Environment/Sustainability Archives

Look at the nearest window. What did you see first—the glass itself or what was on the other side? For birds, that distinction is a matter of life and death.

A dead red-eyed vireo above the entrance to the Brodhead Center at Duke. Every year, millions of birds die after colliding with windows. Buildings with lots of glass are particularly dangerous.

Every year, up to one billion birds die from hitting windows. Windows kill more birds than almost any other cause of human-related bird mortality, second only to feral and domestic cats. Both the transparency and reflectiveness of glass can confuse flying birds. They either don’t see the glass at all and try to fly through it, or they’re fooled by reflections of safe habitat or open sky. And at night, birds may be disoriented by lit-up buildings and end up hitting windows by mistake. In all cases, the result is usually the same. The majority of window collision victims die on impact. Even the survivors may die soon after from internal bleeding, concussions, broken bones, or other injuries.

Madison Chudzik, a biology Ph.D. student in the Lipshutz Lab at Duke, studies bird-window collisions and migrating birds. “Purely the fact that we’ve built buildings is killing those birds,” she says.

Every spring and fall, billions of birds in the United States alone migrate to breeding and wintering grounds. Many travel hundreds or thousands of miles. During peak migration, tens of thousands of birds may fly across Durham County in a single night. Not all of them make it.

Chudzik’s research focuses on nocturnal flight calls, which migrating birds use to communicate while they fly. Many window collision victims are nocturnal migrants lured to their deaths by windows and lights. Chudzik wants to know “how we can use nocturnal flight calls as an indicator to examine collision risks in species.”

Chudzik (back) setting up one of her recording devices on the Museum of Science and Industry in Chicago. The devices record flight calls from birds migrating at night.
Image courtesy of Chudzik.

Previous research, Chudzik says, has identified a strong correlation between the number of flight calls recorded on a given night and the overall migration intensity that night. “If sparrows have a high number of detections, there is likely a high number migrating through the area,” Chudzik explains. But some species call more than others, and there is “taxonomic bias in collision risk,” with some species that call more colliding less and vice versa. Chudzik is exploring this relationship in her research.

Unlike bird songs, nocturnal flight calls are very short. The different calls are described with technical terms like “zeep” and “seep.” Chudzik is part of a small but passionate community of people with the impressive ability to identify species by the minute differences between their flight calls. “It’s a whole other world of… language, basically,” Chudzik says.

Chudzik can identify a species not only by hearing its flight call but also by seeing its spectrogram, a visual representation of sound. This spectrogram, from a recording on Adler Planetarium, has flight calls from four species. The x-axis represents time, while the y-axis shows frequency. The brightness or intensity indicates amplitude.
Image from Chudzik.

She began studying nocturnal flight calls for research she did as an undergraduate, but her current project no longer needs to rely on talented humans to identify every individual call. A deep learning model called Nighthawk, trained on a wealth of meticulous flight call data, can identify calls from their spectrograms with 95% accuracy. It is free and accessible to anyone, and much of the data it’s been trained on comes from non-scientists, such as submissions from a Facebook community devoted to nocturnal flight calls. Chudzik estimates that perhaps a quarter of the people on that Facebook page are researchers. “The rest,” she says, “are people who somehow stumbled upon it and… fell in love with nocturnal flight calling.”

In addition to studying nocturnal flight calls, Chudzik’s research will investigate how topography, like Lake Michigan by Chicago, affects migration routes and behavior and how weather affects flight calls. Birds seem to communicate more during inclement weather, and bad weather sometimes triggers major collision events. Last fall in Chicago, collisions with a single building killed hundreds of migratory birds in one night.

Chudzik had a recorder on that building. It had turned off before the peak of the collision event, but the flight call recordings from that night are still staggering. In one 40-second clip, there were 300 flight calls identified. Normally, Chudzik says, she might expect a maximum of about seven in that time period.

Nights like these, with enormous numbers of migrants navigating the skies, can be especially deadly. Fortunately, solutions exist. The problem often lies in convincing people to use them. There are misconceptions that extreme changes are required to protect birds from window collisions, but simple solutions can make a huge difference. “We’re not telling you to tear down that building,” Chudzik says. “There are so many tools to stop this from happening that… the argument of ‘well, it’s too expensive, I don’t want to do it…’ is just thrown out the window.”

A yellow-bellied sapsucker collision casualty in front of the French Family Science Center last year.

What can individuals and institutions do to prevent bird-window collisions?

Turn off lights at night.

For reasons not completely understood, birds flying at night are attracted to lit-up urban areas, and lights left on at night can become a death trap. Though window collisions are a year-round problem, migration nights can lead to high numbers of victims, and turning off non-essential lights can help significantly. One study on the same Chicago building where last year’s mass collision event occurred found that halving lighted windows during migration could reduce bird-window collisions by more than 50%.

Chudzik is struck by “the fact that this is such a big conservation issue, but it literally just takes a flip of a switch.” BirdCast and Audubon suggest taking actions like minimizing indoor and outdoor lights at night during spring and fall migration, keeping essential outdoor lights pointed down and adding motion sensors to reduce their use, and drawing blinds to help keep light from leaking out.

Use window decals and other bird-friendly glass treatments.

There are many products and DIY solutions intended to make windows safer for birds, like window decals, external screens, patterns of dots or lines, and strings hanging in front of a window at regular intervals. For window treatments to be most effective, they should be applied to the exterior of the glass, and any patterning should be no more than two inches apart vertically and horizontally. This helps protect even the smallest birds, like kinglets and hummingbirds.

It can be hard to see from a distance, but these windows on Duke’s Fitzpatrick Center have been retrofitted with tiny white dots, an effective strategy to reduce bird-window collisions.

A 2016 window collision study at Duke conducted by several scientists, including Duke Professor Nicolette Cagle, Ph.D., identified the Fitzpatrick Center as a window collision hotspot. As a result, Duke retrofitted some of the building’s most dangerous windows with bird-friendly dot patterning. Ongoing collision monitoring has revealed about a 70% reduction in collisions for that building since the dots were added.

One obstacle to widespread use of bird-friendly design practices and window treatments is concerns about aesthetics. But bird-friendly windows can be aesthetically pleasing, too, and “Dead birds hurt your aesthetic anyway.”

If nothing else, don’t clean your windows.

Bird-window collisions don’t just happen in cities and on university campuses. In fact, most fatal collisions involve houses and other buildings less than four stories tall. Window treatments like the dots on the Fitzpatrick building can be costly for homeowners, but anything you can put on the outside of a window will help.

“Don’t clean your windows,” Chudzik suggests—smudges may also help birds recognize the glass as a barrier.

Window collisions at Duke

The best thing Duke could do, Chudzik says, is to be open to treating more windows. Every spring, students in Cagle’s Wildlife Surveys class, which I am taking now, collect data on window collision victims found around several buildings on campus. Meanwhile, a citizen science iNaturalist project collects records of dead birds seen by anyone at campus. If you find a dead bird near a window at Duke, you can help by submitting it to the Bird-window collisions project on iNaturalist. Part of the goal is to identify window collision hotspots in order to advocate for more window treatments like the dots on the Fitzpatrick Center.

Spring migration is happening now. BirdCast’s modeling tools estimate that 260,000 birds crossed Durham County last night. They are all protected under the Migratory Bird Treaty Act. However, Chudzik says, “We haven’t thought to protect them while they’re actually migrating.” The law is intended to protect species that migrate, but “it’s not saying ‘while you are migrating you have more protections,’” Chudzik explains. Some have argued that it should, however, suggesting that the Migratory Bird Treaty Act should mandate safer windows to help protect migrants while they’re actually migrating.

“This whole world comes alive while we’re asleep, and… most people have no idea,” Chudzik says about nocturnal flight calls. She is shown here on Northwestern University, one of the Chicago buildings where she has placed recorders for her research.
Photo courtesy of Chudzik.

We can’t protect every bird that passes overhead at night, but by making our buildings safer, we can all help more birds get one step closer to where they need to go.

Post by Sophie Cox, Class of 2025

To get a fuller picture of a forest, sometimes research requires a team effort

By Robin Smith

On April 1, 2024

In Animals, Biology, Climate/Global Change, Environment/Sustainability, Field Research, Lemurs

Film by Riccardo Morrelas, Zahava Production

For some people, the word “rainforest” conjures up vague notions of teeming jungles. But Camille DeSisto sees something more specific: a complex interdependent web.

For the past few years, the Duke graduate student has been part of a community-driven study exploring the relationships between people, plants and lemurs in a rainforest in northern Madagascar, where the health of one species depends on the health of others.

Many lemurs, for example, eat the fruits of forest trees and deposit their seeds far and wide in their droppings, thus helping the plants spread. People, in turn, depend on the plants for things like food, shelter and medicines.

