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Re: predators and prey
Bill Altimari (walti@AZStarNet.com) writes:
> Among extant large mammals, predators do not "control" prey
I think Bill's trying to swing the pendulum too far the other way.
Author(s): KREBS CJ; BOUTIN S; BOONSTRA R; SINCLAIR ARE; SMITH JNM; DALE
MRT; MARTIN K; TURKINGTON R
Title: IMPACT OF FOOD AND PREDATION ON THE SNOWSHOE HARE CYCLE
Source: SCIENCE V0269 N5227 AUG 25 1995 pp. 1112-1115.
Abstract: Snowshoe hare populations in the boreal forests of North
America go through 10-year cycles. Supplemental food and
mammalian predator abundance were manipulated in a factorial
design on 1-square-kilometer areas for 8 years in the Yukon.
Two blocks of forest were fertilized to test for nutrient
effects. Predator exclosure doubled and food addition
tripled hare density during the cyclic peak and decline.
Predator exclosure combined with food addition increased
density 11-fold. Added nutrients increased plant growth but
not hare density. Food and predation together had a more
than additive effect, which suggests that a three-trophic-
level interaction generates hare cycles.
I also seem to recall reading an article about population dynamics on
a particular island -- as I recall, the conclusion of the paper was
that the predators (wolves, I think) actually were the primary
determinant of the density of prey on the island. Unfortunately I
couldn't find that reference... Anybody else remember seeing it? It
would have been within the last year or two most likely also in
Mickey Rowe (firstname.lastname@example.org)