Glacier Park's Stoneflies Occupy More Habitat Than Once Thought, Researchers Say

Montana Public Radio | By Aaron Bolton

Published May 22, 2020 at 5:31 PM MDT

Researchers survey for stone flies in the backcountry of Glacier National Park, Sept 1, 2019. Two species of stone fly were listed as "threatened" due to warmer water, drought and diminishing meltwater from vanishing glaciers.

Aquatic insects living at high elevations in Glacier National Park may be more resilient to impacts from climate change than was once thought. That's according to a study published this week. Populations of various other species are still expected to decline and potentially go extinct.

U.S. Geological Survey research aquatic ecologist Clint Muhlfeld and his team examined data dating back to the Little Ice Age in 1850 showing that glacial mass has declined 73 percent around Glacier National Park. That’s leading to a decline in suitable habitat for rare insects including the west glacier and meltwater lednian stoneflies.

Researchers at the USGS have been collecting data over the past 10 years on these species, some of which only live around Glacier National Park. They were once thought to be dependent on the streams created from glacial meltwater.

But Muhlfeld’s team’s latest findings show these species also living in cold-water streams fed by snowfields and underground springs.

"They were found in areas that didn’t have glaciers at the end of the last Little Ice Age, they were found in areas that glaciers have disappeared since the last Little Ice Age and they were also found in areas that, where glaciers have greatly diminished," Muhlfeld says.

That means they have more habitat options than previously thought, which is good news. But Muhlfeld says these insects are still expected to lose up to 80 percent of their habitat by the end of the century.

Western glacier stoneflies thrive in glacial meltwater in high-elevation alpine environments. But scientists estimate the famed ice masses and snowfields of Glacier National Park will have mostly disappeared by 2030.

He says this family of insects is likely the canary in the coal mine for the impacts climate change will bring to mountain ecosystems in the northern Rocky Mountains. But Muhlfeld says there’s a lot we don’t know about their functions in the larger ecosystem and, in turn, the impact their decline will have.

"What are the consequences of some of these changes, in terms of extirpation of species on nutrient cycling and food for higher organisms like fish or even birds?"

Those are questions Muhlfeld hopes future studies will answer.