Should We Let the Wolves of Isle Royale Disappear?

October 10, 2013

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Photo: Gary Kramer/U.S. Fish and Wildlife Service

The wolves are disappearing on Isle Royale National Park, a remote wilderness island on Lake Superior. Should we save them?

That may seem a simple question for a conservation blog to answer. Of course we should save an animal disappearing from its native habitat! What other answer could there be?

In reality, there is nothing simple about this story.

In ecological circles, the wolves of Isle Royale hold special resonance. For more than 50 years, biologists have studied how wolves and moose interact, a project considered to be the longest-running research on predator-prey relationships.

The results of that research have helped inform wolf reintroduction in places like Yellowstone, and have become a template for predator-prey studies globally.

The wolf and moose populations have fluctuated throughout the study. In the 1980s, a virus introduced by a visitor’s sick pet decimated the wolf population. It recovered, but now inbreeding and the island’s isolation have again threatened the wolves.

At the beginning of this summer, the wolf population was down to eight animals, and they appeared to not be breeding. That proved untrue – two wolf pups were born in August – but the long-term prognosis for the large predator on the island is not rosy.

The original wolves arrived in the late 1940s, likely via an ice bridge connecting Isle Royale to the mainland. With warmer winters, there have not been ice bridges, so the chances of new wolves reaching the island on their own are slim.

The National Park Service is considering its options. One is to simply let the wolves survive or die out without human intervention. Another is to let them die out, then reintroduce a new population. Or additional wolves could be added to the population now, providing more genetic diversity to the population.

The decision to bring wolves in to bolster the population is pitched by some as assisting species in adapting to climate change. Others see it as protecting the ecological value of large predators, and certainly a significant body of literature has demonstrated that these predators are essential for ecological health.

Rolf Peterson, the longest-serving director of wolf-moose studies on Isle Royale, argued for this view in an op-ed he coauthored for the New York Times:

“The future health of Isle Royale will be judged against one of the most important findings in conservation science: that a healthy ecosystem depends critically on the presence of top predators like wolves when large herbivores, like moose, are present. Without top predators, prey tend to become overabundant and decimate plants and trees that many species of birds, mammals and insects depend on.”

Again, this all seems pretty straightforward, right?

Despite serene appearances, Isle Royale has seen dramatic changes over the past century. Photo: MDuchek under a Creative Commons license.
Despite serene appearances, Isle Royale has seen dramatic changes over the past century. Photo: MDuchek under a Creative Commons license.

But looking at the island’s ecological history makes things a bit more complicated.

On any island habitat, species tend to come and go more rapidly than on large, intact habitats. Some species on islands disappear rapidly. Some evolve rapidly to take over new niches. The smaller the island, the less likely that a species will survive over the long haul – what conservation biologists call island biogeography.

If you visited Isle Royale at the turn of the twentieth century, you would have found a very different island. There were no wolves or moose. There were caribou, coyotes and lynx, animals that had been present on the island for thousands of years.  They’re gone now.

Moose showed up by the early 1900s and prospered a bit too well; some feared they would run out of food.  Nutritious plants that grew in the wake of a large fire allowed the moose to rebound. The wolves arrived in 1948 or 1949.

What is the true natural state of Isle Royale? Is it wolves and moose? Or is it caribou and lynx?

What about new brand-new species arriving on the island, like a bat and several amphibians? Are they natural introductions or should they be viewed as non-native interlopers? And if it’s natural for new species to show up, why is it less so for other species to disappear?

Questions, questions, questions.

Ron Meador, in his excellent MinnPost story, quotes Tim Cochrane, park superintendent of Grand Portage National Monument:  “What is natural on Isle Royale is a dicey question. Whether wolves ‘belong’ on the island is an open question.”

Meador goes on to write:

“Returning the island’s species balance to its longest running iteration, [Cochrane] said not quite seriously, would require letting the wolves disappear, assigning hunters to take out the moose, then reintroducing woodland caribou and lynx.”

Perhaps he was not quite serious. But he has a point. It’s difficult to know the “natural” state of Isle Royale, because islands (or any ecosystem for that matter) have always been changing. Flora and fauna have constantly been coming and going.

