PhD student

Eyes in the sky focus on elephants

Rachel Sauer — Mon, 23 Mar 2026 14:22:27 +0000

Eyes in the sky focus on elephants Rachel Sauer Mon, 03/23/2026 - 08:22

Tiffany Plate

�鶹��Ѱ��Boulder PhD student Liam Jasperse-Sjolander is helping elephant behavioral observation get off the ground—and into the air above Africa

Walking through the quiet, lush rainforests of Gabon, on Africa’s equatorial west coast, forest elephants have a knack for appearing and disappearing just as quickly.

Because they travel in small groups through the thick jungles, forest elephants are much less noticeable—and thus much harder to observe—than their cousins that live on the wide-open African savannas.

For Liam Jasperse-Sjolander, a �鶹��Ѱ�� environmental studies PhD student, that quiet grace is part of the magic of his fieldwork. “They can be very silent, very unassuming,” he says. “Suddenly you’ll see this gigantic creature in the forest, and the next instant they’re gone.”

�鶹��Ѱ��Boulder PhD student Liam Jasperse-Sjolander has been studying elephant behavior since 2016. (Photo: Alain-Djessy Banguiya)

Jasperse-Sjolander has spent years traveling through Gabon and other African countries tracking elephant behavior in a variety of ways: using radio collars, camera traps and, more recently, drones.

And he’s been publishing his findings along the way. In 2025 alone, Jasperse-Sjolander co-authored three publications, one based on data from dung collection in Gabon and two on the benefits and potential ramifications of drones in observations.

Now he’s working to collate years of field data collected from these studies—identifying behavioral patterns and their ecological implications—for his dissertation, and pondering what’s next in his research.

Discovering Africa

Growing up, Jasperse-Sjolander didn’t always know where his love of the outdoors would take him. “I just wanted to do something outside,” he says of his childhood in Colorado. “I was either going to work in science or go run off into the woods to fend for myself.”

Ultimately, he chose the former, earning an undergraduate degree in environmental biology from McGill University in Montreal. During those years he got his first taste of fieldwork, spending a semester learning about conservation and field ecology in Kenya, Uganda and Tanzania—and falling in love with Africa. Why?

“From a conservation perspective I think that many areas still feel wild, with so many megafauna worth protecting. And I love the beautiful diversity and vibrancy of cultures and traditions there.”

That’s why, after finishing his undergraduate studies, he headed right back, signing on as a research assistant for a Duke University PhD student Amelia Meier, who was tracking forest elephants in the Wonga Wongué Presidential Reserve in Gabon. Jasperse-Sjolander was eager to get in the field and watch the elephants with his own eyes, and was pleased to see that Meier was interested in mixing old-school observation methods with some new technologies.

“Her approach was really interesting and it kind of opened my eyes to studying behavior in the field in new ways,” he says.

On the ground in Gabon

That approach required a few radio collars—and sorting through an awful lot of dung. Jasperse-Sjolander and his colleagues would track the forest elephants’ movements, then follow along at a safe distance to capture dung samples for later lab analysis.

The data they collected showed the makeup of the fruits and seeds the elephants were consuming in the forest, and laid the foundation for an October 2025 paper published in the journal Oikos. The article sought to model how elephants may play a role in reseeding forests with trees and other large plant species that can consume large amounts of carbon dioxide.

Forest elephants, once thought to be a subspecies of African savanna elephants, were recognized as their own species in 2021 by the International Union for Conservation of Nature. Part of Liam Jasperse-Sjolander’s work is to help establish a behavioral baseline. “It's really hard to protect a critically endangered species if you don't know what they're doing and where they're going.” (Photo: Liam Jasperse-Sjolander)

The results of the study showed wide variety in when and how the elephants disperse seeds, making it difficult to use a one-size-fits-all model for predicting how they will impact their local ecology.

“A lot of climate initiatives will put an emphasis on elephants being ‘gardeners of the forest,’” says Jasperse-Sjolander. These initiatives’ models assume that if elephants are in the area, carbon will in turn increase by a certain amount. “But if that’s not true in a country the size of Gabon, that’s certainly not true on an international scale.”

While there is still more work to do to better understand this interaction, Jasperse-Sjolander’s work in the field was pivotal to reaching this next step in the research.

In the air in Kenya

Now Jasperse-Sjolander is taking his fieldwork to new heights by studying how drones can be used to track elephants’ movements, eating patterns and group sizes—without disturbing the creatures. “This new format opens up a lot of doors for seeing behavior that we haven’t seen before,” says Jasperse-Sjolander.

In 2024 Jasperse-Sjolander was contracted by Save the Elephants, an African non-governmental organization dedicated to the preservation of elephants and their habitats, to analyze how drones may impact different elephant groups. “Before we start using drones to study behavior, we have to make sure that we're not negatively affecting the elephants,” says Jasperse-Sjolander.

Jasperse-Sjolander analyzed the behavioral data Save the Elephants had captured during trial runs of the drones with 14 distinct elephant groups in the Samburu National Reserve in Kenya. The results, which were published in November 2025 in Scientific Reports, were positive: While some of the elephants exhibited a few changes in baseline behavior—like eating a bit less or staying more alert—after multiple trial runs the group seemed generally unphased.

The researchers performing the trials adhered to some general common-sense protocols about how far to stay from the group.

“We always would launch the drone at least a half kilometer away from the group, since it's really at takeoff that it's the most noisy and disturbing,” says Jasperse-Sjolander. “Then we flew at a height of 120 meters (around 400 feet), which is the maximum height you can fly drones in Kenya. So we're basically as far away as we can be.”

Even at that distance, the latest high-tech drones can still capture high-resolution images; researchers can also use the drones’ embedded infrared camera to follow the elephants at night. That camera allowed researchers to follow some elephants for 24 hours and learn more than they ever knew about the animals’ sleep patterns.

Even at heights of 400 feet, drones’ high-resolution lenses allow researchers to capture important information, such as back length measurements, a common indicator of age. (Photo: Save the Elephants)

“Previously we’d estimated that they only sleep for 15 minutes, but we found that sometimes they’ll all lay down together in a dry riverbed and sleep for a full two hours,” says Jasperse-Sjolander.

“We didn’t really know before what elephants were doing at night,” he adds.. “And so we’re uncovering all these layers of elephant behavior that can help the population.” Knowing where they spend most of their time, when they leave an area and when they are most vulnerable to poaching are all important considerations in the business of saving elephants, he explains.

In May 2025, Jasperse-Sjolander and the Save the Elephants team also published a small field note in the journal Pachyderm about how to maximize these drones’ capabilities, even when there are restrictions on their flight (e.g., in Kenya, where drones are highly regulated). “It can still be a very useful piece of equipment,” says Jasperse-Sjolander, noting that the device’s infrared camera and potential for measuring elephant shoulder height (another common indicator of age) can all be used on the ground, and can take the place of other, more expensive equipment.

In the lab in Colorado

Now, with so much fieldwork data under his belt, Jasperse-Sjolander is back at �鶹��Ѱ��working to finalize his dissertation, comparing behavior between forest and savanna elephants. He’ll build on his master’s coursework (also earned at �鶹��Ѱ��Boulder), which looked specifically at the different behaviors of forest elephants in Gabon—which is 90% forest, 10% savanna—when they’re in the two different biomes.

“Most forest elephant groups are just a mother around their calf and maybe a few relatives,” says Jasperse-Sjolander, explaining that the patchily distributed fruit trees that the elephants feed on are not enough to sustain groups much larger than that.

But, when they emerge from the forest, these groups connect with other small groups.

“Elephants are still very social, and it’s important for them to keep those links and have that larger association network,” says Jasperse-Sjolander, adding that the elephants’ time in the savanna is also important for the exchange of information.

Jasperse-Sjolander’s dissertation will expand the boundaries of his comparison of forest and savanna elephant behaviors to take more of a continent-wide approach to understanding the variations between and among them.

And after that? Jasperse-Sjolander is hoping to head back to Africa for a longer contract with a non-governmental organization like Save the Elephants, where he can use learnings from his PhD to advance our understanding of elephant behavior even further.

“I like just being in Africa and being in the field,” he says. While many researchers in his field go back and forth between the U.S. and Africa, “I like to live and embody the places I study.”

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�鶹��Ѱ��Boulder PhD student Liam Jasperse-Sjolander is helping elephant behavioral observation get off the ground—and into the air above Africa.

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Don’t just explain the science, dance it

Rachel Sauer — Thu, 12 Mar 2026 16:14:04 +0000

Don’t just explain the science, dance it Rachel Sauer Thu, 03/12/2026 - 10:14

Rachel Sauer

Asia Kaiser, a bee researcher and ecology and evolutionary biology PhD candidate, is named social sciences category winner in the international Dance Your PhD contest sponsored by the journal Science

There’s a lot going on with bees right now. Because it was an unseasonably warm winter, queens may be emerging from hibernation and beginning to lay the eggs of their first broods. And since queens can choose the sex of their offspring, they are now or soon will be producing daughters.

