Vanishing glaciers

The sky was cloudless, a spotless expanse of endless blue, and not a single breath of wind rippled the water of Bowman Lake, a long and slender finger of water nestled between two ridges in the northwestern corner of Glacier National Park.

After growing up on the east coast, nine years ago this summer I visited the American West for the first time, and I understood why Montana is nicknamed “Big Sky Country.” I spent eight weeks at the University of Montana’s Flathead Lake Biological Station, where my fellow students and I dove into our field ecology classes, exploring the mountains and lakes of northwestern Montana along the way.

We visited Glacier National Park on several of our field trips, and one day in particular sticks in my mind – the lake was a perfect mirror for the mountains and the sky, and it was too beautiful for us to leave without taking out our cameras.

The sky and surrounding ridges reflected in Bowman Lake, along with several other photographers, in mid-summer 2006.

(Image by Emily Benson)

The majestic scenery of Glacier National Park, however, is changing – scientists estimate that by 2030, all of the park’s glaciers will be gone, melted under the force of global climate change. As the National Park Service notes, “the park’s glacially fed streams provide a constant flow of cold water throughout the summer season, maintaining necessary water levels and regulating stream temperature for fish and other aquatic species. Plant and animal species throughout the park rely on this flow.”

One of those animal species is the western glacier stonefly, an aquatic insect that, in the past, has only been found in alpine streams in Glacier National Park.

Recently, a group of scientists (including one of the professors that I studied with during my summer in Montana) surveyed all of the locations where the western glacier stonefly has been found in the past, as well as some similar habitats, in order to determine whether their distribution is shrinking along with the glaciers in the park.

The researchers detected western glacier stoneflies in only one of the six streams where they’ve been found before; they also found the stoneflies in two new alpine sites within the park, as well as one site about 335 miles away in Grand Teton National Park.

The scientists note that further study on the “status, distribution, and vulnerability” of the western glacier stonefly is warranted, but the results they’ve already gathered “suggest that an extremely restricted historical distribution of [the western glacier stonefly] in [Glacier National Park] has been further reduced over the past several decades by an upstream retreat to higher, cooler sites as water temperatures increased and glacial masses decreased.”

At some point, the western glacier stonefly will run out of mountain as the population searches for higher and higher sanctuaries, and, left with no place to go, it may face extinction. Glacier National Park is still beautiful today, but it isn’t the same park that I visited nine years ago. In nine more years, will there still be a place within the park’s borders where the western glacier stonefly can feel at home?

An adult western glacier stonefly.

(Image by Joe Giersch/USGS)