Professor of Ecology and Evolutionary Biology Nina Fefferman became a mathematician because she loves puzzles. She’s just been awarded $18 million from the U.S. National Science Foundation to solve one puzzle that has the potential to change the world: how, when and why an infection in a population will spread, or cause an epidemic or pandemic, rather than dying out.
Associate Professor Stephanie Kivlin earned a 2024 National Science Foundation (NSF) CAREER Award for her project proposal “Spatiotemporal Dynamics of Plant-Mycorrhizal Fungal Symbioses at Continental Scale.” The work will help build a greater understanding of ways that plant life reacts to changes in global conditions.
The Kivlin Lab, within the UT Department of Ecology and Evolutionary Biology (EEB), researches the drivers of distributions of mycorrhizal fungi—fungi that have symbiotic relationships with the roots of many plants—and how global change may affect them and their interactions with these plants. The CAREER project will expand the lab team’s focus to study foundational trees of North America.
“This CAREER award is pivotal to provide support to map the current and future distribution of plants and mycorrhizal fungi and the outcome of symbiosis throughout the continental US for the first time,” said Kivlin.
Global change is forcing organisms to shift their biogeographical ranges and change their seasonal activities—affecting their growth, survival, and reproduction. Microbial symbionts can modulate the response of host organisms to global change, but it isn’t known how interactions among hosts and these symbionts shift as conditions change planetwide.
Researchers will collect fungi from the roots of 10 foundational tree species across the Eastern US for four years and sequence long-term herbarium samples to understand historical fungal communities. They will address how these trees and their mycorrhizal fungal symbionts may become decoupled over space and time as plants and fungi shift ranges.
“We will leverage the USFS Forest Inventory and Analysis database, which involves more than 14,000 locations, to understand how mycorrhizal fungal distributions have shifted since 2001,” said Kivlin. “We will then assess how plants grow, survive, and reproduce with home fungi versus those that are moved to simulate range shifts under global change.”
For students, the grant will enable the development of two Course-based Undergraduate Research Experiences (CUREs) focused on this research.
“This research and outreach is collaborative with the Easy as Play initiative, led by EEB Professor Liz Derryberry, through which we will engage dozens of middle school students in plant-mycorrhizal fungal research and training,” said Kivlin.
CAREER award funding will also support graduate student Ella Segal in the Kivlin lab, plus a postdoctoral researcher and a technician.
“Graduate students from EEB will also be engaged in CUREs,” said Kivlin. “They will gain valuable pedagogical knowledge in experiential learning, which will prepare them for the workforce upon graduation.”
By Randall Brown
Ecologists from around the world learned about research conducted at the University of Tennessee, Knoxville, during the annual Ecological Society of America meeting this month.
About 20 oral presentations plus poster sessions featured UT faculty and students’ findings in areas including climate change, biodiversity, ecosystems, symbiotic relationships, and species that range from Appalachia to Africa. The ESA meeting in Long Beach, California, Aug. 4-9, drew around 3,000 attendees.
The UT presenters include half a dozen faculty members from the Department of Ecology and Evolutionary Biology (EEB): Distinguished Service Professor Paul Armsworth; Research Professor Richard Norby; Associate Professors Orou Gaoue, Xingli Giam, and Stephanie Kivlin; Lecturer Amanda Benoit; and Adjunct Lecturer Joseph Edwards.
“The ESA annual meeting is an outstanding opportunity for ecologists to learn about new work, network, and meet up with collaborators and colleagues, and is always so inspiring,” said Professor Jen Schweitzer, head of the EEB department. “Everyone attending always returns with new ideas and so much excitement about their research and next directions. ESA also does a great job of providing diverse professional development opportunities to help attendees expand their toolboxes of professional and discipline-based skills. I am thrilled there was such great attendance this year!”
The UT Institute of Agriculture had two faculty members present their research, Professor Jennifer DeBruyn and Assistant Professor Mark Wilber, and affiliates of the National Institute for Modeling Biological Systems (NIMBioS) also were delivering talks at ESA’s meeting.
Two EEB researchers received awards from ESA this year. PhD student Alivia Nytko was honored for her 2023 ESA poster presentation on research that suggests plant rarity might be an evolutionary adaptation. EEB Professor Michael Blum, associate dean for research and creative activity in the College of Arts and Sciences, received recognition for an outstanding ecological research paper, which focused on rapid plant evolution in how ecosystems respond to global change.
By Amy Beth Miller
Animal behavior captivated Gordon Burghardt as a boy, and over more than half a century at the University of Tennessee, Knoxville, his interdisciplinary research advanced ethology in areas including animal play, social behavior, communication, reptile behavior, enrichment, and animal cognitive abilities.