It’s fascinating information about one of the planet’s most complex and charismatic insects, but how to convey it in dance?

PhD candidate Asia Kaiser (in a scene from her Dance Your PhD entry), studies how human land use affects different insect groups and, consequently, the ecosystem services they provide in coupled human-natural systems.

Start with a shimmy—reminiscent, perhaps, of the movement of bees’ wings or the vibration of their flight muscles. Then weave undulating patterns with fellow dancers, gliding and twirling in a choreography of bees in motion. And bring it home with a question about what happens when we remove native flowers from urban environments or destroy bee habitat to build roads or houses (answer: nothing good).

In short, dance your PhD. So, that’s what Asia Kaiser did.

Kaiser, a PhD candidate in the �鶹��Ѱ�� Department of Ecology and Evolutionary Biology (EBIO) and researcher in the Resasco Lab, this week was announced the social sciences category winner in the international Dance Your PhD contest sponsored by the journal Science and the American Association for the Advancement of Science.

Now in its 18th year, Dance Your PhD seeks, through a spirit of fun and of marrying art and science, to address a scenario that scientists commonly experience: “The party is just getting started when the dreaded question comes: ‘So, what’s your PhD research about?’ You launch into the explanation, trying to judge the level of interest as you go deeper. It takes about a minute before someone changes the subject,” contest organizers explain.

“At times like this, don’t you wish you lived in a world where you could just ask people to pull out their phones to watch an online video explaining your PhD research through interpretive dance?”

“I was a dancer all through college, so I have a background in belly dance and Latin dance,” Kaiser explains. “And I like to make music, so I thought this could be a really fun way to explain my research.”

Learning to dance

And what is that research? Bees. Specifically, how human land use affects different insect groups and, consequently, the ecosystem services they provide in coupled human-natural systems. Her research aims to improve the resilience of urban agroecosystems, increase equitable access to fresh produce and promote environmental justice in cities.

As for the dancing, Kaiser had wanted to take dance lessons while growing up in Philadelphia, but there wasn’t room in the budget for them. So, after graduating high school she took a gap year in Brazil to do service work and finally began learning dance. She started with belly dance, then branched into samba and other Latin styles.

When she began her ecology and evolutionary biology undergraduate studies at Princeton University, “I thought, ‘I’m going to invest in my secondary dream,’” Kaiser recalls, which meant stepping away from the books sometimes to immerse herself in the vibrant dance scene in Princeton and the broader New York City and Philadelphia area.

She also is a cellist, so when she came to �鶹��Ѱ��Boulder to pursue her PhD she began making music with other people in her department.

When she heard about Dance Your PhD, it dovetailed with so many of the things she loves: dance and music and science. However, the deadline to submit entry videos was Feb. 20, and she decided to enter the contest a mere two weeks before then.

She started with the music, composing a piece to score the story in her mind: “I wanted to tell a story of bees emerging in early spring in your backyard and what they’re up to. People know a lot about honeybees, but not other bee species, so I wanted to highlight how important they are to urban ecosystems.”

Kaiser put out a call for dancers and fortunately, the response from her fellow PhD students and candidates was abundant and eager. Then she and Ella Henry, a violinist and EBIO PhD student, recorded the music.

Science as art

Because of the quick turnaround, the troupe had time for just two rehearsals before their afternoon of filming in front of the EBIO greenhouses on 30th Street in Boulder. It was an EBIO community collaboration. PhD students Manuela Mejía, Lincoln Taylor, Gladiana Spitz, Kaylee Rosenberger and Ella Henry danced Kaiser’s choreography alongside her. PhD student Luis de Pablo helped with sound engineering and Scott Taylor, EBIO associate professor and director of the Mountain Research Station, was cinematographer. Kaiser’s husband, John Russell, provided voiceover narration for the final video.

And despite the extremely short timeframe, it all came together, Kaiser says. For example, she happened to have a pair of gold Isis wings, a traditional belly dance prop, that Lincoln Taylor wore “to depict the fact that male bees spend their lives flying around,” she says.

The dance, music and costumes united in a science-as-art visualization of her PhD, which she uploaded to YouTube and clicked submit on her Dance Your PhD entry. She was up against scientists from around the world, so learning that she won her category was especially significant.

“Obviously, I love bees,” she says, “and I love to dance and make music, so it was a really cool experience to create this piece with my friends and find a different way to talk about my research.”

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Asia Kaiser, a bee researcher and ecology and evolutionary biology PhD candidate, is named social sciences category winner in the international Dance Your PhD contest sponsored by the journal Science.

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Scholar considers language, identity and the fight over shared symbols

Rachel Sauer — Mon, 16 Feb 2026 17:42:36 +0000

Scholar considers language, identity and the fight over shared symbols Rachel Sauer Mon, 02/16/2026 - 10:42

Cody DeBos

�鶹��Ѱ��Boulder linguistics researcher Kate Arnold-Murray studies what a Facebook fight reveals about identity

In 2019, Washington, D.C.’s Pride celebrations became a flashpoint—but not just for the usual political tensions. Organizers of the annual Dyke March barred participants from carrying the Jewish Pride flag, sparking a wider debate about symbols and the meanings they carry.

Organizers claimed the flag too closely resembled the Israeli flag and could be insensitive to pro-Palestinian participants. Jewish LGBTQ+ activists, many of whom had marched in the event for years, were stunned.

“I was actually living in Washington, D.C., at the time,” says Kate Arnold-Murray, a PhD candidate in the Department of Linguistics at the �鶹��Ѱ��. “I was out of town at the time, so I was looking at things involving the march on Facebook and saw all these arguments going on. I wanted to get to the root of what people were upset about—what people who presumably should be on the same page were arguing about.”

�鶹��Ѱ��Boulder scholar Kate Arnold-Murray has studied how the six-pointed Star of David became the center of conflict in a space that promotes solidarity.

What began as curiosity while browsing turned into years of research for Arnold-Murray, culminating in her recent publication in the Journal of Linguistic Anthropology.

Her study looks at how a single symbol—the six-pointed Star of David—became the center of conflict in a space that promotes solidarity.

Bridging language and politics

In her doctoral work at �鶹��Ѱ��Boulder, Arnold-Murray focuses on how language produces and reflects political identity in America.

“Most of my work involves language and politics on the left in the United States. This piece ties into that work because these are presumably mostly political actors on the left in arguments with each other,” she says.

In her paper, Arnold-Murray examines a trove of public Facebook comments from individuals and organizations reacting to the 2019 Dyke March decision.

“As a member of both the Washington, D.C., queer community and the Washington, D.C., Jewish community, it was like my two sides were fighting, and I wanted to understand why,” she says.

The problem of misrecognition

The controversy centered on the Jewish Pride flag: a rainbow background with a white Star of David in the middle. For some, the star was a proud symbol of Jewish identity that dates back thousands of years. For others, it was too reminiscent of the Israeli flag—and thus a political statement they opposed.

To understand the disagreement, Arnold-Murray turned to the concept of indexicality, or the connection between a sign and its social meaning.

“Indexical misrecognition is accounting for the possibility that we might have misunderstandings based on our lived experiences shaping how we interpret signs like a symbol or word,” she explains.

In other words, what one person sees as an expression of faith or cultural belonging, another may see as a symbol of state violence or exclusion.

“In this instance, each group came with a different notion of what the Star of David means based on their lived experiences—and that’s where we get that misrecognition.”

Arnold-Murray’s paper takes it further. She argues that not only do symbols connect with personal and cultural identities, but they can lead to conflict because their meanings are not fixed. That’s especially true when it comes to symbols like the Star of David, whose associations stretch across religion, nationalism, ethnicity and more.

“If we can find ways to stop arguing about symbols and come together a little more, we can have more political unity. But that has to start with listening to the voices of marginalized individuals and understanding that the signs we use might carry multiple meanings,” says �鶹��Ѱ��Boulder linguistics scholar Kate Arnold-Murray. (Photo: Tom Morris/Wikimedia Commons)

“Another example is the phrase ‘Are you a friend of Dorothy?’ which has been used within the queer community to indicate that someone is queer. But to someone who is not queer, they might not share that same meaning and they might say, ‘Dorothy who?’” Arnold-Murray says.

One flag, many meanings

Arnold-Murray also uses the term bricolage to describe the Jewish Pride flag. In the art world, bricolage refers to a construction created from layers of different materials.

