Wolves and Moose on Isle Royale

Isle Royale National Park is an island in Lake Superior reachable only by ferry from the mainland. Though part of the state of Michigan, it is much closer to Minnesota and the Canadian province of Ontario than to the Upper Peninsula. While it was formerly occupied and used for copper mining, the archipelago is now a designated Wilderness area (there are still historical structures and lighthouses, but no permanent residents or industry). It has also been the site of a long-running study of wolf and moose populations.

As a generally isolated system, the island has been an ideal setting for tracking predator-prey dynamics. However, this has led to problems, particularly for the smaller wolf population, with inbreeding and genetic diversity. In particularly cold winters it is possible for animals to cross onto and off of the island over ice bridges, but there is no guarantee that wolves or moose will do so in any given year. An introduced parvovirus wiped out a sizable number of the wolves and the remaining populations went into a precipitous decline. A lone male in the 1990s had brought some genetic diversity back to the island, but the population is now down to two. A closely inbred pair that has had little success with offspring (one recent pup that has since died was visibly deformed).

The decline in predation has led, not surprisingly, to a substantial increase in the moose population on the island. While this is in some ways good, moose on the mainland are struggling under pressure from ticks and brainworm, it can have damaging long-term consequences for the island's ecosystem and the moose population itself, from over-consumption and soil damage. Perhaps the island can provide a temporary refuge for a population, until conditions on the mainland improve (though with climate change driving many of these changes due to warmer winters that is an iffy proposition). Management of wolves and moose on the mainland in Minnesota is an even more complicated and at times controversial issue, that largely pits hunters, property owners, and conservationists against each other, but in a complicated network. For example, hunters want to hunt moose, but they also want to ensure that there are always moose to hunt. Some oppose hunting moratoriums, while others don't. Some want predators removed (like the wolves) while others want more moose brought in. It's complicated and the state Department of Natural Resources has the unenviable job of balancing the interests of all these people while also maintaining both the animal and physical resources of the state for the benefit of all the people using scientific best practices (subject to political decisions...). But I digress.

Back on Isle Royale, there is a controversy about whether wolves should be allowed to go extinct, be repopulated once they die out, or have new members introduced before they do to refresh the gene pool as a "genetic rescue." At this point, with only two remaining wolves, genetic rescue is out of the question. They are aging and too closely related with a poor track record of reproduction. It is almost certain that the wolves will die out soon, possibly even this year. What happens then? It is possible that as wolf populations increase on the mainland they will repopulate the island in search of prey and new territory. This is likely how wolves originally came to Isle Royale in the 1940s. It is also possible that they don't and that the moose population goes through cycles of boom and crash (with associated problems for plants, soils, and other species). The moose could be managed by removal or hunting, or allowed to cycle and starve. Wolves could also be reintroduced from healthy, genetically diverse populations either from the mainland or elsewhere in the country (some areas are viewed as "over populated," at least in terms of minimizing human-wildlife conflict in fringe areas).

What complicates all of these decisions, in addition to uncertainty about what will versus what could happen, is the fact that Isle Royale is a designated Wilderness, where human intervention is meant to be limited. What that means in practice varies (humans occupied and mined the island, have caused climate change, have introduced illness and other species), but generally means that there will be minimal intervention going forward, regardless of what has happened in the past. This can be contrasted with (and in some ways was a response in the 1960s to) the "Disney-fication" of some of the more popular and iconic national parks, that are actively managed to generate certain views and experiences and provide certain amenities (again, this is a side issue, but for a much longer exploration of the issue, read my undergraduate thesis on it here). My take, which appears to be in line with the current NPS position and that of many scientists, is one of "wait and see." While there are potential harms to allowing wolves to disappear and moose numbers to increase, there is also the question of what it means to return the island to a "natural" state. Should the moose also be removed and caribou and lynx reintroduced to restore the fauna of the 1800s? Should all of them be restored? While any decision, including the decision not to act, will have consequences, it seems most in line with the spirit of the island, and island ecosystems generally, to let things play out as they will, though if a moose crisis truly appears, it can be revisited (including hunting, which isn't categorically prohibited in Wilderness, though it is in National Parks).

Polar Bear News

Two pieces of news about polar bears (Ursus maritimus). The first is some good news in an ongoing saga: Charles Monnett, the scientist who documented cases of drowned polar bears and was subsequently suspended by his agency, BOEMRE (the new acronym, since the Deepwater Horizon proved the final disgrace for a notoriously corrupt agency (discussed here)) has been reinstated from administrative leave. While investigations continue into why he was initially suspended and he will not be returning to the same duties, he has at least been temporarily cleared. This is something to keep watching as it develops though I wouldn't expect it to move with any great speed.

The other is much more unfortunate. A security guard working for BP shot and killed a polar bear with what appears to have been an explosive round when it wandered near a worker camp. While BP claims that the bear was killed by mistake and that the guard believed he was firing a rubber bullet to ward off the bear, it is a positive sign that the Fish and Wildlife Service is taking it seriously enough to do a preliminary investigation. There is nothing in the piece to indicate that anything other than what BP claims is the case, but polar bears are a threatened species and it is important to determine the exact circumstances of the death, whether it was preventable (assuming it was unintentional), and whether it was justified.

Threatened and endangered species receive a large amount of protection from the Endangered Species Act. There is a broadly construed ban on any kind of harm to individuals without a permit, and even then allowances are made only for specific numbers taken in specific ways (for example, a dam might be allowed to "take" 2,000 salmon via turbine action per year or a construction project might be permitted to take a nesting pair of owls via habitat disruption). While there is an exemption for lethal force when necessary to defend human life, that does not appear to be the case here, and scaring it off would have been the appropriate and justified choice for the safety of workers and the bear. The polar bear was listed as threatened due to loss of habitat from climate change and much has been written about that threat to the bear including how best to respond to protect it. However, once listed as threatened, unless specific exemptions have been written into the listing rule, the species is broadly protected from any type of prohibited action. In other words: once listed, it doesn't matter why. Any harm is prohibited harm, even if it isn't the kind that caused the listing. This is another piece that bears (unfortunate pun that wouldn't happen in many other languages) watching though I expect it to disappear into the ether without much closure.