The Animal Behavior Society (ABS) recognized his outstanding lifetime achievement by awarding Burghardt the 2024 Distinguished Animal Behaviorist Award during its annual meeting in late June.
by Amy Beth Miller
Daniel Simberloff’s contributions to ecology and conservation biology as a researcher, educator, and mentor received recognition this spring from Tel Aviv University (TAU).
Simberloff, the Gore Hunger Professor of Environmental Studies in the University of Tennessee, Knoxville’s Department of Ecology and Evolutionary Biology, received an honorary doctorate during a May 30 ceremony at TAU. The certificate cites Simberloff’s “legendary achievements as an ecologist, conservation biologist and invasive species expert.”
Simberloff is the first ecologist to receive an honorary degree from Tel Aviv University, and the university also asked him to open a symposium that week that brought together scientists from across Israel studying biological invasions and government policymakers.
Simberloff first served as a visiting professor at Tel Aviv University in 1996 and before that had co-advised a TAU doctoral student, with whom he continued to collaborate. He also was involved in planning for the university’s Steinhardt Museum of Natural History.
The honorary degree presented to Simberloff notes that his work “is studied by virtually every undergraduate student in the field worldwide” and is “helping to prevent extinctions and protect biodiversity.”
“It’s really gratifying,” he said of the honor, “because it’s a nation with a lot of ecologists doing world-class work and publishing in all the leading journals, and people working right in my major area of biological invasions and much concerned with conservation in a very challenging environment.”
The honorary degrees were presented during the annual meeting of TAU’s Board of Governors, which includes representatives from around the world.
The eight other honorees included the co-founder of WhatsApp and the first Jewish woman appointed to the Supreme Court of Canada, as well as others recognized for academics, contributions to the arts, activism, and entrepreneurship.
During the ceremony, TAU President Ariel Porat said, “Even in wartime, we must maintain our way of life. Especially for a university, it is crucial to continue researching, teaching, and contributing to society. Today’s honorary degrees ceremony shows that the pursuit of science and knowledge never stops.”
Simberloff’s contributions to understanding the natural world also were recognized in August 2023 by the British Ecological Society (BES). The honorary membership he received in the BES is the highest honor it bestows, recognizing exceptional contribution at the international level to the generation, communication, and promotion of ecological knowledge and solutions.
McGill University awarded Simberloff an honorary Doctor of Science degree in June 2023, calling him a pioneer and renowned scholar in ecology and conservation biology. “Studying the susceptibility of ecosystems to biological invasions years before the phenomenon became a thriving subdiscipline, Simberloff is a world leader in this research area,” McGill said in honoring him.
Look closely at a plant in your local park, your garden or even your kitchen, and you’re likely to see some damage. Whether a caterpillar has chewed away part of a leaf or a mealybug is sucking on sap, animals are constantly feeding on plants.
Of course, herbivory, or plant predation, is not ideal for a plant’s survival. So plants have evolved many different defense mechanisms to inhibit this threat, including physical and chemical weapons. For example, cactuses arm their bodies with skin-piercing spines. Herbs such as mint, lavender and rosemary produce volatile scent compounds that can help deter herbivores.
Other plants resort to bribing personal bodyguards by secreting thick, sweet nectar.
Nectar is most commonly associated with flowers, where it is used to entice bees, birds or butterflies to move pollen from one flower to another. But other plants produce different types of nectar glands called extrafloral nectaries. Plants produce these glands to bribe ants with a sweet reward; in return, ants will defend the plant from insect herbivores.
I study plant evolutionary biology, and recently worked with fern biologist Fay-Wei Li at the Boyce Thompson Institute and Cornell University ant biologist Corrie Moreau to examine the evolution of ant-bribing defense mechanisms in plants.
We found something striking: nearly 130 million years ago, during the Cretaceous geologic period, ferns and flowering plants independently evolved ant-bribing nectar glands at roughly the same time. We figured this out by using complex algorithms to estimate the evolutionary origin and history of ferns, flowering plants and ants.
This timing is quite interesting because it was very early in flowering plant evolutionary history, but quite late in fern evolutionary history. Our work demonstrated that old dogs can learn some new tricks – and, even more importantly, how it happened in ferns.
Plants are the primary producers of nearly all of the food supply on Earth, so virtually all living creatures rely on them for survival. For this reason, herbivory is part of life. But it also creates serious costs for many industries, from house plants to agricultural crops. Major pest outbreaks can even threaten global food security.
For all of these reasons, understanding how plants defend themselves against predators is a critical challenge.
The evolution of ant-mediated defense strategies inexorably linked two lineages across the kingdom of life. It meant that ants and plants would eventually evolve together – a process called coevolution. As one species changes, the other may change in response, and these changes can even become encoded in their genes.
Flowering plants originated in the Cretaceous period, around 150 million years ago, and our analyses demonstrated that they formed tight associations with ants early on. These flowering plants and their ant partners seemingly evolved together over time.