But increasingly, deforestation and other disturbances are throwing these interactions out of whack.

DeSisto and her colleagues have been working in a 750,000-acre forest corridor in northeast Madagascar known as the COMATSA that connects two national parks.

The area supports over 200 tree species and nine species of lemurs, and is home to numerous communities of people.

A red-bellied lemur (*Eulemur rubriventer*) in a rainforest in northeast Madagascar. Photo by Martin Braun.

“People live together with nature in this landscape,” said DeSisto, who is working toward her Ph.D. in ecology at the Nicholas School of the Environment.

But logging, hunting and other stressors such as poverty and food insecurity have taken their toll.

Over the last quarter century, the area has lost 14% of its forests, mostly to make way for vanilla and rice.

This loss of wild habitats risks setting off a series of changes. Fewer trees also means fewer fruit-eating lemurs, which could create a feedback loop in which the trees that remain have fewer opportunities to replace themselves and sprout up elsewhere — a critical ability if trees are going to track climate change.

DeSisto and her colleagues are trying to better understand this web of connections as part of a larger effort to maximize forest resilience into an uncertain future.

To do this work, she relies on a network of a different sort.

The research requires dozens of students and researchers from universities in Madagascar and the U.S., not to mention local botanists and lemur experts, the local forest management association, and consultants and guides from nearby national parks, all working together across time zones, cultures and languages.

Forest field team members at camp (not everyone present). Photo credit: Jane Slentz-Kesler.

Together, they’ve found that scientific approaches such as fecal sampling or transect surveys can only identify so much of nature’s interconnected web.

Many lemurs are small, and only active at night or during certain times of year, which can make them hard to spot — especially for researchers who may only be on the ground for a limited time.

To fill the gaps, they’re also conducting interviews with local community members who have accumulated knowledge from a lifetime of living on the land, such as which lemurs like to munch on certain plants, what parts they prefer, and whether people rely on them for food or other uses.

By integrating different kinds of skills and expertise, the team has been able to map hidden connections between species that more traditional scientific methods miss.

For example, learning from the expertise of local community members helped them understand that forest patches that are regenerating after clear-cutting attract nocturnal lemurs that may — depending on which fruits they like to eat — promote the forest’s regrowth.

Camille DeSisto after a successful morning collecting lemur fecal samples.

Research collaborations aren’t unusual in science. But DeSisto says that building collaborations with colleagues more than 9,000 miles away from where she lives poses unique challenges.

Just getting to her field site involves four flights, several bumpy car rides, climbing steep trails and crossing slippery logs.

“Language barriers are definitely a challenge too,” DeSisto said.

She’s been studying Malagasy for seven years, but the language’s 18 dialects can make it hard to follow every joke her colleagues tell around the campfire.

To keep her language skills sharp she goes to weekly tutoring sessions when she’s back in the U.S., and she even helped start the first formal class on the language for Duke students.

“I like to think of it as language opportunities, not just language barriers,” DeSisto said.”

“Certain topics I can talk about with much more ease than others,” she added. “But I think making efforts to learn the language is really important.”

When they can’t have face-to-face meetings the team checks in remotely, using videoconferencing and instant messaging to agree on each step of the research pipeline, from coming up with goals and questions and collecting data to publishing their findings.

“That’s hard to navigate when we’re so far away,” DeSisto said. But, she adds, the teamwork and knowledge sharing make it worth it. “It’s the best part of research.”

This research was supported by Duke Bass Connections (“Biocultural Sustainability in Madagascar,” co-led by James Herrera), Duke Global, The Explorers Club, Primate Conservation, Inc., Phipps Conservatory and Botanical Gardens, and the Garden Club of America.

“Biodiversity Is Essential, and It’s Not a Nice-to-Have”

By Sophie Cox

On March 27, 2024

In Animals, Environment/Sustainability, Policy, Science Communication & Education

Filmmaker Ashley Hillard and cinematographer Alan Dunkin in Yellowstone. Photo by Hillard.

“I have been interested in storytelling and the environment since my earliest memories,” says Ashley Hillard, a documentary filmmaker with an interest in wildlife management and conservation practices in the United States.

Hillard has a background in film, largely with production companies, talent agencies, and independent projects on the side, but she later shifted into climate tech recruitment. Now she is pursuing an environmental leadership Masters in Environmental Management degree at Duke while working on documentary projects. She is also a Communications Assistant Intern in the Duke Environmental Law and Policy Clinic.

She has been working on a film called “Coexistence,” a documentary that spotlights North American species and wildlife management practices. Hillard got the idea for the project when she noticed that U.S.-based researchers often choose to study species in other countries, perhaps “because it’s easier to go over and say ‘Why don’t you try this?’ rather than having to deal with issues in your backyard.”

“We need to pay attention to our own backyards,” Hillard emphasizes. “The hope,” she says, is “more laws and policies and values change along with behaviors as we become more informed and more aware.” She also believes that “local efforts can usually go further.” Part of her goal in creating films about conservation is to help viewers realize that “individuals can be part of change.” Films and other forms of storytelling can inform people about specific species and conservation efforts, but Hillard hopes her work can help shift perspectives more broadly as well. Effective conservation is often “a social attitudes and values issue,” Hillard says. “There needs to be a shift in how we view the environment.”

An American bison that Hillard saw while filming in Yellowstone.
Photo by Hillard.

Shifting baseline syndrome is the idea that people’s expectations of how nature should look reflect their own experiences rather than an accurate picture of the natural state of landscapes, flora, fauna, and wildlife abundance. Our understanding of what nature “normally” looks like changes over generations and is skewed by the societies and time periods we inhabit. The more we damage our environments, the less we collectively remember what they looked like before—and the less motivated we may be to restore them to a condition most of us can’t remember.

When humans and wildlife come into conflict, our perceptions of how nature “should” be can matter tremendously. Gray wolves were recently delisted from the Endangered Species list, then re-listed in most places—both were controversial decisions—but their numbers are far lower than they were historically. Still, some think there are too many wolves. In the Western U.S., gray wolf conservation efforts often clash with the desires of ranchers and and hunters, who may view higher wolf populations as a threat to livestock or game animals like deer and elk. But some of these hunters and ranchers, Hillard says, “are real conservationists doing amazing work,” and she thinks they should get more attention.

While creating the film, Hillard has tried to capture the complexities of wildlife conservation. It’s not as simple as “They’re bad, they’re good, and this is how we solve it,” Hillard says.

There are different ideas about how conservation efforts should be conducted and which animals should be protected in the first place. The dominant approach to wildlife management in the U.S., Hillard says, is rooted in the idea that there are “good” species that people can use and “bad” species that people don’t like to live with, such as wolves and other predators. “This perspective,” she says, “came over with colonists.” She mentions Little Red Riding Hood and the Big Bad Wolf; the stories we tell about animals can reflect societal attitudes toward them. Many indigenous peoples, meanwhile, have traditionally viewed all species as kin. This “cultural aspect” affects people’s willingness to coexist with species like wolves, which in turn affects our conservation practices.

A gray wolf at the Grizzly and Wolf Discovery Center in Yellowstone.
Photo by Alan Dunkin, provided by Hillard.

In this country, very few people are killed by wildlife—about 700 annually, according to one review that counted deaths from bites, wildlife-vehicle collisions, and zoonotic diseases. Car accidents, on the other hand, are more than 60 times more deadly, killing about 43,000 people in the U.S. per year. “We have a certain acceptance of how we die,” Hillard says. “There are a number of things that kill people with much higher percentages [than deaths from wildlife] that we… accept as day-to-day,” but we don’t tend to hear calls to eliminate cars from society, while an animal that harms a human is often given a death sentence. Hillard thinks media in general should be more careful about how they share stories about wildlife, especially negative encounters. If stories focus only on rare but tragic incidents, it can distort perceptions of species and “feed into that doom loop.”

Films, Hillard says, can inspire people “to look at things differently and see things from different perspectives.” Storytelling is also a way of communicating scientific information and encouraging action. Hillard feels that some stories about environmental issues are told in a one-sided, black-and-white way, but the nuances of these problems are important. “Finding those complexities and working through them… and then trying to craft stories around that to share with the public so they can make more informed decisions” is part of the goal of Hillard’s films.

“Coexistence” focuses on well-known, often controversial species like red wolves and mountain lions. “Familiarity and awareness of a species can contribute to interest in protecting them,” Hillard says. Such species are sometimes referred to as charismatic megafauna and can be viewed as ambassadors for conservation or umbrella species whose protection helps other wildlife as well. But Hillard has concerns about the term charismatic megafauna. “It diminishes a species’s value and reduces them to ‘cute’ so you no longer see them as an intrinsic part of an ecosystem,” she says. She believes it’s important to emphasize protection of entire ecosystems, not just specific species within them.

