Biology student tackles big invasives problem

“Going up and down back roads, you see it lining the roads. It’s a very difficult task removing it. And it seems almost hopeless because there’s just so much of it,” he said.

Paul is a fourth-year biology student in UC’s College of Arts and Sciences. For his capstone project, he is working with Professor Denis Conover to study more effective ways to eliminate honeysuckle without using pesticides.

He and his classmates have been helping Conover remove honeysuckle from a patch of woods at the Evergreen Holistic Learning Center near Winton Woods. Owner Kate Nordyke worked with Conover on botanical surveys in Cincinnati.

Conover volunteered to help her remove honeysuckle on her farm, where she does not use herbicides.

Paul said he has become expert at identifying honeysuckle from its bark, even without its telltale leaves. For his project, Paul uses a chainsaw to cut honeysuckle bushes at their base. Then he covers their bare stumps with a black plastic bag held down by garden staples to rob the honeysuckle of life-giving sunlight that would help it regenerate new shoots.

Paul hopes to compare 100 covered stumps to 100 stumps that aren’t covered to demonstrate the efficacy of the plastic bags.

“Our hypothesis is that if it’s covered, it will not regrow. But if you leave it uncovered it will regrow,” he said.

Like a lot of students at UC, Paul wasn’t sure what major he wanted to pursue, so he took part in UC’s Exploratory Program to see what he liked. He took some business classes but really liked his science classes and decided to pursue biology with a predental track. 

“Dentistry has always been in the back of my head with my dad being a dentist,” he said.

Paul said he had memorable visits to national parks such as Yellowstone, Grand Teton and Arches.

“I enjoy learning about nature. I’ve always loved wildlife. Through meeting Dr. Conover and having some classes, I’ve gained an appreciation for plants as well,” he said.

Conover is teaching a class this spring on wildflowers and trees of Ohio. This fall he will teach an upper-level course on identifying flowering plants. Both classes feature a lot of time outdoors, he said.

First introduced to the United States from Asia in the 1890s, honeysuckle was imported by horticulturists as a popular ornamental bush. The plants produce copious red berries that birds eat, spreading seeds that helped honeysuckle escape cultivation. Today, it’s considered one of the most widespread invasive species in the United States. But in Ohio it wasn’t until 1961 that Amur honeysuckle was showing up as an escapee, Conover said.

In her 1961 book “Woody Plants of Ohio,” famed UC botanist E. Lucy Braun wrote that Amur honeysuckle was starting to show up in forests and other untended parts of Hamilton County, Conover said.

Honeysuckle outcompetes many native plants because it leafs out earlier in the spring and stays green longer into the winter, shading out other plants, Conover said. Its allelopathic properties wage a sort of chemical warfare in the soil that discourages competitors from growing nearby, he said.

“You can see the buds are fat already,” Conover said while cutting honeysuckle one Saturday morning in early March. Many other trees were still in winter dormancy.

In place of the removed honeysuckle, Conover and his students are planting dozens of native plants, including red bud, oak and chokecherry. Honeysuckle has been a scourge to Eastern forests, Conover said.

“If you lose your native plants, you lose the base of the food web. Then you lose all your native caterpillars feeding the birds. It’s really devastating,” he said. “We’re focusing on native oaks, birches, cherries. They provide a lot of food for native insects, particularly caterpillars.”

UC environmental studies student Tierney Shafer said she took part in the project to learn more about ways to eliminate honeysuckle without using chemicals such as the common herbicide glyphosate.

“I was really interested in that because I have a lot of honeysuckle in my own yard that I’m trying to remove,” she said. “And the idea of doing that without dumping a lot of chemicals on the soil was appealing to me.”

Shafer said the project gave her a greater appreciation for how impactful honeysuckle can be.

“Seeing so much honeysuckle is really intimidating. But it’s also exciting to tackle it and see how much space you can take back,” she said.

Paul plans to give a poster presentation on the honeysuckle project at UC’s Undergraduate Scholarly Showcase at Tangeman University Center in April.

Paul said he hopes his work will make a difference however small.

“We hope that the native seeds we plant will become established and take over the honeysuckle,” he said.

Featured image at top: UC biology student Griffin Paul is studying better ways to remove Amur honeysuckle without using chemical herbicides for his senior capstone project. Photo/Kallista Edwards/UC Marketing + Brand