This one may be trickier because many believe humans have affected the wolf populations – by introduced viruses and by climate change. But we also can’t definitely say that new wolves would have make it to Isle Royale even without climate change. After all, there is a long history of a wolf-free Isle Royale.

And there is good evidence that moose only made it to Isle Royale because they were prospering on the mainland—due to increased logging. Humans have played a role on Isle Royale for millennia; Native Americans traditionally hunted caribou there, no doubt affecting island ecology.

At a place like Isle Royale, it’s not easy to figure out what is natural and what is human caused – or even if these are valid distinctions.

I am not against human intervention to save species, of course. I think Rolf Peterson and his coauthors put it well in the New York Times:

 “Where no place on the planet is untouched by humans, faith in nonintervention makes little sense. We have already altered nature’s course everywhere. Our future relationship with nature will be more complicated. Stepping in will sometimes be wise, but not always. Navigating that complexity without hubris will be a great challenge.”

But we do have to make decisions. Conservationists will have to prioritize where investing in reintroductions or other extreme measures make sense, and where letting a species disappear is the more “natural” choice.

The existing wolves may yet rebound and thrive, or they might disappear. Either way will have dramatic effects on moose and many other species on the island. No doubt about it.

There are no “right” or clear answers here. But considering the short tenure of wolves on this island, Isle Royale is not a place we should be spending large amounts of money by introducing new wolves to the population.

This is one instance where intervention makes little sense; the island’s animal life has seen many and dramatic changes in recent times. It would make more sense to focus conservation dollars to connect large expanses of land where populations wolves and other wide-roaming wildlife can move freely and interbreed, as in the national parks and public lands of the western United States.

It makes more sense to prevent habitat from becoming de facto islands in places like the Northern Rockies than to try to fight natural processes — including species disappearances — on real islands.

Let Isle Royale’s  fauna continue to come and go as it has for thousands and thousands of years. And let’s continue studying this national park, learning how  fauna and flora adapt, change, survive and disappear over time.

And who knows? Maybe wolves will find a way there on their own. Or maybe lynxes will return. Or a new animal. Let’s just see what natural forces bring, on at least this one island.

Around the world, conservationists will face choices like this. There often won’t be easy answers. It may not be comforting to let a population of charismatic animals disappear, but sometimes it may be the right choice.

What do you think? Should we take measures to save the wolves of Isle Royale, or let the current population run its course, even if that means the population disappears?

Matt Miller

Matt Miller is director of science communications for The Nature Conservancy and editor of the Cool Green Science blog. A lifelong naturalist and outdoor enthusiast, he has covered stories on science and nature around the globe. Matt has worked for the Conservancy for the past 14 years, previously serving as director of communications for the Idaho program. More from Matt

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  1. The writer, who states “we should not be spending large amounts of money…” to maintain wolves in Isle Royale National Park, is quite misinformed about the relative costs of the various options open to NPS. Conservation of the present wolf population through genetic rescue provides the most cost-effective management option, no question about it. The No Action option might well cost the National Park Service (in reality, the taxpaying citizens of the U.S.) millions of dollars, based on previous similar cases of hyperabundant ungulates in Gros Morne National Park (moose, where Parks Canada spent $13 million in 5 years dealing with the issue) and Rocky Mountains National Park (elk, where NPS spent unspecified millions to document elk effects on aspen and set up a culling operation to reduce elk density, simultaneous with fencing off stands of aspen to protect them from elk). Waiting for extinction at Isle Royale (Restore Wolves option) may take many years, allowing the moose population to escape from limitation by predation and possibly committing the NPS to large expenditures similar to the No action option.
    A second reason offered by the writer for No Action echoes a common nostalgic idea that on islands animal species “blink on and blink off”, or “wink in and wink out”, followed by the suggestion that we should “see what happens”, sort of a light mix of Charles Darwin and Rudyard Kipling . This implies that there will be some fascinating and foundational science to be done through No Action, if we can all simply be patient. There is much more required for serious science, but a pre-requisite is adequate funding. There are many, many predator-free islands in Lake Superior and Lake Michigan populated today by hyperabundant ungulates – Slate Islands and Michipicoten Island in Lake Superior, for example, and many of the Apostle Islands, also in Lake Superior. There is little or no science being done on these islands, but given the common visitor reports of severe overbrowsing and their photos showing emaciated animals with protruding ribs nibbling bits of vegetation in campgrounds, I don’t think there is much doubt about what will happen if there are no wolves at Isle Royale.
    When I hear the “wink in…” and “…blink off” description, my mind goes to “Wynken, Blynken, and Nod”. Such a nice story, and unfortunately the NPS adheres tightly to nice stories in their public narratives. If you want to address ecological problems in National Parks, please inform yourself. If you want a nice story, here’s one (last verse):

