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.