A Mexican gray wolf pup at the California Wolf Center. The Mexican gray wolf is a gray wolf subspecies.
Photo by Hillard.

Hillard hopes that her films inspire more awareness of and interest in environmental issues. “There’s a lot of pressure to get it right,” she says. And storytelling can have its own issues when it comes to presenting accurate information. “Information can be left out or shaped in a way to make it more compelling,” Hillard acknowledges. She feels that many wildlife films focus first on scenery and animals, then discuss conservation issues at the end. But “Coexistence” is “very much focused on the issues.” It is expected to be released by early 2025.

“I strive to tell impactful stories in creative ways that are more upbeat in tone,” Hillard says. She believes it’s important for people to be aware of the challenges facing wildlife, but she also wants to inspire hope and the belief that individual actions can matter. “To feel powerless can make you feel hopeless, and there is a lot to be hopeful for,” she says. “But there needs to be a shift in how we view the environment.”

One major problem she sees is our consumerist, materialistic society. “We’re kind of consuming ourselves off the planet,” Hillard says. “How do you change behaviors within a society that’s so hyper-consumptive?”

Films and other forms of storytelling can make scientific information more accessible. “Communicating is that bridge to getting people to care, to understand it, to learn about it,” Hillard says. “Without communication, science studies and research may be siloed in academia.” When we lack accurate and accessible information, we may rely on “‘I heard someone say something about that thing’” rather than science to inform our understanding of issues.

Along with providing accurate information, Hillard wants to encourage “a view of mutualism with other species” and raise questions like “How can we be better neighbors to nonhuman species?”

Ultimately, she wants viewers to recognize that “biodiversity is essential, and it’s not a nice-to-have.”

Hillard at Lands End Lookout in San Francisco.
Photo credit Alan Dunkin, provided by Hillard.

Post by Sophie Cox, Class of 2025

Reducing Food Insecurity and Creating Community at Durham’s Catawba Trail Farm

By Gabrielle Douglas

On February 27, 2024

In Anthropology, Environment/Sustainability, History

At Catawba Trail Farm in north Durham, the idea of community remains at the forefront of all that they do. A space dedicated to growing, learning, and diligent work, the farm invites all willing to become involved. Recently, students at Duke University had the opportunity to bear witness to these qualities, through a course taught by Dr. Brian McAdoo of Duke’s Nicholas School of the Environment.

*Picture of volunteers at Catawba Trail Farm (Credit: @UrbanCommunityAgrinomics on Instagram.)*

The Catawba Trail Farm was once known as Snowhill Plantation, yet despite this co-founder Delphine Sellars refers to it as “a place of healing.” This is because Sellars recognizes the importance of acknowledging the past when attempting to shape the future. Sellars’ focus is on taking land formerly used to abuse enslaved people and transforming it into a place of empowerment and healing. This is seen through the connection between the farm and McAdoo’s course here at Duke. The course, “Exploring Earth Sciences: Surviving Anthropocene in North Carolina,” explores a range of themes such as food insecurity, environmental justice, and global change through the context of environmental studies. Additionally, McAdoo’s course has what is referred to as the ‘Catawba Trail Mission’ where Duke students, in partnership with Catawba Trail Farm, seek to not only target this food insecurity within the community, but also uncover the history hidden within the roots of the farm.

*Picture of* Delphine Sellars (*Credit: @UrbanCommunityAgrinomics on Instagram.)*

The most recent progress of this mission can be seen through the class’s work with the gravesite of William Johnston, who established Snowhill Plantation in 1763. Through a geophysical survey, the class identified several unmarked graves of enslaved people buried with the Johnston family. Through this they have worked to trace their lineages to their loved ones and inform them of their findings. The class has also used this same technology to help identify and ensure that the traits and key aspects of the land are fully understood and respected.

Through the work between Duke and Catawba Trail Farm, students are granted the opportunity to take their learning beyond the textbook and truly begin to understand the depth behind the land outside of technological gadgets. Catawba Trail Farm helps in this journey while simultaneously learning more about the rich nature of the land and its inhabitants. This constant sense of learning and support is what makes students such as Duke master’s student, Roo Jackson, comfortable in saying Catawba Trail Farm “feels like home.”

Post by Gabrielle Douglas, Class of 2027

Glowing Waterdogs and Farting Rivers: A Duke Forest Research Tour

By Sophie Cox

On January 25, 2024

In Animals, Biology, Climate/Global Change, Environment/Sustainability, Field Research, Science Communication & Education

Jonny Behrens looks for aquatic macroinvertebrates with Duke Forest Research Tour participants.

“Who would be surprised if I told you that rivers fart?”

Nick Marzolf, Ph.D., went on to explain that streams release greenhouse gases from decaying matter and gas-producing bacteria. This revelation was one of several new facts I learned at the annual Duke Forest Research Tour in December.

“First and foremost,” says Duke Forest Senior Program Coordinator Maggie Heraty, “the Duke Forest is a teaching and research laboratory.” The Office of the Duke Forest hosts an annual Research Tour to showcase research activities and connect to the wider community. “Connecting people to science and nature, and demystifying scientific research, is a key part of our goals here,” Heraty says.

Duke Forest, which consists of over 7,000 acres in Durham, Orange, and Alamance Counties, lies within the Cape Fear and Neuse river basins, two of seventeen river basins in North Carolina. What exactly is a river basin? Heraty quoted a poetic definition from North Carolina Environmental Education:

“A river basin encompasses all the land surface drained by many finger-like streams and creeks flowing downhill into one another and eventually into one river, which forms its artery and backbone. As a bathtub catches all the water that falls within its sides and directs the water out its drain, a river basin sends all the water falling within its surrounding ridges into its system of creeks and streams to gurgle and splash downhill into its river and out to an estuary or the ocean.”

Located within the Cape Fear River Basin, the headwaters of New Hope Creek, which passes through the Korstian Division of Duke Forest, are fed by roughly 33,000 acres of land, over 5,000 of which are in the Duke Forest. Land outside of the Forest is of vital importance, too. Duke Forest is working in partnership with other local conservation organizations through the Triangle Connectivity Collaboration, an initiative to connect natural areas, create wildlife corridors, reduce habitat fragmentation, and protect biodiversity in the Triangle region.

New Hope Creek in the Korstian Division of the Duke Forest.

Dwarf waterdogs

We walked down a short trail by the creek, and the tour split into two groups. Our group walked farther along the stream to meet two herpetologists studying the elusive dwarf waterdog.

Bryan Stuart, Ph.D., Research Curator of Herpetology at the North Carolina Museum of Natural Sciences, and Ron Grunwald, Ph.D., Duke University Senior Lecturer Emeritus, are involved in a study looking for dwarf waterdog salamanders (Necturus punctatus) in New Hope Creek. Dwarf waterdogs are paedomorphic, Stuart said, meaning they retain larval characteristics like external gills and a flat tail throughout their lives. In fact, the genus name Necturus means “tail swimmer” in reference to the species’s flat tail.

According to Stuart, on October 3, 1954, Duke professor and herpetologist Joe Bailey collected a dwarf waterdog in New Hope Creek. It was the first record of the species in Orange County.

The Duke Forest is in the westernmost part of the species’ Piedmont range, though it extends farther west in parts of the sandhills. “To have a dwarf waterdog record in Orange County—that’s almost as interesting as it gets,” Stuart said.

Ron Grunwald and Bryan Stuart discuss dwarf waterdog research at New Hope Creek.
Photo provided by The Office of the Duke Forest.

In the late 1960s, Michael A. Fedak, Bailey’s graduate student, did a thesis on dwarf waterdogs in the area. His specimens are still stored in the collections of the North Carolina Museum of Natural Sciences.

No one had studied this population since—until now.

Dwarf waterdogs are very sensitive to pollution and habitat disturbance, Stuart said, on top of the fact that New Hope Creek is already at the edge of the species’s habitat. When Fedak studied them several decades ago, the salamanders were abundant. Are they still?

Stuart, Grunwald, and other researchers want to find out. “The challenge of salamander biology,” Grunwald said, “is that it always happens when it’s freezing.” Surveying salamander populations, he explains, isn’t like watching birds or counting trees. It requires you to go where the salamanders are, and for dwarf waterdog research, that means dark, cold streams on nights when the water temperature is below 55 degrees Fahrenheit.

Researchers bait funnel traps with chicken liver or cat food and set them underwater overnight. Sometimes they catch crayfish. Sometimes they catch nothing. And sometimes they catch exactly what they’re hoping to find: the elusive dwarf waterdog. After all this time, these slippery, nocturnal, chicken-liver-loving salamanders are still here.

