Tuesday, November 28, 2006

"a vortex of extinction"

From physorg.com comes this interesting summary of a new study showing that the human penchant for rarity can lead to unexpected exploitation of endangered species, with "alarming implications for species survival." An excerpt:
This phenomenon, the authors explain, resembles an ecological process called the Allee effect, in which individuals of many plant and animal species suffer reduced fitness at low population densities, which increases their extinction risk. The authors' model now shows that humans can trigger an "anthropogenic Allee effect" in rare species through a paradox of value. When rarity acquires value, prices for scarce species can skyrocket, even though continued exploitation will precipitate extinction. And as long as someone will pay any price for the rarest of the rare, market price will cover (and exceed) the cost of harvesting the last giant parrot, tegu lizard, or lady's slipper orchid on Earth.
I can’t help but wonder how this "anthropogenic Allee effect" relates to the historical decline of my favorite endangered or extinct (depending on your point view) species of the moment, the Ivory-billed Woodpecker. The full study, published in the open-access journal PLOS Biology, can be viewed here.


Blogger Tucano said...

Regarding the IBWO, Jackson's book has a good discussion of the impact of collecting. Basically the creation of many new colleges at the turn of the 19th into the 20th and the many private collectors of that time created a huge market for IBWO specimens. As the bird became rarer the price went up. An interesting example: according to Jackson, based on his research of extant specimens, at least 200 IBWOs were collected along the lower Suwannee River in Florida during a period of 20 years at the end of the 19th century. If Tanner's home range figures are credible this pretty much wiped out most of the population near the river.


November 28, 2006 3:13 PM  
Blogger John L. Trapp said...

Very interesting, Dalcio. Thanks for the comment. I've just started reading Jackson's book this week. It appears to be a very scholarly contribution (as I would expect). I look forward to reading his discussion of collecting.

November 28, 2006 5:43 PM  

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