The western glacier stonefly already lives in a small world. It spends most of its life as a larva in a few hundred meters of ice-cold water in Glacier National Park in Montana, before spreading its wings to leave the water, mate and die within a few weeks.
Due to steadily increasing temperatures, the western glacier stonefly's world is getting even smaller, as the glaciers that create its meltwater habitat continue to shrink. And that, says Bucknell University Professor Steve Jordan, biology, could have a big impact for our world: The stoneflies could become the first species officially classified as endangered due to climate change.
Jordan is part of a team of researchers from Bucknell, the University of Montana and the U.S. Geological Survey (USGS) who have found compelling evidence that the range of the western glacier stonefly, Zapada glacier, has shrunk as Montana's glaciers have receded. (There were about 150 glaciers larger than 25 acres in Glacier National Park circa 1850; there are 25 today.) Jordan and his colleagues published a paper presenting that evidence late last year, and are preparing another with similar findings about a second species: the meltwater stonefly, Lednia tumana.
Conservation organizations have petitioned the U.S. Fish and Wildlife Service to classify both species as endangered under the Endangered Species Act. If they were added to the endangered list, Jordan said, they would be the first species listed because of climate change. (Polar bears, he noted, have been classified under the act as threatened, not endangered.)
"If that happens, the U.S. Fish and Wildlife Service would be required to develop a species recovery plan, and what's a species recovery plan for climate change?" Jordan questioned. "Do we further regulate tailpipe emissions and coal plant emissions because of a little critter that lives in glaciers in the mountains? Heads would explode — and yet that's what the law says has to happen."
While the petitions for endangered status predate Jordan's paper by more than five years, the Fish and Wildlife Service has yet to issue a decision. Jordan says much research remains to be done before a final decision is made, but that these results suggest significant cause for concern about the welfare and future of this species.
"Our research team has done some very sophisticated lab work and computer modeling to suggest that these species may be vulnerable to climate change, and the genetic data we generated helps delineate their range much better than it had been," Jordan said. "By comparing our range map to maps going back 20 or 30 years, we're able to see that their range has gotten smaller. That's what we would expect if they were in trouble from climate change."
Jordan's contribution to the project has been to identify genetic markers to differentiate between stonefly nymphs in the larval stage — something that was nearly impossible with visual cues alone, even under a microscope. Jordan has previously applied similar DNA fingerprinting techniques to study insects in Hawaii and other Polynesian islands.
"We sequenced a particular gene that's good for telling different species apart," he said. "Using that gene, we could sequence DNA from the larvae that USGS collected, and from adults we could identify, and we were able to make the association between the adult and the larvae."
Using the genetic tools Jordan provided, the USGS team led by Joe Giersch gained the ability to identify stonefly habitats nearly year round — any time they could reach them — rather than waiting for the three-week window when the insects emerge from the water to mate. A picture of the western glacier stonefly's shrinking range soon became clear, and evidence suggests the same may be true of the meltwater stonefly.
"The glaciers there are vanishing, and if current trends continue, they could all very well be gone in 15 years or so," Jordan said. "That could wipe out entire high-elevation stream communities. There are other invertebrates too: crustaceans and a bunch of other insects."
Jordan fears that little can be done to spare the western glacier stonefly its fate, but he says their fight for survival against the odds still deserves attention.
"There is very little any individual could do that would have a major impact on these insects, so we have the sad burden of honestly witnessing the damage that our actions and choices, whether as individuals or collectively as a society, are having on fragile, rare and wonderfully adapted organisms like these in this and many other ecosystems," he said. "They're a bellwether species that tells us that our actions are reaching deep into the wilderness and harming vulnerable, beautiful things."