Poop Reveals an Immigrant in Isle Royale Wolves’ Gene Pool

The population of wolves on Isle Royale was formed when a pair of wolves crossed frozen Lake Superior in 1949 from Canada. Since 1958, one of the most important and longest studies of wolf/moose interactions has taken place there. The wolves and moose have fluctuated up and down due to many causes such as tick infestations, genetic inbreeding and fluctuations of forage for moose and prey for wolves. These interactions are seen as a microcosm of wolf prey interactions and demonstrate the many influences on populations.

In the course of this study researchers have found that another male wolf crossed the frozen lake and joined the population. His genes are now represented in 56%, or 9 wolves, of the population of 16 now present on the island.

Besides genetic inbreeding, there is another issue which could eliminate wolves from the island and that is the possible loss of the two remaining female wolves. That has prompted a proposal to bring a few new wolves from the mainland to supplement the population’s genetics and increase their fitness. This runs counter to the National Park Service’s policy to allow natural processes to take place so there will surely be debate about this in the future.

Isleroyalewolf.org has an interesting graph showing the historical wolf and moose population fluctuations that you can see here: http://vicksta.com/wolf%20and%20moose%20graph7.html

Poop Reveals an Immigrant in Isle Royale Wolves’ Gene Pool
Michigan Tech News.

Controversial wolf hunt over, Sweden now wants to import wolves

Purpose of import is not due to excessive wolf mortality during the hunt. It is lack of genetic diversity-

Sweden wants to import 20 genetically diverse wolves over the next five years.  Although the Swedish Parliament wants to limit the wolf population to about 200 wolves, and so had their first wolf hunt this year, apparently the population is based on too few founding wolves and suffers from inbreeding.

The ill effects of inbreeding do not go away when a population based on just a few animals grows in size. Therefore, the importation of new wolves and the hunt are not related. Regardless of one’s opinion about the wolf hunt, bringing in unrelated wolves will benefit the health of the 200 or so Swedish wolves.

The official number of wolves killed in the recent wolf hunt was 27.

Sweden to import wolves
. UPI.com

There is a lesson here for all those people who prefer a “natural” (unassisted recovery) of any animal — unless there is a large in-migration, the renewed population is not likely to be genetically healthy even if it becomes fairly large.

Inbreeding taking toll on the wolves of Isle Royale

Crippling effects of inbreeding show the problem with natural wolf recovery based on a few wolves-

A fair number of people think that wolf restoration should be “natural,” — based solely in the in-migration of 2 to a dozen or so wolves, but there is not enough genetic variety in a small number for such a population to survive over time. The situation in Isle Royale shows this.

Story in Newsweek. Inbreeding taking toll on Michigan wolves. Scientists find bone deformities in wolves on island in Lake Superior, caused by inbreeding. By John Flesher. Associated Press Writer | AP