“Here, we have the Jewish Pride flag as a construction of bricolage, where there are the meaningful horizontal rainbow stripes of the queer pride flag and then the white Star of David, which can indicate Judaism or potentially Israel, depending on one’s reading,” she says.

The ambiguity of meaning in signs consisting of multiple parts is what often leads to misrecognition. Since the Jewish Pride flag combines two strong identity symbols, any interpretation is bound to stir deep emotions, Arnold-Murray explains.

“It’s when we have these signs that are so tied up with our identity and who we are that we get these big conflicts among, presumably, a queer community where a lot of people agree on political issues overall.”

For many Jewish participants in the 2019 Dyke March, banning the flag was more than a debate over a symbol.

“A lot of the commenters who were against the ban of the Jewish pride flag were claiming that the ban was anti-Semitic and against them as Jews and that they felt excluded from the march,” Arnold-Murray says.

For organizers, allowing the flag could have been seen as endorsing a political stance they didn’t share. It was a lose-lose situation made worse by how personal it felt for everyone involved.

What’s at stake

Arnold-Murray is careful to warn that there isn’t a one-size-fits-all solution to symbolic conflict. But she does suggest that understanding how symbols work, and why layered meanings can spark conflict, can lead to more empathetic conversations.

“I think the stakes are huge. When we have these signs that are tied to identity, it can feel like a personal attack to be contesting what they mean,” she says.

“If we can find ways to stop arguing about symbols and come together a little more, we can have more political unity,” she adds. “But that has to start with listening to the voices of marginalized individuals and understanding that the signs we use might carry multiple meanings.”

In a political landscape increasingly fractured by culture wars and identity debates, that goal may feel out of reach. But for Arnold-Murray, it all comes back to understanding.

“Meaning isn’t fixed. When it comes to situations like this, what’s really important is listening, being willing to apologize, and being willing to move forward while being as inclusive as possible,” she says. “Understanding that meanings come from lived experiences is a good starting point.”

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�鶹��Ѱ��Boulder linguistics researcher Kate Arnold-Murray studies what a Facebook fight reveals about identity.

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Top photo: Ted Eytan/Wikimedia Commons

Young voices must rise in the climate conversation

Rachel Sauer — Thu, 12 Feb 2026 21:27:51 +0000

Young voices must rise in the climate conversation Rachel Sauer Thu, 02/12/2026 - 14:27

Cody DeBos

�鶹��Ѱ��Boulder geography PhD student Ethan Carr joins colleagues worldwide to confront climate change across continents

Ethan Carr has always been drawn to cold places. Growing up, he spent summers exploring national parks and winters immersed in the stark beauty of Alaska.

Now, as a PhD student in the �鶹��Ѱ�� Department of Geography, he spends his days researching the world’s melting ice and participating in an innovative youth leadership forum alongside fellow climate activists from around the world.

They are part of the Hindu Kush Himalaya (HKH) - Arctic Youth Leadership Forum, an ambitious new initiative connecting young people from mountain and polar regions to amplify voices in the climate fight and search for new solutions.

“Not everybody needs to be a scientist or a strict climate activist to have an impact. Really, all you need is to have a voice and a passion for it," says Ethan Carr, a �鶹��Ѱ��Boulder PhD student in geography. (Photo: Ethan Carr)

From soldier to scientist

“It’s been a long, kind of windy road to get to where I’m at today,” Carr says.

That road, it turns out, began at West Point.

Carr didn’t originally set out to become a climate researcher when he enrolled at the U.S. Military Academy at West Point. But a mandatory earth-science course nicknamed “DIRT” sparked an interest he didn’t know he had.

“That was kind of the first time I realized that you can make a career out of studying and being in really cool environments while you do it,” he says.

After graduating in 2020 and serving as an infantry officer, Carr’s career was redirected by an injury, forcing him to reassess his path forward. Business school wasn’t appealing, but geography still was.

“I took a couple of pre-MBA courses and couldn’t have been more bored in those,” he recalls. “So I said, ‘I have this geography degree, I might as well try to make a career out of it.’”

That decision led him to �鶹��Ѱ��Boulder, one of the country’s top hubs for cryosphere research. He moved to the area before even getting into grad school, taking a chance on himself that would soon pay dividends.

First came a master’s degree. Then he turned his attention to pursuing a PhD in geography with support from the Cooperative Institute for Research in Environmental Sciences (CIRES).

Climate leadership across continents

Carr was recently named part of the inaugural class of youth champions in the HKH - Arctic Youth Leadership Forum, a yearlong fellowship launched by the International Centre for Integrated Mountain Development (ICIMOD) in Nepal. The forum brings together 12 young leaders from some of the world’s most climate-vulnerable regions.

Carr first saw the application on LinkedIn and was intrigued not just by the opportunity, but by the forum’s emphasis on public education and policy.

“One thing I’ve realized in my scientific journey so far is you have a lot of scientists who are obviously very intelligent, but not everyone wants to engage in public education, especially on the policy side,” Carr says.

Coming from a military background, he was already used to thinking geopolitically, so he saw the forum as a way to merge science with diplomacy while making a real impact.

“Within our cohort, we represent nations that are some of the largest emitters, being the U.S., China, and India,” Carr explains. “But we also have representatives from some of the countries that are experiencing the effects of climate change firsthand.”

While studying at the U.S. Military Academy at West Point, Ethan Carr took a mandatory earth-science course nicknamed “DIRT” that sparked an interest he didn’t know he had. (Photo: Ethan Carr)

In the Arctic, Carr points to the rapid melting of the Greenland ice sheet, a reality threatening both biodiversity in the region and Indigenous fishing economies. Meanwhile, countries like Pakistan, Nepal, and India, home to thousands of Himalayan glaciers, are confronting retreating ice sheets that underpin their water security.

“We see a lot of similarities in how things are changing, but this collaboration shows the kind of differences in who’s being affected and the populations being affected more so,” he says.

Data meet lived experience

As part of his doctoral work, Carr studies glacial lake outburst floods in Greenland—events in which meltwater lakes suddenly burst through glaciers, often with destructive force. He relies on satellite data to track water levels, but he’s also learned to listen to what local people are witnessing on the ground.

“Local fishermen have been noticing trends where, after these drainage events, they see an increase in primary productivity in local fjords. That has a significant impact on fishing for the year,” he says.

“That’s not something I would have expected as a scientist just looking at satellite imagery.”

This experience is one among many that has shaped Carr’s belief in combining scientific knowledge and the lived experiences of those native to the regions being studied. It also helped reinforce his understanding of the importance of bringing more voices to the table.

“Our generation and the generation after us are going to be the ones that are inheriting the climate mess we’ve been given by former generations, so those voices need to be heard,” he says.

Speaking of his fellow members on the leadership forum, Carr adds, “These are people that are passionate and empowered youth that have good ideas.”

A global generation

Carr sees connection as a unique advantage in his generation’s ability to catalyze change in the climate arena.

“We’re the most globalized generation there has ever been. My parents couldn’t pick up the phone and directly communicate with someone living in Bangladesh or Bhutan. But we can do that and form genuine working relationships with somebody 12 hours across the globe and work on projects that connect our regions,” he says.

He says the ability to collaborate across borders and cultures is a crucial advantage in the fight against climate change.

But so is perspective.

In his conversations with peers in South Asia, Carr has come to appreciate just how immediate the crisis is elsewhere and why people closer to home might not be able to recognize the urgency.

“In the U.S., I think sometimes we can be kind of separate from understanding what’s really happening in the world. Obviously, we’ve had massive disasters, but we’re not going to be seeing the 10-, 15-million people being displaced in Southeast Asia if sea level rises a few centimeters,” he says.

Ethan Carr (bottom row, left) and his colleagues in the Hindu Kush Himalaya (HKH) - Arctic Youth Leadership Forum. (Photo: Ethan Carr)

“These are real impacts happening on that side of the world that we can be pretty ignorant to in the U.S., and it’s something I’ve become way more aware about after talking with folks from over there. They have a lot more urgency in their fight for climate solutions because they can’t afford to wait as long as other parts of the world can,” he adds.

A message for future climate leaders

When asked what he would say to those who feel overwhelmed by the negativity surrounding climate change, Carr doesn’t hesitate. He knows the scale of the crisis can feel suffocating, but he’s also quick to challenge the idea that only scientists belong in the fight.

“Not everybody needs to be a scientist or a strict climate activist to have an impact. Really, all you need is to have a voice and a passion for it,” he says.

Carr believes that the most effective climate solutions will come not just from labs or policy think tanks, but from every corner of society. In fact, he sees this diversity of thought as essential.

“We need climate-minded people in all professions, from business to economics, engineering, and especially journalism. The more we talk about it, the more awareness we can bring to the issue,” he says.

