their findings on vertebrates showed that "nature's backbone is at risk".
Around 3,000 scientists from around the world have worked to put this Red List together. They have found that 25 per cent of all mammals, 13 per cent birds, 41 per cent amphibians, 22 per cent reptiles and 15 per cent fishes risk extinction, mostly due to loss of their habitats and some due to overhunting.
A recent study by the Kew Botanical Gardens had found that around six million species - 20 percent of all plants and invertebrates - face the extinction threat too.
But it's not all bad news. IUCN has found 64 species that have improved their status in the Red List, moving from the critically endangered to the endangered category, for example. Stuart said all these were in areas that had been protected, "proving the importance of conservation". Results show that the status of biodiversity would have declined by at least an additional 20 per cent if conservation action had not been taken.
The successes include three species that were extinct in the wild and have since been re-introduced back to nature: the California condor and the black-footed ferret in the US, and Przewalski's horse in Mongolia.
Conservation efforts have been particularly successful at combating invasive alien species on islands. The global population of Seychelles Magpie-robin, increased from fewer than 15 birds in 1965 to 180 in 2006 through control of introduced predators, like the brown rat.
In Mauritius, six bird species have undergone recoveries in status, including the Mauritius kestrel, whose population has increased from just four birds in 1974 to nearly 1,000.
But very few amphibians - the most threatened vertebrates - have shown signs of recovery.
This year's study used data for 25,000 species from the IUCN Red List of Threatened Species, to investigate the status of the world's vertebrates (mammals, birds, amphibians, reptiles and fishes) and how this status has changed over time. The results show that, on average, 50 species of mammal, bird and amphibian move closer to extinction each year due to the impacts of agricultural expansion, logging, over-exploitation, and invasive alien species.
"The 'backbone' of biodiversity is being eroded," said the doyen of ecologists, Edward O. Wilson,of Harvard University. "One small step up the Red List is one giant leap forward towards extinction. This is just a small window on the global losses currently taking place."
Southeast Asia has experienced the most dramatic recent losses, largely driven by the planting of export crops like oil palm, commercial hardwood timber operations, agricultural conversion to rice paddies and unsustainable hunting.
Recently, a UN-sponsored study called The Economics of Ecosystems and Biodiversity (TEEB) calculated the cost of losing nature at $2-5 trillion per year, predominantly in poorer parts of the world.
A recent study found one-fifth of more than 5,000 freshwater species in Africa are threatened, putting the livelihoods of millions of people dependent on these vital resources at risk.