Joe Giersch: Biologist, United States Geological Survey
Joe Giersch, a biologist from USGS, sat down with InterDigital to discuss technology’s role in the study of stream ecology, and explain why we should all know about the insect, Lednia tumana, that he has spent his life studying.
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An interview with Joe Giersch | Biologist, United States Geological Survey
Technology’s role in the study of stream ecology is to assess the
impact of a warming climate – Joe Giersch, USGS “
There’s an insect living in Montana that most people will never meet. Scientifically, it’s called Lednia tumana,
commonly known as the meltwater stonefly. Joe Giersch, a biologist with the US Geologic Survey, spends his
life studying this little bug, because the story it tells is one that will affect us all.
Giersch came to this species almost by accident. He first met Lednia tumana while working for The University
of Montana in the late 1990s on a research project studying the effects of climate change on several freshwater
streams in Glacier National Park (GNP). Initially fascinated with its ability to persist in such a harsh alpine
environment, he began collecting samples of the species. Over time, his collection of Lednia tumana (and many
other aquatic invertebrate species) grew.
In 2011, the US Fish & Wildlife Service (USFWS) contacted Giersch -- who began working with the USGS field office
in GNP in 2010 -- about the insect. “At that point, this stonefly species was only known from a handful of locations,
all streams fed by glaciers,” Giersch says. “The USFWS had been petitioned to list the species under the Endangered
Species Act due to the effects of climate change-induced snow and ice loss. As part of the status review of the
species, USFWS requested information on any records of locations, collections, or ecological data on Lednia tumana.
It turns out that I had collected more records on this species than anyone, so of course I was eager to help.”
So began a collaborative effort where Giersch and his team at USGS worked with USFWS and other scientists to
gather as much data as they could on the distribution and ecology of Lednia tumana and another stonefly species
called Zapada glacier.
These insects occur only in very high alpine environments. Because of the extreme elevation, most of these
environments are very remote and see little human activity. This combination of factors makes them an ideal
place for Giersch’s work.
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“The ecology and biology of these insects are very closely tied to the temperature of the water,” Giersch explains.
“They need very cold temperatures to survive. So they live very close to the source of the streams - oftentimes
that’s near a glacier, a permanent snowfield, or a groundwater spring.”
These insects are small, but they tell a much larger story, the ramifications of which Giersch is working to define.
Glacier National Park – situated in the northern Rocky Mountains of Montana – contains 25 named glaciers, making
it one of North America’s most accessible glaciated areas, and one of the main reasons for the park’s popularity
among tourists. Apart from being merely a recreation area, GNP is a living laboratory for scientists like Giersch to
study insects like Lednia tumana and Zapada glacier, both of which are isolated to cold stream habitats found in
The USGS has surveyed glacial size and distribution for several decades, and detailed maps have been produced
by USGS since the 1960s. “We’ve known for decades that these glaciers are retreating,” says Giersch. “I’m working
to understand how this retreat impacts the insect species living in the streams that flow out of them.”
I’m working to understand how this retreat impacts the insect
species living in the streams that flow out of them.“
So what is Giersch finding? The answer is not surprising: water temperatures increase with distance from the
stream source. With the change in temperatures comes a change in the stream community of insects and other
invertebrates, with the most cold-tolerant species restricted to the upper reaches of the stream closest to the
source, and more species joining the community downstream. The community of algae and diatoms - the plant
species that make up the base of the alpine stream food web - changes as well. Some species close to the source
may be especially tolerant of these cold environments, but they may also be limited by the amount of nutrients in
the stream. Researchers have yet to unlock the interactions between the different components of the food web
and communities in alpine streams in GNP. In short: This warming trend is shrinking the habitat of the sensitive
species where he focuses his work.
“The very cold portions of the stream might be within a couple hundred meters of the source of the stream,” says
Giersch. “That’s essentially the sweet spot where these rare insects live.” He explains that the warmest average
August temperatures these species are able to tolerate is about 9° C (48.2° F). That’s still a very cold temperature,
but these insects simply don’t survive in streams that have warmer extended temperatures higher than that.
What happens if that sweet spot disappears? Giersch tells us that the insects will have to work their way up in
elevation to the upper reaches of the stream. As that happens, they become more and more isolated genetically,
a fact that threatens their viability as a species. To make matters worse, the habitat for the insect becomes very
harsh and unstable the closer it gets to the outlet of the glacier feeding the stream.
In essence, Lednia tumana and Zapada glacier are what’s known as “indicator species”. Their life cycles on an
insect scale tell us a lot about what’s happening at a planetary scale.
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Giersch uses a relatively old technology as one of the
primary tools of his research: a water temperature sensor.
