Riley Thoen grew up in Bloomington, Minnesota, a suburb of Minneapolis, in a family shaped by rural roots. Both parents were raised in farm country before choosing a more urban life. Thoen found a way to bridge those worlds, returning often to rural landscapes through fieldwork in plant ecology.

“I was fascinated by the plant diversity in rural areas,” Thoen says. “But seeing those landscapes fragmented by agriculture sparked my interest in conservation and how we protect these species for the future.”

Thoen will graduate this week from the Franklin College of Arts and Sciences with a Ph.D. in plant biology.

At Franklin, Thoen joined the lab of Megan DeMarche, associate professor in the Department of Plant Biology. Under her mentorship, he focused on granite outcrops in the southeastern United States, ecosystems that support rare species adapted to thin soils and extreme conditions. These sites include places such as Stone Mountain.

“In the case of granite outcrops, they have historically been quarried, which has destroyed considerable habitat for Porter’s sunflower and other endemic species,” Thoen says.

That work led to a clear finding. Populations of Porter’s sunflower respond poorly to drought. Climate projections suggest that native populations in Georgia could face extinction by the end of the 21st century. Studying species in decline made the effects of climate change immediate.

“This research connects directly to my desire to inform conservation,” Thoen says.

Graduate school also brought challenges, especially with writing. For a time, progress on papers and the dissertation stalled. A turning point came through persistence and work as a teaching assistant in the Writing Intensive Program.

“Reading students’ writing helped me overcome my own struggles and pushed me toward teaching at the college level,” Thoen says. “I feel like I have something to offer students because I have been through that process.”

That experience changed how Thoen approached writing.

“There’s nothing I like more than reading a student’s work and feeling their passion through the page,” Thoen says. “It pushed me to write about my research with the same passion I have for conservation.”

Fieldwork brought its own lessons. Early on, Thoen counted the wrong plant species and only realized the mistake when the plants flowered. In another project, seeds from one site were buried at another, which required hours of excavation and reburial. At the time, each error felt significant. Over time, they became part of learning how to conduct careful science.

“In hindsight, these experiences are similar to the problems that native plant populations face,” Thoen says. “We need to understand whether populations can recover from setbacks, and if they cannot, how to support them with appropriate conservation action.”

After graduating, Thoen will begin a postdoctoral position in the lab of Daniel Anstett at Cornell University. The research will examine how extreme drought affects the genomic health of native plant species.

Looking ahead, Thoen plans to pursue a faculty career at a primarily undergraduate institution, where teaching and research are closely linked. The goal is to lead a research lab while teaching courses in ecology and evolution and to prepare students to address environmental challenges.

Thoen’s work reflects urgency and purpose, grounded in careful research, mentorship and a commitment to conservation.