ENDANGERED SPECIES

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A History of Extinction Non-random Nature of Species Extinction  
- Animals in the Red (press release)    
-AMERICAN FISHERIES SOCIETY POLICY STATEMENT Protection of Marine Fish Stocks at Risk of Extinction - Pacific Biodiversity Institute  
-BIOLOGICAL DIVERSITY E. O. WILSON Frank B. Baird, Jr. ...CHAPTER 1 - Red List of Endangered Species  
-BIOLOGICAL RESOURCES - Scientists Warn of Mass Extinction  
-denali.com -Species Extinctions, Causes and Consequences  
- Endangeredpecies.com - The rarest endangered species information around    
-Extinction and Depletion from Over-Exploitation -Study of tropical forests overturns important theory in ecology  
-EARTH IN THE BALANCE, WORLD BOOK ENCYCLOPEDIA (classroom material) -Species 2000  
- Endangered Species Information Network -SPECIES: UNPRECEDENTED EXTINCTION RATE, AND IT'S INCREASING  
-ENDANGERED SPECIES - NOT US -The Folly of Human Ecology Article on factory farming  
- Extinctions, Past and Present (World Book) -THE ENDANGERED SPECIES PROGRAM  
-Grazing to Extinction - The Natinal Collection of Endangered Plants (USA)  
-HOW MANY SPECIES ARE THERE? -THREATENED ANIMALS OF THE WORLD  
-HUMAN IMPACT ON EXTINCTION -Threatened and Endangered Species in the National Park System  
JanAnimals - Excellently detailed    
Kootenai River Population of White Sturgeon - an example of U.S./Canada cooperation in the protection and recovery of an endangered species. -TURNING POINT  
-Mahogany Trees, Forests, Wood, Lumber, Plywood Near Extinction from Illegal Logging and Sales -US FISH AND WILDLIFE ENDANGERED SPECIES  
-Mass Extinction Underway Excellent Resource! Don't pass this one by. - World Species List - Endangered Species, US  
-MONITORING AND ASSESSING THREATS TO RARE AND ENDANGERED PLANTS, THEIR POLLINATORS AND HABITATS - World Species List - Endangered, expanded index  
  - Zoological Record  

BY THE NUMBERS

Threatened Mammals

For some time, many naturalists have felt that the world is entering a period of major species extinction, rivaling five other periods in the past half a billion years. A new study by the World Conservation Union (also known as the IUCN), issued in October 1996, provides strong support for this theory. Using more thorough study methods than previously, the IUCN finds a much higher level of threat to several classes of animals than was generally thought. It found that an astonishing 25 percent of mammal species-and comparable proportions of reptile, amphibian and fish species-are threatened. Of five classes of animals, birds are the least at risk [see bar chart ].

Of the 4,327 known mammal species, 1,096 are at risk, and 169 are in the highest category of "critically endangered"--extremely high risk of extinction in the wild in the immediate future. (The other two are "endangered," meaning very high risk in the near future, and "vulnerable," a high risk in the medium-term future.) Of the 26 orders of mammals, 24 are threatened. Among the most affected are elephants, primates and Perissodactyla species (such as rhinoceroses and tapirs).

Although the IUCN data probably understate the number of threatened mammal species in some regions, it is possible to draw conclusions about the pattern on the map, in particular, that habitat disturbance by humans increases the threat to mammals. Also important is a high proportion of endemic species, especially in the case of geographically isolated areas. Such regions have unique evolutionary histories and fixed boundaries to species ranges, and thus, degradation of such habitats is more likely to take a toll on animals. Striking examples are the Philippines and Madagascar, where 32 and 44 percent, respectively, of all mammal species are threatened. In both countries, well over half the species are endemic, and habitat disturbance is high. In contrast are Canada and the U.S. with, respectively, 4 and 8 percent of mammal species threatened. Less than a quarter of the species in the U.S. and only 4 percent in Canada are endemic. Habitat disturbance is moderately above average in the U.S. and very low in Canada.

The countries with the most threatened mammals are Indonesia, with 128 species, and China and India, both with 75. These three account for 43 percent of the world's population and are among the most densely populated.

--Rodger Doyle

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Images: Rodger Doyle.

Data Source: 1996 IUCN Red List of Threatened Animals, by IUCN (Gland, Switzerland, 1996); and Biodiversity Data Sourcebook, by World Conservation Monitoring Center (Cambridge, England, 1994)

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