Two dwarf waterdogs in a funnel trap before being released back into New Hope Creek.

Though the traps have been successful at capturing some individuals, they will never catch them all, so researchers calculate the recapture rate to estimate the total population. Imagine a bag of rice, Grunwald said. You could count each individual grain, but that would be challenging and time-consuming. Alternatively, you could pull out one grain of rice, color it, and put it back in the bag, then estimate the total number by calculating the probability of pulling out the same colored grain of rice again. In a very small bag, you might draw the same rice grain several times. But the more rice you have, the less likely you are to draw the same grain twice.

To figure out if any of the dwarf waterdogs they catch are recaptures, the researchers mark each individual with a visual implant elastomer, which is “just a fancy way of saying rubber that we can see,” Grunwald said. The material is injected under a salamander’s “armpit” with a small syringe, creating a pattern visible under ultraviolet light. With two colors (fluorescent yellow and red) and four possible injection locations (one behind each leg), there are plenty of distinct combinations. Grunwald showed us a waterdog that had already been marked. Under a UV flashlight, a spot just below its right foreleg glowed yellow.

Captured dwarf waterdogs are injected with a special rubber material that glows under a UV light. Each salamander is marked with a distinct pattern so researchers can recognize it if it’s ever recaptured.

Establishing a recapture rate is essential to predicting the total population in the area. The current recapture rate? Zero. The sample size so far is small—about a dozen individuals—and none of them have been caught twice. That’s an obstacle to statistical analysis of the population, but it’s good news for the salamanders. Every new individual is one more dwarf waterdog survivor in New Hope Creek.

Ron Grunwald with Research Tour participants looking at dwarf waterdogs in bags.
Photo provided by The Office of the Duke Forest.

Stream health

Next, at a different spot along the stream, we met Nick Marzolf, Ph.D., a postdoctoral scholar, and Jonny Behrens, a Ph.D. student, to learn more about New Hope Creek itself. Marzolf and Behrens have both been involved with aquaterrestrial biogeochemistry research in the lab of Emily Bernhardt, Ph.D., at Duke University.

Protecting New Hope Creek requires understanding individual organisms—like dwarf waterdogs—but also temperature, precipitation, oxygen levels, pesticide runoff, and biodiversity overall. When humans get stressed, Behrens said, different organs have different physiological reactions. Similarly, different organisms in a stream play different roles and respond to stress in different ways.

Jonny Behrens and Research Tour participants look at aquatic macroinvertebrate samples.
Photo provided by The Office of the Duke Forest.

Behrens passed around vials containing aquatic macroinvertebrates—specimens big enough to see with the naked eye—such as the larvae of mayflies, crane flies, stoneflies, and dragonflies. They are known for being good indicators of stream health because there are many species of macroinvertebrates, and they have different tolerances to stressors like pollution or changes in water temperature.

Aquatic macroinvertebrates can indicate the health of a stream through their species diversity and abundance.
Photo provided by The Office of the Duke Forest.

The water downstream of a nearby wastewater treatment plant is much warmer in winter than other waterways in the area, so researchers see more emergent adult midges and caddisflies there than they do here. Aside from temperature, organisms need to adapt to other changing conditions like oxygen levels and storms.

“Rain is really fun to watch in streams,” Behrens said. The water level rises, pulling up organic matter, and sand bars change. You can tell how high the water got in the last storm by looking for accumulated debris on trees along river banks.

Farting rivers and the peanut butter cracker hypothesis

Marzolf studies hydrology, or “how water moves through not only the landscape but also the river itself.”

Nick Marzolf demonstrates a technique to measure gasses in streams using a syringe.

Part of his research involves measuring gases in water. Streams, like cars and cows and people, release greenhouse gases, including carbon dioxide and methane. In fact, Marzolf and colleagues hypothesize that New Hope Creek contributes more CO₂ to the atmosphere per unit area than anywhere else in the Duke Forest.

Decaying matter produces CO₂, but that isn’t the only source of greenhouse gasses in the creek. Microscopic organisms, like methane-producing bacteria, produce gases as well.

The “peanut butter cracker hypothesis,” Marzolf said, compares organic matter such as leaves to a cracker, while the “peanut butter,” which makes the cracker more palatable, is the microbes. Scrumptious.

Disturbing the sediment at the bottom of New Hope Creek causes bubbles to rise to the surface due to the metabolic activities of gas-producing bacteria.

Marzolf turned to Behrens. “Do you want to walk around and see if you can stir up some methane bubbles?” Behrens waded into the stream, freeing bubbles from the pressure of the overlying water keeping them in leaf mats. We watched the bubbles rise to the surface, evidence of the activities of organisms too small to see.

Behrens walks around in New Hope Creek to stir up gas bubbles from aquatic bacteria.

Restoring a stream to protect its pigtoe

Finally, Sara Childs, Executive Director of the Duke Forest, discussed stream restoration projects. Though structures in the Duke Forest like remnants of old mills and dams can alter and damage ecosystems, they can also have historical and cultural significance. Duke Forest prioritizes restoration projects that have meaningful ecological, teaching, and research benefits while honoring the history of the land.

For instance, the Patterson Mill Dam was built in the late 1700s and probably remained in use for about 100 years. The stream has already adapted to the structure’s presence, and there isn’t necessarily ongoing degradation because of it. Duke Forest restoration projects, Childs said, don’t revolve around very old structures like the Patterson Mill Dam. Instead, they are planning to remove two more recent structures that are actively eroding banks, threatening wildlife habitat, and creating impounded, oxygen-poor areas in the stream.

One of the structures they are hoping to remove is a concrete bridge that’s endangering a threatened freshwater mussel species called the Atlantic pigtoe (Fusconaia masoni). Freshwater mussels, according to Childs, require a fish species to host the developing mussel larvae on their gills, and the Atlantic pigtoe favors the creek chub (Semotilus atromaculatus). The concrete bridge forms a barrier between the pigtoe and the chub, but removing it could reunite them.

Before starting construction, they will relocate as many mussels as possible to keep them out of harm’s way.

New Hope Creek, home to waterdogs and pigtoe and farting microbes, is precious to humans as well. Heraty describes it as “a really spectacular and beautiful waterway that we are lucky to have right in our backyards here in Durham.”

Post by Sophie Cox, Class of 2025

Capital, Canaries, or Catalysts: Insurance Industry’s Role in Climate

By Samera Eusufzai

On December 1, 2023

In Animals, Business/Economics, Climate/Global Change, Environment/Sustainability

*Mining foreman R. Thornburg shows a small cage with a canary used for testing carbon monoxide gas in 1928. Credit: George McCaa, U.S. Bureau of Mines*

Throughout the 19th and 20th centuries, canaries were used in coal mines to assess the risk of toxic gasses. If the birds became ill or passed away, their fate served as a warning for miners to vacate the premises.

Similarly to how a canary detects unseen risks, the insurance industry is responsible for matching assets to liabilities based upon risks, according to Francis Bouchard, the managing director for climate at the insurance company Marsh McLennan. Bouchard spoke at Duke University on November 10 to discuss the insurance sector’s responsibility to tackle risks as a result of climate change.

During a one-year residency that begins in January, Bouchard will explore ways in which the insurance sector can incentivize and support advances in management of climate risks by helping Duke to build new research partnerships and networks with the insurance and other affected sectors.

Historically, the insurance industry has served as a catalyst to influence safety regulations for the welfare of citizens, as opposed to a canary that withers under risks. Take, for instance, the World Columbian Exposition in Chicago in 1893. It was the first time in history “anyone would deploy electricity on a large level,” Bouchard said. Therefore, an insurance company sent an engineer to examine the security of the electricity and determine the hazards for attendees. Consequently, the brightest minds of this sector banded together to create the Underwriters Laboratories, which is now the largest testing laboratory in the United States.

But more recently, the insurance sector has not acted as a catalyst in its role to address climate risk. Several policies and systems “distort the purity of the risk signals insurance companies send.” Firstly, its inability to combat systemic level risks as they are providing individual incentives. The industry is highly effective in “handling individual risk and incentivizing immediate actions to address an immediate risk,” Bouchard said, but this method cannot translate on a systemic level.

Secondly, the insurance sector provides a “temporal mismatch” as they sell 12 months of risk, but the lasting impacts of climate change will not occur within a year. Therefore, their “ability to capture in a 12 month policy, decades worth of climate change risk is impossible.”

Thirdly, the regulations for insurance differ between states. In most states, the insurance commissioner dictates the price of insurance based upon the company’s risk assessment because when “risk goes up, price of risk also goes up.” When citizens cannot afford insurance, commissioners are more likely to side with the experts of the insurance companies as opposed to their disadvantaged constituents.