He also sees a need to reframe how climate change is discussed.

“The same rhetoric that’s been used the last few decades of, ‘This is bad because our planet is warming up, and we aren’t going to be able to live,’ hasn’t delivered. Changing how we discuss it to focus on what climate change will do in certain regions and how it will affect local people and economies, I think, is a better way to look at it,” Carr says.

More than anything, Carr encourages young people to speak up and get involved—even if they don’t have a degree or defined role yet.

“The world needs the youth to step up in these spaces. Don’t wait to be asked. Make a space for yourself and move into it. Use your voice to make good things happen in the world.”

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�鶹��Ѱ��Boulder geography PhD student Ethan Carr joins colleagues worldwide to confront climate change across continents.

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Top image: Ethan Carr (third from left) and fellow member of the Hindu Kush Himalaya (HKH) - Arctic Youth Leadership Forum (Photo: Ethan Carr)

Researchers learn new lessons from old butterflies

Rachel Sauer — Fri, 06 Feb 2026 18:00:00 +0000

Researchers learn new lessons from old butterflies Rachel Sauer Fri, 02/06/2026 - 11:00

Alexandra Phelps

Research co-authored by �鶹��Ѱ��Boulder PhD graduate Megan E. Zabinski and evolutionary biology Professor M. Deane Bowers reveals how museum butterfly specimens, some almost a century old, can still offer insight into chemical defense of insects and plants

You’re sitting in a field, a garden or another outdoor space, basking in a beautiful summer day. Clouds drift across the sky when something catches your eye. You turn to see a butterfly, its delicate wings and vibrant coloring shifting as it moves from flower to flower. For a moment it’s there, but soon, it moves too far away for you to see.

At first glance, butterflies appear to be just simple, dainty creatures that fly around feeding on plants. For �鶹��Ѱ�� PhD graduate Megan E. Zabinski and evolutionary biology Professor M. Deane Bowers, however, butterflies are anything but simple. Beneath their wings lies a complex system that plays an integral role in their survival.

In recently published research, �鶹��Ѱ��Boulder PhD graduate Megan E. Zabinski (left) and evolutionary biology Professor M. Deane Bowers (right), emphasize the value that museum specimens have in current scientific research.

In a recently published study in the Journal of Chemical Ecology, Zabinski and Bowers researched how two Euphydrays butterfly species—E. phaeton and E. anicia—sequester certain chemical compounds, a process by which organisms capture and store substances from their host plants to defend themselves against their enemies. The researchers found that they were able to understand how these butterflies sequester substances using both historic specimens as well as fresh ones.

Their project points to the value museum specimens can have in scientific research. By comparing historic butterfly specimens from �鶹��Ѱ��Boulder’s Museum of Natural History (CUMNH) with freshly collected and laboratory-reared butterflies, their research demonstrates the benefits, as well as the limitations, of using preserved insects to study chemical defenses decades after collection.

Hatching a plan

Although museum collections house billions of specimens, only a small fraction are used in research after they are acquired. Recognizing this gap inspired Zabinski to begin her research. While Zabinski was still a graduate student, an encounter with Bowers helped shape the trajectory of her academic career.

“Deane came up to me one day—I was in the EBIO club—and she told me she had a job for me. And I thought, ‘A job! You mean I can quit waiting tables at Applebee’s?’”

This opportunity allowed Zabinski to explore her interest in insects and plant-insect interactions within a laboratory setting.

“I absolutely loved being in the lab, doing the physical work with my hands, (whether it was) being able to be outside in the field or looking after the plants,” she says.

Working alongside Bowers—whose research also focuses on how insects interact with their environments—Zabinski began developing her own research questions. She specifically focused on how butterflies in different developmental stages consume and store defensive chemicals to use them later.

Zabinski became interested in whether museum butterfly specimens—which have rarely been investigated and examined for their chemical defenses—could still be helpful.

“We thought about how detecting sequestered defenses in museum specimens really has rarely been done,” she says. “The world of sequestration hadn’t really delved into museum collections. So, we were curious if there was utility there.”

The project was made possible in part by Bowers’ extensive research background and personal butterfly collection, which is housed at CUMNH. The collection includes the species used in the study. When combined with outside specimens, this collection, which includes the species used in the study, allowed Bowers and Zabinski to enrich their understanding of the butterflies.

The Euphydryas anicia butterfly is able to sequester compounds that plants create in defense against herbivores. (Photo: Robert Webster/Wikimedia Commons)

“There has been work done on detecting chemical compounds in plants,” Bowers says. “But there had been less done on insects, and Megan’s thesis had centered on looking at how this particular group of compounds in my lab has worked on particular compounds. We thought it would be really interesting to see if we could find them in old specimens.”

For Zabinski, the combination of Bowers’ expertise and insects available for research made this experiment uniquely valuable.

“It’s kind of the perfect storm for a good experiment. You have a colony in the lab; you also know where there is a field lab where you can get fresh specimens. You know that the museum also has them, but one of the species we had sequestered a high amount, so we thought that … even if there was some degradation, we would still be able to detect them,” she says.

Crawling toward a new understanding

Zabinski and Bowers analyzed specimens from two checkerspot butterfly species in the genus Euphydryas: Euphydryas anicia and Euphydryas phaeton. The species were selected because they are known for their high sequestration ability, abundance in the CUMNH entomology collection and the ease of obtaining live adult specimens. Their research aimed to better understand how the insects use and store these compounds after consuming them as larvae.

Both species sequester iridoid glycosides (IGs), which Zabinski explains are “compounds created by the plants in defense against the herbivores. They’re trying not to get eaten, but there are certain insects— including these butterflies—that capitalize off this process.” Bowers adds, “I’ve tasted (iridoid glycosides), and they’re really bitter. So they are a really good defense against predators and diseases.”

“They’ve been able to find a way to store these compounds in their own bodies and then they can confer some defense against predators,” Zabinski says.

In an initial pilot experiment, the researchers chemically extracted from only one set of wings—a forewing and a hindwing—from historic specimens to determine whether IGs could be detected from the wings alone. Previous experiments have determined that, because in butterfly wings there’s hemolymph (a circulatory fluid similar to blood), it’s possible to detect IGs there. Unfortunately, the results showed extremely low concentrations. To obtain detectable amounts, they found it necessary to analyze both the body and a pair of wings together. For documentation and future research, the set of right wings from each specimen was removed and preserved.

With their methodology established, they chose six E. phaeton specimens from the CUMNH that had been collected from 1936–1977. For comparison, E. phaeton larvae were collected from Burlington County, Vermont, brought back to Boulder and raised in the laboratory with their host plant, white turtlehead, Chelone glabra. Once the butterflies reached adulthood, they were freeze-killed and analyzed for their IG content.

Zabinski and Bowers also examined nine historic E. anicia specimens collected between 1933–1998. Fresh adult E. anicia were collected from Crescent Meadows in Eldorado Springs, Colorado, freeze-killed and immediately underwent extraction for chemical analysis. Although it’s almost impossible to tell what plant the freshly caught butterflies consumed as larvae, the field they were collected from is known to have four catalpol-containing host plants. Catalpol, an IG that is found in these plants, allowed the researchers to determine whether the butterflies were sequestering these compounds, even if they weren’t sure what specific plant was the butterflies’ food source.

“Raising butterflies is not easy,” Zabinski says. “Plants can’t just be alive and available—they have to be high quality, because it’s been shown in studies with these plants that if the plant is not happy, it will not allocate energy to create those compounds. Then your caterpillars are not going to want to eat it.”

Shifting predetermined perceptions

Despite being preserved for decades, the historic specimens still contained detectable traces of sequestered chemical defenses. While IG concentrations were significantly lower in museum specimens than in freshly collected butterflies, Zabinski’s results demonstrate that even after nearly a century, chemical traces of larval diets can still be detected in preserved specimens.

Euphydryas phaeton butterflies have "been able to find a way to store (plant defense) compounds in their own bodies and then they can confer some defense against predators,” says researcher Megan E. Zabinski. (Photo: Joshua Mayer/Wikimedia Commons)

By focusing on the detectability of chemical compounds in older specimens, Zabinski’s work contributes to a broader discussion about preservation methods. She notes that museums often have little control over how donated specimens were originally collected or preserved. She says that despite this, “If you’re a collections manager and you have a researcher that conducted a research experiment and would like to donate them to your collection, if you have the capacity to access them, you’re probably not going to say ‘no.’”

Zabinski explains that previous research demonstrating how preservation methods affect scientists’ ability to detect DNA in museum specimens really shifted how people preserve certain organisms.