    Wynken and Blynken are two little eyes,
    And Nod is a little head,
    And the wooden shoe that sailed the skies
    Is a wee one’s trundle-bed.
    So shut your eyes while mother sings
    Of wonderful sights that be,
    And you shall see the beautiful things
    As you rock in the misty sea,
    Where the old shoe rocked the fishermen three:
    Wynken, Blynken, and Nod.

    1. I agree 100% with Rolf. Humans have done the damage to the Earth that has caused the extinction of so many species. It is about time we at least tried to undo some of the damage.

  2. I am deeply troubled by the stance taken by the author regarding the wolves of Isle Royale. To reduce the selection of a response to the genetic issues through monetary evaluation is absolutely myopic. The scale of Isle Royale is small but the benefits to knowledge are large. The study is followed in k-12 education and often sparks the interests of our future ecologists.

    As a long term supporter of The Nature Conservancy I am troubled by the publication of this opinion. The disclaimer of opinion does little when published through The Nature Conservancy. The wolves of Isle Royale are a resource worth protecting. The long term data clearly attributes the lack of ice bridges to the warming of Lake Superior. The changes in Caribou are also very likely the effects of man in the logging and mining era on the island. The issues are indeed complex but the continuing value of the study is valuable beyond simply economic measure.
    I favor an introduction of new genetics to the existing population.

    1. Tom, Cool Green Science is a science blog — we publish pieces by Conservancy scientists and science writers that reflect ideas, research, opinion and debate from that community and the conservation science community at large. We also publish dissenting comments such as Rolf Peterson’s and yours. Such a forum and its ethos, we believe, reflect both the spirit and practice of science, which in turn informs the best conservation practice.

  3. Wolves may not have been on Isle Royale 100 years ago (probably due to poisoning by humans) but they were certainly part of the island caribou-lynx-snowshoe hare ecosystem for millennia.
    Only moose are recent interlopers, not wolves.
    Rick Page, PhD

  4. I’ll be blunt. I find the way you chose to approach the subject of the wolves impending demise on Isle Royale to be in poor taste. As I read the piece, I had a sense that you were in support of an intervention to rescue what few wolves remain on the island—especially after you quote Rolf Peterson TWICE. Then, in the final paragraphs, you throw Rolf under the proverbial ‘bus’.

    What’s even more disconcerting is that you fail to mention that moose began to thrive on the island after heavy logging in the 1800s opened the forest canopy and created a lush and abundant amount of brush growth. The same can be attributed to the copper mining operations that set fire to the forest to unearth ore deposits.

    You also glossed over canine parvo virus and the subject of climate change.

    ”In 1981 the deadly dog virus reached Houghton, Michigan, my hometown and a point of departure for many visitors to Isle Royale. Sick and dying dogs were brought by the score to the three local veterinarians, and dog owners were reminded that a new vaccine was available to protect their pets.

    The local appearance of parvovirus coincided with a spectacular crash in the Isle Royale wolf population, including the unprecedented loss of all nine pups born in 1981—distributed in three packs. ”


    It is a fact that, on July 4th 1981, Chicago residents brought their infected dog to the island illegally. That same dog was taken to a vet in Duluth and, inadvertently, infected another dog. Both animals died.

