Botkin Chapter 3: The Wolves and Moose of Isle Royale

Sharon is busy with schoolwork this week and has asked me to pinch-hit on the Botkin book discussion blog. PLEASE make all comments at the book blog location once this has been posted here by using the link in the upper right hand corner under the Botkin book icon. If you haven’t visited the site yet, the best place to start — and to introduce yourself — is:

Rather than provide a summary of Chapter 3, as I did with Chapter 2, I am reprinting a recent post by Dr. Ralph Maughan, an expert on wolves and a strong proponent of their reintroduction in former habitats: The reason for doing this is that Maughan is commenting on the very focus of Botkin’s 3rd chapter, which starts with the story of his (Botkin’s) experiences researching the predator/prey relationships between moose and wolves on Isle Royale, an island in Lake Superior near the Canadian border that is over 200 square miles in size and contains 45 lakes of its own. What has made the island particularly interesting for this type of study is that it has never been heavily influenced by people; moose first arrived there from the mainland only about 100 years ago; and wolves didn’t arrive (except for a failed National Park Service attempt to establish them with zoo animals in the late 1940s) until the lake froze over more than 50 years later — after the moose had a half-century to build their population without a major predator to inhibit their reproduction.

As with Chapter 2, Botkin uses this story and others — sandhill cranes, Canadian lynx and microbes — to examine the “balance of nature” as it has been defined mathematically and as actually observed, to examine the differences between the two. Both writers cite the work of long-time Isle Royale researcher and wildlife ecologist, Rolf Peterson, but they seem to come to different conclusions as to why that work is important:

I would like to thank Dr. Maughan for permitting me to repost his work here. Of the 72 comments on this topic on his blog, a significant number were my own in sometimes heated response to many of his regular commenters. Tree and Matthew will understand. It was my second visit there, and both times I seemed to stir up the natives with my thoughts and opinions — mostly because of the old “anonymous commenter” discussion. I think JZ first sent me there and after I went and got a similar reaction, he said he was just joking. Maybe it was Derek, but you will see the result if you read the comments, too.

I will leave it up to actual readers to determine their own thoughts on these two perspectives, but I’ll repeat Botkin’s analogy of “resilient stability” in regards to the “balance on nature” argument by his comparison of a person with a drink building a house of cards on a train: the house of cards will collapse with a bump or large vibration, but the drink will only slosh around before it returns to its former level. One is a fragile balancing act, and one is resilient. For me at least, that provides a clear metaphor for this discussion. Now for Maughan’s post:

Should the declining inbred wolves of Isle Royale N.P. be augmented?

Should there be genetic rescue (outside wolves brought in)-

For many years the wolves and moose of Isle Royale National Park in Lake Superior have shown that wolves do not wipe out their prey. When wolves become abundant enough that the disappearance of prey seems probable, the wolves die back.

On the other hand, when wolves have declined to few in number, the moose population expands and begins to decimate its prey — the moose-edible vegetation of the island.

This rough balance has existed ever since wolves colonized the island one hard winter. In 1949 a pair of wolves walked over to the island on the frozen lake. The pair found an island overrun with moose. The moose themselves had migrated to the island 40 years earlier.

The wolf population expanded, of course, and brought the moose number in check (and more). Then the wolves began to starve off and the cycle began.

The moose prefer aspen, and they do well eating it. However, they mostly wiped that out before the wolves came.  Ever since, they have relied primarily on the less nutritious balsam fir and lichens.

Both the moose and the wolves are also subject to inbreeding. It is especially a problem for the wolves, all of which descended from the original pair. So, in addition to the cyclic malnutrition when the moose population drops too low, the wolves have been seen to suffer from increasing genetic defects. One of these is poor reproduction even when there is enough food.

Down to just 8 wolves, they seem doomed without outside genes from new wolves. There have been up to 50 wolves at a time on the island, although many scientists think a stable number is about 25. It should be noted that there have always been wide fluctuations around this “mean.” The eight wolves seem to have gained a brief reprieve with the birth of 2 or 3 pups in 2013 after several years with none. Nevertheless, it is hard to see how the unaugmented population can survive much longer. It is less and less likely that the lake will freeze and wolves from Minnesota, Michigan or Wisconsin find their way to the island.

The wolves and their relationship to the moose and the vegetation have been studied since 1958. Dr. Rolf Peterson, in particular, is the person most closely associated with the studies. He would like to see some genetic rescue. Dr. Dave Mech, however, who is another avid student of the island’s wolves is reported to want to first let natural events play out.

With the wolf population so low, we would now expect the moose population to be expanding. It is. However, it is increasingly suffering from tick infestation. This is a problem for moose in general during winters, but Isle Royale has seen warmer winters as the climate changes. This makes the effects of the bloodsucking  arachnids more severe.

Rolf Peterson recently sent out the following letter.

The National Park Service is interested to receive your input on the pending decision regarding the future management of wolves on Isle Royale.  Please send your input to the following email address: (note the “underscore” between ISRO and Wildlife)

The Park Service is considering three options:  (1) do nothing, even if wolves go extinct; (2) allow wolves to go extinct (if that is what they do), and then introduce a new wolf population; or (3) conserve Isle Royale wolves with an action known as genetic rescue by bringing some wolves to the island to mitigate inbreeding.

While expressing your view, consider providing as much detail on the reasons for your preference, as the Park Service believes the reasons for your view are as important as your view.  If you have any questions on the process or anything relating to providing input, please do not hesitate to ask me.