Evidence of global extinction crisis builds.

* Evidence of global extinction crisis builds: On September 28, 2000, the World Conservation Union (IUCN) released an update of its Red List of Threatened Species, further documenting the acceleration of biodiversity loss. The 2000 survey found that close to one in four of the world's mammal species and one in eight of the world's bird species are threatened with extinction. There have been at least 103 documented cases of bird species going extinct in the last two centuries. These are a fraction of the numbers of all species that many scientists estimate have actually disappeared--at rates from 100 to 1,000 times the "natural" extinction rate.

The new report's most significant contribution is its comprehensive assessment of mammals and birds. The update lists 24 percent of the world's mammal species as threatened; for birds, the figure is 12 percent. These figures have risen only slightly since the 1996 Red List, but for many groups the situation has become increasingly dire. The number of threatened primates, for example, rose from 96 to 116. The IUCN recognizes three levels of threat: "vulnerable" (facing a high risk of extinction in the wild over the medium term), "endangered" (very high risk over the short term), and "critically endangered" (extremely high immediate risk). Since 1996, many threatened primate species have moved to the next category of decline. For example, 6 moved into the critically endangered category, bringing the number of primates in this category to 19. The number of primates listed as endangered jumped from 29 to 46. The principal threats appear to be habitat loss and hunting.

For birds, the most significant changes were observed in groups known as Procellariformes (albatrosses and petrels) and Sphenisciformes (penguins). All 16 species of albatross are now threatened--compared to 3 in 1996. Longline fishing is the primary threat to these birds. The number of threatened penguin species rose from 5 to 10--out of a total of 18 species of penguins.

Indonesia, India, Brazil, and China ranked highest in the total number of threatened mammal species, while Indonesia, Brazil, Colombia, and China ranked highest in the number of threatened birds.

The picture for other classes of animals is less certain, as they have received less attention. Fewer than 15 percent of all reptile and amphibian species were evaluated, along with fewer than 10 percent of fish species, and even smaller percentages of insects, crustaceans, and other invertebrates. Of the species assessed, 25 percent of reptiles, 20 percent of amphibians, and 30 percent of fish are threatened. One of the most notable changes since 1996 was new evidence for the rapid deterioration of species in the order Testudines (turtles, terrapins, and tortoises), especially freshwater turtles in Southeast Asia. Unsustainable and unregulated exploitation for food and medicine was cited as the primary force behind the decline of these species.

With its strong focus on vertebrates, the 2000 Red List provides just a glimpse of the true state of the world's biodiversity. About 95 percent of all known animal species are invertebrates and only a tiny fraction of these were reviewed.

Unlike previous reports, the 2000 Red List combines assessments for both plants and animals. As with other groups, the assessment of the world's plant species is far from complete--only 4 percent of the world's 266,000 known plant species were evaluated in the report. The IUCN published a Red List of Threatened Plants in 1997 that was more comprehensive (see January/February 1997 issue), but the group is reworking the categories and criteria used for the assessment of plants to make them consistent with those used for animals. Conifers were the best-studied group (nearly three-quarters of these species were reviewed) and 22 percent of the species evaluated were categorized as threatened.

The report finds that the most pervasive and dominant threat to birds, mammals, and plants is habitat loss and degradation. Habitat loss is primarily caused by agricultural activities such as crop and livestock farming and timber plantations; extraction activities such as mining, fisheries, and logging; and various forms of development such as buildings, roads, and dams. More than a third of threatened plants and mammals are threatened by direct loss and exploitation, which includes hunting, collecting, and trade. Other threats highlighted in the report include invasive species, natural disasters, and pollution.

For the first time, the IUCN Red List has been released on CD-ROM and is searchable on the web at www.redlist.org.