Faculty, staff and students from EEB gathered on May 18, 2023 to celebrate the end of the semester, recognize award-winners, and honor retirees. Check out this YouTube video to see all of the winners, along with some photos from the celebration.
Spring 2023 EEB honors graduate Colton Adams received a Fulbright student award. Read about his plans here: https://news.utk.edu/2023/05/17/11-ut-students-receive-fulbright-awards/?utm_source=newsletter&utm_medium=email&utm_content=2023-24%20Fulbright%20student%20awards&utm_campaign=TN%20Today
Understanding how birds respond to climate change is a critical area of research that Elizabeth Derryberry, associate professor in the UT Department of Ecology and Evolutionary Biology, and her colleagues are racing to understand, including the increased prevalence and intensity of heat waves. In a new study published online in Molecular Ecology, the researchers examined how heat impacts the behavior and physiology of Zebra finches.
“Most of what we know about the behavioral and physiological effects of heat comes from aquatic organisms or terrestrial cold-blooded animals, but heat waves could be a real problem for terrestrial birds and mammals too, especially if heat interferes with critical components of their reproductive behavior and physiology,” said Sara Lipshutz, assistant professor at Loyola University Chicago, former graduate student at UT, and first author on the publication. “We wanted to understand how that happens as a first step towards understanding how to manage these problems.”
Heat waves can be lethal for warm-blooded animals, but behavioral and physiological effects are missing from recent high-profile studies on climate change. The researchers wanted to know about sub-lethal effects of heat that do not kill animals, but still might impact their ability to adapt and thrive as the climate changes.
Lipshutz and colleagues exposed zebra finches to a four-hour heat challenge, similar to what wild birds might experience during the afternoon heat on a summer day. Zebra finches were selected for the study because these songbirds experience extreme temperature fluctuations in their native Australia.
The team measured heat effects on thermoregulatory behavior and looked specifically at how heat changed gene activity in tissues that are critical to reproduction – the testis that control fertility and a part of the brain that regulates singing, which is an essential mate-attraction behavior in birds. They discovered that heat altered the activity of hundreds of genes in the testis, but fewer in the brain, suggesting that the brain may be less responsive to extreme temperatures.
“At the same time, we found evidence that dopamine-related signaling was affected in the brain, meaning that even sub-lethal heat may change a bird’s ability to reproduce, via changes in motivational circuits for song production,” Lipshutz said. “If they can’t sing, or sing well, they aren’t going to breed.”
Bird populations have been dramatically declining over the past few decades, and male songbirds need to sing to attract a mate. Coupled with previous studies showing that birds sing less during heat, this project reveals potential underlying mechanisms by which heat may contribute to avian population declines.
“It’s really a triple-whammy,” said Derryberry, corresponding author on the publication. “Heat’s not only affecting their brains, but it also appears to affect testicular gene networks related to self-maintenance and sperm production. So, there’s potentially less motivation to sing, reduced gonadal function, and greater investment in self-maintenance, all of which can detract from successful reproduction.”
The study also provided some hopeful insights for birds and their ability to handle the threat of climate change. Males that panted more often during the heat challenge exhibited more limited effects on gene activity in the brain and testis.
“For a long time, researchers have reasoned that behavioral flexibility might be key for animals’ ability to handle novel environmental challenges,” said Kimberly Rosvall, associate professor of biology at IU Bloomington, whose lab oversaw that genomic side of this project. “We saw that some individuals better used behavioral thermoregulation to dissipate the physiological effects of heat. If animals are able to adjust their behavior. or if behavior can evolve to keep pace with climate change, birds may be able to adapt.”
According to Lipshutz, the results have important implications for sexual selection in a warming world as well.
“Some individuals, or even some species, may perform well under extreme temperatures,” she said. “That could influence both how thermal tolerance evolves and how behavior evolves too.”
Additional authors on the study are Clara Howell (former master’s student in Derryberry’s lab), Aaron Buechlein (bioinformatician, IU Center for Genomics and Bioinformatics) and Douglas B. Rusch (lead bioinformatician, IU Center for Genomics and Bioinformatics).
The researchers’ work was funded by U.S. National Science Foundation fellowship and published online May 14, 2022, in Molecular Ecology.
For decades, scientists have worked to understand the intricacies of biological diversity – from genetic and species diversity to ecological diversity.
