Tag Archives: biodiversity

more extinctions on the way

The western gorilla is “critically endangered” — close to extinction — and all the great apes are in trouble. A number of corals have moved to more endangered positions; the Asian crocodile “Gharial” has moved to critically endangered — only 182 breeding adults in 2006. A number of vultures have declined — largely because of drugs given to livestock and intentional poisonings of carcasses. Here in North America, 90 reptile species are threatened with extinction and 738 are threatened. The Wild Apricot tree in Asia has been declared Endangered, and a Malaysian herb has officially been declared extinct.

All this is from the new report from the IUCN (World Conservation Union), which maintains a “Red List” of threatened species. The Red List of Threatened Species lists 41,415 species in all, listing the threatened species from “vulnerable”, “endangered”, to “critically endangered”. The “critically endangered” category faces an “extremely high risk of extinction in the wild”, based on rapid decline in population (more than 90% in last 10 years or 3 generations) or range, or extremely small numbers of mature individuals — e.g., fewer than 250.

The 2007 reports lists for “critically endangered”: 1 in 4 mammals, 1 in 8 birds, 1 in 3 amphibians, and 70% of all plants that have been studied are threatened with extinction — a total of 16,306 species in all, an increase of 188 from last year’s list of endangered species. The numbers of threatened species are increasing across almost all the major taxonomic groups. Extinction rates are 100-1000 times higher than natural background rates. Species in the tropics are still at the greatest risk. Australia, Brazil, China, and Mexico hold large numbers of threatened species. Continental extinctions are becoming as common as island extinctions.

On the math: Does the “increase of 188” count species that went extinct last year? The IUCN is not counting the Yangtze River dolphin as extinct, although the most recent survey concluded that they were likely extinct. But, say there were 10 extinctions last year, then that would be 198 species added to the critically endangered list, and 10 taken off as they were moved to extinct. Something to figure out.

I think I want a Battlestar Galactica-like survivors count for Earth. 2007 Sept. 13 CE, survivors count:

  • 6,000 species of mammal (of which the Yangtze River dolphin was one);
  • 10,000 species of birds;
  • 8,000 species of reptiles;
  • 13,000 species of freshwater species;
  • 6,000 species of amphibian.

AP 9/13 via boston.com, Red List Categories & Criteria v.3.1, Introduction to the IUCN Red List of Threatened Species, IUCNredlist.org, “Extinction Crisis Escalates” (9/12 press release from IUCN).