“Most insects are preserved as dried specimens, although some are preserved in alcohol,” she says. “In other groups of organisms, like vertebrates and other invertebrates besides insects, they’re often preserved in alcohol or formaldehyde. We now know that using formaldehyde destroys DNA, and so I think the protocol for specimen preservation has changed, trying to preserve the DNA. That’s been one change that museums have been trying.”

Zabinski’s project and others like it are creating an incentive. “As more research comes out about the extended museum specimen and the utility of specimens—particularly with standardization—museums will find a draw to create some uniformity,” she says.

Soaring to new heights

On that summer day, someone who was watching the butterflies move was Bowers.

“I started collecting insects when I was a little kid,” she says. “In undergrad, I did some independent research on butterflies, [and later,] in graduate school, I had a really supportive advisor who told me to spend my first summer going out and looking at butterflies and seeing if I could find some interesting questions. That’s been the focus of my research since.”

Recognizing Zabinski’s curiosity and potential, Bowers recalls, “I brought Megan into the fold.”

“We hear a lot about climate change and we don’t really hear about these smaller interactions that are quite literally under our feet every day,” Zabinski reflects. She says this paper offers one example of how museum specimens are not just remnants of the past, but tools that can be used to better understand specimens today. As technology advances and more research is conducted into chemical defenses, Zabinski says museum specimens can prove to be even more valuable in understanding how organisms interact with their environments long after they’ve been collected.

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Top image: Euphydryas anicia butterfly (Photo: U.S. Fish and Wildlife)

Scholar considers limits on God and freedom for humans

Rachel Sauer — Wed, 07 Jan 2026 16:50:59 +0000

Scholar considers limits on God and freedom for humans Rachel Sauer Wed, 01/07/2026 - 09:50

Clay Bonnyman Evans

�鶹��Ѱ��Boulder philosophy PhD student Nathan Huffine offers ‘limited foreknowledge’ to solve the paradox of human free will and an all-knowing deity

For many believers, squaring belief in a traditional “omni” deity—a god that is omniscient, omnipotent and omnibenevolent—with the notion that human beings possess free will poses a quandary.

Here’s how �鶹��Ѱ�� philosophy PhD student Nathan Huffine describes the paradox:

“If there is an omniscient being, such as God, who infallibly knows the truth-values of all propositions, including propositions about future human actions, then no human action can be performed freely. No human action is free, since any human action is subject to the implications of this eternal and infallible knowledge of God. Such knowledge implies that an agent cannot do otherwise than what God knows she will do.”

Nathan Huffine, a �鶹��Ѱ��Boulder philosophy PhD student, argues that belief in both divine foreknowledge and free will are necessary to address the classic theological “problem of evil,” also known as the “problem of suffering."

Huffine argues that belief in both divine foreknowledge and free will are necessary to address the classic theological “problem of evil,” also known as the “problem of suffering”—if a deity is all-powerful, all-knowing and all-good, why is there suffering and evil?

“If one believes there is a god, one also ought to posit that humans have libertarian free will”—individuals are free to make, and therefore must take responsibility for, all their choices—“in order to deal with the problem of evil,” Huffine says.

But in his recent paper, “Limits on God, Freedom for Humans,” published in the International Journal for Philosophy of Religion, Huffine defends the foreknowledge-freedom problem from assertions that it’s merely a game—an intellectual bauble or “pseudo-problem” —and considers two potential solutions to the conundrum, settling on one as most viable.

“It’s an interesting subject because the ideas of God and free will are important to me, and to many other people in their daily lives,” Huffine says.

He first considers what’s commonly referred to as “the eternity solution,” which posits that an atemporal deity—one that exists “outside” of time and space—would be always and eternally aware of everything that is, was and will be. Or as he describes it, “all times are equally real.”

Huffine describes a hypothetical situation in which a woman, Ellie, skips work to go to the beach. While there, a bottle washes onshore, bearing a message predicting that she will skip work and go to the beach that day.

“Suppose Ellie does have the ability to choose otherwise, and that the prophetic statement … has existed since 102 BC. … Also suppose that Ellie actually goes to work … never visiting the beach,” he writes. “Given this, the prophetic object (the bottle) from 102 BC would be wrong, and consequently, God would be wrong.”

But if a deity is inerrant and infallible, such a “conclusion is absurd,” Huffine writes. Because under eternalism, there is no time at which the bottle and message did not exist, “Therefore, there is no moment in Ellie’s life where she can act otherwise.”

Limited foreknowledge

Huffine finds the next potential solution, that of “limited foreknowledge,” more viable and persuasive.

First, he argues, one must assume an omni-deity cannot “do the metaphysically impossible”—the classic example is that a deity cannot create a stone that is too heavy for it to lift; or, as Aquinas argued, God cannot make a circle a square.

But if one defines God as “that than which nothing greater can be ideally conceived,” Huffine writes, then “one cannot ideally conceive of any being that is capable of performing metaphysically impossible feats.”

And if it is metaphysically impossible—contradictory—to square human free will with a deity that is already is aware of every future event, then something has to give, Huffine concludes.

“Therefore, God does not know the truth-value of all propositions but only those propositions it is possible for God to know without threatening human freedom,” he writes. If that’s true, he acknowledges, then “Jesus’ prophecies had the potential to be wrong.”

Huffine acknowledges that his thesis includes complicated, debatable metaphysical arguments, such as whether a deity limited is truly omniscient or omnipotent, given that metaphysics and logic can appear to trump its abilities.

“But you have to explore all these crazy pretzels,” he says. He cites the field of quantum mechanics: “We have to try to make sense of it, and whatever the data says, we have to try to square it with macro-reality.”

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�鶹��Ѱ��Boulder philosophy PhD student Nathan Huffine offers ‘limited foreknowledge’ to solve the paradox of human free will and an all-knowing deity.

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Medical issues and neighborhood opportunity can affect infant development

Rachel Sauer — Mon, 04 Aug 2025 20:21:30 +0000

Medical issues and neighborhood opportunity can affect infant development Rachel Sauer Mon, 08/04/2025 - 14:21

Sarah Kuta

�鶹��Ѱ��Boulder researcher Emily Yeo finds that some babies may benefit from more support and resources so they can grow up to lead long, happy and healthy lives

In an ideal world, every baby would be born perfectly healthy. Unfortunately, many newborns arrive prematurely or suffer from medical conditions that could hinder their future development.

Some of these high-risk infants live in neighborhoods with access to healthy food, low crime rates and affordable housing. Others, however, live in worse-off communities with limited access to quality education, health care, housing and jobs.

Now, new research led by �鶹��Ѱ��Boulder’s Emily Yeo explores how medical complexity and neighborhood opportunity might affect the development of high-risk infants.

Emily Yeo, a PhD student in the �鶹��Ѱ��Boulder Department of Integrative Physiology, led research exploring how medical complexity and neighborhood opportunity might affect the development of high-risk infants.

The findings, recently published in the Journal of Pediatrics, suggest some babies may benefit from more support and resources so they can grow up to lead long, happy and healthy lives.

“What the study highlights is that there’s sort of a double burden on medically complex infants living in lower-opportunity neighborhoods,” says Yeo, a doctoral student in the Department of Integrative Physiology. “There needs to be a lot more research into how we can better support these infants, especially within the first couple of years of their lives, which are critical for development and when small interventions could have a huge, life-long impact.”

Studying high-risk infants in California

Public health professionals have long understood that social, environmental and economic factors affect human health and development. Everything from a person’s income and education levels to the purity of the air they breathe and their access to grocery stores can play a role in their well-being.

Against this backdrop, scientists wanted to understand whether there was a relationship between the complexity of infants’ medical conditions, their neighborhood opportunity and their developmental progress.

“To fully understand the developmental challenges these infants face, it is essential to consider how their medical conditions interact with the social and environmental contexts of their upbringing,” says Yeo.

The team studied 440 infants born in Southern California between 2014 and 2023. Doctors had deemed these babies “high-risk” because they were born prematurely, had very low birth weights or suffered from conditions that required treatment in a neonatal intensive care unit.

By reviewing the infants’ medical records, scientists were able to categorize them based on the seriousness of their situation. Infants with the highest level of medical complexity, for instance, had conditions like permanent brain damage or chronic respiratory issues. Those with the lowest level of medical complexity, meanwhile, had more easily treatable conditions, like acute lung or eye infections.

Researchers also assessed each child’s neighborhood opportunity level, based on their home address. For this, they turned to the Child Opportunity Index, a pre-existing, composite index that analyzes education, health, social and economic data from every census tract in the United States.

Some neighborhoods earn high scores, because the children who live there have access to quality schools, clean air, health care, playgrounds and other conditions that will help them grow up healthy and become thriving adults. Other neighborhoods, however, offer very few or none of these resources. Black, Hispanic and Native American children are more likely to live in very low-opportunity neighborhoods compared to their White peers.

