http://www.mtu.edu/
By Jennifer Donovan
The number of wolves at Isle Royale National Park has dipped to nine—the lowest number seen since Michigan Technological University’s wolf-moose predator-prey study began 54 years ago. What should be done if this furry icon of wilderness culture dies out altogether?
Michigan Tech researchers John Vucetich and Rolf Peterson and Michigan State University environmental ethicist Michael Nelson tackle this controversial subject in an article in the March 2012 issue of the George Wright Forum, a conservation journal.
Wolves on Isle Royale
The issue is a prickly one because there is conflict among environmentalists and ethicists about how we should—or should not—relate to nature and the environment. Some say, “let nature take its course.” Others believe humans should work to maintain ecosystem health, and that may on some occasions require intervention.
“The appropriate approach is to acknowledge and understand all the values at stake, and then develop a perspective or position that would least infringe upon that set of values,” say Vucetich, Peterson and Nelson.
A central management principle of wilderness policy is non-intervention. Non-intervention is preferable to humans’ tendency to try to control nature, its advocates say. Non-intervention can help maintain natural conditions and the character of natural landscapes.
Wolves pursuing Moose
However, even according to established wilderness policy, non-intervention is not necessarily the best management option when “nature’s course” has already been altered by humans, the authors say. Intervention may be necessary for maintaining ecosystem health.
In the case of Isle Royale, the wolves have been affected by disease and climate change. And humans have had a hand in these influences. A pet dog brought to the island by a visitor in the 1980s set canine parvovirus loose, nearly wiping out the wolves. Reverberations of that population crash persist to the present day. Climate change, which few dispute has been caused in part by human actions, likely exacerbate the impact of winter ticks, resulting in a significant decline in the moose population, the wolves’ primary food source. It also decreases the possibility that another ice bridge might form between Canada and Isle Royale, making very unlikely even the possibility of new wolves crossing to the island with the effect of improve genetic diversity.
“Humans exacerbated the extinction risk of wolves and significantly reduced the chances of natural recolonization. Because of this, intervention would enhance and honor the wilderness values of Isle Royale,” the authors say.
Isle Royale Wolves claim their dinner
In addition to the questions that arise from principles of non-intervention, the authors suggest the need to also consider the cost of sacrificing the longest predator-prey study ever conducted.
There are three possible kinds of intervention that could save the wolves of Isle Royale:
•Wolf reintroduction—reintroducing wolves if the present wolf population were to go extinct.
•Female reintroduction—reintroducing female wolves when all present females have gone extinct.
•Genetic rescue—introducing new wolves on Isle Royale while some of the present population remains, to broaden and strengthen the gene pool.
If the wolves are allowed to go extinct, the moose population on the remote island will grow unimpeded, until the moose strip the island of its vegetation and eventually, starve.
“The bottom line is, as long as there are moose there, keep the wolves there,” says Vucetich.
“All things considered, if the wolves go to extinction, reintroduce them,” Peterson concludes.
Michigan Technological University (www.mtu.edu) is a leading public research university developing new technologies and preparing students to create the future for a prosperous and sustainable world. Michigan Tech offers more than 130 undergraduate and graduate degree programs in engineering; forest resources; computing; technology; business; economics; natural, physical and environmental sciences; arts; humanities; and social sciences.
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Keeping an Eye on Two Intimate Wolves
www.nytimes.com By JOHN VUCETICH
A male and female wolf walk shoulder to shoulder.John Vucetich, a wildlife ecologist from Michigan Technological University, leads the wolf-moose Winter Study at Isle Royale National Park.
Thursday, Feb. 23
We take off, and soon we’re following tracks on the island’s south shore, a few miles southwest of Lake Halloran. They almost certainly belong to the wolves we’ve named the West-End Duo.
With every step, as a wolf swings its leg forward, it lowers its paw, at first only gradually toward the ground, just grazing the snow with the top of its foot. Then, extending its ankle, toe pads pointed down, the wolf plunges its paw deep into the snow. The next step begins by lifting a paw up high and right out of the snow. So, from the air and under the right snow conditions, a wolf track is one long series of comet-shaped footprints. The grazed snow is the comet’s tail, and the hard step is the comet’s head, pointing in the wolf’s direction of travel. These wolves are heading northeast, and so are we.
