Half of all mammal species are in decline, and 25% of them are endangered. More than one-fifth of all reptile species are at risk of extinction. And 1,983 amphibian species are either threatened or extinct.

All told, the 2008 Red List of Endangered Species, released today by the IUCN, paints a pretty bleak picture of the world's biodiversity. According to its data, at least 38% of the world's assessed species are currently threatened with extinction.

The new Red List update took five years and 1,700 researchers to complete. It contains data on more than 45,000 species -- just a fraction of the estimated 1.64 million species on Earth, but still the best list and best total research available anywhere. Even with all of this research, only 25,000 of the Red List species are fully documented and at least 4,800 are still data-deficient.

Sadly, some areas of the world with the greatest levels of biodiversity also have the greatest numbers of species at risk:

  • Madagascar: 636 species at risk
  • Tanzania: 589 species at risk
  • China: 816 species at risk
  • Indonesia: 1,087 species at risk
  • Malaysia: 1,141 species at risk
  • Philippines: 641 species at risk
  • Mexico: 897 species at risk
  • United States: 1,192 species at risk
  • Ecuador: 2,208 species at risk
  • Australia: 788 at risk

Habitat loss remains the greatest factor putting so many species at risk of extinction.

Story by John Platt. This article originally appeared in "Plenty" in October 2008.

Copyright Environ Press 2008

Red List of Endangered Species: 'Bleak'
An astonishing percentage of the world's species face the threat of extinction.