    With respect to ice bridges, why didn’t you mention that they used to occur every two to three years? Today, it’s once every decade. While you are correct in stating that we cannot be sure that more wolves would have made it to Isle Royale without climate change, mankind’s indifference to the environment has reduced the odds significantly.

    That said, how can you be of the opinion that we should just sit back and let nature takes its course, when mankind has been messing with its navigational system for the past 200+ years?

    Finally, I cannot help but think that The Nature Conservancy has lost its way because the position you take is antithetical to its motto: “Protecting nature. Preserving life.”

  5. I have spent most of my life hearing about Isle Royale from family to friends. Yes, I would love the wolves to be saved but in the end nothing can escape death. Plus is the prey populations on the island high enough to support more wolves if they were to be introduced? And if not look at the charts made by Rolf Peterson as he watched how abundance of moose effected the wolves to how a low population of moose effected the wolves. We can’t see into the future to see how either choice will effect the future so we would be jumping into the dark in some ways. A single grain of rice can tip the scale so in ways many things can happen to effect Isle Royale over the years.

    I am not a expert on conservation on the topic of wolves and moose. But I do know that every action has a reaction that can be good or bad so what ever choice is made about the wolves of Isle Royale, there will be things that will result from that choice.

  6. Mr. Miller’s conclusion that there should be no intervention in the case of the wolves of the Isle Royale wolf is built upon two sets of premises: those that appeal to the relative cost of options, and those that rest upon an appeal to naturalness.

    Commentary on the fate of the wolves of Isle Royale should satisfy some basic criteria. As Rolf Peterson suggests above, it should be accurate. I suggest it should also be free of logical errors. Professor Peterson has pointed out an important factual mistake regarding the cost of genetic rescue, thereby undermining a critical premise in one of Miller’s arguments against intervention. I’d like to point out a logical error in Miller’s other argument against intervention.

    Mr. Miller also attempts to conclude that we ought not intervene (either with genetic rescue or with reintroduction) with the wolves of Isle Royale by employing the notion of naturalness to settle the issue. In doing so he commits the naturalistic fallacy. Appeals to naturalness to arrive at prescriptions for action suffer from two great challenges. First, one has to be able to determine what is natural in the first place. To put it mildly, this is a very serious challenge, especially in the case of Isle Royale wolves. Miller does not meet this challenge. Second, even if he did meet it and we could decide what is natural, it is not at all obvious that what is natural is the appropriate guide for our actions, because it is not at all obvious that what is natural is what is good and therefore is what we ought to do. History is littered with examples of horrific actions taken in the name of naturalness.

    Those who are following this particular conservation issue are advised to read not only the opinions of the researchers found in the New York Times op/ed, but the more serious reasoning behind those opinions found here – http://www.georgewright.org/291vucetich.pdf

  7. Very generally, I have found TNC to be increasingly indifferent to the importance of top predators in our ecosystems. Perhaps my impression comes from TNC’s trend towards believing that Nature is mostly about providing services for humans? Anyway, gray wolves are under considerable political pressure for their existence in the Lower 48. Why not provide for their success on Isle Royale? Surely the cost of strengthening that population is not that great.

      1. Bob,

        Please take another look at that piece’s link, and you’ll see that comment #2 was mine. I still don’t think TNC is doing anything close to what is needed. Why does Peter suggest having a “new conservation NGO” work on top predators? Shouldn’t that also be TNC’s work?


