Archives for November 2017

50th Anniversary of Island Biogeography Studies

November 9, 2017 by wpeeb

In honor of the 50th anniversary of the seminal Simberloff and Wilson island biogeography studies, the Bulletin for the Ecological Society of America published a special extended edition of their “Paper Trail” series in October. In this series, young researchers tell stories of how a particular paper influenced them, and the original authors of the papers in turn describe their experiences with the paper.

For this special edition, a collection of researchers, ranging from graduate students to full professors, describe how the Simberloff and Wilson 1969 papers influenced their careers. From our department, Jeremiah Henning, Jordan Bush (graduate students), Christy Leppanen (lecturer and post doc), and Kimberly Sheldon (assistant professor) all contributed to this section. Dan Simberloff and Edward O. Wilson then wrote a reflection on the original paper, complete with photographs and stories from the mangrove experiments.

A Pioneering Adventure Becomes an Ecological Classic: Editor’s Note
(overview, by Young, Stephen L.)

A Pioneering Adventure Becomes an Ecological Classic: The Arising and Established Researchers
(Authors: Henning, Jeremiah A.; Leppanen, Christy; Bush, Jordan; Sheldon, Kimberly S; Gotelli, Nick; Gravel, Dominique; Strauss, Sharon)

A Pioneering Adventure Becomes an Ecological Classic: The Pioneers
(Authors: Simberloff, Daniel; Wilson, Edward)

Kwit Featured in Podcast

November 8, 2017 by wpeeb

Assistant Professor Charles Kwit was featured in the November 4 podcast of Tennessee Farm Table, entitled “The Wild Persimmon of Appalachia.” He starts talking around 2 min 25 sec into the podcast. He talks about the biology of the native persimmon, Diospyros virginiana.

Fire Sparks Life

November 6, 2017 by wpeeb

In late November of 2016, a single spark started a fire on a mountain in the Great Smoky Mountains National Park (GSMNP) that quickly became one of the largest natural disasters in the history of Tennessee. When it was finally over, the wildfires burned close to 18,000 acres in and around the Park, destroyed over 2,400 buildings, and claimed 14 lives. They were the most deadly and destructive wildfires in the Southeastern United States in 2016.

For faculty in the Department of Ecology and Evolutionary Biology, the fires sparked unique opportunities for ecological research and discovery from fungi and soil microbes to plant communities and invasive ecology.

Fungi play two roles in the environment. They decompose organic matter and return nutrients to the soil. Fungi also have a symbiotic relationship with plants and provide them with essential minerals and water in exchange for sugar.

“Fungi are an understated, but essential part of the environment,” says Professor Karen Hughes, who is working with colleague Brandon Matheny and a team from the University of Illinois to understand why a completely new group of rapidly growing “fire-response” fungi are appearing.

Fires are rare in the Smokies, since 1934 when the National Park Service established the GSMNP, mainly due to a change in perception of fire and its role in ecosystem health. The high-intensity fires that raged through the Smokies destroyed most fungi in the fire zones, which gives Hughes and her team an opportunity to study new “fire-response” fungi which appear after the fires and if they are different from those in the Western United States where fires are more common.

“We are identifying fire-response fungi that may be ‘new to science’ and documenting other fungi that are enhanced rather than destroyed by fire,” Hughes says. “The health and recovery of the forest depends on fungi being restored to the soil. The normal processes of decomposition and symbiosis must be re-established if forests are to recover.”

The soil these fungi grow in is the focus of Jen Schweitzer’s research in the Smokies. With exploratory funding from the UT Office of Research, Schweitzer, an associate professor in EEB, Hughes, and other researchers from UT’s Department of Civil and Environmental Engineering are examining soil properties and processes in sites ranging from non-burned areas to areas with low-, medium-, and high-intensity burns.

“Our research is focused on the dual impacts, together and in isolation, of the effects of fire and urbanization on soils, soil microbial communities, and soil-plant interactions,” Schweitzer says.