After a few miles, we come to a long section of shoreline where wind and sun have left the beach increasingly bare of snow. As the snow patches get smaller, the tracks became more difficult to follow. Eventually we lose the tracks.
We know very little about these wolves that they don’t know much better themselves. We also know little about the specific habits of these two wolves. However, for the past 10 or so generations of wolves at Isle Royale National Park, when they travel northeast along this stretch of beach, they tend to head to Lake Halloran. It’s the easiest place to cross overland from the south shore to Siskiwit Bay. So we fly to Halloran hoping to pick the tracks up again. No luck.
Tracks like these, left by the West-End Duo on Mud Lake, are indicative that these wolves have copulated.John Vucetich
.We fly off to find the Chippewa Harbor Pack. That should be easy, since the wolves are most likely sleeping at the site of their most recent kill. If so, we can make those observations quickly and return to spend the rest of our time looking for the West-End Duo.
After an hour, we return to Lake Halloran and find wolf tracks that hadn’t been there an hour ago. The comet tails are useful, but there’s no substitute for seeing a wolf track at ground level. So we land, taxi to the tracks and, without getting out of the plane, confirm their direction — northeast, as we thought. The duo is not far ahead.
We take off again and follow their tracks for another mile along the open ridge that extends northeast from Halloran. The tracks disappear at the end of the ridge into a small patch of cedar trees. We circle and circle, straining to see where beneath the forest canopy the tracks lead next. Nothing. Have we lost their trail, or is this where the tracks end, with the wolves resting in the cedars?
We are almost out of fuel. In the time it takes to refuel, the West-End Duo changes directions, emerging onto Siskiwit Bay. Don and Rolf watch the pair walking side by side, shoulder to shoulder. Tracks indicate that they have done so for several miles.
That behavior is significant. Wolves usually walk one after the other. Sometimes it reflects the ease of walking through the snow in another’s footsteps. Sometimes it reflects the pack’s hierarchy. Wolves in courtship, however, are peers — equals in the pack. And a wolf in courtship must show unequivocal interest. Courting wolves frequently walk shoulder to shoulder in the days just before and after copulation. It’s a subtle sign, but we recognize it immediately. We are excited by the prospect
In the late afternoon, we go out for a short flight. Don and Rolf find the West-End Duo bedded a few miles farther down the shoreline.
The male of the West-End Duo inspects the reproductive organs of the receptive female.When the wolves stand up, the larger, presumably male wolf moves over to the smaller, presumably female wolf. He places his nose at her rear end. She accommodates by holding her tail to the side. Female wolves are fertile for a very short time. To avoid missing that time, a male wolf regularly sniffs for the scent of hormones.
Meanwhile, the wolves in the Chippewa Harbor Pack do what they mostly do. They sleep at the site where, four days earlier, they killed a calf.
Saturday, Feb. 25
It is windy, but we’re anxious to catch up with the West-End Duo. A storm is expected tomorrow. We’ll almost certainly have difficulty finding the wolves after the storm. Also, the winter study is almost over. If we are fortunate enough to see the duo today, it could be the last time until next winter.
In the afternoon, winds subside to levels that are barely tolerable. We fly. On the south side of Mud Lake, just a few miles from the last sighting of the duo, we see the kind of tracks that wolves make during the several minutes when they are joined in copulation. We see them again on the north side of Mud Lake. Later we find the West-End Duo, still shoulder to shoulder, walking southwest toward Hay Bay.
They follow the scent of a moose upwind, a moose that has been foraging on the ridge overlooking Hay Bay. The moose detects the wolves while they are about 40 meters away. They stop and consider a chase. The moose does not give an inch. After about a minute, the wolves move on.
A few minutes later, they disappear into the forest, perhaps for the last time, as far as this winter’s observations are concerned. We wait all throughout the winter study to make the kind of observations that we’ve made the past three days. In the past three years, the Isle Royale wolf population has declined by about two-thirds, and the Chippewa Harbor Pack seems to be struggling. This West-End Duo very well may be the future of the Isle Royale wolf population.
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