Hunt for Lost Plots in Glacier Bay Yields Key Data

Posted by on Jul 27, 2017

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20th century ecologist William Skinner Cooper has a long legacy. He spurred the establishment of Glacier Bay National Park and was one of the first American scientists to use the technique of aerial photography. His name lives on through Alaska’s Mt. Cooper and the biggest award offered by the Ecological Society of America.

William Skinner Cooper returns to Glacier Bay fifty years after his first visit (Source: Robert Howe/NPS).

That legacy continues in new and unexpected ways in Glacier Bay National Park with a treasure hunt to find nine plots established by Cooper there in 1916. Cooper developed the plots in order to study how vegetation develops after glacial retreat. As soil evolved and buried the marker stakes, the plots were lost. A century after Cooper began his experiment, Brian Buma, professor of ecology at University of Alaska Southeast, was determined to relocate the plots and launched the hunt.

Such bridges between the past and present are what national parks are all about, according to Glacier Bay National Park ecologist Lewis Sharman. In 1916, Cooper recognized that Glacier Bay was changing rapidly as its glaciers retreated and exposed new land to primary plant succession.

“Glacier Bay is one of the most dynamic landscapes on earth,” said Lewis. “It’s the quintessential national park in that it encompasses a landscape with great scientific value. Scientists here are like kids in a candy store.”

“It was the most fun I’ve ever had on any science project,” added Buma, who recently published his results in the journal Ecology. “It had everything: adventure, old documents, old-school orienteering.”

The first clues to the plots’ whereabouts came from a paper Cooper published based on his trip to the area in 1916. “The directions literally read “‘From large rock, walk 30 degrees east 40 paces, to small cairn.’ It was very Indiana Jones,” said Buma. The project’s National Geographic funding included a trip to the archives in Minnesota that house Cooper’s original field notes. Some notebooks are stained by water and others burnt by sparks from campfires, according to Buma.

His research in the archives pointed to “Teacup Harbor,” a distinctive round inlet in the West Arm of Glacier Bay. Buma decided to start there, in a search he called “truly for a needle in haystack.” Magnetic north has changed by eleven degrees since Cooper’s day, so the original compass bearings were wrong, and large boulders Cooper used as landmarks are now cloaked by plants.

The plots are located in the West Arm of Glacier Bay. Photo A shows the view from plot Q1 in 1941, and Photo B shows the same view in 2016 (Source: Brian Buma/Ecology).

Isostatic rebound, the rise of land formerly depressed by the weight of a glacier, also transformed Glacier Bay’s landscape and confounded Buma’s search. Rebound has dramatically changed Teacup Bay’s shoreline and the distance of some plots from the water. Undaunted, the team headed to Glacier Bay. Their search process involved scouting from a boat, matching the landscape before them with photographs from the 1970s, and “stumbling around the woods looking at 100-year-old sketches, trying to decipher what a ‘pace’ was,” said Buma. At a likely site, they’d use a metal detector to hunt for the stakes framing the meter square plots.

Cooper’s experience locating the plots would have been far less arduous. A distance Cooper would have tromped in five minutes across the gravel takes thirty minutes or longer today, tortuously zigzagging through brush, according to Buma. “I’d love to know what he’d think if he could come back and see the plots,” said Buma.

Bushwhacking through willows up to five meters tall and staying vigilant for bears, the team found the first three plots fairly quickly, but it took four days to find the next. One plot was lost to erosion in the 1930s, but by the end of their search, the team had found the other eight.

Locating the oldest successional plots in the world came with a wealth of data. In tandem with studying the current plant communities, Buma is analyzing data generated by Cooper and one of his graduate students from as far back as the 1920s. “The collaboration is still going,” said Buma. “This is the longest record of this kind.”

The record shows that whichever species first colonizes the new terrain tends to dominate the landscape. This is the reason for the lack of trees in the area, according to Buma— they can’t establish a hold in the ground that willows colonized first. Today, the plots are surprisingly different in terms of species composition, percent cover, and soil characteristics. Those nearest to the mouth of Glacier Bay, closer to potential seed sources, have the highest species richness.

Each pair of photos is taken from the same spot, facing the same direction. The landscape has changed dramatically (Source: Brian Buma/Ecology).

This experiment is emblematic of the importance of national parks as protected areas, says Lewis. “National parks protect American heritage for present and future generations, and provide the opportunity to conduct long-term scientific research,” said Lewis.

After delving into the past, Buma’s eyes are set on the future. This summer, he’ll return to Glacier Bay with a dendrochronologist and population ecologist to expand the plots, hopefully extending their usefulness another hundred years. Now that succession rates from the last century have been established, the team will seek sites where glaciers receded in the late 20th century in order to compare how rates of succession shift with climate warming. “Is succession moving faster now that the planet is warmer?”  Buma wonders.

As he thinks about the future, he is determined that the plots’ locations will never be lost again and that this important data set will outlast his own research. The GPS points are now on file with the National Park Service, and people will have to apply for access to the coordinates.

First, Glacier Bay was a land of ice, then a land of rock, and now it is a land filled with plants. “As climate warms up, it’s not good news for Glacier Bay,” said Buma, “But it will be interesting to see how the flora changes.”

John Hopkins Glacier has retreated a great deal since Cooper’s time (Source: NPS).

The linkages forged by this study, between landscapes and scientists of the past, present, and future, will be essential to understanding the changing landscape of Glacier Bay.

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