As scientists began to understand the depths of diversity across the planet, they noticed an interesting pattern. The number of species increases drastically from the Poles to the Equator. This phenomenon, known as the latitudinal gradient of species diversity, has helped define the tropics as home to most of the world’s biodiversity. From plants and insects to birds, amphibians, and mammals, scientists estimate that tropical forests contain more than half the species on Earth.
These biologically rich areas are known as biodiversity hotspots. To qualify as a hotspot, a region must have at least 1,500 vascular plants species occurring nowhere else and have 30 percent or less of its original natural vegetation. In other words, biodiversity hotspots must be irreplaceable, but also threatened.
While scientists agree that most biological diversity originated in the tropics, the jury is still out on how tropical species diversity formed and how it is maintained. A new study published in Science addresses these long-standing questions.
In “The evolution of tropical biodiversity hotspots,” researchers argue that tropical species form faster in harsh, species-poor areas, but accumulate in climatically moderate areas to form hotspots of species diversity. Drawing on decades of expeditions and research in the tropics and the scientists’ own knowledge and sampling of tropical bird diversity, they assembled a large and complete phylogenomic dataset for a detailed investigation of tropical diversification.
“This is our magnum opus,” said Elizabeth Derryberry, associate professor in the UT Department of Ecology and Evolutionary Biology (EEB) and a senior author of the study. “This research is the product of a decades-long international collaboration to produce a completely sampled evolutionary history of a massive tropical radiation – the 1,306 species of suboscine passerine birds.”
Roughly one in three Neotropical bird species is a suboscine, making it the predominant avian group in Neotropic terrestrial habitats – from the Andes snow line to the Amazon lowlands – and the perfect group to examine the origins of tropical biodiversity.
“The tropics are a natural laboratory for speciation research,” said Michael Harvey, recent EEB postdoc and lead author of the study. “Many high-profile studies over the years sought answers to fundamental questions concerning species formation and maintenance, but even the best of these studies sampled only a minority of the existing species within the clade in question.”
In addition, nearly all of the previous studies used highly incomplete data matrices and supertree analyses, which left results open to large estimation errors in downstream analysis, according to Derryberry.
For this study, Derryberry, Harvey, EEB Professor Brian O’Meara, and fellow researchers used a time-calibrated phylogenomic tree to provide information needed for estimating the dynamics of suboscine diversification across time, lineages, and geography. They also used the tree to test links between the dynamics and potential drivers of tropical diversity.
“We took no shortcuts in this study,” Derryberry said. “We leveraged this unparalleled sampling of tropical diversity to illustrate the tempo and geography of evolution in the tropics. It is the first study to demonstrate conclusively that tropical biodiversity hotspots are linked to climates that are both moderate and stable.”
The team discovered species-rich regions in the tropics contain diversity accumulated during a protracted evolutionary period and are not just a locus of young diversity. A key result of their study is that the best predictor of elevated speciation rates in New World suboscines is low species diversity. In other words, new species form at higher rates in areas containing relatively few species.
“The qualities that nurture diversity, lower extinction, and promote the gradual accumulation of species are, paradoxically, not the ones that support biodiversity hotspots,” Harvey said. “The hotspots are seeded by species born outside the hotspot in areas characterized by more extreme and less climatically stable climates.”
The team discovered that, overall, extreme environments limit species diversity, but increase opportunities for populations to evolve to become distinct species. Moderate climates, on the other hand, limit speciation, but provide more opportunities for species diversity to accumulate.
“Our study is the first to be able to address tropical diversification with a large, comprehensively sampled clade and will pave the way for future investigations of evolution in the world’s diversity hotspots,” Derryberry said.
The international collaboration for this study included researchers from Colombia, Brazil, Uruguay, and Venezuela, as well as ornithologists from groups underrepresented in the sciences, include Latinx and women researchers.
“This paper marks not only a change in our understanding of evolution in the tropics, but also in acknowledgement and valuation of the diversity of culture, expertise, and perspective in the field of ornithology,” Derryberry said.
The US National Science Foundation, Brazilian Council for Scientific and Technological Development, and the São Paulo Research Foundation funded the study.
Birds respond to a half-century soundscape reversion during the COVID-19 shutdown
When the novel coronavirus swept across the country, forcing most businesses to close their doors and people to stay home as a measure to stop the spread, people looked to the little things for signs of hope. For Elizabeth Derryberry, hope came in the form of songbirds.
