Century-Long Glacier Study May Help Us Crack Climate Change

It's not often an ecologist gets to play sleuth in so adventurous a fashion—picking through musty papers in the Midwest for 100-year-old hand-drawn maps that lead through dense Alaskan underbrush populated by wolves and brown bears. But that's how scientist Brian Buma tracked down the work of a legend—a godfather of modern ecology so prominent in his field that the Ecological Society of America has an award named after him.

Buma, a University of Alaska, Southeast, assistant professor, was hunting for nine tiny patches of land in the enormous wilderness of Alaska's Glacier Bay National Park. These square-meter-sized plots first mapped in 1916 by botanist William Skinner Cooper were central to one of the longest-running natural experiments in science, and to our understanding one of the most-studied and dynamic places in the country.

Cooper knew the rich history of Glacier Bay, had read the expedition diaries of Capt. George Vancouver from the 18th century, had followed naturalist John Muir's canoe trips, when Muir compared its geology to Yosemite Valley's. Cooper even had led the charge to have the region declared a national monument, 55 years before it became a national park in 1980.

But the hidden patches where Cooper had done groundbreaking work that still makes it into college textbooks somehow had been lost to time. Buma aimed to find it.

"I grew up with Indiana Jones and I've always liked discovery and finding old things, chasing down forgotten places, pushing the boundaries," Buma says. "This had it all."

So, last summer, a century after Cooper began, Buma carted historical photos, a metal detector, and bear mace, and, funded by a National Geographic grant, he uncovered Cooper's worksites. Now he's using them to reframe our thinking about the surprising ways plant communities may shift with climate change. In a paper published Thursday by the Ecological Society of America, he showed, as Cooper before him, that as glacial ice in the bay recedes faster than almost anywhere on Earth, new shrubs and forests are springing up, just not as simply and uniformly as one might expect.

"People used to assume that plant communities change in a very orderly way, that every time you go to a forest that's a thousand years old, everything got there in the same way," Buma says. "But there was no way to test that assumption without observing a landscape over a long time, which is what Cooper tried to do. And now we've revived it."

Chasing an Old Mystery

For Buma, it started as a mystery. The first non-indigenous recorded sighting of Glacier Bay came in 1794, when British explorer Vancouver's expedition described a 20-mile wide patch of ice some 4,000 feet thick, a shoreline "terminated by solid compact mountains of ice." By 1879 when the region was visited by Muir, who was hoping to see in real time how glaciers carve landscapes, that ice had retreated almost 50 miles as part of its natural process.

In 1916, Cooper came along, and in the sterile rubble beneath the melting ice he used maps drawn by Vancouver to walk off small plots in which to track, over time, what grew in their place. Over the years and then decades, as rich soils and spruce seedlings and willows emerged, he and his students noted the randomness of the new landscapes, how each section began to appear slightly different than the others, based on the vagaries and randomness of nature. As he aged, his students took over documenting in detail how the region grew and changed.

"That's what Cooper recognized right away," says Lewis Sharman, an ecologist with the park. "Here's this opportunity to conduct this long-term experiment and learn about this dynamic landscape over time."

Says Buma, "He established the longest-running successional plot network in the world; information from those plots forms our understanding of ecology today. It was foundational stuff."

But by the early 1990s, the plots had been abandoned. The last person who knew where they were had died. This famous landscape was still shifting, but this unique window was gone.

So Buma traveled to the University of Minnesota archives. He unearthed Cooper's original data, including old photographs, hand-written notebooks from 1916, and sketched maps. Cooper's directions were like those on a pirate map: Go to a big rock and turn 15 degrees north and at 45 paces you'll find a smaller rock. Buma photocopied every scrap.

He trekked to Alaska and kayaked to the farthest reaches of Glacier. But, of course, everything had changed. Magnetic north had moved. The rocks had been replaced with iron spikes. He waded through willows as thick as a child's jungle gym. "Sometimes it took an hour to go half a mile." He saw bears and wolves.

But he also found the plots. And they were revealing.

Rewriting Textbooks?

One plot was thick with 8-foot willows, with old dead trees forming a dense thicket on the ground. Sixty feet away another plot, now shaded by the bow of a large spruce, held barely anything but needles. Some willow sections looked the same as they did 100 years ago. Others were now parts of an alder forest.

"For a layperson it's a fascinating thing. It shows how unpredictable nature can be," Buma says. "The chance fall of willow seeds in one spot and other seeds in another can really make a difference. You kick a rock in here and see the effects 100 years later."

Many ecology books that talk about plant succession suggest "first you get herbs, then mat-forming plants, then shrubs and early successional trees," Buma says. "These assumptions are built into many models"—including many of the ones scientists use to predict the effects of climate change. Cooper's purpose, Buma says, was a rejection of this tendency to rely so heavily on such inference in favor of direct observation.

As glaciers retreat and plants move north and uphill, many scientists suspect forests will expand. But Buma says it might not be so simple. "We're not seeing much of that," he says. "We're seeing willows and shrubs take over and monopolize."

He knows it's impossible to draw landscape-scale conclusions from such small plots, but that doesn’t mean there aren't lessons. Species will respond differently to warming, and some moving north will block others. "It's often the little ones that inhibit the big ones because they can move faster," Buma says.

In other words, Buma says, "models that predict an orderly process may be naive."

Sharman, for one, is grateful that Buma now plans to continue where Cooper left off.

"Cooper was a scientist who recognized the value of preserving Glacier Bay for its potential to contribute to science in the future," Sharman says, adding that science is explicitly called out in Glacier Bay National Park's mission. "There are actually remarkably few national park that have that purpose in their establishing language. That emanates directly from Cooper's influence."