Endangered Species Handbook

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It's Too Late

The Recent Picture: A Rapid Rise in Extinctions

     The current extinction rate is estimated to be up to a thousand times higher than prehistory rates (Leakey and Lewin 1995, Stearns and Stearns 1999).  This phenomenon has been described as the sixth wave of extinctions by scientists Richard Leakey and Roger Lewin ‒ ecosystems are being disrupted around the world, and the wondrous tapestry of living things that supports human existence is unraveling. 
     Since 1500, approximately 375 species of invertebrates, 81 species of fish (Hilton-Taylor 2000) and 291 species of mammals, birds, reptiles and amphibians (see Appendix) have become extinct.  About three-fourths of vertebrates other than fish have disappeared since 1800, while only 80 species died out in the previous three centuries.  These figures represent a minimum number.  An estimated 5 million species of animals and plants exist in tropical rainforests, a conservative figure that may apply to insects alone, according to biologist Edward O. Wilson (1988).  About half of these species are restricted or localized in distribution (Wilson 1988).  With this in mind, at the present rate of destruction of tropical forests, some 17,500 species are being lost per year ‒ a rate 1,000 to 10,000 times greater than extinction rates prior to human intervention (Wilson 1988). 
     Human activity lies at the root of this potentially catastrophic phenomenon.  Killing for food or sport, as well as conditions created by humans, such as habitat destruction and competition, predation and disease from introduced animals, is responsible for the vast majority of these extinctions.  It is with this perspective that we can see the present situation as an unnatural event, not linked to climatic changes, meteors or volcanic eruptions, but a result of human-caused changes wrought in the Earth's environments and by direct extermination.

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