          1. I clearly believe that wolves should be added to the remnants of the surviving wolf population on Isle Royale due to the genetic restrictions that now currently are driving the wolf population towards extinction. I obtained my Master’s of Science in Biology in 1989. Under static conditions, I studied the effects of species richness of 28 species of microscopic algae with and without an apex predator. Each replicated “island” was subjected to several rates of invasion with a without a predator after several months so the “islands” could obtain various degrees of equilibrium. Needless to say, in systems that were dominated by species in which the predator preferred, the predator opened up those “islands” so that more species could survive; however, if the predator selected non-dominate species, the number of species that “island” could support was reduced. My point is that Isle Royale is not a closed system and numerous manmade activities on the island by man such as altering the flora and fauna via climate change which severely reduces the possibility of new wolves or moose as well as other previously mentioned species from reaching the island thus limiting the genetic variability of the wolves more than their prey, introducing specific canine diseases which nearly drove the wolves almost to extinction as well as further limiting genetic variability, hunting, mining, and altering the vegetation have nearly doomed the fate of the wolves to extinction, which is almost inevitable few years. I’m sorry for all of the “scientific jargon” I’ve thrown out, but by now you probably know which side I’m on. Man has doomed the wolves to almost certain extinction and I believe the best option is to inoculate the wolves for the parvo virus and supplement the existing survivors. As far as cost, why don’t we let the wolf slaughter in the west spare a “few” wolves and send them on a little boat cruise to Isle Royale!

          2. Sorry, Ted — didn’t realize a question was still pending. From my last conversations with him, he is keenly interested in addressing this issue publicly.

          3. Thanks, Bob. It will be interesting to see what he says. It is no secret that many traditional conservationists still believe in protecting natural lands, ecosystems, species and diversity for their intrinsic values and not just for what supports people and their economies. TNC’s leadership and Peter in particular have lost a lot of respect for having so publicly walked away from the values that originally motivated TNC founders.
            You have a chance to redeem yourselves in part by advocating for and actually defending apex predators. This work would be well within TNC’s original mission and within the current capabilities of your organization.
            Government agencies, ranchers, and others with utilitarian mindsets persecute predators relentlessly. Please do something positive to correct this.

  8. This is a complicated and fascinating if wrenching issue. I think Matt Miller has done a very interesting job of considering the difficulties involved in making decisions about how to proceed. You don’t have to agree with his conclusion to find this discussion informative. I also appreciate that this blog allows for the discussion to be continued from different points of view in the comment section. I appreciate reading Mr. Peterson’s comments. I will be thinking about this issue for some time to come and the ideas raised here.

  9. It is unfortunate that Dr. Durward Allen, who initiated the project, is no longer alive because it would have been great to hear his take on this issue. I graduated from Purdue in 1970 and worked three summers (1969, 1970 and 1972) on the project working with Dr. Mike Wolfe and Rolf as a field assistant. I believe Rolf has been on this project since 1970 and I think his take on this issue has the most credibility.

  10. Climate change is mentioned often in the comments. How has climate change affected the wolf population? I am new to this discussion, so I am open to scientific answers, but not

  11. I think that the National Park service should study the wolves and give them Monthly vet checkups.

  12. I also think that they should make it illegall for everyone besides scientist to go to the island

    1. To what end? If a particular animal decided to make its home in your backyard would you be fore the illegal travel to your property?? The island has had humans (a natural animal, if you’ve forgotten we’re mammals) for longer than it had wolves per the article. So to what end?? should we limit human activity to metropolitan urban sprawl only leaving places such as all national parks illegal to use close the grand canyon, barricade yellow stone, and Yosemite valley, how about make laws to make it a crime to mine, refine fossil fuels and just take a step back to the “natural” world the Neanderthal had. I hear the tropical areas of the planet is perfect for our natural abilities, no need for clothes (animal skin or plant fibers) good place for foods not required to cook. Mango comes to mind.. so if we make isle Royal illegal for human use, what other “natural” area are you willing to give up…your backyard?

  13. You can not expect an area or region to maintain it’s “state”, year after year….evolution occurs….the introduction of animals is indictive of development and creation in motion…..

    We have no right to interfere with normal developments in evolution….everything happens for a reason….

  14. I think the wolves should be given a chance to survive. Just how costly is it to move wolves to the island? Can’t you just put them there and let nature take it’s course? Does it have to be a huge, expensive study? Put them there at the optimal time and wait for spring or whenever most pups are born.

  15. Bring the wolves back!!! Im John Cena and i approve this message (not really John Cena)

  16. I think wolfs in isle royale should stay because they can keep the balance of animals in the ecosystem and keep it from one organism over populating and the whole ecosystem collapsing.

  17. I agree with Rolf because humans always are the cause of ruining nature I feel it’s time they try and fix it.