The challenge of balancing life in the complex ecosystem of Isle Royale


An aerial view of the east end of Isle Royale is pictured.


Story and photos by Scot Stewart

“The art of simplicity is a puzzle of complexity.” –  Douglas Horton

It is perfect when all the pieces of a jigsaw fit into place.  With even one piece missing it just looks terribly wrong.  The image of the ecology of Isle Royale National Park, one of the nation’s finest parks, is one of those grand puzzles, perhaps the most perfect of all in the national parks system.
Isle Royale National Park is a truly remarkable wilderness area in many ways. Located in northern Lake Superior, it is the second largest island in the Great Lakes, after Manitoulin Island in Canada. It is the third largest island in the Lower 48 after Long and South Padre Islands. It is the only U.S. national park completely closed in winter.  It hosts the longest large mammal study in the world – the wolf-moose-beaver study started in 1958 – 60 years ago.
In 1958 Durward Allen, a professor of wildlife ecology and wildlife management at Purdue University began a study of the wolf-moose relationship at Isle Royale. Wolves had crossed over the lake on an ice bridge in in the winter of 1948-1949, bringing a controlling factor to the moose population on the island. The effects of an uncontrolled moose population on the vegetation of the island became a concern on the island shortly after they arrived around 1910. The examination of the moose-wolf relationship became a hallmark investigation in large mammals, the longest running study of its kind, and a powerful scientific study of the ”balance of nature” – the interactions of all the elements of an ecosystem, one with seemingly little interference from man.
This island complex is a remote complex of 400 islands in Lake Superior, about 15 miles from the Minnesota and Canadian mainland and 56 miles from the Michigan mainland. It contains 132,018 acres of wilderness, 99 percent of the total area, does not allow hunting or pets and is closed between November 1 and April 15 annually. It would seem to be one of the most pristine places in the Lower 48 states, and it is.
Isle Royale is considered a very special place.  An island, out in the middle of a cold, big lake. That lake, because it is cold, and extremely temperamental discourages even large boats from visiting. Commercial boats working with the U.S. National Park Service take park personnel, equipment and visitors to the island from Copper Harbor, Houghton and Grand Portage, MN. A seaplane has taken equipment and visitors to the island on and off over the years from Houghton too. Private boats are allowed to visit, but only the most intrepid of sailors visit on their own, and some elect to follow larger craft as a measure of safety. All told, the island has around 28,000 visitors a season, the fewest of any national park.

A wolf is shown atop a beaver dam at Isle Royale.

The wolf-moose relationship has been a dynamic one, drawing in some of the world’s finest biologists and ecologist – Allen, L. David Mech, Phillip Shelton, Rolf and Candy Peterson, and John and Leah Vucetich. It began with the wolves and moose, added other animal species on the island like snowshoe hard and American beaver, then the island’s vegetation, the climate, and man. The study has worked to consider all the factors that paint the picture of the island’s ecology.
The picture would always be perfect, the problem is people keep messing with it. The tableaux include a large three-quarter ton, palmate-antlered plant eater called a moose, the largest living member of the dog family–the wolf, a balsam fir, best known for its role as a Christmas tree and its forest home, and a moderate temperate climate.  There are plenty of bit players: beaver, some salty aquatic plants, forest fires, plan succession, a snail, and a tapeworm. There are plenty of pieces to the puzzle, and it is probably one of the most complex for its seeming simplicity
The changes man has made to Isle Royale have been many, some bewildering. The search for copper was one of the first ways humans have touched Isle Royale. For an island 15 miles from the mainland, that canoe paddle alone was an impressive journey to make even on a calm, flat-water day. Since then, the hand of man has found many ways to touch this land. Some of them have been seemingly small.
For thousands of years, starting at least as far back as 2,500 B.C., people went there just to visit, hunt and pick berries. Eventually they went also to mine a little copper – native copper, the pure, natural metallic kind for use in tools and jewelry. They made small pits in the rock as they pounded the living daylights out of the basalt to pry out the malleable brownish-red metal. It was some of the purest natural copper ever found in nature. That early discovery led to a major assault on the island from the 1840’s to the1890’s
The first stations on the island were of commercial fishermen, set up by the American Fir Company between 1837 and 1841. Commercial fishing has continued on to modern day, though the arrival of the sea lamprey in 1967 nearly ended the practice. Today only small limits are allowed in the waters surrounding the island. It was shortly after the arrival of the fisherman that the copper miners arrived.
In the 1970’s studies showed fish in Lake Superior, and even more surprisingly Lake Siskowit on Isle Royale, contained significant levels of toxaphene, a mixture of 670 chemicals used as pesticides on a large variety of crops, but primarily on cotton fields in states hundreds of miles to the south.  In sufficient doses, toxaphene causes damage to the human nervous system, kidneys and liver of humans and can even cause death. In a great article produced by the Minnesota Sea Grant,, details explain how prevailing summer winds carried the chemicals, usually attached to water droplets northward in summer and precipitation dropped them on the lakes.  Once in the water, the chemicals move through the food chain, eventually accumulating in larger concentrations in fish. No similar chemicals were being used anywhere close to the park in large quantities.  Those pesticides are banned in the U.S. today, but are still found in the area’s fish. Other chemicals, like DDT and PCB’s have also found their way to Isle Royale in similar ways.
Copper was first sought along the rugged, nearly bare shores of Isle Royale. As more exploration occurred the search moved inland. The land was cleared as commercial copper mining spread across the island with the timber used to build homes and other structures and warm them. According to information from MTU and Isle Royale National Park, Historic Isle Royale Mining Companies, commercial mining on Isle Royale produced nine major mines and fell within three major periods, the start, between 1843 and 1855, a middle period from 1873-1881, and a final four year boom between 1889-1893.
The population on Isle Royale in these early days peaked in 1847 when 120 labored there.  Most were ferried back to the mainland each winter. At the Siskowit Mine a dozen men lived in a building serving as both the general store and a barracks. During mining operations copper was removed in masses and sheets, placed in barrels in pieces with some waste rock still attached, and in smaller pieces stamped out of the rock. This ore was heated first to help make the poor rock more brittle for stamping. Timber was cut for the heating and stamp sand was left behind after the crushing.

