MISSOULA — An obscure aquatic insect found exclusively in the high alpine streams of Glacier National Park will remain a high-priority candidate for endangered species protection because it is at risk of extinction due to climate change, the U.S. Fish and Wildlife Service announced last week.
The rare stonefly, called Lednia tumana, has narrow temperature requirements and lives only in cold-water streams fed by Glacier Park’s melting glaciers and snowfields — a mountain ecosystem rapidly disappearing due to global warming. It was included on the most recent list of 192 candidate species eligible for protection under the Endangered Species Act. However, it did not receive emergency listing for protection.
“Emergency listing is not warranted at this time because the species is not under immediate threat of extinction. Glaciers still exist in Glacier NP and are expected to be present through the next decade,” according to the Fish and Wildlife Service’s assessment of the species. “However, if at any time we determine that issuing an emergency regulation temporarily listing the meltwater lednian stonefly is warranted, we will initiate the action at that time.”
The stonefly was designated a candidate species with a listing priority of five, meaning threats were high in magnitude but not “imminent.”
“The threats that the stonefly faces from melting glaciers and other environmental changes that result from climate change are high magnitude because of the recent observations of glacial shrinking and loss in Glacier NP and the projections that all glaciers in Glacier NP may disappear in the next 20 years,” according to the agency’s assessment.
In August 2009, the Fish and Wildlife Service listed Lednia tumana in a group of 29 species deserving a full-status review under the Endangered Species Act. The stonefly was eligible for federal protection solely because of “climate-change-induced glacier loss,” but did not receive listing following the status review.
Also known as the mist forest fly, Lednia tumana would become the first species recognized as endangered by the federal government with global climate change as its primary threat.
Even if the agency declares Lednia an endangered species, however, there are few protective measures toward better ground management practices in a remote, undisturbed environment like Glacier Park.
“The habitats occupied by the species remain relatively pristine and are managed to be generally free from direct human impacts,” according to the Fish and Wildlife Service assessment. “Environmental changes resulting from climate change are reasonably certain to occur, but we have no empirical evidence that the resulting threats to the species are imminent, or ongoing.”
Still, the agency’s recognition of climate-change-induced glacier loss as the sole cause for protection would be significant, scientists say.
Recent research shows that once the park’s 26 remaining glaciers are functionally extinct — conservative estimates predict they will be gone by 2030; other data suggest an even shorter trajectory — the stonefly will face a high likelihood of extinction and significant range contraction.
A 2011 study by government researchers in the park links the insect’s survival directly to the fast-declining glaciers, and the research helped inform the Fish and Wildlife Service’s decision to include the stonefly as a candidate for federal listing.
The article, published in the journal Climatic Change, incorporates 14 years of research and represents the most comprehensive information published to date on the little-known stonefly, said Clint Muhlfeld, an aquatic geologist at the U.S. Geological Society’s Glacier Park field office and the lead author of the study.
“What our analysis shows is that the species, found nowhere else on the planet, is at high risk of extinction in the foreseeable future,” Muhlfeld said. “2030 is right around the corner, and our modeling shows that when the glaciers disappear there is a massive deduction in habitat.”
Joe Giersch, an aquatic entomologist with USGS who conducted much of the field research and co-authored the study, said the listing would be significant not just for the stonefly, but for an entire mountain ecosystem that harbors native species dependent on cold water for survival.
The Center for Biological Diversity, a conservation group that filed a lawsuit arguing that delays in protecting candidate species like Lednia tumana are illegal, has criticized the decision by the Fish and Wildlife Service to deny the insect protection, saying that its chances of survival are dramatically reduced.