Evidence of global extinction crisis builds.* Evidence of global extinction crisis builds: On September 28, 2000, the World Conservation Union (IUCN IUCN
International Union for the Conservation of Nature and Natural Resources. ) released an update of its Red List of Threatened Species, further documenting the acceleration of biodiversity biodiversity: see biological diversity.
Quantity of plant and animal species found in a given environment. Sometimes habitat diversity (the variety of places where organisms live) and genetic diversity (the variety of traits expressed 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 Birds, The
Hitchcock film in which birds turn on the human race and terrorize a town. [Am. Cinema: Halliwell, 51]
See : Birds 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 long·line
A heavy fishing line usually several miles long and having a series of baited hooks.
long 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 amphibian, in zoology
amphibian, in zoology, cold-blooded vertebrate animal of the class Amphibia. There are three living orders of amphibians: the frogs and toads (order Anura, or Salientia), the salamanders and newts (order Urodela, or Caudata), and the 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 reptiles
terrestrial or aquatic vertebrates which breathe air through lungs and have a skin covering of horny scales. They are poikilothermic, oviparous or ovoviviparous, and, if they have legs they are short and constructed solely for crawling. , 20 percent of amphibians amphibians
members of the animal class Amphibia. Includes frogs, toads, newts, salamanders and cecilians all capable of living on land or in water. , 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 Southeast Asia, region of Asia (1990 est. pop. 442,500,000), c.1,740,000 sq mi (4,506,600 sq km), bounded roughly by the Indian subcontinent on the west, China on the north, and the Pacific Ocean on the east. . 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 Plants and Animals are a Canadian indie-rock band from Montreal, comprised of guitarist-vocalists Warren Spicer and Nic Basque, and drummer-vocalist Matthew Woodley. They are signed to Secret City Records. . 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
Invasive species is a phrase with many definitions. The first definition expresses the phrase in terms of non-indigenous species (e.g. , natural disasters, and pollution.
For the first time, the IUCN Red List The IUCN Red List of Threatened Species (also known as the IUCN Red List or Red Data List), created in 1963, is the world's most comprehensive inventory of the global conservation status of plant and animal species. has been released on CD-ROM CD-ROM: see compact disc.
in full compact disc read-only memory
Type of computer storage medium that is read optically (e.g., by a laser). and is searchable on the web at www.redlist.org.