For each child, researchers also collected developmental scores from standard tests conducted when they were between the ages of 4 months and 36 months old. The scores came from the Bayley Scales of Infant and Toddler Development, which doctors consider the “gold standard” for evaluating infant cognitive, motor and language skills, the researchers write in the paper.

�鶹��Ѱ��Boulder researcher Emily Yeo found that childhood development is affected by both medical and social factors, which aligns with what pediatricians see in daily practice. (Photo: Emily May/Unsplash)

When the scientists analyzed all of the data they had gathered, some clear patterns began to emerge. Developmental scores got worse as medical complexity increased, meaning that infants with more severe and complicated health conditions had lower cognitive, motor and language scores. These finding are consistent with previous studies, says Yeo, which have found that infants with fewer medical complications are also likely to face fewer challenges achieving growth milestones.

The study also found that medical complexity had a more significant effect on developmental outcomes than gestational age, or how early a baby was born. This is an important takeaway for pediatricians, who have long used gestational age to predict potential developmental delays or issues, says Yeo.

“Gestational age might be useful for infants who are not medically complex, but if you’re looking specifically at those infants, we need a more granular tool,” she says. “With this group of infants, we saw that gestational age didn’t really play a huge role in deciphering differences in development, whereas their degree of medical complexity did.”

The researchers also found a correlation between lower neighborhood opportunity scores and decreased language scores, but not cognitive and motor scores. The reasons for this discrepancy are not clear. But, overall, this finding indicates that where an infant lives does seem to play a role in their development.

Importantly, the study also ruled out differences in development based on race and ethnicity alone. Black and Hispanic babies did have lower developmental scores than White babies, but the findings indicate those disparities resulted from differences in the infants’ socio-demographic and medical factors.

“The differences do not come from race and ethnicity itself—they come from other influential factors that tend to be worse in those groups,” says Yeo, adding that this finding aligns with the general shift from race-based to race-conscious medicine.

More social supports for development

Together, the study results align with what pediatricians see in real life—that childhood development is affected by both medical and social factors. The research also highlights the importance of early intervention programs and policies designed to help children succeed.

“It’s one more indication of how, if we really want to move the needle and improve the outcomes of these babies that are born with medical risk factors, we need to put as many social supports in place as we can to support their development,” says study senior author Christine Mirzaian, a pediatrician at Children’s Hospital Los Angeles and an associate professor of clinical pediatrics in the Keck School of Medicine at the University of Southern California.

“It’s not just the child’s medical diagnosis that is going to impact their development—it’s also the neighborhood the child is brought up in, how much medical care their family is able to afford and other barriers.”

The study did not explore the possible mechanisms at play—that is, why medical complexity and neighborhood opportunity seem to be linked with development. But the researchers have a few theories.

For one, children with very serious health issues often need to use medical equipment that helps them breathe and eat—like feeding tubes in their stomachs or oxygen tubes in their noses. From a purely physical standpoint, these devices may make it difficult for infants to do “all the basic things babies do,” Mirzaian says, like rolling around or pulling themselves up to a standing position.

Another possible explanation is that a child’s appointments and treatments may leave little time for activities that promote development, like reading and playing with toys, Mirzaian adds.

Families living in neighborhoods with low opportunity scores, meanwhile, may be grappling with poverty—and having a baby with a serious medical condition likely only adds to their stress. Through no fault of their own, caregivers may need to focus more on basic needs—like how they’re going to pay next month’s rent or put food on the table—and less on their child’s development, says Mirzaian.

‘Medical Data Alone Does Not Tell the Whole Story’

Looking ahead, the co-authors hope other researchers will repeat and replicate the study, perhaps in other geographic locations or with slightly different populations. Future work might also involve following the same children as they grow up, to see whether and how their developmental outcomes change over time.

For now, though, the study is a good first step toward understanding the link between medical complexity, neighborhood opportunity and development. Zooming out, the findings also reinforce the idea that “medical data alone does not tell the whole story,” says Yeo.

“It’s important for researchers to consider social explanations to formulate a holistic picture of infant development,” she adds. “It’s not just the child’s medical diagnosis that is going to impact their development—it’s also the neighborhood the child is brought up in, how much medical care their family is able to afford and other barriers.”

In addition to Emily Yeo, Nathan Young, Joseph Cleveland, Tamara Simon, Douglas Vanderbilt, Juan Espinoza, Christine Mirzaian and Tanya Alderete contributed to this research. Alderete was previously a faculty member in the �鶹��Ѱ��Boulder Department of Integrative Physiology.

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�鶹��Ѱ��Boulder researcher Emily Yeo finds that some babies may benefit from more support and resources so they can grow up to lead long, happy and healthy lives.

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Top photo: Philip Mroz/Unsplash

How deep is that snow? Machine learning helps us know

Rachel Sauer — Thu, 10 Jul 2025 13:30:00 +0000

How deep is that snow? Machine learning helps us know Rachel Sauer Thu, 07/10/2025 - 07:30

Blake Puscher

�鶹��Ѱ��Boulder researchers apply machine learning to snow hydrology in Colorado mountain drainage basins, finding a new way to accurately predict the availability of water

Determining how much water is contained as snow in mountain drainage basins is very important for water management, because measuring it is a necessary part of predicting the availability of water—especially in places that rely on snowmelt for their water supply, like Colorado and other western states.

Snow water equivalent is the amount of water in a mass of snow or snowpack. The depth of this water is a fraction of the snow depth, and this fraction is obtained by multiplying the depth by the snow density, which is expressed as a percentage of the density of water. If there are 10 inches of snow with a density of 10%, the snow water equivalent is 1 inch.

A persistent challenge is that snow water content is calculated from both snow depth and snow density, yet it remains unfeasible to directly measure snow density over a large area. Traditionally, this issue has been addressed with remote sensing, which allows for consistent and relatively large-scale measurements. However, remote sensing methods have their own limitations, which has prompted the search for an alternative in machine-learning technology.

�鶹��Ѱ��Boulder researchers Jordan Herbert (left), a PhD candidate, and Eric Small, a professor of geological sciences, developed a model that can estimate the snow density at times when and in places where it has not been observed or sensed.

In their study on the subject, �鶹��Ѱ�� Ph.D. candidate Jordan Herbert and Professor Eric Small of the Department of Geological Sciences developed a model that can estimate the snow density at times when and in places where it has not been observed or sensed. This model is split into different scenarios, each trained on a different subset of the data, and while performance varied, all scenarios were more accurate than extrapolation from remote sensing methods, according to Herbert and Small.

Model performance analyses also demonstrated that information from Airborne light detection and ranging (LIDAR) can be transferred to different times and places within the region it was collected.

LIDAR and SNOTEL data

LIDAR surveys are an important tool in snow hydrology, as they provide detailed information about snow properties, specifically through their detection of snow depth.

“You fly the plane twice,” Small says, “once when there’s no snow, once when there is snow. The laser reflects off the surface, and if you know where the plane is and the distance to the surface, then you know the height of the snow relative to the ground surface.” This is called differential LIDAR altimetry.

While LIDAR is very useful in snow hydrology, it does have some limitations. The first is that it only measures snow depth, but snow density (either measured or modeled) is also needed to determine snow water equivalent. This isn’t a unique limitation, however, because snow density cannot be surveyed in the same way as snow depth.

“Measuring snow density in the field reveals just how variable the snowpack is,” Herbert explains. “Depending on if you dig a snow pit under a tree or on a north versus south facing aspect, you can get a completely different answer.”

This is a major limitation of on-site observations. Density also varies with depth, and remote sensing signals will be affected by the amount of liquid water content in snow, which makes measuring snow density remotely or over a broad scale impossible for the foreseeable future.

The second and more easily addressed issue with LIDAR surveys is the logistical issues associated with necessary plane flights.

“You can’t fly a plane all the time,” Small says. “It’s too expensive, and we don’t have enough planes to fly everywhere.” Planes also cannot be flown when the weather is bad, and surveys only provide a snapshot of snow depth, which can change rapidly as snow falls or melts.

“Measuring snow density in the field reveals just how variable the snowpack is. Depending on if you dig a snow pit under a tree or on a north versus south facing aspect, you can get a completely different answer,” says �鶹��Ѱ��Boulder researcher Jordan Herbert. (Photo: Pixabay)

These limitations can be worked around by using the LIDAR data to train computer models. “Based on that,” Small says, “you can use the LIDAR information to make predictions in the absence of LIDAR at another time or date or location. So, you’re leveraging the scientific information from LIDAR to improve your knowledge generally.”

Snow telemetry (SNOTEL) is an automated system of snow and climate sensors run by the National Resource Conservation Service, which is part of the U.S. Department of Agriculture. There are about a thousand SNOTEL sites across the western United States—small wilderness areas filled with sensing equipment that measures precipitation, snow mass and snow depth.

