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Introduced prey alters predator ratio



Ahoy!

Not dinosaur, but of interest:
>From _Science_ Feb 8, 2002, the editors choice:
"The Eagle Has Landed"
http://www.sciencemag.org/content/vol295/issue5557/twil.shtml
one has to sign in - free registration for abstracts and such, need to
be a subscriber to get full articles and pdfs
Check out the jellybellies on the same page - trace fossils!

ECOLOGY: The Eagle Has Landed

      Introduction of alien species, especially to islands, often has
dramatic effects on native ecosystems and their flora and fauna. Roemer
et al. report a case of wholesale restructuring of the predator
community in the California Channel Islands, after the introduction of
an exotic prey species--the pig. The ensuing abundance of feral piglets
enabled a top predator species, the golden eagle, to colonize from the
mainland. The eagles also preyed on the islands' native mammalian
predators--foxes and skunks--and thereby altered the competitive
dynamics of these two species. The island skunks, being mainly
nocturnal, were less vulnerable than foxes to eagles. The fox
populations declined rapidly, allowing the skunk population to increase
as its dominant competitor became increasingly scarce. This case
illustrates how the introduction of a prey species can indirectly cause
the decline of a predator, probably leading to cascading effects down
the rest of the food chain. -- AMS

      Proc. Natl. Acad. Sci. U.S.A. 99, 791 (2002).

-mpc
Michael Patrick Corriss
http://www.gate.net/~mcorriss