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 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".