The western glacier stonefly lives in extremely cold waters below glaciers in high-elevation
streams in Wyoming and Montana. New research has discovered the western glacier stonefly
-- Wyoming’s only insect protected under the Endangered Species Act -- has a range
wider than previously known. This photo is from Grand Teton National Park, where UW
researchers monitor for the insects annually. (Lusha Tronstad Photo)
A group of researchers, led by the University of Wyoming, recently discovered the
western glacier stonefly -- Wyoming’s only insect protected under the Endangered Species
Act -- has a range wider than previously known.
Lusha Tronstad, lead invertebrate zoologist with the Wyoming Natural Diversity Database
(WYNDD) at UW, led the research, which took place in Wyoming the past two summers with funding
from Region 2 of the U.S. Forest Service.
The western glacier stonefly, or Zapada glacier, is known from two areas in Montana -- Glacier National Park and the Beartooth Mountains
-- and one area in Wyoming, the Teton Range. However, the latest research discovered
the western glacier stonefly in eight separate cold streams located below glaciers
in the Beartooth, Absaroka and Wind River ranges.
“This is a range extension, and this information will be used for the recovery plan
for this species,” Tronstad says. “This is big news, because this protected stonefly
was only known from three areas previously, and we found it in two new mountain ranges
(Absaroka and Wind River) in Wyoming. Our data will directly influence management
decisions.”
Tronstad stresses that WYNDD only supplies the data and does not have any role in
management decisions.
Tronstad was lead author of the paper “Are Western Glacier Stoneflies (Zapada glacier) More Widely Distributed in Wyoming Alpine Streams?” that was written for the U.S. Forest Service and published April 28.
Bryan Tronstad, an assistant invertebrate zoologist with WYNDD; Audrey Lindsteadt,
a WYNDD technician and a soon-to-be UW graduate student from St. Joseph, Mo.; and
Scott Hotaling, with Utah State University’s Department of Watershed Sciences, also
contributed to the paper. Bryan Tronstad collected and processed samples and identified
the invertebrates. Lindsteadt collected samples and prepared insect samples for DNA
barcoding, which is the only way to identify larval western glacier stoneflies. Hotaling
analyzed the DNA barcoding results.
“We did surveys in the Big Horn, Beartooth, Absaroka, Wind River and Snowy (Range)
mountains of Wyoming, surveying alpine streams draining cold water sources,” Lusha
Tronstad says. “We discovered the western glacier stonefly in eight streams in the
Beartooth, Absaroka and Wind River mountains. These are areas that were previously
unknown, and seven streams were distant from known populations of the stonefly. Our
study expanded the range of this threatened species.”
Audrey Lindsteadt (left), a Wyoming Natural Diversity Database (WYNDD) technician
and a soon-to-be UW graduate student from St. Joseph, Mo., and Sasha Maxey, another
WYNDD technician, sample below Heap Steep Glacier in the Wind River Range for the
western glacier stonefly on a cold August day. (Lusha Tronstad Photo)
Alpine streams sampled for the insect included surface glacier, rock glacier, springs
and snowmelt. The genus of stonefly was collected in 60 percent of the streams sampled.
But the species was only found in eight streams that originated from surface glaciers
and rock glaciers. Streams fed by rock glaciers had the widest range of invertebrate
biomass and richness, or the number of taxa collected. Rock and surface glacier streams
had the coldest water temperatures, and rock glacier-fed streams had the highest specific
conductivity, which is the concentration of salts or ions in water.
“Rock glaciers -- think of a surface glacier covered with rock debris -- are thought
to persist longer on the landscape because the ice is insulated from the atmosphere,”
Lusha Tronstad says. “Surface glaciers are predicted to disappear during the next
century due to increasing air temperatures, but streams draining rock glaciers are
hypothesized to persist longer. Streams draining rock glaciers may be refugia for
cold-adapted insects, such as the western glacier stonefly.”
Lusha Tronstad says she thinks further surveys dedicated to looking for the western glacier stonefly in Wyoming
and Montana “have a good probability of finding more populations.”
About WYNDD
WYNDD offers the most complete source of data for species and vegetation communities
of management concern in Wyoming. Its mission is threefold: Identify and rank species
that are priorities for management in Wyoming; amass existing data and develop new
data for species needing management efforts, and for Wyoming vegetation types; and
distribute these data upon request, under the philosophy that the best decisions regarding
natural resources will be made only when everyone has access to complete and current
scientific data.
