Dunn's Woods Project
IU faculty, students and community step up effort to protect Dunn’s Woods
August 20, 2012
Significant progress is being made in an effort to eradicate the invasive purple wintercreeper plants that have carpeted IU Bloomington's iconic Dunn's Woods for decades, crowding out native plants and degrading the forest ecosystem.
IU faculty, staff, students, and community volunteers have spent hundreds of person-hours pulling the invasive plants by hand, without making much of a dent. So this month, a dozen people donned protective gear and sprayed the remaining wintercreeper vines with herbicide.
As the plants die, IU scientists and community partners will step up efforts to re-establish native plants at the site, putting into practice lessons they have learned from forest ecology research.
"Now the hope is that we can go from pulling to planting," said Heather Reynolds, associate professor of biology in the College of Arts and Sciences, who with her students has worked on and studied invasive species control and native plant restoration in Dunn's Woods and elsewhere.
Dunn's Woods, a 10-acre woodland at the site where Indiana University was established in the 1880s, is often credited with giving the campus much of its bucolic charm. The effort to protect and restore the woods brings together IU biologists, historians, landscapers, and community organizations–including MC-IRIS (Monroe County Identify and Reduce Invasive Species), southern Indiana's Sassafras Audubon Society and the Bloomington Parks and Recreation Department.
An IU sustainability research development grant in 2010 helped boost the effort to combine research, teaching and outreach regarding Dunn's Woods. This year, the initiative was awarded a $18,664 Toyota-Audubon TogetherGreen grant to support work at Dunn's Woods and at Latimer Woods, a similar woodland managed by the city on the east side of Bloomington.
While a number of invasive plants are found in Dunn's Woods, by far the biggest problem is with purple wintercreeper (Euonymus fortunei), a woody, vining plant native to East Asia. Widely used in landscaping as a ground cover, the plant can spread aggressively, forming dense mats of vegetation.
It crowds out native plant species, disrupting the food web of insects, birds, mammals, and other species that evolved to depend on native plants, reducing biodiversity and weakening the capacity of the ecosystem to perform services such as carbon storage and water conservation.
From research by project historians Jim Capshew and Anita Bracalente, it appears that wintercreeper invaded Dunn's Woods sometime after the 1950s or 60s as a result of its use in campus landscaping. It eventually took over the forest floor.
"I came here 23 years ago and I was horrified. I had never seen a place so covered in wintercreeper," said Ellen Jacquart, an invasive plant expert with The Nature Conservancy and a founder of MC-IRIS.
Volunteers have been hand-pulling the wintercreeper for over a decade, and in recent years, dozens of people have taken part in weekly pulling sessions. The process is effective but painstakingly slow. Organizers estimated their years of effort had cleared about 0.3 acre, out of approximately five acres in Dunn's Woods that were seriously overgrown with wintercreeper. So on Aug. 1, they sprayed the remaining plants with triclopyr, an herbicide that targets broad-leaf weeds with few long-term effects; the chemical breaks down in the soil in 30-90 days.
The dense, green vines will turn brown as the plants die off this month. This winter, the woods will be checked again to see if the eradication was effective and if additional spraying or hand-pulling is needed. Meanwhile, the group will be working to replace the invasive plants with native species.
"There has been a lot of ecological research going on in the woods for some time," Reynolds said. "That has helped guide the restoration that we are doing."
Studies by Reynolds and her students have examined the relationship between plants, soils and microbes, leading to better understanding of the interactions between native and invasive plants.
Jonathan Bauer, a biology Ph.D. student with Reynolds, has established small experimental plots in Dunn's Woods to study what happens once wintercreeper is eradicated. He has shown that native plants tend to do better if they are planted as seedlings rather than if they are started from seeds in the woods. But if native plants are not introduced, areas tend to go back to wintercreeper or other invasive species.
Reynolds and Bauer have been working with IUB Volunteers in Sustainability and other student and community volunteers to grow thousands of plants at the IU Greenhouse at Jordan Hall for eventual planting in Dunn's and Latimer Woods. This summer alone, sustainability intern Hayley Prihoda led dozens of volunteers in planting more than 700 native seedlings in the woods. All of the plants are native woodland species, including cardinal flower, wingstem, white snakeroot, great blue lobelia and hairy wood mint. Plantings of cardinal flower have already attracted hummingbirds to the woods.
Another thrust of the Dunn's Woods project is to raise awareness of the problems caused by invasive plants and encourage people and institutions to use native species in landscaping. If nothing else, it's a safe bet that the students who spend hours on hands and knees, tugging at stubborn wintercreeper vines, will be careful what they plant on their own property.
To learn more about the Dunn's Woods Project, to keep abreast of volunteer opportunities, and to follow the project's progress, visit the IU Office of Sustainability's Dunn's Woods Restoration Project website.
A student walks along a path through Dunn's Woods.