Fire and urbanization are two widespread disturbances that are increasing due to climate change and the growing number of people living in cities. Researchers, however, rarely have a chance to examine their effects together. The proximity of Gatlinburg to the Smokies provides Schweitzer and her team a unique opportunity to study the impacts. Most of what researchers understand about fire is based on studies in the arid Western United States, but the results will most likely differ from studies in the mesic areas of the Southeastern United States.

“An additional opportunity with these sites in the urban-wildland fire gradient is to examine the independent and combined roles of fire and urbanization as selective forces on plant evolution,” Schweitzer says. “There is almost no information about population-level evolutionary responses to these disturbance events. With increasing disturbance around the globe, understanding the long-term evolutionary consequences of fire on plants is critical.”

Understanding what happens to plant communities after a fire event is exactly what Mona Papeş is out to discover. Will the native plants be more successful or will there be more invasive plants in the burnt areas? It is a matter of adaptation and dispersal.

“The fires burned different areas with different intensity,” says Papeş, assistant professor in EEB. “The basic goal is to understand how fire affects plant communities in terms of number and abundance of species.”

In areas of high-intensity burns, the forest canopy changed from completely closed to completely open. This affects the amount of sunlight that reaches the forest floor, which in turn, affects the types of plant communities sprouting up after the fires. Papeş and her team are assessing and comparing the recovery of plant communities in the low-, mid-, and high-intensity areas to reference unburned sites, with the goal of documenting any shifts in the plant communities.

“We are interested in the number of plant species, as well as the abundance of species,” Papeş says. “This will allow us to forecast the trajectory of understory plant communities under different intensity fires in the future, which may or may not affect how we use fire as a forest management tool.”

The devastation of the fires still hangs in the air for many people who call the area around the Smokies home. If there is one lesson learned, it is that nature is resilient, and in the Park, it is making a comeback. Whether it will look the same in the future is still an unknown, but EEB researchers are rolling up their sleeves and digging in to find out.

Noise Pollution and Songbirds

November 6, 2017 by wpeeb

Derryberry (center, back) identifying songbirds during a workshop with middle-school students.

A songbird belting out its song – whether from the top of a tree in a forest or on a street corner downtown – is what motivates new Assistant Professor Elizabeth Derryberry’s research program.

“People always smile when I tell them my lab studies bird song and then immediately ask if I can identify this one bird that always wakes them up in the morning,” Derryberry says.

Apart from its general appeal to the public, bird song is a fascinating behavior with many parallels to human language.

“Many birds learn their song, just as children learn their words: from their parents,” Derryberry says. “A bird’s song has become an important model for how traits can change through mistakes and innovations made across generations – known as cultural evolution – not just genetic changes.”

Because cultural evolution can happen much more rapidly than genetic evolution, researchers use culturally evolving traits to measure rapid responses to environmental change. Derryberry does just that in her lab by examining how songs change in response to noise pollution, which is a global issue.

Over the past five years, she has studied the effects of noise pollution on song, using a common songbird that persists in the urban parks of San Francisco – the white-crowned sparrow. Her group finds that songs have increased in pitch and become narrower in their frequency range over the past 30 years. Birds hear these songs at greater distances in low-frequency urban noise. These changes come with a cost, however, as female sparrows prefer songs with a broader frequency range, most likely because such songs are more difficult to produce.

White-crowned sparrow male singing above the din in San Francisco

“One of the best parts of this project was that I had the opportunity to conduct an experiment to test whether cultural evolution really can explain these changes in song over time,” Derryberry says.

In her lab, she raised nearly 50 baby songbirds over two years in different noise environments and demonstrated that birds preferentially learned songs least masked by noise in their environment. Once they learned that song, however, they did not change it even when their noise environment changed.

“Let’s just say that feeding 50 baby birds every half hour dawn to dusk was good training for developing a work-life balance,” Derryberry says.

As her team worked in the field setting of urban San Francisco, heat waves were a serious issue. The fact that heat waves are increasing in frequency and magnitude across the globe has inspired a new line of research in Derryberry’s lab. Her team, along with former postdoc and collaborator Ray Danner at UNCW, is now studying how heat stress affects singing and mate choice behaviors in songbirds.

