Slowly but surely, Joe Giersch has been scouring streams below glaciers and snowfields in Glacier National Park for rare and mysterious aquatic insects that in some cases haven’t been detected anywhere else on earth.
The effort has been paying off for Giersch, an aquatic entomologist with the U.S. Geological Survey who is based out of West Glacier.
“There’s a whole host of these alpine stream insects that are not only isolated below these high alpine streams, but many of these species are only found in this part of the world,” Giersch said.
Just two years ago, very little attention had been paid to vibrant aquatic insect communities that seemingly would not exist in the coldest trickles of water emanating from the park’s glaciers and snowfields, many of them feeding the eastern-most headwaters of the Columbia River Basin.
All of the species had been discovered, or “described” in entomology terms, but little was known about them.
Many species were identified during field surveys in the 1950s and 1970s, but “no one had done any work on these streams and no one had seen them and reported on them since,” Giersch said.
The star of the cast is Lednia tumana, the meltwater stonefly, a species found only in Glacier that was petitioned for a listing under the Endangered Species Act in 2009. Two years ago, the rare stonefly was identified at only two high-elevation locations in the park.
But last summer, Giersch hit the field for the Geological Survey in Glacier after years of independent contracting work for the University of Montana and Idaho State University.
His Glacier field work mainly has involved “presence/absence” surveys in streams, springs and seeps that most people would assume to be void of aquatic life. Some of the streams are buried under snow most of the year.
Giersch has since detected a variety of bugs in the park’s coldest waters.
“Some of them we weren’t aware they were in the park,” he said. “That just has to do with the fact that very little work has been done in these types of streams.”
In one case, he surveyed a spring that emerges from one side of Mount Piegan near Logan Pass that apparently is fed by a glacier on the other side of the mountain.
“The species we find coming out of that stream, it’s as if we had gone and collected directly below the glacier,” said Giersch, noting that the exact same midge species was found in water flowing below the glacier on the other side of the mountain.
Some of the species have been described from other parts of the Northern Rockies, but not in Glacier before.
A caddis fly, Allomyia Hector, was first described in Canada’s Waterton Lakes National Park, for instance, but has since been found by Giersch in Glacier.
Another odd find was an amphipod — a tiny crustacean similar to a scud — that only lives in groundwater and had been previously found in only three locations, two of them in the park and one in a cave in the North Fork Flathead River drainage.
“I have found it from four other locations in the park,” Giersch said. “The places I’m finding it are in high alpine springs and seeps.”
Giersch’s work also has revealed certain tolerances and preferences common among high alpine aquatic insects.
“As you go down the stream course, the water warms up very quickly. The habitat that these real rare insects need is very isolated and close to the stream source,” he said. “As you go downstream more species come in that you might find at lower elevations. But eventually, those cold-loving species drop out very quickly.”
To Giersch, the high-elevation species represent the park’s abundant biodiversity.
“There’s a huge diversity of aquatic insects, but in Glacier Park the diversity is very high due to it being a very pristine system,” he said. “Glacier is a biological convergence zone.... You have several large river systems that converge right here in GP. You have a lot of species that you might find on the West Coast and also some things from the Missouri Basin and also from the Hudson Bay drainage.”
The high alpine species also are viewed as an important barometer for the effects of climate change in a park where glaciers have been receding over the last century and are expected to be gone by 2030.
“These major habitat reductions imply a greatly increased probability of extinction and/or significant range contraction for this sensitive species,” states a recent study on the meltwater stonefly that was led by Clint Muhlfeld, a Geological Survey aquatic ecology scientist who is based in the park.
But the meltwater stonefly was considered “warranted but precluded” from listing under the Endangered Species Act by the U.S. Fish and Wildlife Service last April for practical reasons.
The agency contends there is little that can be done about receding glaciers because “existing regulatory mechanisms do not address environmental changes due to global climate change.”
As the agency’s regional listing coordinator in Denver put it two years ago: “What environmental organizations are interested in doing is tying carbon emission activities to the Endangered Species Act and regulating them through that. And it was never intended to do that.”