But ferns didn’t. While they had the potential to develop nectaries at the same time as flowering plants, they didn’t start to evolve nectaries at fast rates until they learned to live among the trees.
Ferns originally were terrestrial plants, but after flowering plants evolved into large trees, ferns jumped onto their branches as epiphytes – plants that grow on other plants, often with no attachment to the ground.
Ferns can also climb up trees, as ivy does, or create their own trunks in the case of tree ferns. This also helped ferns get into the canopy.
The fact that ferns didn’t start producing nectar for ants until they moved up into trees confused me as a fern biologist. That was, until my coauthor Corrie Moreau pointed out that most ants lived in treetops.
This made perfect sense. As ferns became canopy dwellers, they began to grow closer to ants that were already associated with nectary-bearing trees. Comingling with these ants, ferns eventually tapped into the established mutually beneficial relationship between the ants and flowering plants.
While our study discovered new aspects of ant-mediated plant defense, it left many questions unanswered. For instance, are some ants specializing on ferns, or are they generalists that can feed on nectar from a wider range of plants? How, exactly, did plants originally develop the physical capacity to produce extra-floral nectar? Are the genes that encode for nectary development the same between ferns and flowering plants? Is the chemistry of fern and flowering plant nectar the same?
Our study lays the foundation for further research into the evolution and ecology of these nectaries. This is important foundational science. It’s also conceivable that research in this area could contribute to breeding programs that promote nectary-mediated ant defense, reducing the need for pesticides to protect plants from predators.
Jacob S. Suissa, Assistant Professor of Plant Evolutionary Biology, University of Tennessee
This article is republished from The Conversation under a Creative Commons license. Read the original article.
by Randall Brown
Two Vol researchers from the UT Department of Ecology and Evolutionary Biology (EEB) earned honors in the 2024 Ecological Society of America (ESA) Awards. These awards recognize outstanding contributions to ecology in new discoveries, teaching, sustainability, diversity, and lifelong commitment to the profession.
EEB Professor Michael Blum, associate dean for research and creative activity in the College of Arts and Sciences, shared in the ESA’s George Mercer Award, given annually for an outstanding ecological research paper published within the past two years with an early-career lead author.
EEB PhD student Alivia Nytko earned the E. Lucy Braun Award for Excellence in Ecology for her poster presentation at the 2023 ESA Annual Meeting titled, “Plant rarity related to phylogenetic divergence in biomass: Implications for ecosystem function.”
“We are so pleased that our EEB researchers have been recognized by ESA for their scientific achievements,” said College of Arts and Sciences Interim Executive Dean Robert Hinde.
Blum collaborated with lead author Megan Vahsen, a postdoctoral fellow at Utah State University, Associate Professor Scott Emrich from UT’s Tickle College of Engineering, and others on the study “Rapid plant trait evolution can alter coastal wetland resilience to sea level rise,” published in Science in January 2023. Their work calls attention to the significant role of rapid evolution in shaping how ecosystems respond to global change.
They examined a dominant coastal marsh sedge to reveal how genetically based variation in a plant’s traits can evolve rapidly and influence a marsh’s resilience to sea level rise. The team used a unique approach, growing “resurrected” plants from decades-old seeds recovered from marsh soils and employing an ecosystem modeling approach. Bridging quantitative genetics and ecosystem modeling, their study highlights the need to consider evolutionary processes in ecological forecasting.
Nytko’s winning research challenges conventional views on plant rarity by suggesting that rarity might often be an evolutionary adaptation rather than a result of environmental constraints. She used data from 25 Eucalyptus species to examine how natural selection influences plant traits that in turn shape plants’ range sizes and habitat needs. Her findings reveal that rare species are consistently smaller than their more common counterparts and that this trait has evolved multiple times across different groups. Her work highlights potential pathways for promoting conservation of rare plant populations.
“This excellence in ecology award from ESA for Alivia is fitting and well-deserved,” said Professor and EEB Department Head Jennifer Schweitzer. “Alivia is such a creative graduate student and this rarity work with Professor Bailey is innovative and has the potential to change how we think about, predict and manage rare species in nature.”
Nytko’s award is named for E. Lucy Braun, an eminent plant ecologist and one of the charter members of the ESA, studied and mapped North American forests and described them in her book, The Deciduous Forests of Eastern North America.
“It is such an achievement that two researchers in the EEB department have been honored for their work in ecology on the national stage,” said Professor Kate Jones, divisional dean for math and natural sciences. “Alivia Nytko winning the Braun Award for Excellence in Ecology and being singled out for her poster presentation at the Ecological Society of America’s annual meeting is a huge honor. It is also fantastic to see my colleague Mike Blum’s work with Megan Vahsen being recognized in this way.”
