Wolves, moose, and genetics oh MY!

Wolves and moose, the classic predator-prey system of Isle Royale (image from: http://hunts-upguide.com/isle_royale_wolves_and_moose.html#.UZ50noKYeTR)

Science just published a news focus article titled: Are Isle Royale’s Wolves Chasing Extinction? This article is about how inbreeding (and perhaps climate change) is likely going to mean the decline and eventual extirpation of wolves on Isle Royale in Michigan, prompted by the apparent lack of wolf pups on the island. Experts failed to observe or hear wolf pups as of last summer, which is indicative of a lack of breeding. It is suggested that this is a result of inbreeding, there are currently two packs and a total of 8 wolves, since wolves are known for avoiding mating with closely related individuals.

These wolf and moose populations are the classic example of predator-prey dynamics. It is a wonderful system where wolves are feeding almost exclusively on moose, and is functionally a one-predator one-prey system (a rare find). A quick Web of Science search shows 136 publications from the search for Isle Royale  (with a “wolves or moose” modifier). The first is WOLVES VERSUS MOOSE ON ISLE ROYALE published in a 1963 issue of National Geographic.

The question now, as put forward in the Science article is whether we should make an attempt to genetically rescue the population, or continue the “hands-off” approach that has been adopted these past 50+ years. As noted in the article, there is evidence to suggest that a genetic rescue is plausible citing the Florida panther as an example. Additionally there has been a documented impact of the arrival of new genes into the wolf population through analysis of the DNA of wolves collected over time. The article points to the story of a single male wolf entering the population and becoming a dominant male of a pack. A few years later and that male’s Y chromosome completely dominated the wolf population of Isle Royale. This suggests that introducing a few new wolves to the island could have dramatic effects on the genetics of the wolf population. Further, because Isle Royale is such a well studied system it could provide a wealth of information that could benefit the conservation of numerous other species.

In my opinion genetic rescue, while interesting, is scientifically less interesting than not interfering. Through extensive studies of this system we know that wolves are exerting top down control, as evidence suggests that trees on the island grow better when wolf populations are high.

What I think would be interesting is watching, in real time, the natural (local) extinction of a species, and the ensuing effects on the properties of the ecosystem. We don’t often get to see the non-anthropogenically (mostly) caused extinction (extirpation) of a population, more often than not it is human’s fault for destroying habitat, or overhunting, etc. Not to mention the fact that the population could very well re-stabilize itself, the article mentions that the moose population has been low, but a recent boom in moose births could lead to future production of wolf pups in the next few years.

Beyond that, I would like to use this opportunity to learn what happens in an apparent top-down control system when the predator is eliminated. It would provide an excellent chance to study density dependence in the moose population (although I recognize that this could prove devastating to the ecosystem in the short term). Also, wouldn’t it be interesting if we found that the moose population continued to cycle even after the loss of wolves (like the lynx hare system).

Of course, these are just my off hand thoughts about it. They have folks coming up with solutions who are much more knowledgeable about this issue than I  (a mere 2nd year grad student). Does anyone else have thoughts about to genetically rescue or not to genetically rescue?  Because in the end that is the question.

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