Goats may very well be the greatest of all time—GOATs, literally and figuratively!—when it comes to controlling the spread of invasive buckthorn. Easy to transport, able to access dense growth areas where humans and machines can't easily go, goats are a nontoxic replacement for harsh chemicals used in eradication efforts.
Invasive buckthorn is particularly tough to address because it has few natural deterrents, says Sigrid Resh, research assistant professor in the College of Forest Resources and Environmental Science (CFRES) and coordinator of the Keweenaw Invasive Species Management Area (KISMA).
In general, invasive species often lack competitors, predators, and diseases. In the case of glossy buckthorn, "native herbivores and insects avoid it, further aiding its expansion," says Resh. "Eventually, it crowds out most native species, and as it replaces native plants, it reduces the food supply and shelter options for native species."
Resh says goats can play an important role in glossy buckthorn remediation in the understory. "They eat almost anything, so they're perfect in those areas where native plants struggle in dense infestations."
Because goats have expansive digestive tracts, the seeds they ingest don't germinate after being passed. It's also helpful that goats trust people and keep to the herd, making them easy to manage. They can shelter for days or weeks at grazing sites.
Goat remediation projects are a key experimental tool for KISMA, one of 22 cooperative invasive species management areas (CISMAs) in Michigan. CISMA coordinators use outreach and education to prevent and manage invasive species across land ownership boundaries.
KISMA goes beyond invasive species removal, restoring native plants to habitats to add food sources and habitats for pollinators, helping to increase forest ecosystem resiliency by increasing biodiversity.
Enjoying the Goats in Action
KISMA has been funding goat remediation at Swedetown Mountain Bike and Ski Trails in Calumet, Michigan, for two years under a USDA Forest Service Great Lakes Restoration Initiative in partnership with Swedetown Trails Club and Calumet Township. As a result of their visits, the goats have cleared a four-acre section of buckthorn near the recreation area's chalet. Resh and the KISMA team monitor the goats' work in test plots. They measure soil, vegetation, insect herbivory, and bird impacts resulting from both goat and buckthorn presence, and conduct creative frequency tests.
For example, after goats enjoyed their first buckthorn meals in late spring, researchers wanted to see if a second round of munching would accelerate the remediation. Lacking the funding to bring the goats back more than once per summer, Resh improvised. Students from the CFRES Earn and Learn program manually snipped the buckthorn growth a second time during the summer. This second round of buckthorn leaf area removal will continue for two more Septembers in a subset of the goat browsing area.
Resh thinks this hybrid effort might show improved remediation in comparison to a one-time goat-only process, and hopes funding can be secured to bring the goats back next year for a final round of munching, followed by human pruning. Afterward, the KISMA team will review the data they've collected. Will this combined effort dethrone goats as the GOAT? Stay tuned!
Other Solutions on the Horizon?
Resh is constantly looking for new ways to remediate buckthorn, including collaborating with Carsten Külheim, associate professor in CFRES, on the possibility of introducing recombinant rDNA or messenger RNA as a means of vaccinating the buckthorn. The process would involve injecting a small piece of genetic code into the invasive plant, instructing cells to grow when they would normally be dormant, expending all their energy and dying.
She's also exploring artificial intelligence and robotics to help tackle three remediation challenges: how hard it is to manually uproot tenacious buckthorn, the difficulty volunteers have identifying the plant, and preventing misidentified native plants from being pulled.
AI could be used to identify the plants. And, Resh is in the early stages of working with computer and mechanical engineers to explore the possibility of developing a robot that could wrench buckthorn from the ground. As future solutions take shape, the goats will retain their title—for now—with no danger of losing their popularity with visitors.
Michigan Technological University is a public research university founded in 1885 in Houghton, Michigan, and is home to nearly 7,500 students from more than 60 countries around the world. Consistently ranked among the best universities in the country for return on investment, Michigan’s flagship technological university offers more than 120 undergraduate and graduate degree programs in science and technology, engineering, computing, forestry, business, health professions, humanities, mathematics, social sciences, and the arts. The rural campus is situated just miles from Lake Superior in Michigan's Upper Peninsula, offering year-round opportunities for outdoor adventure.
