Final Recovery Plan Completed for Endangered Glacier Stoneflies

According to U.S. Fish and Wildlife Service, climate change remains the primary threat to two obscure aquatic insects, one of which is found exclusively in Glacier National Park

By Tristan Scott
Meltwater Lednian Stonefly larva. Courtesy USGS

Federal wildlife managers have completed the final recovery plan for two rare mountaintop stoneflies endemic to Glacier National Park’s alpine environment, where the tiny aquatic insects require glacial-fed streams for survival. The imperiled species are among the first to gain Endangered Species Act (ESA) protections as a sole result of climate change.

The U.S. Fish and Wildlife Service (FWS) on Jan. 18 announced the completion of its long-awaited recovery plan for both species of stonefly — the meltwater lednian stonefly, or Lednia tumana, which lives exclusively in cold-water streams fed by Glacier Park’s melting namesake, and the western glacier stonefly, or Zapada glacier, which occupies similar habitat extending into adjacent wilderness areas in northwest Montana, as well as southwest Alberta and Wyoming’s Grand Teton National Park. The plan says the stoneflies warrant protection through listing because the glaciers supplying their cold-water refuges are disappearing at a rapid pace.

The plan’s recovery criteria sets forth a range of habitat requirements, including the species’ need for cold, flowing water and more than 3,000 acres of glaciers and snowfields if they are to survive the warming world that’s threatening them with extinction. The stoneflies live less than 500 feet downstream of glacial meltwater sources, rendering habitat degradation due to climate change their greatest threat.

“Most remaining glaciers and snowfields in Glacier National Park, one of the primary locations where these species are found, are predicted to completely melt by 2030,” according to the federal plan, which suggests the possible transplant of some of the insects to new areas and theorizes about measures to artificially propagate populations and promote heat tolerance.

Opportunities for the species to migrate to more sustainable habitat are limited as they already exist on a pin’s head, environmentally speaking.

“These species cannot adapt to these changes as they already exist in the highest alpine environment possible,” the recovery plan states.

The plan’s completion follows the December 2021 publication of a draft recovery plan and the landmark November 2019 decision to furnish federal protections on the obscure aquatic bugs. According to scientists, the stoneflies’ contracting habitat means action to mitigate the effects of climate change on the species is imperative.

“Climate change continues to significantly impact cold meltwater availability in the range of these species by reducing glaciers and snowfields from warming temperatures and fluctuating snowfall,” according to FWS’ recovery plan, which is available on the federal agency’s website.

In finalizing the plan, FWS relied on years of field research conducted by U.S. Geological Survey (USGS) scientists in Glacier National Park, where researchers adopted the term “charismatic microfauna” to describe the species. Two of the scientists, Joe Giersch and Clint Muhlfeld, have noted that, while the aquatic insects don’t loom as large as some of North America’s most iconic species of climate-induced concern, such as polar bears, grizzlies and wolverines, the implications to the tiny stoneflies are no less significant due to their dependence on high-alpine meltwater streams in Glacier Park.

“They are kind of a canary in a coal mine. They serve as a real indicator of the health of the ecosystem,” Giersch told the Beacon. “We talk about glaciers as being the water towers of the continent, the source of not just cold water but also permanent water, and the effects of their loss will be felt not just by people but the ecosystem as a whole.”

Recovery plans are non-regulatory documents that act as a guidebook towards a shared goal of ensuring a species’ long-term survival in the wild. It outlines site-specific management actions that contribute to the recovery of the species, describes the time and cost estimates for implementing those actions, and outlines measurable criteria for delisting. More information about recovery planning is available on our website.   

According to FWS, the agency continues to work closely with the Confederated Salish and Kootenai Tribes (CSKT), National Park Service, U.S. Forest Service, and “greatly appreciates the efforts of these agencies and Tribes in supporting recovery planning and actions.”