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Interview With Glenn Olson: The Bird Ambassador
Wildlife: Inherit the Wound
Sealife: The Friendliest Catch
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Inherit the Wound
Decades of inbreeding are taking a toll on Isle Royale’s embattled wolves.
In nearly 40 years of study on Isle Royale National Park in Lake Superior, biologist Rolf Peterson had never found a wolf killed by a moose. That changed last winter with the discovery of a young wolf that apparently had been kicked to death by a moose. Despite its youth, the wolf had a severely arthritic back, and Michigan Tech researchers believe the animal wasn’t agile enough to dodge the fatal blow. The backbone malformations the wolf suffered, the result of 60 years of inbreeding, are rampant on Isle Royale.
The incident, and the pervasive deformity, shows that wildlife managers may need to launch a “genetic rescue” by bringing in outside wolves to expand the gene pool, says Peterson. That proposition in turn raises the issue of whether people should meddle with nature in a designated federal wilderness. “This is not a decision for scientists alone to make,” Peterson says. The National Park Service and other agencies, wolf experts, conservation and animal-rights groups, and the public will likely all have a say in the debate. Other genetic rescues include the introduction in 1995 of eight female pumas from Texas to the handful of remaining Florida panthers; today the hybrid population numbers fewer than 100. But the scheme and its success remain controversial.
The 24 wolves counted on Isle Royale this winter are all descendants of one female and two or three males that crossed a rare ice bridge extending the 15 miles from the island to the Ontario shore in the late 1940s (see “The Long View,” March-April 2008). The wolf–moose research team routinely collects skeletons, and an expert in wolf anatomy, Jannikke Räikkönen, recently examined the bones of 36 Isle Royale wolves that died between 1964 and 2007. She found that 58 percent exhibited spinal deterioration and that the last normal skeleton dated to 1993. In an outbred wolf population, only one percent of the animals would exhibit this malformation.
A genetic rescue attempt would involve bringing unrelated wolves to the park, probably from a vigorous population in Minnesota or Ontario. Up to now, the policy has been to let nature take its course even though the park’s wolf population has teetered on the edge. Still, as study co-leader John Vucetich says, “Genetic rescue is a potentially important conservation tool, but one that we don’t understand very well. We have an opportunity here to learn more, but it is not clear if the scientific value outweighs other concerns, such as the wilderness value of not intervening.”
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