Finally, their climate model is not advanced enough to estimate how specific cities will change within a few decades due to climate change. Therefore, it cannot entirely predict its risks either.

You can watch Bouchard’s talk, with slides, on YouTube

The insurance industry has been successful in its asset-liability matching “in committing some of its capital to advancing climate technology or green technology.” However, this sector receives “publicity around insurance companies withdrawing capital from wildfire or climate exposed jurisdiction.”

This system is explained by the TCFD Filing, which was created by the Bank of International Settlements to discover insurance companies exposure to climate transition issues, physical risks from climate change, and their strategy to aid clients. Essentially, most insurance companies are not “concerned about physical risks” as they would simply reprice their 12-month insurance policy if there is a heightened threat to physical risk. According to Bouchard, the “insurance industry has already signaled through its TCFD filings precisely what their strategy is: ‘we’re gonna play this game as long as we can and then we’re going to withdraw.’” Therefore, an insurance company would continue to increase their cost until a person can no longer afford its price or actually endures physical damage to which they would cease providing insurance. “These last resort-type mechanisms are when the government steps in,” Bouchard said. He even estimates that the government will control 30% of this $1 trillion industry ($2 trillion globally) within ten years. This is dangerous as the government is already enduring fiscal dilemmas and will not be equipped to manage the complexity of the sector.

Bouchard, with 30 years of experience in this industry, said he “truly, truly believes in the social role that the industry plays. I’m petrified that we’re not going to be there to help society cope with climate with the technical knowledge we have, the expertise we have, the mechanisms we have, and the money.” If the sector continues upon this path, they will dissolve under the risks, similarly to a canary in a mine.

Francis Bouchard’s work in combating climate battles with insurance is of the utmost necessity. Continued global warming will force citizens to rely on this industry for aid against climate disasters. The most recent Conference of Parties, created by the United Nations for climate change discussions, recognized the insurance industry as a “key finance player in climate transition alongside private industry and government because the world is recognizing that we have a key part to play.”

By Samera Eusufzai, Class of 2026

“Wonders and Realities of the Universe”: Rachel Carson’s Legacy

By Sophie Cox

On October 12, 2023

In Biology, Climate/Global Change, Environment/Sustainability, Lecture, Science Communication & Education

Rachel Carson was a twentieth-century marine scientist, conservationist, and writer. She is the author of Silent Spring, a groundbreaking book about the dangers of DDT and other pesticides.
Photo courtesy of the Rachel Carson Council.

Robert K. Musil, Ph.D., M.P.H., recently visited Duke to talk about Rachel Carson’s environmental legacy and its implications for North Carolina today. Musil is the president and CEO of the Rachel Carson Council, an environmental organization founded in 1965 by friends and colleagues of Rachel Carson — a twentieth-century marine scientist, conservationist, and writer — after her death.

Robert K. Musil, Ph.D., M.P.H., president and CEO of the Rachel Carson Council.
Photo courtesy of Musil.

Musil began his presentation with a stirring quote by Carson: “The more clearly we can focus our attention on the wonders and realities of the universe about us the less taste we shall have for the destruction of our race. Wonder and humility are wholesome emotions, and they do not exist side by side with a lust for destruction.”

Rachel Carson is famous for writing Silent Spring, a groundbreaking book warning of the dangers of DDT and other pesticides. Carson published Silent Spring in 1962. She died in 1964. In 1972, the United States banned DDT.

More than half a century later, in our world of climate crisis and biodiversity loss, Carson’s devotion to the natural world is still incredibly timely.

Rachel Carson’s Silent Spring documented how the insecticide DDT was harming not just insects but also animals farther up the food chain, human health, and the environment as a whole. The book spent thirty-one weeks on the New York Times bestseller list.
Image courtesy of the Rachel Carson Council.

Carson, Musil says, “believed that you had to develop real empathy for other creatures, other beings, other people, other nations… that unless you loved it, you would destroy it.” In Carson’s first book, Under the Sea-Wind, she takes the perspective of animals like the black skimmer, the mackerel, and the eel. Carson was writing about the perils facing marine ecosystems, but she was doing it “from the point of view of the ‘other,’” as Musil puts it, focusing our attention on creatures other than ourselves.

A black skimmer, a bird Rachel Carson wrote about in Under the Sea-Wind.
“Black skimmer (Rynchops niger) in flight” by Charles J. Sharp is licensed under the Creative Commons Attribution-Share Alike 4.0 International license.

“With the dusk a strange bird came to the island from its nesting grounds on the outer banks. Its wings were pure black, and from tip to tip their spread was more than the length of a man’s arm. It flew steadily and without haste across the sound, its progress as measured and as meaningful as that of the shadows which little by little were dulling the bright water path. The bird was called Rynchops, the black skimmer.”

-A passage from Under the Sea-Wind by Rachel Carson. Rynchops, Carson’s name for the black skimmer, comes from the bird’s genus name.

Musil describes how Carson would lie on the beach and hear crabs scratching the sand and listen to birds and imagine “how this life came to be, how these creatures, incredibly unique, came to this place in evolution.”

Carson was a marine scientist well before she published Silent Spring. She attended graduate school in marine biology with a full fellowship to Johns Hopkins University. At the same time, Musil says, she was working as a research assistant, teaching part-time at the University of Maryland and Johns Hopkins, and caring for extended family. Afterward, she worked for the Department of Fish and Wildlife and eventually became an author. Under the Sea-Wind was her first book; she wrote Silent Spring two decades later.

Carson is credited with spurring the modern environmental movement. Silent Spring and the concerns Carson raised about DDT prompted the President’s Science Advisory Committee, under the orders of John F. Kennedy, to investigate its dangers. Ultimately, DDT was banned in the United States, though Carson didn’t live to see it.

Rachel Carson and Hawk Mountain - Rachel Carson Council — An “iconic photo” by Shirley Briggs of Rachel Carson on Hawk Mountain.
Photo courtesy of the Rachel Carson Council.

But Musil emphasizes that throughout all Carson’s accomplishments, she did not act alone. He shows an “iconic photo,” as he describes it, of Rachel Carson sitting on Hawk Mountain and looking off into the distance through binoculars. The same photo is on the cover of Musil’s book Rachel Carson and Her Sisters: Extraordinary Women Who Have Shaped America’s Environment. He looks at the audience and asks a question: “Is Rachel alone on top of the mountain?” In the photo, Carson seems to be alone in a great expanse of wilderness, but the obvious answer to Musil’s question is no. Someone, after all, had to be there to take the picture.

That someone was Shirley Briggs, a friend of Carson’s and a scientist in her own right. “Rachel Carson,” Musil emphasizes, “was not alone.” Friends, colleagues, and mentors worked alongside her. And many of those people continued her work after she was gone. Before Carson died, Musil says, she asked Shirley Briggs and others to form an organization to carry on her work. The Rachel Carson Council was founded the following year. Nearly six decades later, the Council is still committed to “Carson’s ecological ethic that combines scientific concern for the environment and human health with a sense of wonder and reverence for all forms of life in order to build a more sustainable, just, and peaceful future,” according to a statement on their website.

According to Musil, North Carolina was one of Carson’s favorite places. After she had a breast cancer operation, he says, “she took refuge at Nags Head and walked its beaches.” The Rachel Carson Reserve commemorates Carson and preserves coastal habitats and wildlife. Musil believes that Carson’s legacy has broader environmental implications as well. One pressing issue in North Carolina today is Concentrated Animal Feeding Operations, or CAFOs, where many animals are raised in confinement. North Carolina produces ten billion gallons of hog waste from CAFOs each year—enough to fill 1500 Olympic swimming pools, according to Musil.

This is an ecological and animal welfare issue but also an environmental justice case. CAFOs are more often built near lower income and minority communities, and the waste from CAFOs can negatively affect human health, pollute waterways, and lead to fish kills and other ecological problems. Living near CAFOs is associated with higher rates of asthma and other health conditions, according to Musil. He acknowledged Francesca Cetta in the audience, who along with Lucy Goldman, both Duke Stanback Fellows at the Rachel Carson Council, did the research and writing on the Rachel Carson Council report, Swine and Suffering: An Introduction to the Hidden Harms of Factory Farms.

Environmental justice was not a term Carson used, but she had similar concerns about who was most affected by environmental issues. In Silent Spring, Musil says, Carson wrote about farmers who dealt directly with DDT and how unjust that was. Today, environmental justice is gaining momentum as organizations and governments wrestle with fairness and equality in the environmental sphere.

