If you drive behind the intramural fields on Mason’s Fairfax Campus, you may notice a fenced-in grassy area with numerous big black tubs planted with various kinds of wetland vegetation.
The scientific experiments being done in this outdoor facility are the products of Mason ecological engineer Changwoo Ahn  and his students.
An associate professor in the Department of Environmental Science and Policy, Ahn studies human-created wetlands that mimic the benefits of ecosystem services of natural wetlands.
As more and more natural wetlands and habitats are destroyed because of human development and construction, it is vital for ecological engineers such as Ahn to determine the best way to re-create these habitats to maintain diverse, healthy, and productive wetlands, thus minimizing the impact of climate change and other environmental hazards.
The Ahn Wetland Ecosystem Laboratory  compound on Mason’s campus is just the beginning of what Ahn hopes to accomplish here. As a graduate student at Ohio State University, Ahn helped create the Wilma H. Schiermeier Olentangy River Wetland Research Park, a long-term, large-scale wetland research facility in Columbus, Ohio. With that experience under his belt, he hopes to continue to build and expand the outdoor research possibilities at Mason.
“My intention is really to maximize the use of this facility for students and allow them to have this amazing outdoor experience,” says Ahn.
The wetlands complex has been fully functional for two years, and it not only provides valuable opportunities for students to learn, but also allows for externally funded scientific research. The facility focuses on the type of wetlands found in Virginia and the Chesapeake Bay area.
“What if a coastal area is flooded from a hurricane or storm? What if we receive an extreme drought for a longer time than we expected—how would that affect communities in coastal areas or near wetlands? We can do that kind of experiment here in the compound with confidence,” says Ahn, who is the associate editor and book review editor for Ecological Engineering: The Journal of Ecosystem Restoration.
A mentor and a teacher as much as a researcher, Ahn is committed to bringing scientific experiences to students. He participates in Mason’s research apprenticeship program for undergraduates and has been a mentor for Project SEED at the American Chemical Society. Through these mentorships and internships he provides voluntarily at the wetlands lab, he is able to bring high school students to Mason to work directly with wetlands research projects and gain valuable hands-on learning experiences.
His students monitor and record water levels, help plant and harvest the various mesocosms in the facility, and work closely with him to interpret results. Ahn also teaches an undergraduate course, Ecological Sustainability (EVPP 378/BIOL 379), that uses the resources of the outdoor compound. The course was designated as a Green Leaf course by Mason’s Sustainability Office, which recognizes course offerings that contribute to students’ understanding and practice of sustainability.
Ecological Sustainability students helped Ahn put in some additional plants for an upcoming experiment. Support for this course came from Mason’s Students as Scholars Program, the university’s Patriot Green Fund, and Jeffress Memorial Trust.
Ahn and his research team of students are currently conducting a biodiversity study that looks at how the diversity of plants affects the productivity of a human-created wetland.
“There is a question in ecology: is productivity better or diversity better?” says Ahn. “If we restore a wetland, is it better to have just one single plant that does really well reintroducing carbon back into the soil and fights against global warming, or is it better to have another system that has a bit less productivity but a higher diversity of species and therefore provides more diverse habitats for a variety of organisms?”
Just as financial experts weigh whether to diversify their portfolio or invest all their money in one single stock, the ecological engineer has to determine whether it would be more beneficial to add variety to a human-created wetland or put all their resources into one species of plant. Both are beneficial—though neither one compares with a natural wetland that has been working in harmony for 100 years.
“Through work we’ve been doing, we’ve seen there is an age trajectory in wetlands. Meaning that older restored wetlands behave more like natural wetlands in terms of organic materials, soil processes, and such, which are important in delivering ecosystem services,” says Ahn. “However, younger created wetlands are still very different from natural wetlands. Time is certainly necessary to this, but we want to facilitate and speed up that process—and these types of studies help give us more information.”