Like most people during spring 2020, Derryberry focused on keeping her family safe and healthy and balancing work and homeschooling. When she saw photos of an empty Golden Gate Bridge in San Francisco, however, her scientific curiosity kicked in.
“When I saw those photos, it struck me just how little traffic there was in the city,” said Derryberry, an associate professor in the Department of Ecology and Evolutionary Biology (EEB). “I was curious to find out if this meant it was much quieter and what that might mean for the songbird I study.”
Actions taken to control the COVID-19 pandemic reduced motor vehicle traffic, potentially alleviating auditory pressures on animals that rely on sound for survival and reproduction. Derryberry, working with fellow EEB professor Michael Blum, collaborated with a team from California Polytechnic State University, George Mason University, and UT to evaluate if and how songbirds might respond to the newly emptied acoustic space that resulted from fewer people on the road.
Their findings, recently published in Science, were based on a comparison of soundscapes and songs of the white-crowned sparrow across the San Francisco Bay Area prior to and during the recent statewide shutdown. The researchers also looked at singing performance, evaluating how acoustic qualities important for mate attraction and territorial defense shifted to accommodate background noise conditions.
For more than a decade, Derryberry has recorded birds in San Francisco to study how noise affects bird song. In 2012, she began working with David Luther, an ecologist and assistant professor of biology at George Mason University, to study the effects of noise pollution on the sparrows. This involved recording noise and bird song from both urban and rural sites across the San Francisco Bay Area from April through June of 2016.
Jennifer Phillips, who completed her doctorate with Derryberry, captured noise and song recordings from the same areas in April and May of 2020 while working as a postdoc at California Polytechnic State University, San Luis Obispo. This allowed Derryberry and her collaborators, including UT research scientist and data analyst Graham Derryberry, to draw comparisons to pre-pandemic conditions.
The team found that the dramatic reduction of human movement during the shutdown had effectively erased a half-century of urban noise pollution. Not only had traffic, as evidenced from Golden Gate Bridge records, returned to levels not seen since 1954, but also there were no longer differences in noise levels between densely urban areas of San Francisco and rural Marin County.
The researchers also found that white-crowned sparrows responded by producing songs at lower amplitudes, but because it was so quiet, they were able to maximize communication distance.
“When the noise levels dropped, birds sang more softly,” Luther said. “Even though they sang more softly, their songs travelled twice the distance because it was so much quieter.”
This also meant that people could hear effectively four times more birds than usual and helps explain media reports suggesting that bird songs sounded louder during the shutdown. Birds sounded louder because people could hear more of them.
This study illustrates how noise pollution impacts communication during normal conditions.
“Our study substantively advances fundamental understanding of animal behavior,” Derryberry said. “We observed changes in behavior during the COVID-19 shutdown that went far beyond those that have been documented in small scale, short term manipulations of the noise environment – both in captivity and in the wild. In fact, we demonstrated for the first time that prior work does not accurately predict wildlife responses to landscape-scale remediation of noise pollution. Our research provides a more accurate description of this relationship.”
Derryberry will continue navigating the uncertainties the novel coronavirus brings with it, but appreciates the silver lining of this study and the hope that it brings.
“COVID-19 has been devastating in many ways for our society,” Derryberry said. “The loss of human life alone is overwhelming. It’s a testament to people though that there are still bright spots amid such loss. One of those bright spots has been how much more people are noticing birds, particularly in cities, around the world. I hope this study seizes this moment to highlight how much noise affects wildlife and how noise is one form of pollution that people can directly address in ways that can rapidly and dramatically change the quality of life for wildlife.”
The 2019 College of Arts and Sciences Faculty Awards banquet took place Thursday, December 5 at the Holiday Inn Downtown. From Diversity Leadership to awards in research, advising, and teaching, the annual awards banquet honors faculty excellence in all areas of the college mission.
Elizabeth Derryberry, Charlie Kwit, and Beth Schussler received awards for their work in the Department of Ecology and Evolutionary Biology.
“As we recognize particularly outstanding faculty this evening, I want to thank all of our faculty in the college, individually and collectively, for everything you do— your teaching, research, service on college and university committees, thesis committees, and tenure and promotion committees, and service to the public through community engagement,” said Theresa Lee, dean of the college and emcee for the awards ceremony. “A college can be no greater or stronger than its faculty and the College of Arts and Sciences is a college of excellence because each of you has a passion for our profession and you work selflessly to make our students, departments and university the best they can be.”