In spite of ongoing environmental degradation, Musil remains hopeful. “I have incredible hope for the future,” he says, because of his organization and its mentoring of future generations of environmentalists. “It’s not like every single person has to go out and go birdwatching — though I would recommend it,” he says, but he does believe it is important to learn about and appreciate the natural world and to recognize how it intersects with, for instance, capitalism and social justice. “Designing a much more equitable, greener society is critical,” he says, and when it comes to working toward that future, he is “never going to stop.”

He references the photo he showed earlier of Carson on the mountain: “I like to think instead of looking at hawks, she’s looking across those ridges and seeing… ranks and ranks of young people from Duke and across the country carrying on her vision.”

Post by Sophie Cox, Class of 2025

Bolivia’s Lithium is Like White Gold in the Salar de Uyuni

By Isabella Helton

On October 2, 2023

In Anthropology, Chemistry, Climate/Global Change, Economics, Environment/Sustainability, Faculty, Field Research, Policy, Students

As the world undergoes the great energy transition — from fossil fuels to alternative energy and batteries — rare earth metals are becoming more precious.

Open The Economist, Forbes, or Fortune, and you’ll see an article nearly every day on Lithium, Nickel, or Copper. For investors seeking to profit off of the transition, lithium seems like a sure bet. Dubbed “white gold” for electric vehicles, the lightweight metal plays a key role in the cathodes of all types of lithium-ion batteries that power electric vehicles (EVs). Although EVs produce fewer greenhouse gasses than gas- or diesel-powered vehicles, their batteries require more minerals, particularly lithium.

On Sept. 26, Duke’s campus welcomed the first in a series of discussions on climate and energy diplomacy focused on the challenges and opportunities of mining and development in South America’s Lithium Triangle. In a room crowded with curious undergraduate and graduate students alike, some lucky enough to have snagged a seat while others stood at the perimeters, three experts discussed the possible future of Bolivia as a major player in the global lithium market.

Professor Avner Vengosh of the Nicholas School

Duke Distinguished Professor Avner Vengosh, Nicholas Chair of Environmental Quality in the Nicholas School of the Environment, began by highlighting the staggering EV growth in 2020-2022: Sales of electric cars have more than tripled in three years, from around 4% of new car sales in 2020 to 14% in 2022. That number is expected to rise to 29.50% in 2028. Speaking of the critical element to EV production, lithium, Vengosh said frankly, “we don’t have enough.”

Lithium is mined from two major sources, Vengosh explained. The first is from hard-rock pegmatite, where lithium is extracted through a series of chemical processes. Most of these deposits are found in Australia, the world’s biggest source. The second is from lithium-rich brines, typically found in Argentina, Bolivia, and Chile, also known as the “Lithium Triangle.” These brine deposits are typically found in underground reservoirs beneath salt flats or saltwater lakes. The Salar de Uyuni in Bolivia is the world’s largest salt lake, and the largest lithium source in the world. It stretches more than 4,050 square miles and attracts tourists with its reflective, mirror-like surface.

Mountains surrounding the Uyuni salt flat during sunrise By Diego Delso, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=47617647 — *Mountains surrounding the Uyuni salt flat during sunrise, (Diego Delso)*

A group of Duke students led by a PhD candidate pursuing research on Bolivian lithium development recently traveled to Bolivia to understand different aspects of lithium mining. They asked questions including:

How renewable is the lithium brine?
Are there other critical raw minerals in the lithium-rich brines?
What are the potential environmental effects of lithium extraction?
What is the water footprint of the lithium extraction process?
Is water becoming a limiting factor for lithium production?

The Duke team conducted a study with the natural brine in the Salar, taking samples of deep brines, evaporation ponds, salts from evaporation ponds, wastewaters, and the lithium carbonate. Vengosh said that “we can see some inconsistency in the chemistry of the water that is flowing into the chemistry of the brine.”

This indicates that there is a more complex geological process in the formation of the brine than the simple flow of water into the lake. The team also confirmed the high purity of the lithium carbonate product and that there are no impurities in the material. Additionally, the Duke team found that the wastewater chemistry produced after lithium carbonate production is not different from that of the original brines. Thus, there are no limitations for recycling the water back to the Salar system.

After Vengosh shared the findings of the Duke research team, Kathryn Ledebur, director of the Andean Information Network (AIN) in Cochabamba, Bolivia and Dr. Scott MacDonald, chief economist at Smith’s Research & Gradings and a Caribbean Policy Consortium Fellow, discussed Bolivia’s lithium policy. With the largest untapped lithium deposits in the world, Bolivia has constructed a pilot plan for their lithium production, but Ledebur highlighted that the biggest hurdle is scaling. Additionally, with a unique prior-consultation system in place between the central government and 36 ethnic and indigenous groups in Bolivia, natural resources are a key topic of concern and grassroots action. Ledebur said, “I don’t see that issue changing any time soon.”

Another hurdle is that Bolivian law requires that the extraction process is controlled by the state (the state must own 51%). Foreign investors have been hesitant to work with the central government, which nationalized lithium in 2008 despite, critics said, lacking much of the necessary technology and expertise.

Maxwell Radwin, a writer for Mongabay, writes, “Evo Morales, the former socialist president who served from 2006 to 2019, nationalized the industry, promising that foreign interests wouldn’t plunder Bolivia’s natural resources as they had in the past. Instead, he said, lithium would propel the country to the status of a world power. Morales didn’t just want to export lithium, though; he wanted to produce batteries and cars for export. This complicated deals with potential investors from France, Japan, Russia and South Korea, none of which came to fruition because, among other things, they were required to take on YLB (the state-owned lithium company) as an equal partner.”

Ledebur said, “At this point in time, the Bolivian government has signed three contracts… and I think things will fall into place.”

Naysayers say that the Bolivian government hasn’t done anything to take advantage of the massive market sitting beneath their Salars and that grassroot consultations don’t work. Ledebur said, “I don’t think that it’s perfect, but it’s happening.”

Duke students will return to Bolivia with professor Vengosh next year to conduct more research on the lithium extraction process. Then, they’ll be able to see the effects of this ‘happening’ first-hand.

By Isa Helton, Class of 2026

Into the Damp, Shady World of the Bryophytes

By Sophie Cox

On April 21, 2023

In Biology, Environment/Sustainability, Faculty, Science Communication & Education, Students

Clockwise: Jonathan Shaw, Adam Kosinski, Natalie Farris, and Kavya Menke looking at bryophytes on a log.

On a bright Sunday afternoon in April, I did something I had never done before. I went for a walk in the woods specifically to look for mosses. No, that’s not strictly true — we were looking for bryophytes. I learned, among other things, that not everything I had always called moss was really moss at all. (The word bryophyte comes from ancient Greek components and literally means “moss plant.”)

A patch of moss on the Al Buehler Trail. Moss is one type of bryophyte; liverworts and hornworts are the two others.

The walk was organized by Wild Ones, an undergraduate nature club I’m involved with. Biology Professor Jonathan Shaw, Ph.D., and Blanka Aguero, data and collections manager in the Duke University Herbarium, volunteered to teach a group of undergraduates about mosses and other bryophytes on the Al Buehler Trail adjacent to the Duke golf course.

Jonathan Shaw and members of the Wild Ones holding moss. Mosses, liverworts, and hornworts together represent the bryophytes.

Bryophytes (which include mosses, liverworts, and hornworts) represent one of several large groups of terrestrial plants. Other groups include angiosperms (flowering plants), gymnosperms (cone-producing plants like conifers and ginkgos), pteridophytes (vascular, spore-producing plants including ferns and horsetails), and lycophytes (an ancient group with about 1200 surviving members). According to Shaw, bryophytes are “the second biggest group after the flowering plants, but the flowering plants are an order of magnitude more diverse.” Aguero says that North Carolina has 462 moss species, 211 liverworts, and 7 hornworts.

Zach Pracher (Wild Ones member) and Blanka Aguero looking at bryophytes on a log.

Unlike the other terrestrial plant groups, bryophytes are nonvascular, meaning they lack the water transport tissues that other plants use. Without vascular tissue and without lignin for support, bryophytes can’t grow very big because they have no way to efficiently move water from their base to the rest of the plant. Instead, they grow close to the ground and absorb water directly from the environment into their cells.

Despite their preference for damp habitats, bryophytes can live for a long time without water. Some plants (like cacti) survive droughts by storing water, but bryophytes have a different strategy. They go into a state of dormancy, or suspended animation, and simply wait. Then, when it next rains, “they go hog-wild, photosynthesizing again in minutes,” Shaw says.

So if bryophytes don’t rely on constant moisture to survive, why do they like it so wet? Water, as it turns out, isn’t just important for hydration. Bryophytes rely on it to reproduce as well.

