Perspectives Online

Impressive Investigations - Three graduate students' symposium presentations reveal far-flung research efforts.

At the Cape Fear River, zoology graduate student Jessica Brewster displays the catfish that is central to her research.
Photo courtesy Jessica Brewster

The room was dark. A giant insect loomed on a screen at the front of the Blue Room in N.C. State University's Talley Student Center.

The audience of students and professors was quiet, intent: All eyes were on the images Benoit Guenard's PowerPoint projected as he explained his survey of an invasive ant species.

But science, not a giant ant, was on the march at this spring's tenth annual Zoology and Plant Biology Graduate Student Research Symposium. The event is an exchange of graduate students' scientific ideas, research presentations and friendly and supportive interactions with the scientific community.

Plant biology graduate students Brenda Wichmann (top, left) and Caitlin Elam (right), with a canine companion, prepare to study diverse plant communities. Dr. Jon Stuckey (bottom, center) works with Wichmann and Elam.
Photos by Tom Wentworth
Guenard and about 15 other graduate students in the College of Agriculture and Life Sciences' Zoology and Plant Biology departments presented their studies at a March event that also included a poster display.

"Annual graduate student symposia are a hallmark of the nation's finest graduate programs and an important component of the graduate school experience," says Dr. Tom Wentworth, a professor who specializes in plant community ecology in the College's Department of Plant Biology and who advises several student researchers.

Their professors encourage students to present work either orally or as a poster at the symposium, even if the research is only at the questions-and-hypothesis stage. As a result, students gain valuable input on their study design. And if they have collected and analyzed data, they can practice defending their scientific arguments.

Science is what these students love most, and their dedication is noteworthy.

For instance, peripatetic Brenda Wichmann, plant biology graduate student and this year's symposium coordinator, last year visited and plotted out diverse plant communities in roughly 70 mountain bogs in North and South Carolina.

Because they're relatively flat, high-elevation areas, these nonalluvial wetlands - mountain bogs - shelter rare plant species: Gray's lily, the northern green orchid, protected long-stalked holly, to name a few.

And, notes Wichmann, "Preliminary results suggest that the plant communities of these bogs are more diverse than previously thought."

But a growing, choking ring of home (or other) developments threaten many high-country bogs - including one of Wichmann's study sites: Tater Hill in Ashe County near West Jefferson. She also worked at Sugar Mountain and nearby Pineola bogs, which make up the state's new protected Mountain Bog Natural Area, home to unique lilies and threatened species like the purple leaf willowherb, the bog rose and the bog fern.

Here's Wichmann's field research routine: Hike in with backpack full of tools and gear, bushwhack - often through thick rhododendron walls and mucky ground - lay out a 10-by-10-meter grid, work in from the corners to log the frequency of species, measure the size of shrubs, saplings, trees. Extract a soil sample and core. Repeat as often as necessary.

While some might characterize such drudgery as boring, to Wichmann and her graduate school colleagues, it's worth it.

"These bogs contribute significantly to the regional plant species pool and are floristically diverse, containing both northern and coastal plain species," she says. "Many of North Carolina's imperiled vascular plant species depend on these unique ecosystems for survival." Vascular plants - ferns, clubmosses, horsetails, flowering plants, conifers and others - use specialized tissues to conduct water, minerals and photosynthetic products through their systems.

Wichmann works with Wentworth, her major adviser, and with Drs. Robert Peet, UNC-Chapel Hill biology professor and ecology curriculum chair, and Dr. Ted Shear, research professor in N.C. State's Forestry Department. Her project is funded by the N.C. Department of Environment and Natural Resources' Ecosystem Enhancement Program and the Carolina Vegetation Survey.

"Brenda's work is important because it will provide the first comprehensive inventory of natural communities and flora of our southern mountain bogs," Wentworth says. "The results of her work will be of interest from an academic perspective, but also will inform conservation and restoration of these rare and imperiled species."

Caitlin Elam, Graduate Student Association representative in plant biology, also spends time mucking about in bogs, but hers are down east.

Elam, who in April was named an outstanding teaching assistant for 2006 in her department, works with Wentworth; Dr. Jon Stuckey, associate professor, who specializes in biology of rare plants and wetland ecology; and Dr. James Gregory, professor of forestry, College of Natural Resources.

In a plant biology lab, graduate student Wade Wall (left) confers with Wichmann (center) and Elam
Photo by Tom Wentworth
She's studying and inventorying the number, distribution and relationships of plant species around the Weyerhaeuser Co.'s Cool Springs Environmental Education Center (CSEEC) between Kinston and New Bern. So far, she's noted the obvious swamp vegetation, as well as some botanically varied small-depression wetlands, and one possibly new woodland plant community that includes loblolly pine and Darlington's oak.

Elam has comprehensively inventoried vascular flora at CSEEC: 400 species in 100 plant families, including documentation of several rare species such as Pondspice and Coastal goldenrod. She also identified 12 distinct plant communities and their soil associations at the center, including the uncommon Longleaf Pine Savanna and Bald Cypress-Tupelo Gum Swamp.

"The high diversity of plant communities reflects the high diversity of soil types, ranging from excessively drained deep sands to large wetlands with very poorly drained organic soils. Documentation of the flora and natural communities at CSEEC will inform land management decisions and future ecological and biological studies," Elam says in an abstract.

Between mountains and coast, Jessica Brewster is trying to determine the "Trophic Relations of Introduced Flathead Catfish in a North Carolina Piedmont River." The large carnivorous catfish, introduced to the Atlantic Slope from the Mississippi River Basin, reportedly cause native fish population declines.

However, Brewster has determined that the catfishes' trophic preferences - their diets - vary by season, river habitat and fish size. Significantly, they prefer sunfish and mayflies, but coexist with and don't eat rare and imperiled fish such as the Carolina redhorse and the endangered Cape Fear shiner. Contrary to previous speculation, she has found that the catfish feeds rather randomly, regardless of prey species, water depth and habitat complexity.

"Working with an introduced species is very interesting, because I was able to look at how an invasive species competes with native fish both for food resources and through direct predation," says Brewster. "This was an ideal thesis project for me, as I spent summers working on the Cape Fear River, handling large carnivores and making a difference in our aquatic resources."

Brewster works with Dr. Thomas Kwak, associate professor of zoology and unit leader of the U.S. Geological Survey's N.C. Cooperative Fish and Wildlife Research Unit at N.C. State, who highlights the ecological importance of Brewster's research.

"Flathead catfish are among the most detrimental aquatic species introductions in North America," Kwak says, "and state and federal agencies are anxious to apply Jessica's results toward improved understanding and management of the situation. She is the first to combine observational and experimental approaches to study trophic relations of the species."

Back in the Blue Room, Benoit Guenard wraps up his talk with a reassuring finding of his own: In the lab, an invasive East Asian ant (Pachycondyla chinensis) could and would dominate another invasive ant species, but not a native ant species.

Feeling perhaps somewhat safer, the students pack up their notebooks and laptops and depart for the poster session just beginning in the Brown Room next door.

And science marches on.