Nonprofit, nonpartisan journalism. Supported by readers.


Options narrow for Isle Royale wolves, and genetic rescue option falls off the table

The National Park Service will now focus on the core question of whether to replace the island’s crashed wolf population with new wolves rounded up and imported from elsewhere.

A new winter study indicates that the number of surviving wolves has fallen from three to just two.
Photo by Rolf Peterson, Michigan Technological University

The wolves were heading for shore and we only had one more opportunity to circle overhead before they reached shore. We circled and then headed for the landing spot at the other end of the lake. I craned my neck and kept watching the wolves. I thought it ironic that as the wolves reached shore, they were framed by the long shadows of tall fir trees, trees that existed now only because of previous generations of wolves that had reduced moose density in the 1970s. This scientific finding is 20 years old, but it hasn’t penetrated the thinking of everyone.

Finally, the wolves disappeared in the trees and we were on approach to land. Without saying it, I thought, “Thank you, wolves, for all you’ve taught us … I’m sorry, very sorry, that it wasn’t quite enough.”

 … Before the engine was quiet, I had dried my eyes … knowing this was the last time anyone would see wolves on Isle Royale this winter, and perhaps for a very long time to come.

— From Rolf Peterson’s post at the blog of the Isle Royale Wolf-Moose Study, marking the end of the 2015 winter study.

Article continues after advertisement

In the year since those words were posted, two things have happened that bear heavily on the fate of the Isle Royale wolf population:

  • A new winter study indicates that the number of surviving wolves has fallen from three to just two.
  • The National Park Service, having reached the obvious conclusion that these numbers mean “natural recovery of the population is unlikely,” has decided to pick up its pace on deciding whether to restore them.

After a public-comment period and “additional internal deliberations,” the service said in its announcement last week, managers will henceforth shelve such fanciful notions as bringing in hired hunters to replace wolves as the primary control on the island’s swelling moose population, which poses a serious threat to the island’s fir forests, among other bad ecosystem impacts.

Instead, they will focus on the core question of whether to replace the island’s crashed wolf population with new wolves rounded up and imported from elsewhere.

‘Rescue’ off the table

But those of you who have been paying attention will notice that a third option considered superior by many – restoration of the existing wolves to population health through “genetic rescue” and its infusion of new DNA – is also off the table, and necessarily so.  

Two wolves are simply too few to rescue this way, and for that matter, three wolves probably weren’t enough either. For genetic rescue to have had a chance, the park service would have had to act three, four or even five years ago, when the population started its current plunge toward extinction, and maybe try it more than once.

Instead, the service let its focus be drawn toward such hazy (though important) matters as how a changing climate might reshape the island’s ecosystems, and what precedents would be set by tinkering with wolf packs in a heavily visited national park that also happens to be designated wilderness for the most part. Whatever else it means, last week’s change would seem to include an indirect acknowledgement of error there.

In the spring of 2014, with the wolf population fallen to nine from a six-decade average of about 22 (and a high-water mark above 50), Park Superintendent Phyllis Green announced the opening of a decision-making process whose initial scoping phase would run until late 2017, with a few additional years beyond that to implementation.

Now that the scoping has been compressed to just four alternatives – three reintroduction options and one hands-off – all of the work may be wrapped up by the fall or winter of 2017.  

That won’t be quite fast enough to satisfy, say, Michigan’s two U.S. senators, Debbie Stabenow and Gary Peters, who have been pressing the park service to have a solution in place by this July.  

Article continues after advertisement

But of course these things take time.

Three action options, one hands-off

Here are the four alternatives the park service will consider, and on which it will receive public comment until May 16:

Alternative A (No-Action Alternative) The NPS would not intervene and would continue current management. Wolves may come and go through natural migration, although the current population of wolves may die out.  

Alternative B The NPS would bring wolves to Isle Royale as a one-time event over a defined period of time (e.g. over a 36-month period) to increase the longevity of the wolf population on the island. This action would occur as soon as possible following a signed record of decision.  

Alternative C The NPS would bring wolves to Isle Royale as often as needed in order to maintain a population of wolves on the island for at least the next 20 years, which is the anticipated life of the plan. The wolf population range and number of breeding pairs to be maintained on the island would be determined based on best available science and professional judgment. This action would occur as soon as possible following a signed record of decision.  

Alternative D The NPS would not take immediate action and would continue current management, allowing natural processes to continue. One or more resource indicators and thresholds would be developed to evaluate the condition of key resources, which could include moose or vegetation-based parameters. If a threshold is met, wolves would be brought to Isle Royale as a one-time event (per alternative B) or through multiple introductions (per alternative C).  

Reading over the alternatives put in mind of several fascinating conversations I’ve had with John Vucetich, who is Rolf Peterson’s colleague at Michigan Technological University and a few years ago succeeded him as director their wolf/moose research project – apparently the longest-running study of predator/prey relationships in a closed ecosystem.

Vucetich isn’t speaking publicly about the park service decision or the Isle Royale research just now; he and Peterson are busy finishing up this year’s annual report in time for its release in a couple of weeks.

The case for rescue

But over several years he has made a strong case – persuasive, in the end, even to the initially reluctant Peterson – that of all the options available to park managers for preventing a moose-driven trashing of the island ecosystem, genetic rescue was the best for at least four reasons:

Article continues after advertisement

  • It preserves in the island’s gene pool the DNA of the historic wolf population, including perhaps important, genetically encoded knowledge gained from adapting to its closed ecosystem.
  • It most closely mimics the “natural” processes that brought new wolves to the island from mainland sources, over ice bridges that are becoming less common in a warming climate.
  • It leads to new scientific knowledge about genetic-rescue techniques and results. (We already know a lot about wolf and predator reintroduction to correct extinctions in places like Yellowstone, Vucetich likes to say; augmenting an ailing population with healthy new members is a newer but less well understood alternative).
  • It is perhaps the fastest way to restore a predator population to a level of health that can exert effective control over a prey population, which now has been lost on Isle Royale for the past few years and at least a few years to come.

But of course the rescue only works if performed in time, and the time for rescuing Isle Royale’s wolves has now passed.