Two stoneflies found in high-elevation coldwater streams in and near Glacier National Park are being considered for protection under the Endangered Species Act by the U.S. Fish and Wildlife Service.

The joint status review will examine the condition of the meltwater lednian stonefly and the western glacier stonefly, found only in a handful of streams in Montana.

In 2011, the federal agency determined that the listing for the lednian stonefly was “warranted but precluded” — meaning the species was eligible to be considered “threatened” or “endangered,” but was not a high-enough priority for the agency.

Because the insects’ habitats are in the extremely cold and highly oxygenated waters immediately downstream from glaciers and permanent snowfields, they could potentially become extinct by 2030, when most of the park’s glaciers are predicted to disappear.

Most scientists have linked the disappearing glaciers to climate change, which creates obvious difficulties when it comes to determining management actions to protect the species.

“Existing regulatory mechanisms do not address environmental changes due to global climate change, which is the primary cause of the loss of glaciers and resulting threat of habitat loss and modification for the species,” the agency wrote in 2011.

The lednian stonefly was first discovered in 1952 and has been found in some locations in the Bob Marshall Wilderness in addition to Glacier Park.

The even rarer western glacier stonefly wasn’t discovered until 1971 and so far scientists have only confirmed its presence in a few coldwater streams in Glacier: the outlet of Grinnell Glacier and downstream from a couple of coldwater springs in the Many Glacier area.

“These alpine streams do tend to be very shallow, at least during the later parts of the season, the water can warm up very quickly, so the habitable zone for these species is very isolated to just the upper reaches of the streams,” said Joe Giersch, an aquatic entomologist with the U.S. Geological Service.

He has been studying the two species since 2010. Each summer he and his team survey alpine streams throughout the park in search of the elusive insects.

Usually the season for his field work extends only from August through late September, but he said this year’s early snowmelt and warm weather allowed him to sample an estimated 70 streams, bushwhacking through the highest climes of the park and visiting areas that may never have seen human disturbance before.

He said he’s still analyzing samples and will incorporate measurements of temperature, stream connectivity and suspended solids into the team’s findings. The team also operates remote sensors in 25 of those streams to record long-term temperature data.

Based on the limited information available on the two types of stoneflies, Giersch said it’s difficult to make a determination of whether they will be threatened by the regional warming trends projected from global climate change.

Still, he expects that the rare western glacial stonefly would likely perish without additional protections, given the confines of its distribution in the park.

“We haven’t been able to show that necessarily with the other stonefly species, although based on the general trends of glacial loss within the park, which has been shown, we can say that the distribution of the lednian stonefly has shrunk considerably over the last 100 years.”

There’s still hope for the insects after the park’s glaciers disappear. They’ve been found downstream from alpine springs, and there’s the possibility of “translocating” the insects to other places, where glaciers are expected to hang on for a longer period of time.

“They do this with some fish species and so forth, where you would move individuals from a population to another location, basically seed those locations,” he said. “We also could use some genetics tools to help us figure out which populations would be able to recover or would be better used for translocation than others.”

He said that despite the exclusivity of the two species, their plight is far from insignificant.

“This work is very important because these alpine stream communities are very good indicators of climate change, ultimately. Not just for these two stonefly species, but there’s a handful of invertebrates whose ecology is very closely tied to temperature,” he said. “Keeping track of that community is the best way, at this point, to really keep an eye on what’s happening on a big-picture, regional basis.”

Giersch’s research will be a major component of the limited body of scientific data from which the U.S. Fish and Wildlife Service will draw when deciding whether to propose any protections.

That decision is due Sept. 30, 2016.

The reviews will take into account the current status and potential risks to the stoneflies’ distribution, including the potential for climate change to reduce the number of glaciers in the park.

“We’re batching them together, even though we’re at a different point in the process in reviewing the two stoneflies,” said Jim Boyd, a biologist with the Fish and Wildlife Service’s Helena office. “Essentially it makes sense to do that; it saves time and money to conduct simultaneous reviews on species that are very similar and share similar habitat.”

He added that if the Fish and Wildlife Service proposes a listing for one or both of the species, a final rule is required within a year, meaning that any associated management actions would go into effect sometime around September 2017.

Information and comments from the public and from state and federal resource agencies will be accepted until Dec. 15.

Comments can be mailed to: U.S. Fish and Wildlife Service, Montana Field Office, 585 Shepard Way, Suite 1, Helena, MT 59602.

Reporter Samuel Wilson can be reached at 758-4407 or by email at swilson@dailyinterlake.com.