“Mosses are the amphibia of the plant communities,” Shaw says. Just as many amphibians can live on land but must return to the water to reproduce, bryophyte sperm has to “swim” to an egg cell to fertilize it. Therefore, they need water in order to reproduce, but they don’t need much. It could be mist from a splashing waterfall or a puddle in the woods or rainwater trickling down a tree. It could even be dew.

Moss on a tree trunk. Bryophytes can grow in a wide range of habitats across the world.

The day was warm and sunny, but the ground was dotted with puddles from recent storms. Armed with small hand lenses, we set off down the trail, stopping periodically to scrutinize tree bark, fallen logs, and thick patches of moss on the forest floor.

You need not travel far to find bryophytes. Mosses and their cousins colonize all sorts of hidden nooks: damp logs, trailside divots, tree bark, riverbanks, forgotten corners of backyards. Compared to seed-producing plants, bryophytes tend to have larger geographic ranges, perhaps in part because spores disperse more easily and because bryophytes can survive dry spells. Shaw estimates that about 75% of the moss species found in North Carolina are also found in Europe, and some of them are found in Asia as well.

Atrichum moss viewed through a hand lens. Note the thin line down the middle of each leaf. That line is a midrib and is one feature that sets mosses apart from liverworts.

We learned that most mosses have a midrib in the middle of each leaf, whereas liverworts have no midrib.

“A liverwort,” Shaw explains helpfully, “is like a moss, but it’s a liverwort.”

Liverworts are relatively flat in comparison to mosses because their leaves are in two parallel rows, whereas mosses tend to have a more spiral shape, with leaves emerging from all sides of the stem. The flat appearance of liverworts explains why they are sometimes called scale mosses. Another feature to consider if you’re trying to distinguish mosses and liverworts is the presence of lobed leaves, or leaves with protuberances off the main leaf (think of maple or oak leaves, for example). Some liverworts (but not all) have lobed leaves, but no mosses do.

A liverwort (main image) and the same liverwort viewed through a hand lens (top right). Liverworts and mosses can look very similar, but a hand lens makes it easier to spot the differences between them. Note the relatively flat appearance of the liverwort leaves compared to moss leaves, which tend to grow in a spiral fashion around the stem.

Aguero and Shaw both point out that the features we use to visually distinguish bryophytes aren’t necessarily the same features that officially set mosses and liverworts apart. The main difference between mosses and liverworts involves differences between their sporophytes.

Frullania is a genus of liverworts that forms dark patches, like the spots on this tree. If you see patches like these, Aguero says, they are “invariably” Frullania liverworts.

“It’s not true that if you’ve seen one moss, you’ve seen them all,” Shaw says. They’re small, yes, but they are not all the same.

We looked at one particularly lush patch of moss in the Bryoandersonia genus, named after a Duke professor. If you’re trying to identify trees, Shaw says, you might start with features like whether the leaves are broad or narrow and whether the tree is shrubby or not. With mosses, on the other hand, one of the first questions to ask is whether it’s pleurocarpous or acrocarpous. Pleurocarpous mosses, such as the Bryoandersonia we looked at, tend to have highly branching stems and grow in sprawling patches. The stems of acrocarpous mosses, meanwhile, have little or no branching and grow mostly vertically, often forming tight clumps.

Kavya Menke (Wild Ones member) examining a thallose liverwort we found by a stream.

After learning about patches of Frullania liverworts on trees from Aguero, we examined a large clump of liverworts growing beside a stream. Unlike the other liverworts we’d seen, this was a type of thallose liverwort, set apart from so-called leafy liverworts by the presence of thallus (a ribbon-like structure) instead of leaves. We also had the chance to smell it. Interestingly, liverworts also have a distinctive smell, sharp and earthy. The scent can be so strong that you might sometimes smell liverworts before you see them.

A thallose liverwort in the genus Conocephalum. Thallose liverworts are characterized by thalli (plural of thallus) instead of leaves. The other liverworts we saw were leafy liverworts.
Photo by Adam Kosinski.

According to Shaw, the term liverwort dates back to when botany and herbal medicine were considered largely the same. The so-called Doctrine of Signatures is the long-held idea that plants’ physical features reveal their medicinal uses. Thallose liverworts were thought to resemble livers and were used to treat ailments of the liver, hence the name. Similarly, the walnut looks rather like a brain and was used to treat mental illness, while the Dutchman’s breeches flower (the white flowers are said to resemble pants) was used for sexually transmitted diseases.

Aguero says that some liverworts do contain chemicals with antimicrobial properties, but she advises people not to eat liverworts.

Moss sporophytes, which release spores into the air. (Top right: close-up through hand lens.) The sporophytes are the only part of a bryophyte that are diploid (containing two sets of chromosomes instead of one). The trees in the background are also diploid; most plants (with the exception of bryophytes) are diploid during most of their life cycle.
Photos by Adam Kosinski.

Near the end of our walk, we found something we’d been keeping an eye out for but hadn’t yet seen: moss sporophytes. Bryophytes have a unique life cycle. Most of the time when we see a plant or an animal, it is diploid, meaning each cell contains two full sets of chromosomes (one from each parent). Every human cell, for instance, contains 46 chromosomes—with the exception of female egg and male sperm cells, which contain only 23. Cells that have only one set of chromosomes (like human egg and sperm cells) are called haploid. Plants undergo alternation of generations, meaning that one phase in their life cycle is haploid and one is diploid. In the case of most plants, the dominant and most conspicuous part of the life cycle is the diploid phase, but bryophytes are different. The fuzzy green carpets of moss we see are made of haploid cells, while the diploid phase is short-lived and only appears during reproduction. In mosses, the diploid phase (also known as the sporophyte) resembles thin filaments emerging from the haploid bed of moss. These sporophytes release spores (the spores are haploid) that grow into the next generation of moss.

“I wish we could be like the moss spores and let the wind carry us,” said Kavya Menke, one of the undergraduates on the walk. “Cheaper than Uber.”

Clockwise: Wild Ones members Natalie Farris, Adam Kosinski, and Zach Pracher examining patches of Frullania, a liverwort genus.

Occasionally, I paused my own bryophyte observations to watch others watching bryophytes. I found myself wondering if people are similarly bemused when they see me standing in a swamp with binoculars or crouching down on the way to class to move an earthworm off the sidewalk. I am accustomed to the world of birding, and looking for creatures like dragonflies, snakes, and salamanders feels natural to me as well. But this was a delightful opportunity to enter a world in which I had little to no experience: the shady, damp world of the bryophytes.

Adam Kosinski taking a close look at a bryophyte specimen placed on a log.

If you make a habit of going on walks with birders, you may spend a lot of time waking up before dawn, craning your neck upward, and straining to hear the alleged differences between a dozen kinds of short chirps. If you go out looking for snakes, you might spend a warm afternoon flipping over sun-warmed boards and scanning rocks and other basking spots. Searching for salamanders will likely involve scrutinizing wet soil, leaf litter, and ponds in early spring, possibly on a dark and rainy night. But searching for bryophytes is an experience all its own.

For one thing, you can go at any time of day and be equally successful, seeing as bryophytes neither crawl nor slither nor fly. You can also feel free to move as slowly as you wish. Aguero compares bryologists to lichenologists: “Moss people and lichen people work together frequently,” she says. “We walk similarly slowly.”

Blanka Aguero discussing bryophytes with students.
Photo by Adam Kosinski.

You could walk the same trail a hundred times and see it a hundred different ways. You could focus on birds or earthworms or snakes, wildflowers or changing leaves, clouds or trees or rocks. The next time you are in the mood to explore a new world, consider taking a walk — either somewhere new or a path you’ve walked a hundred times before — and turning your attention to the wonderful world of the bryophytes. Pet the moss. Feel its springiness and dampness and softness. Run your fingers lightly over the thin sporophyte stalks and notice how they tickle your palm. Smell the liverworts. See the dark patches of Frullania on a tree trunk. Bryophytes are nearly everywhere. Look for them. Look at them. See them.

Bryoandersonia moss viewed through a hand lens.
Photo by Adam Kosinski.

Post by Sophie Cox, Class of 2025

A Naturalist’s View of “Extraordinary” North Carolina

By Sophie Cox

On April 17, 2023

In Animals, Art, Biology, Climate/Global Change, Environment/Sustainability, Lecture, Science Communication & Education

Naturalist Tom Earnhardt on Black River in North Carolina. The forests around Black River are home to the oldest trees in eastern North America, 2,700-year-old bald cypresses.
All photos courtesy of Tom Earnhardt.