Elizabeth Derryberry, associate professor, received a Mid-Career Award for Research and Creative Achievement. Derryberry’s research focuses on passerine bird evolution and bird songs – important topics that are notoriously difficult to study. Her exciting project on the effects of human-mediated noise in urban environments on bird song demonstrate both changes in song parameters in response to noise and consequences for ecosystem fitness. Derryberry is the author of more than 50 highly cited papers and an associate editor for two prestigious journals: Evolution and Journal of Animal Behavior. Her work is top-notch, broad-thinking, impactful science at its best. She is an outstanding student mentor and passionate about her outreach to increase opportunities for girls and women in science.
Charlie Kwit, professor and joint faculty in EEB and the Department of Forestry, Wildlife, and Fisheries in the Herbert College of Agriculture, received the Academic Outreach Award for Teaching. His work to promote natural history knowledge in the Southeast exemplifies academic outreach in teaching. This year, he received a grant to increase HBCU representation to the Southeastern Chapter of the Ecological Society of America and support students engaged in the work of the Society. He also organized a session at the annual ESA meeting that spotlighted the biodiversity of the Southeast and the challenges we face in maintaining that rich biological heritage. Kwit also fosters UT students in outreach through clubs and courses. Students in his class experience the very best of what is intended as part of the new Experience Learning efforts. They see the utility of what they are learning, enriching their engagement with the material, while also helping to build relationships between UT and the community that strengthen the institution.
Beth Schussler, professor, received the James R. and Nell W. Cunningham Teaching Award, the college’s highest teaching honor. There are no specific requirements listed for the award, but there are some things that are typical of the winners. One, excellence in the classroom. Schussler is highly praised by students and peers for her work in some of the more demanding biology courses. Two, contributions to excellence in others. Schussler supervised the lecturers and GTAs in the general biology courses, and helped train the GTAs, which came from all three of the departments in the Division of Biology. Finally, contributions to teaching beyond their courses and department. Schussler has organized workshops on teaching for STEM departments, and continues to be involved with nation-wide efforts and grants helping to improve biology and STEM instruction.
Congratulations to our Department of Ecology and Evolutionary Biology faculty award winners.
Elizabeth Derryberry, a professor of ecology and evolutionary biology, received recognition in a timeline of important female ornithologists in a Cornell Lab of Ornithology article, focusing on the achievements of female ornithologists and their role in determining the causes of evolutionary advancements in birds.
Part of Derryberry’s research focuses on the how bird songs are shaped by urban environments.
“One of the things I’ve been most interested in over the last five years is looking at how urban noise affects bird song,” she said.
Through research in San Francisco of urban and coastal white-crowned sparrows, Derryberry and other researchers determined that the volume and frequency of a song is correlated to the birds’ environment. As noise frequency increases in a city or along the coast, so does the birds’ songs. This creates loud, high pitched notes in shorter intervals, as compared to songs from birds living in low noise frequency environments.
“We found that within a population, males vary their vocalizations in their songs based on how loud it is on their territory,” said Derryberry. “As traffic noise increases and city noise levels increasing, we are seeing a shift up in frequency.”
The article provides a recognition of women ornithologists and highlights the importance their research has had. “I think women have been really impactful in ornithology for a long time,” she said. “It’s really just a matter of recognition. It’s great to see those sorts of efforts.”
The Graduate Student Senate Awards were held on April 4. Check out all the winners from EEB!
Graduate Research Mentor of the Year: Associate Professor Elisabeth Schussler
Excellence in Teaching: Justin Hendy (Small Lab)
Excellence in Research: Sara Lipshutz (Derryberry Lab)
Excellence in Service: Alannie Grant (Kalisz Lab)
Two EEB grad students are competing in the 3-minute thesis competition next week: Jordan Bush (Simberloff Lab) and Sara Lipshutz (Derryberry Lab). This is a University-wide competition, so we are doing well to have two EEB-ers representing us! See pdf for details.
Jordan and Sara are speaking on February 26, 2018 at 3:30 p.m. in room 160 of the Plant Biotechnology Building, in the first of three Three Minute Thesis semi-final competitions. The Three Minute Thesis competition is one in which graduate students have three minutes and a single slide to explain their dissertation or thesis research to a group of judges and an audience (that may not even be familiar with the academic area). It’s a valuable exercise and a great way to showcase the amazing work being done by UT graduate students. It’s also a perfect way to start Graduate Education Week, so come by and watch the competition and support our graduate students!