“All snow hydrology is based on data from these stations,” Small says. “The problem is that they only cover a small area. If you take all the SNOTEL stations in the western U.S. and put them next to each other, they’d be about the size of a football field, so they’re vastly under sampling. That’s why people want to use LIDAR to fill in all the spaces around them.”

The random forest model

Linear regression makes quantitative predictions based on one or more variables, but it becomes difficult to perform when many of these variables interact with each other in complex ways. In this case, some examples are elevation, solar radiation, slope, tree cover and so on. The difficulty of working with all these variables can be minimized by a modeling tool called a regression tree.

“A binary regression tree splits your sample into two groups, and it splits that sample to figure out which variable has the most effect on the thing you're trying to predict,” Small explains. The branching structure created by these splits gives the model its name and is designed to minimize errors. Each branching point is a condition like true/false or yes/no, the answer to which determines the path taken.

Regression trees are useful in that they fit the data better than multiple linear regression models, which are the other option when it comes to using linear regression when there are many variables involved. The better a model fits the observed data, the better it will be at predicting data that have not been observed, Small says.

However, regression trees have their own limitations.

“The downside of a binary regression tree is that it only gives you categorized values,” Small says. “For example, snow depth could be 70 centimeters, 92 centimeters or 123 centimeters. You end up with a map that just has these particular values.” This issue can be solved by combining multiple regression trees into a random forest model.

“What a random forest does,” Small explains, “is take a bunch of these binary regression trees and samples them randomly to give you continuous distributions of the variable that you care about. So instead of it being in these categories, it's more like how we think about snow depth.”

“All snow hydrology is based on data from (SNOTEL) stations. The problem is that they only cover a small area. If you take all the SNOTEL stations in the western U.S. and put them next to each other, they’d be about the size of a football field, so they’re vastly under sampling," says �鶹��Ѱ��Boulder Professor Eric Small. (Photo: Ruvin Miksanskiy/Pexels)

Machine learning

While using binary regression trees allows the predictive model discussed in this study to fit the data better, there are other things to consider, Small says. “In machine learning and other statistics, there’s this trade-off between how well a model can fit the information you give it and how generalizable it is. If I keep adding training data, training the model and tuning the parameters, I can have it fit the data pretty well, but then it becomes fixated on those very specific data, and it’s not going to make good predictions elsewhere.”

This is called “overfitting,” and it can be described simply as the model becoming too used to patterns in the data it was trained on. In anticipating these patterns, the model will make incorrect predictions that would have been right in the same place or under the same circumstances as the training data were collected, but aren’t otherwise.

This explains the different performance of the three different versions of the model: the site-specific model, the regional model and the site-specific and regional (SS+Reg) model. The site-specific model makes predictions about a given basin using LIDAR data from the same basin that was collected at other dates, whereas the regional model makes predictions about a basin using data from other basins and at other dates. The SS+Reg model was trained using all available data.

The SS+Reg model was the most accurate, but all models were generally accurate, both compared to models from prior studies and remote sensing methods. Because models of the sort used in this study output on the 50-meter scale, this scale was used to compare this study’s models to existing ones, and the former were more accurate. The models’ outputs were at a scale of 50 meters, but these were upscaled to 1- and 4-kilometer scales as well.

The 1- and 4-kilometer scales are more typically used in water management applications, and all three models became more accurate when applied to these scales, outperforming SNOTEL. This means that the models were more accurate than extrapolation from observation data. The success of both the SS+Reg and regional models indicates that information gained from LIDAR is transferable to different times and locations within the Rocky Mountain Region.

Besides fitting the data well and being adaptable to different scales between the three model scenarios, this approach is also beneficial because it does not rely on modeling physical processes (like snow formation, accumulation and melt) or on uncertain weather data. This makes it so that, once a model is trained, it doesn’t take long to make predictions. “The big gain is that it's much more computationally efficient and it just takes a fraction of the time,” Small says. “It's about 100 times faster.”

Herbert says “machine learning has been a huge benefit to my research, with the results to back it up. It’s freed up my time in the winter to put skis on and dig more snow pits to get the density data we desperately need.”

“For whatever reason, all our physically based models and our knowledge of science just gets in our way of making predictions,” Small explains, “because we've tried to boil it down to these simple equations, but it's not simple.”

"Machine learning has been a huge benefit to my research, with the results to back it up. It’s freed up my time in the winter to put skis on and dig more snow pits to get the density data we desperately need."

Expanding to other regions

The primary limitation of the snow density-measuring framework that the researchers created for this study was its reliance on on-site and LIDAR data for snow depth measurements. Small says that this could be addressed by bringing in other data sets, which would provide a more independent test of success than models’ ability to predict snow density in regions they were not trained on.

One of these data sets, the fractional snow-covered area (how much of the ground is covered by snow), could be measured using LIDAR equipment mounted to a satellite rather than relying on airplanes. While LIDAR has been used with satellite technology, this doesn’t address the limitations of plane-mounted LIDAR, because as Small says, “the (satellite) overpass interval is very slow. It’s about 90 days before it comes back to the place you’re looking at. So, you get a snapshot very infrequently, but it’s everywhere on the planet.”

The next step of developing this kind of model is to apply it to other regions, and it remains to be seen how easily that translation can be made, Herbert says.

“We’ve just begun running the model in California to see if the model works in regions with different climates,” he says. “We want to see how transferable data from one region is to another, and California is an ideal test site since it has more LIDAR than anywhere else in the world.”

The presence of LIDAR is important because these data were the most useful when it came to statistical model validation, or making sure that the models were accurate and reliable, compared to data limited by the small-area reporting of SNOTEL and the variability of on-the-ground snow density measurements. Without data to judge models’ predictions against, it is impossible to determine how well they do, because the actual snow depth is unknown.

Also, because LIDAR isn’t available everywhere, it is important to continue developing other methods of validation, the researchers say. Small says reducing reliance on LIDAR will help the innovative modeling framework apply to many parts of the country.

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�鶹��Ѱ��Boulder researchers apply machine learning to snow hydrology in Colorado mountain drainage basins, finding a new way to accurately predict the availability of water.

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Supporting survivors of sexual assault through community

Rachel Sauer — Thu, 03 Jul 2025 00:31:29 +0000

Supporting survivors of sexual assault through community Rachel Sauer Wed, 07/02/2025 - 18:31

Cody DeBos

�鶹��Ѱ��PhD graduate Tara Streng-Schroeter's research offers a new way to support survivors of sexual violence

The first time Tara Kay Streng-Schroeter stepped into a sorority house to deliver her sexual assault support training, she hoped it would help students feel more prepared to support one another.

She didn’t anticipate the crowd of women lining up afterward to ask questions and offer thanks.

“At one chapter, many women came up to me and thanked me for being there, told me how important they think this training is,” she recalls. “Some said it was better than any training they’ve received from school or as an RA (resident advisor).”

�鶹��Ѱ��Boulder scholar Tara Streng-Schroeter, who earned a PhD in sociology in May, designed a peer-based intervention program designed to help students respond supportively when someone they care about discloses they have experienced sexual violence.

That moment reaffirmed Streng-Schroeter’s belief in what she’d spent years building: a peer-based intervention program designed to help students respond supportively when someone they care about discloses they have experienced sexual violence.

Her program, called Building Support for Survivors (BSS), offers a promising new approach to how college campuses can support students who experience sexual violence.

“We know the majority of survivors never seek support from the police or formal support from a non-profit or university resources. They instead disclose to a close connection,” Streng-Schroeter says.

Yet most students haven’t been trained to handle such a sensitive moment. Even well-intentioned responses can backfire, leading to shame, self-blame or isolation for survivors.

That’s the gap Streng-Schroeter, who in May earned her PhD in sociology from the �鶹��Ѱ��, hopes to close.

Taking innovative research to the front lines

Streng-Schroeter has spent more than a decade working both professionally and academically in the field of sexual-violence response. She has coordinated sexual-assault response teams, trained volunteer victim advocates and witnessed firsthand the long-term effects of both harm and healing.

After talking with hundreds of survivors, she was acutely aware of the opportunity that existed to help college students support their peers who have experienced sexual violence.

Building Support for Survivors, a 90-minute training intervention that she designed to be implemented with peer groups of college students and has piloted with sorority chapters, combines education about the prevalence of sexual violence with hands-on learning around how to listen, what to say and what not to say.

As part of Building Support for Survivors, Streng-Schroeter also provides customized flyers listing local confidential and non-confidential support options.

“Even though there are so many victims within campus communities, students don’t necessarily know the right thing to say to someone who’s experienced this kind of violence unless they have received training,” she says. “And it’s those individuals that don’t have the training but need it that we’re trying to help.”