There are many ways to think of North Carolina. It was the 12th U.S. state to enter the Union. It is bordered by Virginia, Tennessee, Georgia, and South Carolina. North Carolina’s capital city is Raleigh, and it has an estimated population of 10,698,973. These are all facts, but they tell only part of the story: the human side of it.

Naturalist Tom Earnhardt offers other ways to view North Carolina: the state contains the oldest forest in the eastern United States, with trees up to 2,700 years old. It has 17 river basins, and some of its rivers show evidence of fishing weirs used by indigenous tribes hundreds of years ago. And from the Atlantic coast in the east to the Appalachian mountains in the west, North Carolina is home to thousands of native plants, animals, and fungi. There are 3,000 species of moths alone in North Carolina, and “Every one is essential; not one is optional.”

“North Carolina,” Earnhardt says, “is still one of the most biodiverse and extraordinary places on the planet.”

A prothonotary warbler. Prothonotary warblers inhabit swamps and coastal rivers in North Carolina. They are one of only two warblers in America that nest in cavities.

Earnhardt is a naturalist, photographer, writer, and attorney. He wrote and produced the show “Exploring North Carolina,” a series of dozens of episodes about North Carolina’s biodiversity, geography, and history. Earnhardt recently visited Duke to speak at the Nasher Museum of Art.

One inspiration for his talk was the ongoing Nasher exhibit “Spirit in the Land,” an exploration of ecology, culture, and connection to the natural world. “Art in its many forms,” Earnhardt says, “tells a story of love, loss, and renewal.”

Earnhardt has spent much of his career balancing caution and hope. We are facing environmental crises, including climate change and biodiversity loss. Earnhardt believes it’s important for people to know that, but he has put a lot of thought into how to get that message across. Earnhardt has learned that it can help to “tell it as though it was your best friend or brother who needed to hear an important story.” Science alone isn’t always enough. “To hear bad news of any kind is not easy,” Earnhardt says, “and people want to hear it from people they know, people they trust or can relate to.”

The stories he tells aren’t always easy to hear, but they are important. We need to know — whether on a local, state, national, or international scale — what exactly we stand to lose if we continue on a path of environmental destruction. Many species are becoming more scarce, Earnhardt says, “but we still have them.” They can’t be protected once they’re gone, but many of them are still here and can still be preserved. The goal for all of us should be to keep it that way.

North Carolina, Earnhardt says, is at “the epicenter of the temperate world.” The state has a range of climates and habitats. It marks the northernmost native range of the American alligator, while coniferous forests in the North Carolina mountains resemble boreal forests of the northern U.S. and Canada. North Carolina, according to Earnhardt, contains “whole ecosystems that other states only dream about.”

Eastern North Carolina is characterized by beaches, salt marshes, and other coastal ecosystems. Here you can find “wildflowers that grow in salty sand” and painted buntings, multicolored songbirds unlike any other in North America. On four occasions, he’s even seen manatees in North Carolina.

A male painted bunting, a summer resident on North Carolina’s barrier islands. Female painted buntings are bright green.

“Travelers from around the world vacation here and raise their families in the summer,” Earnhardt says—and he’s not talking about humans. Many shorebirds and sea turtles lay their eggs on North Carolina’s beaches. Human disturbance, including artificial lighting and crowded beaches, can put their babies in danger. Minimizing light pollution near beaches, especially during turtle nesting season, and staying away from nesting shorebirds can help.

A longleaf pine savanna in southeastern North Carolina.

Moving farther west, we can find savannas of grasses and pine trees. “You drive past this, and people go, ‘ho hum, a pine barren.’” To that Earnhardt says, “Look a little closer.”

White-fringed orchids, one of North Carolina’s 80 native orchid species. Earnhardt took this photo in the Green Swamp, a longleaf pine savanna nature preserve.

These pine barrens are home to some of North Carolina’s 80 species of orchid, like the white-fringed and yellow-fringed orchids. “Look at them from all angles,” Earnhardt urges, “because from up above it becomes a sunburst… for those who watch.”

A yellow-fringed orchid, viewed from the side.

Be one of those who watches.

A yellow-fringed orchid, viewed from above.

North Carolina rivers, forests, and swamps are also home to many wildlife species. Forests around Black River contain “huge buttresses of tupelo that hold the world together” and bald cypresses that have been alive for 2,700 years. The early years of these now-ancient cypress trees coincided with the fall of the Assyrian Empire and the establishment of the first emperor of Japan. Many centuries later, they are the oldest trees in eastern North America.

Cypress trees on Black River. Both tupelos and cypresses have buttresses at their bases to provide stability in the water.

They are also in danger. “If seas rise three feet,” Earnhardt says, “there will be enough pressure to flood these [trees]…. We could lose them.” But “they are worth saving.”

Still farther west are the Appalachian mountains, another biodiversity hotspot. North Carolina is home to 60 species of salamanders, many of which live in the mountains. The southern Appalachians and western North Carolina contain more salamander diversity than anywhere else on the planet. One species that lives here is the American hellbender, a two-foot-long denizen of mountainous streams.

Despite increasing human development, North Carolina is still rich in flora and fauna. “We have wild places,” Earnhardt says. North Carolina has more than 450 bird species, over 30 native pitcher plants, 20 freshwater turtles, and 38 snakes—“and they’re all good neighbors,” Earnhardt adds.

Venus flytraps in a longleaf pine savanna.

North Carolina has pink and yellow lady slippers and ten-foot-tall Turk’s Cap lilies; crayfish and thousands of mushrooms; native azaleas and insects that depend on them. It has Earnhardt’s “new favorite bird,” the swallow-tailed kite, and vultures, “the clean-up crew: not optional.” That’s a refrain throughout Earnhardt’s talk. “Nothing I’ve shown you tonight is optional,” he says.

“Both in banking and nature,” Earnhardt says, “when we make too many withdrawals and not enough deposits… there’s a deficit.” There are too many creatures we have already lost. The eastern cougar. The Carolina parakeet. The passenger pigeon. Too many more. There are still others that are threatened or endangered but not yet gone. “We humans tend to forget the failures and close calls,” Earnhardt says. While talking about biodiversity loss, he references a quote by biologist E.O. Wilson: “This is the folly our descendants are least likely to forgive us.”

A swallow-tailed kite. Earnhardt says that these kites, which spend their winters in South America, now nest along several rivers in southeastern North Carolina.

So what can be done? To preserve biodiversity, we have to consider entire ecosystems, not just one endangered animal at a time. “We are part of the natural world, part of links and chains and pyramids,” Earnhardt says, and humans too often forget that. Everything is connected.

He recalls visiting entomologist Bill Reynolds’s lab and noticing crickets hopping across the floor. “Don’t step on the transmission fluid!” Reynolds warned. He was referring to the crickets and to insects more broadly. Like transmission fluid in cars, insects are essential to making sure the systems they are part of run smoothly. Insects serve crucial roles in food webs, pollination, and decomposition. Studies show that they are declining at alarming rates.

“We are at a crossroads,” Earnhardt says. “Our transmission fluid is low, and we have made too many withdrawals from the bank of biodiversity.” Still, he emphasizes the importance of not giving up on wildlife conservation. Given a chance, nature can and will regenerate.

Tupelo tree buttresses on Tar River near Greenville, North Carolina.

Despite all our past and current failures, conservation also has remarkable success stories. The brown pelican is one North Carolina resident that almost went extinct but has since “come back in incredible numbers.” The bald eagle is another. Its population plummeted in the 20th century, largely due to the insecticide DDT as well as habitat loss and hunting. By 2007, though, after intensive conservation efforts, it had rebounded enough to be removed from the endangered species list. Until about 1980, Earnhardt had never seen a bald eagle in North Carolina. Today, Earnhardt says, “I see them in every county.”

A bald eagle that Earnhardt saw near the Raleigh-Durham airport. Bald eagles, once on the brink of extinction, can now be seen in every county in North Carolina.

“Everyone’s going to have to fly in the same direction,” to preserve North Carolina — not to mention the rest of the world — at its best and wildest, Earnhardt says. But individual actions can make a difference. He suggests planting native flowers like milkweed and coneflower, both of which are good food sources for pollinators. And if you choose to plant ornamentals like crepe myrtle, “Treat that as a piece of art in the yard and then plant the rest as native.”

Lady Bird Johnson, a former first lady and conservation advocate, once said that “Texas should look like Texas, and Mississippi like Mississippi.” Choosing native plants can be a powerful way to help native wildlife in your own yard. “If you plant it,” Earnhardt says, “they will come.”

One audience member asks, “How do you recommend that we recruit non-believers?” It’s a conundrum that Earnhardt has put a lot of thought into. “It takes time, and it takes patience,” he says. “Some of my best friends are not full believers, but I work on them every day.”

Post by Sophie Cox, Class of 2025

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