Gray wolves could become extinct on Isle Royale
As a proposed Minnesota Department of Natural Resources wolf hunt opens in Minnesota to thin the burgeoning wolf population, two wildlife scientists from Michigan Tech are advocating for more wolves to be brought to Isle Royale to bolster the wolf pack— now down to a population of nine with only one female in the mix— to stave off extinction at the island.
There are pros and cons to this dilemma, notes Isle Royale Superintendent Phyllis Green.
“The possibility of extinction of a species in any national park should be cause for concern. What to do about it, however, with all the current challenges that species face needs a very thoughtful approach. The results of the 54th annual winter study at Isle Royale National Park show that the wolf population is at the lowest level since the study began.”
The two scientists advocating for more wolves (or reintroduction should the current wolves be allowed to die out) are Michigan Tech researchers Dr. John Vucetich and wildlife Dr. Rolf Peterson. They spend seven weeks in the winter living on the island studying wolf-moose predation. Vucetich is an assistant professor of wildlife ecology and population biologist and Peterson is one of the world’s foremost wolf experts and has been with the study since 1970. Both are part of the 54-year old study of moose/wolf interaction conducted by Michigan Tech University, the longest continuous predator/prey study of its kind ever conducted.
Wolves first came across on an ice bridge from Canada in either the late 1940s or as late as 1950, making a winter crossing when a portion of Lake Superior froze. Wolves (mostly) thrived on the island until 2009, when the population started to crash. Their numbers have fallen from four healthy packs of 24 wolves to nine wolves. Six wolves live in a pack, one is on its own, and a male and female are currently off together, hopefully, say the researchers, mating.
Reasons for their demise are many, but interbreeding, disease, and wolves killing wolves are thought to be the main culprits.
In separate papers Vucetich and Peterson argue that man in part has caused the demise of the wolf, and because of this, the wolf needs to be brought back to the island by man.
They cite an incident in the 1980s when a dog was brought to Isle Royale and spread a disease that ravaged the wolves. The scientist also argue that because temperatures have risen from pollution (global warming) it has caused the winter tick population to radically increase (ticks, sometimes thousands, latch onto and infect moose and weaken them) and they argue the chances of another ice bridge forming from Canada to Isle Royale—some 17 miles away—are slim. They also say if left unchecked, the moose will overpopulate and strip the island of much of its vegetation. A recipe that could in turn cause the moose to be decimated by disease and starvation.
But the last theory Vucetich and Peterson put forth has been countered by wildlife biologists who note that moose predated the wolves by at least 50 years on the island, and some of them say that climate, habitat, and available browse may be more important than the role wolves play in determining how moose fare on the island.
According to researchers, moose can live to be 17 years old and weigh as much as 1,800 pounds. In a typical summer day they eat 40 pounds of vegetation. In the recent winter survey conducted by Vucetich and Peterson the population of moose on the island increased from 540 in 2011 to 750 in 2012.
Wolves will live up to 12 years but typically die before their 4th birthdays. They die mostly from starvation or from a fight with another wolf over food. A wolf can eat as much as 20 pounds of meat at one feeding. Ravens, who follow wolves, will eat as much at 2 pounds of meat at a feeding. Red fox will also eat some of a moose kill, but it is in small relationship to what wolves and ravens eat.
These are just a few interesting facts learned by the Michigan Tech researchers, and both want to continue the study, noting that about every five years something happens that they can’t predict. While they say that from a scientific viewpoint, man’s interaction with these animals is best left out, but because of the uniqueness of studying moose and wolves on an island where hunting and trapping is forbidden, much more can be learned, and that should weigh heavily in any decision made by the National Park Service.
“The options that the Michigan Tech University researchers have put forward for intervention are all viable and will be evaluated along with others that take into account the broader context of wildlife management and wilderness,” said Green.
Helping the National Park Service with its decision is an interdisciplinary group of National Park Service wildlife biologists, wilderness specialists, and natural resources experts. They have met once and are awaiting more data from the Michigan Tech researchers. Once enough data has been collected they will move forward with a decision that will take into account a variety of factors, including climate change, species interactions, and ecosystem dynamics. Green said she hopes that happens within the next 9 months.
“I hope by the next winter’s study we have the best options available to us so we can go forward with a plan. Right now we have more questions than answers. It’s good to address the questions now, when we have the time, in a very thoughtful way,” said Green.
Even if there aren’t any new wolves added to the current mix, including pups born on the island, some of the current wolves might live up to a decade longer.
So do they bring wolves in to expand the breeding potential? Do they let the current group die out if they can’t make it? Then reintroduce wolves to the island?
“We have seen the population of wolves expand on the mainland while their numbers decline in isolation, away from the mainland, with limited resources available on the island,” said Green.
But if the wolf is saved, or can save itself, the world’s longest predation study will continue, and, as Green noted, that too, has a lot to offer.