Due to the remote locations where he conducts his
research, he may only be able to visit each stream at most
once every 12-24 months. Further complicating his research
is the fact that during several months a year, these locations
are under so much snow — sometimes 15 feet or more —
that it’s not feasible or safe to be there in person to retrieve
the data. So Giersch has a busy summer each year, hiking
into the backcountry of GNP with an assistant or two to
place stream temperature sensors in temporary positions
along the length of a stream where these species live, and to
retrieve sensors and data he has placed in prior years.
He uses small, waterproof digital temperature loggers. “I
have them set to record temperature every hour, and they
have a five-year battery, so they can contain a lot of data
points,” he says.
Each of these small waterproof devices features an optical
connection so that data can be quickly downloaded to a
handheld data capture device he packs with him on his trips.
Each temperature data set is tagged with geolocation and
timestamp markers, so that he is able to spend his winters
manipulating the data to learn what’s happening in a variety
of locations throughout the park, year over year.
Giersch has been collecting data in these streams since
2010. It’s a time-intensive process, given how remote the
locations are, and he tells us that he sees a couple of ways in
which this technology could be improved.
“Right now, we can only download this data from
these temperature loggers about once a year,” he says.
“Ultimately, it would be great if we would be able to have
some sort of wireless connection to a satellite or base
station, so I could pull data from them more frequently.”
This seems like a simple request: there are several
devices in production today that can connect wirelessly
to a network, and even in rugged and wet environments.
But in GNP, this comes with challenges. It’s difficult in a
national park or a remote wilderness area to justify the
cost of putting cellular base stations in remote areas, and
many wilderness areas have restrictions on installation of
permanent structures anyway.
Data showing overall decline in the L.
tumana population, increase in stream
temperature, and distance from snowmelt
source in Lunch Creek, Glacier National Park.
Stream temperatures, percentage of Lednia
tumana versus the total macroinvertebrate
community (in red), and number of taxa
(in green - species or genus, lowest level of
identification) observed from longitudinal
sampling of Lunch Creek. Distances (m)
are to stream source. Dark lines on the
temperature graphs indicate average daily
temperature with gray area indicating
Giersch says his small temperature loggers aren’t a problem, because their small size and temporary installation
makes them unobtrusive in the wilderness environment, but “having a base station or a cell tower is a problem,
because it’s so visible to the public, and would impact the wilderness experience, while also introducing something
permanent into the ecosystem that wasn’t there to begin with.”
From his perspective, the challenge begins to look like this: How can we come up with a solution that allows
scientists to remotely collect environmental data from remote areas, some of which are underwater, or even buried
in a bitterly cold stream under 15 feet of snow?
On some level, real-time data collection isn’t important, because the stream temperature isn’t fluctuating that
rapidly. But increased speed isn’t why Giersch would like to see some innovation in these sensors. His concerns are
driven by other factors, which may not seem obvious at first.
“Retrieving stream temperature data takes a lot of time. If the data could be retrieved remotely, I would have to
spend less time getting to and from each site, which means that money could be spent in other ways,” he says. “In
that scenario, I could afford more sensors, and deploy more of them along the length of a stream, and deploy them
in more streams. All of this would give me more data points, and higher resolution with the data.”
Higher resolution, he says, would allow him to determine in a much finer scale, exactly where these insects live, and
to determine with a much higher degree of accuracy how their habitat is being impacted, which would allow him to
produce more accurate models of what the future holds for this ecosystem.
Unfortunately right now, the future looks quite grim for Lednia tumana and Zapada glacier. The glaciers and
snowfields feeding the streams where they live are predicted to vanish within the next century, a fact that has
dire consequences for all of us - because we all live downstream from alpine glaciers. Glaciers and permanent
snowfields are a critical and year-round source of cold water that feeds agriculture, supports native fisheries and
ultimately feeds all of humanity.
While these species are small insects, and their environments are isolated and rare, they are indicative of much
larger issues facing humanity. “It looks like these two species may go extinct within the next 50 years,” Giersch
laments. “At that point, I think our main concerns are going to be over world access to water, and the effect that
will have on agriculture. Those effects are going to be very drastic worldwide.”
Giersch tells us that the technology he uses for his research wouldn’t be possible without the private sector and
the tremendous innovation happening over the last couple of decades. “It’s very important for me, as a scientist
working on these things, to be able to connect the dots between my study organism and the greater effects on
humanity as a whole,” Giersch says, with a hint of optimism. “Our projections for the future are based on models
that rest on a foundation of very specific data. The more data points we have to feed our models, the more
accurate and useful these models will be. We need the private sector to advance this technology that the scientific
community can use. Competition and innovation really drives this. That cannot be understated.”
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It’s very important for me, as a scientist working on these things,
to be able to connect the dots between my study organism and
the greater effects on humanity as a whole.“