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How Isle Royale Biologists Chose Wolves For Their Recovery Operation

Nov 28, 2018 06:18AM ● By Editor

A remote camera captured one of the new wolves, a female, feeding on a moose carcass at Isle Royale National Park this fall.  Photo:  National Park Service

By Kurt Repanshek of National Parks Traveler - November 28, 2018

You probably wouldn't feel comfortable being uprooted from your community and tossed into a new one with three other strangers. So why did National Park Service biologists capture four unrelated wolves to begin to rebuild a population of the predators at Isle Royale National Park in Lake Superior? Part of it was strictly chance.

"While we brought four different individuals from four different pack territories, our objective was to acquire a related pair if possible and if not unrelated individuals," explained Mark Romanski, the park's natural resources division chief. "This is extremely difficult to do when conducting a foothold trapping operation. The advantage of bringing pair bonded individuals is that it is presumed they would breed this winter. However, in the translocation of wolves to Idaho in the mid-1990s, individuals were moved and they did find each other and pair bond."

Four wolves -- three females and a male -- were captured earlier this fall on the Grand Portage Reservation and transported to Isle Royale in a bid to recover the park's wolf population, which had dwindled to just two. Isle Royale wolves have been in decline for more than a decade, as chronic inbreeding has impacted their health.

There was hope that "ice bridges" that formed between the Lake Superior island and the Canadian mainland during the winter of 2013-14 would enable wolves to arrive from Canada with new genes. But no new wolves reached the island, while one female left and was killed by a gunshot wound in February 2014 near Grand Portage National Monument.

In recent years, park managers have discussed wolf management on the 209-square-mile island with wildlife managers and geneticists from across the United States and Canada, and have received input during public meetings and from Native American tribes of the area. Those discussions examined the question of whether wolves should be physically transported to Isle Royale, in large part due to concerns that a loss of the predators would lead to a boom in the moose population that likely would over-browse island vegetation.

Last winter's moose population was estimated at about 1,500, and biologists believe the island can support 1,100-1,200.

Under the plan adopted earlier this year, up to 30 wolves are to be set free at Isle Royale over the next three years in a bid to build genetic diversity into the park's wolf packs. It was hoped that six wolves would be moved to the park this fall, but deteriorating weather conditions ended the operations after four animals had been released there. And then, the male wolf brought to the island this fall was found dead of unknown causes; necropsy results have not yet been received.

This winter, efforts will be made to capture several wolves in Ontario, Canada, and move them to the park.

Biologists left moose carcasses in different spots on the island to give the new wolves a start. Whether they have killed any on their own remains to be seen, said Romanski.

"Monitoring of GPS collar data gives us presumed predation sites to investigate in spring of 2019," he said in an email. "The collar will provide clusters of positions, a series of subsequent locations in the same location that we will visit on the ground to determine if a predation event occurred. The collars have already provided several prospective sites for both moose and beaver predation events."

How the two resident wolves have reacted to the newcomers also is unknown.

"We do not have any recent data on the two wolves in the park prior to translocation," said Romanski. "We have images from remote cameras obtained over the summer. We know from GPS collar data that the translocated wolves entered the existing wolves' territory on several occasions."

In the years to come, the Park Service plans to monitor ecological conditions and other factors, such as predation rates, genetics, moose-wolf ratios, and terrestrial and aquatic vegetation impacts, to evaluate project success.

To read the original article and see related stories about our National Parks, follow this link to the Parks Traveler website.

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