Over the course of her study, Streng-Schroeter partnered with sorority chapters at nine universities across the country, delivering her training in person at four of them.

A wake-up call

“We know the majority of survivors never seek support from the police or formal support from a non-profit or university resources. They instead disclose to a close connection,” says �鶹��Ѱ��Boulder researcher Tara Streng-Schroeter.

One of the most striking findings of Streng-Schroeter’s research was just how many students have been affected by sexual violence. More than half of the sorority women who completed her surveys reported experiencing sexual violence in their lives.

That number is significantly higher than national averages had previously suggested.

“It could have happened in the week or the month or the semester leading up to when they took a survey,” Streng-Schroeter says, “but it also could have happened when they were a child, or when they were in high school.”

She notes that sorority members, as well as queer students, are disproportionately affected by sexual violence on college campuses. However, many studies only ask about incidents within a narrow time frame, obscuring the full picture.

“Knowing more about what the actual affected population looks like was very important to me,” Streng-Schroeter says.

The data from her study underscores the urgency of making peer support more effective. Fortunately, there are many promising signs that her intervention works.

Rethinking support for survivors

After completing Streng-Schroeter’s BSS training, students showed meaningfully improved responses in how they thought about and responded to sexual-assault disclosures.

Participants who received the training reported lower levels of rape-myth acceptance—the false or harmful beliefs about what “counts” as sexual violence or who is to blame.

“The program also increased how often participants in chapters that received the training actually provided positive responses to their friends’ disclosure of sexual victimization,” Streng-Schroeter says. “And the data also appears to show that the training reduced negative responses and reduced how often participants anticipate that they will use negative responses when faced with a disclosure of sexual violence in the future.”

Streng-Schroeter believes that her community-first training model is an essential part of why it’s so effective.

Unlike large, anonymous lectures, her program is delivered in already-formed social networks. She theorizes that within peer groups where trust already exists and that experience disproportionately high levels of sexual violence, individuals may be more likely to disclose being the victim of sexual violence to one another.

"Even though there are so many victims within campus communities, students don’t necessarily know the right thing to say to someone who’s experienced this kind of violence unless they have received training."

“The social community aspect is a really important aspect of why we saw promising results with this,” Streng-Schroeter says. “Deploying the exact same training in an orientation for new students … it wouldn’t have the same effect because those friendship networks aren’t there yet.”

In other words, the best way to support survivors may be to start with the people they already lean on by giving them the tools to respond appropriately.

Healing together

With her dissertation completed and defended, Streng-Schroeter now hopes to expand the BSS program. She believes the model could scale to more chapters—and other student communities where close peer-bonds exist—with more funding.

She says, “One goal is to secure funding so I can provide this training across a whole network of a sorority, every chapter. That could impact thousands of people’s lives.”

She’s also eager to adapt the training for queer student organizations, college athletic teams and other student clubs.

Streng-Schroeter knows institutional and cultural reform takes time. But helping students become better friends, listeners and supporters can happen right now.

“People just voluntarily sharing that they felt this training was impactful really meant a lot. It made me think, ‘Okay, something good is happening here,’” Streng-Schroeter says.

As her training and research show, the most important support doesn’t always come from an office or through official channels. Often, healing begins when one person is ready to talk and another is prepared to hear them.

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�鶹��Ѱ��PhD graduate Tara Streng-Schroeter's research offers a new way to support survivors of sexual violence.

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Tree rings offer clues to small-population growth

Rachel Sauer — Thu, 05 Jun 2025 15:54:21 +0000

Tree rings offer clues to small-population growth Rachel Sauer Thu, 06/05/2025 - 09:54

Daniel Long

In a recently published paper, PhD student Ellen Waddle and her coauthors provide some clarity on a decades-old problem

When researching what drives the growth of small populations, ecologists consider several factors, says Ellen Waddle, a PhD student in the �鶹��Ѱ��’s Department of Ecology and Evolutionary Biology.

“There’s climate. There’s density, which can be thought of as both the total number of individuals in a population or how crowded or spread out individuals are. And then there’s stochasticity, which is this big word that just means variance” or random chance.

�鶹��Ѱ��Boulder scientists Ellen Waddle (left), a PhD student in ecology and evolutionary biology, and Dan Doak (right), a professor of environmental studies, and their research colleagues found "that climate data alone did a pretty poor job of predicting population growth (in small tree populations)."

But whether any of these drivers matters more than the others is a question that has challenged researchers since at least the 1950s, and one that Waddle and her coauthors Mark R. Lesser, Christopher Steenbock and Dan Doak take up in a paper recently published in Ecology and Evolution.

Time and perspective

Researchers have tended to fall into opposing camps with this question, Waddle explains.

“There’s a lot of people that think if we can perfectly predict what the climate’s going to be in an area, we’re going to be able to perfectly predict how that population is going to grow through time. And then you have another set of ecologists that argue, well, it also really matters how many individuals you have in the population.”

Yet in their paper, Waddle and her coauthors come to a less divisive conclusion. By analyzing the rings of two long-lived tree species, Ponderosa pine and limber pine, “we found that climate data alone did a pretty poor job of predicting population growth. We needed to include other drivers (in our predictive models), like competitive density effects and stochasticity, to accurately reconstruct population dynamics over time.”

This means that no individual driver proved more influential than the others. They all mattered.

Which was somewhat surprising, Waddle says, considering the long timescale she and her colleagues were dealing with—many hundreds of years. (The oldest tree they sampled dates back to 1470, half a century before Queen Elizabeth I was born.)

“We're averaging over such a long timeframe that you might be tempted to think that random fluctuations and stochasticity are less important, but this sort of study highlights that that's not always true. There's a lot of uncertainty in how long it's going to take small populations to grow.”

“The most important aspect of our work, to my mind,” adds Doak, professor of environmental studies at �鶹��Ѱ��Boulder and head of the Doak Lab, “is showing that simplifying assumptions we often make about population growth don’t seem to hold up.”

‘The entire history of a tree’s life’

Tree rings, says Waddle, are a gold standard for measuring a tree’s history, one with which most people are familiar. The center, or pith, signifies when the tree established, or secured its roots and became capable of growing on its own, and each concentric ring around it represents a year of growth.

�鶹��Ѱ��Boulder researchers studied small populations of Ponderosa pine (seen here) and limber pine to better understand how drivers such as climate data and competitive density affect growth. (Photo: Wikimedia Commons)

But for their study, Waddle and her coauthors used tree rings—in the form of tree cores, or centimeter-wide rods extracted from living tree trunks—a little differently.

“What we did, which has not been done often, was to core every single tree in the population,” says Waddle, which enabled her and her coauthors to get a clearer picture of how tree populations changed over time than they would have gotten coring only a handful of trees.

“Another way to put it: The tree core data basically allows us to reconstruct annual censuses of population from start (1400s-1500s) through present day because we can know exactly how many individuals were alive in each year and when each individual first established.”

The tree-core samples themselves came from Bighorn Basin, a mountain-encircled plateau region in north-central Wyoming about 500 miles from Boulder. Waddle collected some of the tree cores herself in 2017, while an undergrad at CU, for what turned out to be her first camping experience.

Yet the bulk of the core samples owe their existence to Lesser and Steenbock. Lesser alone cored around 1,100 Ponderosa pines between 2007 and 2008, in hot, sometimes tense conditions.

“We (Lesser and an undergraduate field technician) would start hiking to the first trees of the day typically around 5 a.m. to avoid the worst of the heat,” Lesser recalls. “Trekking up dry streambeds to reach the trees we would encounter multiple rattlesnakes each morning and on one occasion a mountain lion that set us on edge for the rest of the day! Many days we would core fewer than 20 trees due to the low density of the population and the ruggedness of the terrain—getting from one tree to the next often took an hour or more negotiating cliff faces, ravines and steep slopes.”

But the effort, he says, was worth it.

“Coring the trees itself was an incredibly rewarding experience—sizing up the tree to get a sense of its shape and where the pith was and then extracting the entire history of its life!”

Pick a species, any species

This research on small-population growth is no small matter, says Doak, “because all populations start small,” and “understanding what controls the growth of new populations has a new urgency as we try to predict whether wild species can shift their ranges to keep up with climate change.”

“Pick some species you care about,” says Waddle, who is currently writing her dissertation on how mountain terrain affects plant species’ ability to follow their preferred climate. “What I care about might be different than what someone else cares about, but there’s probably a species that matters to you, whether it’s a food species or your favorite animal.

“If we want to help keep those populations on the landscape, we need to know how small populations grow and how they persist.”

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In a recently published paper, PhD student Ellen Waddle and her coauthors provide some clarity on a decades-old problem.

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