ESA will present the 2024 awards during a ceremony at the society’s upcoming annual meeting, August 4–9 in Long Beach, California.
by Randall Brown
Collaborations across research disciplines can lead to unexpected breakthroughs and discoveries. Collaborations across species lead to unexpected evolutionary paths of mutual benefit.
For example, some plants have managed to recruit ant bodyguards. They produce sugary nectar on their leaves that attracts the ants, then these very territorial and aggressive ant mercenaries patrol “their” plant and sting or bite herbivores that try to eat it.
These relationships are well-documented in flowering plants, but they also occur in non-flowering ferns. This is weird news for researchers, as it has long been thought that ferns lack the nectaries for such complex biotic interactions.
Jacob Suissa, assistant professor in the UT Department of Ecology and Evolutionary Biology, worked with colleagues at Cornell University, including fern expert Fay-Wei li and ant expert Corrie Moreau, to investigate how this phenomenon developed over the millennia. They recently published findings in Nature Communications about the evolutionary timeline and underlying factors of this interspecies partnership.
“The new elements of this work are twofold,” explained Suissa. “First, we discovered that nectaries—the structures that produce sugary nectar to attract ant bodyguards—evolved in ferns and flowering plants around the same time.”
This happened some 135 million years ago, coinciding with the rise of plant-ant associations in the Cretaceous period.
“This timing is quite spectacular given that it is very late in fern evolutionary history, nearly 200 million years after their origin,” said Suissa. “But it’s very early in flowering plant evolutionary history, nearly at the start of their origin in the Cretaceous.”
The second new element is how it all happened. Ferns originally flourished as terrestrial plants, growing on the forest floor. They transitioned in a major way in the Cenozoic Era, around 60 million years ago, becoming epiphytic, or tree dwelling, plants.
They learned some new habits on their way up.
“We discovered that as ferns left the forest floor and moved into the canopies, either as epiphytes, climbers, or tree ferns, they tapped into the existing ant-flowering plant interactions and evolved nectaries,” said Suissa.
This presents a curious dynamic in the ecological and evolutionary history of these two plant lineages. Ferns and flowering plants diverged from a common ancestor more than 400 million years ago, but then hit their stride in parallel with their nectary evolution and the mutually beneficial ant-plant tradeoff.
“This suggests that there may be some ‘rules of life’ governing the evolution of non-floral nectaries and ant-plant mutualism,” said Suissa. “This work can help future investigations by providing the evolutionary framework or backdrop for ecological, developmental, or genomic analyses.”
Read Suissa’s full paper, “Convergent evolution of nectaries in ferns facilitated the independent recruitment of ant-bodyguard from flowering plants,” in Nature Communications.
by Randall Brown
Post-doctoral researcher Joe Edwards and graduate student Sarah Love, both in the Department of Ecology and Evolutionary Biology, published findings this spring that can save fellow researchers a lot of time and energy when storing soil samples for later study of their microbial content.
The preferred method for storing soil samples for the study of microbes has long been to freeze them to keep the DNA intact for studies that might need to extract information years down the road. The downside is the need to power these freezers and maintain facilities to house them.
Edwards and Love examined a wide array of soil samples in a project funded by the National Science Foundation and the US Forest Service. Their analysis indicates that soil stored under refrigerated or air-dried conditions can still retain the needed information for understanding microbial community composition and structure for many years.
“We wanted to show that these air-dried soils were still useful for understanding soil microbial communities,” said Edwards. “We’re using dried soil microbes from an archived national database to look at long-term, continent-wide spatial patterns in fungal communities and compare those with forest census data from all of those same plots.”
This soil database stores a history of the ecological changes in an area over long periods of time. Researchers want to study these soils with relatively new methods to build a timeline of ecological changes in fungi at the microbial level.
“This microbial sequencing technology has only been around for maybe the last 10 to 15 years or so,” said Edwards. “We don’t have very long-term trajectories for these microbiomes. The cool thing about these archives is that they were sampled more than once, so we have multiple resampling. We can look at how much of that community changes over time and get historical patterns for them, which is something really nobody has done yet.”
The results that Edwards and Love found show that dry-storage soil samples can be extremely useful for studying how soil properties and fungal communities change over longer periods, potentially up to decades.
“What we were saying in the paper is a little nuanced,” said Edwards. “We managed to maintain the environmental variance that was explained in the microbial community. The method isn’t quite as reliable if you’re just trying to track specific taxa of fungi across time. But for looking at broad patterns in community diversity and community composition, it’s useful. We can get a good idea of the overall shape of these communities as they change over space and time.”
Knowing the reliability of available archived information can help future researchers know that their samples will give them the accurate data they need.
Edwards and Love will apply the findings themselves to the next phase of their own soil research: sequencing thousands of air-dried soils from across the country. The information they find can offer important new understanding of long-term, global patterns of change.