“Our initial findings are really exciting, and suggest both cognitive and motor impairment at temperatures experienced in current heat waves,” says Derryberry, who looks forward to pursuing these questions at UT as the research breadth and strength of the department promises many great collaborations.

Researching Animal Behavior

November 6, 2017 by wpeeb

By her senior year Hannah Anderson, an EEB major, had already been involved in several projects. She started in the Riechert Lab where she continues to maintain a large population of spiders under the guidance of graduate student Angela Chuang. Frequently left in charge of the lab in Angela’s absence, Hannah has been learning many of the more practical concerns required for maintaining a living population in a lab setting and the process of collecting living samples.

Hannah has also been involved in a project in the Simberloff Lab exploring the behavior of the native green anole and responses to the invasive brown anole. Though her time on this project was relatively brief, it provided invaluable knowledge regarding the study of animal behavior in a natural setting and the complications therein. The grant application process and protocol review by the Institutional Animal Care and Use Committee (IACUC) also gave Hannah additional experience.

Hannah did not stop there. In the fall of 2016, she took a Comparative Animal Behavior lab, where groups work together to create research projects. Though the class is over, Hannah has not let the project end. With the help of Professor Todd Freeberg, Hannah works directly with graduate student Johnathan “Alex” Grizzell and uses all of the experience she has gained up to this point to help design a field experiment exploring the behavioral responses of native birds to anthropogenic noise. During background research, Hannah noticed something odd in the scientific literature: though there had been many studies on the effects of anthropogenic noise on various organisms, most of them used modulated white noise as a replacement for anthropogenic noise. There were virtually no studies, except for one on frogs, that tested whether or not white noise was a suitable replacement for anthropogenic noise. Using a playback experiment, Hannah is attempting to prove that the two are not equivalent when it comes to Carolina chickadees and tufted titmice. Hannah intends to use her experience as a fully involved data gatherer and data coder for further research and to publish before she enters graduate school.

Fire Impacts on Species Richness

November 6, 2017 by wpeeb

After spending nearly six years at Oklahoma State University, Assistant Professor Monica Papeş has traded the Cross-Timbers and Great Plains ecoregions for the Appalachians and Blue Ridge ecoregions by joining EEB in January 2017. Consequently, her regional research focus has shifted to the Great Smoky Mountains National Park, where Papeş and her master’s student Mali Lubic are beginning to investigate the effects of the 2016 fires on understory plant communities.

The US Forest Service classified the fire intensity from Landsat satellite imagery into three categories: low, medium, and high. High-intensity fires are more likely to occur after extended periods of fire suppression, which is the case in the national park. This study will compare plant species richness and abundance on sites selected across regions of low, medium and high fire intensity to unburned reference sites. The main objective is to determine whether significant differences exist in plant community changes across the fire gradient as these communities recover from the fire. This work is part of a larger EEB initiative to investigate the effects of the 2016 fire on organisms and ecosystems in the park.

On a much broader scale, Papeş is investigating the use of satellite imagery to map tropical forest diversity. This project makes use of data collected by a NASA experimental sensor, Hyperion. This is the only satellite sensor that records the amount of light reflected off the surface of Earth in hundreds of narrow spectral bands. This type of data allows identification of tree species and measuring vegetation diversity from space. The goal of this project is to identify areas of high species richness that could be targeted for conservation.

Moving to UT has been a remarkable career advancement for Papeş. Through a partnership between EEB, geography, and NIMBioS, Papeş has the unique opportunity to establish and direct a shared facility centered on spatial analysis: Spatial Analysis Lab (SAL). Spatial analysis makes use of geo-referenced data to visualize and study processes (for example, species’ geographic ranges; the spread of a disease; optimal size of a protected area). The SAL will be open to all UT faculty and students and will be fully operational by the end of 2018.

Papeş’ research interests focus on understanding species’ distributions from local to continental scales. This fundamental question has applications in diverse fields, such as biogeography, biodiversity conservation, and global change. EEB faculty are a dynamic and diverse group that excel in these fields.

November 2017

Archives for November 2017

Graduate Student Spotlights

EEB Students in the News