An old steam hoist, abandoned from industrial activities on the island a century or so ago, sinks into the forest floor at Isle Royale.

Today there are remnants of the copper mining era still visible on the island.  Poor rock piles are visible near Rock Harbor, stone foundations can still be found around some of the mine sites, and ancient pits from the distant past, exploration pits from the 19th century and abandon mine shafts can still be seen across the island. One of those mine shafts claimed the lives of three of the twelve wolves still left on the island in 2011.
As in many places, like Colorado, Arizona, Nevada, Montana, and even the Keweenaw Peninsula, where boom days of mining ended, tourism replaced mineral extraction as viable way to create jobs and bring income to a depressed area. Visitors had come to visit the island since ancient times. As steamers made the trip easier and faster in the late 1800’s more came to see this isolated paradise. In 1931 Congress designated it for national park status. Because of private claims on land were complex, it took nine years to finally gain national park status on April 3, 1940. Due to the pressures of World War II, it was not officially dedicated as a national park until August 27, 1946.
The impact of settlements from the mining days had been largely erased by forest succession. A large fire had raged across the park in 1936 burning through more than 20 percent of the forest. It provided a new area of fresh vegetation to feed a moose population that had gone through some tremendous ups and down because there were no large predators to control the population and no hunting on the island. But then the wolves came during the winter of 1948-1949 and the island slowly fell into a quiet balance. Once well established on the island, two dozen wolves seemed to stabilize the moose population at about 750-1000. It seemed to prove there was a balance of nature in an “undisturbed” state.
The island held tight on nearly all of its inhabitants and the role appeared to be minimal – hikers, trails, some boats at docks, a few buildings. Most of the island was declared wilderness. In winter the only visitors were members of a team of researchers counting wolves and moose, looking for signs of other species and checking to find out what moose were being impacted by the wolves.
Then some serious cracks began to develop in the picture. The pieces of the puzzle did not have the snug fit they once had. Because there was not much movement of wolves from the mainland to the island, inbreeding began to take its toll on the genetic vitality of the wolves began to sag, with little added diversity of genetic stock. Only one new male had made a dent in the problem of inbreeding on the island.
In 1980 a dog was taken to the island aboard a private boat. It carried canine-parvovirus, a highly infectious viral disease easily spread. The symptoms of the most common form are intestinal distress leading to anorexia usually in older animals, and an attack of cardiac tissue in pups usually under the age of four months.  Both forms can be fatal.  This brief visit of the dog to the island is believed a part of what led to a major crash in the wolf population in 1980-1982, basically cutting the number of wolves in half.
The wolf population on Isle Royale was at an all-time high. Other factors may have also contributed to the decline, including inter-pack conflict and lack of available food, but it wasn’t until the late 1980’s the virus disappeared from the island and the wolf population did not rise above 20 again until 1986. Since then the state of the wolf’s health on Isle Royale has be one of concern. Climate change has had a variety of effects on the elements of the island. Wolf numbers did climb to 24 in 2009 but plummeted to only 12 before the mine disaster in 2011. By last summer it had dropped to two, a father and daughter, after their offspring, a sad wolf with a crooked spine and spindly tail, dubbed “The Thing” by Rolf Peterson, died.
As the population plummeted again, both Peterson and Vucetich pondered the future of the moose and the vegetation on the island. The population of the moose would skyrocket again, and the plants would be over-browsed. The balsam fir cover had disappeared from much of the island and currently stands at six percent, a fraction of its former part of the island mosaic of vegetative cover. Scientists, national park administrators, park visitors and wilderness lovers have debated the topic for years. Does the park wait for the wolves to die then reintroduce more wolves to control moose numbers, or introduce wolves now?
The decision on wolves on Isle Royale has not been an easy one.  Even the question about what is natural on the island is a cloudy picture on human visitation, exploitation, investigations and appreciation, entangling an isolated boreal forest. The National Park Service mission states: “The National Park Service preserves unimpaired the natural and cultural resources and values of the national park system for the enhancement, education, and inspiration of this and future generations.”
The debate centers around the idea of man’s role on the island: should we intercede?
(Next Month: A decision is made – how will it affect Isle Royale?)

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