How Did That Get Here? A Naturalist’s View of Isle Royale

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We heaved our backpacks – loaded with high-energy foods, waterproof tents and warm clothing – onto the ferry dock at dawn. Waves crashed around the Voyageur II.

When the ferry captain came to greet us, we expected him to say something like “All aboard!” Instead, with a bemused smile, he boomed over the stormy bluster to the waiting crowd and said, “We’re not going.”

At first there was stunned silence and a few hesitant chuckles (he looked like he might enjoy pulling your leg). But he wasn’t joking, and neither was Lake Superior. Eight-foot waves and 30-mph gusts across a 20-mile expanse of cold water are nothing to mess with.

“This is your one chance for a refund,” he said. “Otherwise be here by 4:45 a.m. tomorrow.”

The park ranger at Grand Portage National Monument didn’t miss a beat when we noted our delayed departure. “Welcome to a long tradition of people waiting at Grand Portage for good enough weather to start a journey on Lake Superior.”

Icy water, big winds and craggy rocks don’t make for safe or easy crossing. Gardens of shipwrecks can attest to that.

But rising out of the crystal-clear water, 14 miles from shore, is a bit of an anomaly – Isle Royale, a 45-mile-long, 9-mile-wide bedrock island. Only 10,000 years ago it emerged, cold and barren, from under the glaciers. Today it teems with life that somehow made the treacherous journey.

The next morning with the rolling, wet, cold ferry ride behind us, we disembarked gratefully at the Windigo dock on the southwest corner of the island. Finally, our long-awaited, hiking and camping vacation was about to really begin.

Before long we met several pairs of hikers just ending their trips. We asked about their route on the island, their hometown and which ferry they took. In essence, we wanted to know: “How did you get here?”

Mostly they came by water, but one couple arrived in a float plane.

Considering once again the vibrant life of the island, I soon started to apply my question – “How did you get here?” – to everything we saw.

While humans rarely arrive by air, it's obvious that many of the island's wild residents took that route.

The haunting wails of loons drifted up from every lake we passed. Chickadees chattered above us as we hiked while flocks of cedar waxwings played follow-the-leader between berry-laden mountain ash trees. All told, more than 160 kinds of birds live on or visit the island.

It’s not hard to imagine how the birds got here, or, consequently, how the seeds of their favorite fruits got here either.

Slowing down to pick thimbleberries left us open to attack from other air travelers – the delicate mosquitoes that once made that dangerous crossing.

Pleasantly, the whine of mosquitoes was rare, but red squirrels scolded us incessantly.

Water seems the only plausible route for the squirrels. Did the first squirrel on the island drift here on a raft of vegetation? What a frightening ride that would have been without motor, rudder, rain gear or food. How many attempted journeys failed – with no refund? Now the red squirrels have been here so long, separated from the mainland population by that arduous journey, that they are considered their own subspecies: Tamiasciurus hudsonicus regalis (regalis for “royale”).

A crashing in the brush next caught our attention. Through the spruce trunks, we glimpsed the hulking silhouette of a cow moose as she vanished into woods. The park’s prevailing view is that moose swam here around 1900 during a time of high population on the mainland.

Having sighted one of the iconic species of Isle Royale, we were now on the lookout for the other: wolves. Large, hairy scat on the trail signaled their presence, as did a few big, four-toed tracks on muddy trails. With only two wolves left on the island, that was more sign than I’d dared to hope for. Wolves likely crossed the ice bridge in the winter of 1948-49 and helped stabilize the moose population for many years. Now these wolves suffer from inbreeding – one liability of living on an island – and the National Park Service is exploring management options from doing nothing to introducing new packs.

Suddenly something caught my eye. “Rattlesnake!” I hissed under my breath, the surprise sighting stopping me in my tracks.

No, this wasn’t a fierce predator striking fear into my heart; it was whorls of grayish-green leaves with white markings hidden within the leaf litter along the Minong Ridge Trail.

The checkerboard pattern adorning this plant’s leaves is said to resemble a rattlesnake’s mottled camouflage, while the broadly oval leaves recall plantain leaves (a plant common in yards and disturbed areas).

Together, these features resulted in an unappealing name – rattlesnake plantain orchid – for this beautiful little plant.

Traveling across the island in late August, I spotted the leaves of several orchids, already past flowering. Orchid flowers are alluring, but what happens to the seeds after pollination fascinates me even more.

Orchid seeds are almost microscopic; more than 1 million fit into the capsule that develops from a single flower.

Unlike island backpackers, these seeds don’t carry their own food rations. For the dustlike orchid seed to germinate, it must first be infected by a specific fungus. The fungal mycelia provide the seed with sugar and nutrients. Once colonized by fungi, a baby orchid plant, called a protocorm, grows and eventually produces leaves and roots. Some orchids never produce leaves or chlorophyll at all, and live out their days entirely as a parasite on a fungus.

Knowing these basics of orchid germination, my “How did it get here?” question baffled me even more for these plants. How could tiny, fragile seeds make such a long, treacherous journey, 14 miles across the Lake, and then just happen to land where their friendly fungal partner was already established?

My amazement only deepened when I used the latrine near our Rock Harbor campsite. The educational poster on the inside of the door bragged that Isle Royale is home to 32 species of orchids. With only 600 or so plants identified on the island, that means 5 percent of them are orchids!

When I shared my amazement with a fungus-loving mycologist friend, he was less impressed. “It’s almost inevitable,” he shrugged.

Turns out that the numerous, minuscule seeds of orchids are well-adapted to wind dispersal. It’s how they colonize tree trunks in the rainforest. Likewise, fungal spores are often wind-dispersed, even over many miles, and the species of fungi that orchids must parasitize are quite common. They likely were subjected to the same Lake winds.

A little more research revealed that Ontario, the province upwind of Isle Royale, hosts more than 50 species of orchids. So, maybe, 32 on Isle Royale isn’t that impressive after all.

Then again, maybe it is.

By air, by water or by ice, it’s fascinating to imagine how such a diversity of seemingly fragile organisms came to colonize the largest island on the world’s largest freshwater Lake.

As we found out, for humans, too, the journey can be arduous and require a bit of luck. Perhaps I’m biased, but I think that makes the creatures who do get here a little more special.

Emily Stone is the naturalist and education director at the Cable Natural History Museum in Cable, Wisconsin. She writes a weekly nature column for the museum and has a new book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses.