Striking photographs from the Mountain Legacy Project, an initiative to retake and compare images made by early surveyors, show how Canada’s mountain environments have become less icy and more uniform over time.
These changes, researchers say, spell trouble for alpine birds and could mean a greater number of severe forest fires in the future.
The historic images date as far back as 1861, when surveyors clambered up mountains to make maps of the area. Their age makes them valuable to researchers because it allows them to see the kinds of environmental changes, including melting glaciers, that happen over a century. Satellite images would only cover a few decades.
Environmental scientist Julie Fortin categorized the types of land cover in 46 pairs of historic and modern photographs taken in Alberta’s Willmore Wilderness Park, a rugged landscape only accessible by hiking or horseback trails.
She painstakingly outlined areas of forest (dark green), alpine meadows (light green and light yellow), ice (light blue), and wetlands (periwinkle) in digital versions of the images to quantify how much of each habitat there was in the early 1900s compared to today.
She saw forests growing bigger, creeping into other habitats like alpine meadows or wetlands—such as this area across the valley from Bury Ridge, where sparsely covered slopes are now obscured with dense green foliage: Because Willmore is so inaccessible and resource extraction is forbidden, any landscape changes are likely due to climate change or wildfire management.
Although trees help sequester carbon from the atmosphere, helping lower global temperatures, more trees aren’t necessarily a good thing, Fortin explained to me over the phone.
“I got out here [from Montreal] and I realized more forest is good for some species but there are some species that rely on other kinds of habitats that are being negatively impacted,” she said.
Using a computer model that related the type of habitat to the likelihood of particular bird species living there, Fortin showed that birds that breed or live in alpine areas—like the American Pipit—have declined in numbers over the past century.
Other birds, not investigated by Fortin, could also see a drop in numbers, according to the recent State of the Mountains report by the Alpine Club of Canada. Close to 35 percent of Canada’s birds use high mountains for migration stopovers to fatten up before flying on, the report states, and a quarter of those birds are on national conservation lists. Scientists are unsure how the birds will deal with shrinking alpine areas, or whether they’ll be able to cope at all.
The way we manage fires is also part of what contributes to the changing alpine landscape, Fortin explained.
Almost 100 years ago this site—15 kilometers southeast of Mount Persimmon—had more natural breaks in the landscape, seen on the right side of the image above, which served as a roadblock for spreading fires. Partly, those breaks came from sections of the forest that were allowed to burn. As communities moved closer to alpine forest areas and fires were controlled, the breaks have almost completely closed up.
Vast swaths of forest make the parks more vulnerable to forest fires. “It’s basically just this big tinderbox that when it lights it’s hard to stop,” Fortin said. This means British Columbia may not have seen the last of its record-breaking wildfires, which burned close to 13,000 square kilometres of the province and forced 65,000 people out of their homes over the course of three months.
“Mountains create their own particular type of fire risk,” added ecologist Eric Higgs, who has taken some of the modern photographs for the Mountain Legacy Project to understand how to restore mountain habitats.
“They provide you with a visual argument,” said Higgs. “The interplay of our values at present and what we’re seeing from the past shapes where we ought to go.”
Higgs argued that environmental restoration initiatives must consider controlled burning and include community awareness. Fortin is now using the images from her project to show locals in Grande Cache, a town directly bordering the Willmore Wilderness Park, how their mountain neighbourhood has changed. The photos also help inform controlled-burning projects in the area.