A fifth of the world’s known mammals, a third of amphibians and reptiles and more than two thirds of plants are threatened with extinction, according to the latest “Red List” of endangered species.

Of the 5,490 mammal species that have been identified by scientists, 79 are extinct or extinct in the wild, 188 are critically endangered, 449 are endangered and 505 are classed as vulnerable, the International Union for the Conservation of Nature (IUCN) said.

The annual Red List, published yesterday, also shows that 70 per cent of identified planets, 35 per cent of invertebrates, 37 per cent of freshwater fish, 30 per cent of amphibians, 28 per cent of reptiles and 12 per cent of birds are under threat. The survival of a total of 17,921 species is in jeopardy.

“This year’s IUCN Red List makes for sobering reading,” Craig Hilton-Taylor, manager of the IUCN Red List Unit, said. “These results are just the tip of the iceberg. We have only managed to assess 47,663 species so far; there are many more millions out there which could be under serious threat.

“We do, however, know from experience that conservation action works so let’s not wait until it’s too late and start saving our species now.”

New additions to the register include the eastern voalavo, a mountain rodent from the tropical forests of Madagascar,which is endangered because of the threat from slash-and-burn farming.

Two hundred and ninety-three reptiles have been added to the list this year, including 165 species from the Philippines alone. These include the Panay monitor lizard, which is endangered because of habitat loss caused by agriculture and logging, and people hunting it for food.

The sail-fin water lizard, another species from the Philippines, is listed as vulnerable because of habitat loss and the collection of hatchlings for the pet trade and food.

Among amphibians, the Kihansi spray toad, found near the Kihansi Falls in Tanzania, has been moved from the critically endangered category to be declared extinct in the wild.

The construction of a dam upstream of the Kihansi Falls has cut off 90 per cent of water flow to the gorge where the toad lives and it has also been affected by chytridiomycosis, a fungal disease that has wiped out or threatened many amphibian species worldwide.

Chytridiomycosis has also contributed to the plight of Rabb’s fringe-limbed treefrog, from central Panama. The fungus was reported to be present in its habitat in 2006, and only a single male has been heard calling since then. Though some individuals survive in the wild, breeding programmes have so far failed.

The tally of 2,639 threatened invertebrates includes 1,360 newly added damselflies and dragonflies, such as the giant jewel dragonfly of southeast Nigeria and southwest Cameroon, which is classed as vulnerable because of forest destruction.

Jane Smart, director of the IUCN’s Biodiversity Conservation Group, said: “The scientific evidence of a serious extinction crisis is mounting. January sees the launch of the International Year of Biodiversity. The latest analysis of the IUCN Red List shows the 2010 target to reduce biodiversity loss will not be met.

“It’s time for governments to start getting serious about saving species and make sure it’s high on their agendas for next year, as we’re rapidly running out of time.”

Times recommends

• Energy-saving ideas from switched-on professor
• Rooks are as clever with tools as chimpanzees
• Burping of the lambs blows roast off menu