Still
jittery from the excitement of the day, I headed out of Ashland, WI, along the
lake. A glimmer of twilight still lit the sky, and a bright planet hung above
the road. The calm waters of Lake Superior reflected the heavens with a
magical, luminous beauty. My imagination skittered out across the glassy
surface, landed briefly on two almost mythical islands, and then back to the
events of the day.
Rolf
O. Peterson had just concluded his keynote address at the Midwest Wolf Stewards
Conference at Northland College. Hearing him speak for the first time was a
thrill. I grew up without much of an interest in wolves, but Rolf changed all
that. After reading his landmark book, “The Wolves of Isle Royale,” while
preparing to teach winter plant identification for a wolf ecology course, I
became captivated by the incredible stories and valuable knowledge generated by
his long-term research project on Isle Royale. Wolves protect plants by
controlling herbivores, he revealed. With that, I was hooked.
The
story still fascinates me. Moose swam the 15-20 mile expanse to Isle Royale in
the early 1900s. With their hollow, buoyant hair, large paddle feet, and huge,
warm, biomass, moose are excellent swimmers. Almost anything else needs wings,
an ice bridge, or a boat to get to the island. For fifty years, the moose
population boomed and busted in response to weather conditions and food
abundance. Then, in the 1940s, wolves crossed an ice bridge and “introduced a
new management plan,” joked Rolf.
The
wolves also initiated a new human interest in the island – research. Wildlife
biologist Durward Allen worked for years to get funding and permission to
research the newly arrived wolves. He finally succeeded in 1958, and pioneered
the project. Rolf Peterson was his final graduate student. Through their
efforts (and the many people who help them), we’ve all had access to the
incredible drama unfolding on Isle Royale.
As the numbers of both
wolves and moose fluctuated widely over the years, our mythical beliefs of a
system in balance were challenged. The wolf population on the island rose to
the highest density ever recorded in nature, and then plummeted dizzyingly with
the introduction of canine parvovirus. The moose population took off, while the
wolves struggled, now handicapped by genetic anomalies caused by severe
inbreeding.
With the fluctuation in the
numbers of charismatic megafauna came ups and downs for vegetation on the
island, too. After the huge wolf crash due to parvovirus in the early 1980s,
moose exploded and ravaged the trees. Rolf showed horrific photos of young
balsam fir trees stripped bare up to their tips. But, as the wolves recovered,
so did the trees.
This winter, Rolf and his
research staff found that the wolf population had decreased from nine wolves to
only three, while moose had risen to 1,250. One of those three wolves has so
many genetic anomalies from inbreeding, that Rolf suspects it may already be
dead. Two new wolves came and explored the island for a few days, but traveled
back to the mainland just a few days before the ice bridge melted.
With the moose management
that wolves brought to the island effectively gone, what might happen in the
future? The moose are on track to double their numbers in a few years. The
remaining mature balsam fir trees are nearing the end of their lives, with
little hope for their seedlings to escape browsing. The National Park Service
is conducting an Environmental Impact Statement for various management options,
but that process may take years.
As the future of wolves on
Isle Royale seems to teeter at the brink, a thrilling new story is emerging on
another island in Lake Superior. During the morning session at the Wolf
Stewards Conference, Brent Patterson, of the Ontario Ministry of Natural
Resources and Forestry, reported on three wolves who have just arrived on
Michipicoten Island in northeastern Lake Superior. This little Provincial Park
is the third largest island on Lake Superior, and sits about ten miles
offshore. Caribou were reintroduced to the island in the 1980s, and they have
been doing well.
Last October, a kayaker
unzipped his tent to find two wolves staring back at him. Later, tracks of
three wolves were discovered walking down the beach. This February, Brent and
others collared three very large wolves – an adult male and adult female, and a
young female. Preliminary data show that these wolves are eating “high on the
hog,” and are able to subsist on only the choicest bits of the many winter-starved
caribou they take down.
Researchers are on the edge of their seats, waiting to
see if the adults will breed, how the caribou will fare, and what unforeseen
events will result in more questions than answers.
When asked to compare and
contrast the situation on Michipicoten to the one on Isle Royale, Brent quickly
listed a few ideas – they are both protected islands in Lake Superior with a
single ungulate prey, and a single large predator. Unlike Durward Allen’s long
delay in starting research, Brent is able to jump right in with the latest
satellite tracking technology. Both islands had three wolves at our last count.
“But,” Brent added with a chuckle at his understatement, “those wolves are on
very different trajectories.”
For over 45 years, the Cable Natural
History Museum has served to connect you to the Northwoods. Come visit us in
Cable, WI! We are currently constructing our new exhibit: “Lake Alive!” which will
open May 1, 2015.
Find us on the web at
www.cablemuseum.org to learn more about our exhibits and programs. Discover us
on Facebook, or at our blogspot,
http://cablemuseumnaturalconnections.blogspot.com.
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| The last wolves of Isle Royale. Photo by Rolf Peterson. |
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