by Carolyn Bernhardt
April 14, 2026
“Who doesn't love goats?” says Tiffany Wolf, DVM, PhD. Humans clearly have a longstanding affinity for ruminants, having first domesticated them over 10,000 years ago and relying on them for their fiber, milk, meat, and ability to graze on unwanted vegetation. A decade ago, when targeted goat browsing became something of a trendy (though under-tested) buckthorn removal tactic, a group of University of Minnesota researchers dove headfirst into studying its effectiveness. “Ultimately, their small size, gentle nature, and foraging tendencies—browsing shrubs, trees, and vines—make them a great option for woodland restoration,” Wolf says. “They are also a treat to see for visitors to our local parks, where they're often used.”
For years now, a team of MITPPC-funded experts, led by Wolf, an associate professor in the Department of Veterinary Population Medicine at the College of Veterinary Medicine, and Daniel Larkin, PhD, professor in the Department of Fisheries, Wildlife and Conservation Biology, at the College of Food, Agriculture and Natural Resource Sciences, have been investigating nearly every aspect of goat browsing. Along the way, they’ve searched goat droppings for viable buckthorn seeds after feeding experiments, and even tested co-grazing goats with waterfowl to help mitigate a deer parasite that often infects goats on the shared landscape. But perhaps most importantly, they’ve spent years observing grazed areas, watching the long-term ecological effects of goat grazing slowly unfold.
Their fastidious work has helped move the field away from polarized views that goats are either “good” or “bad” for restoring buckthorn-degraded woodlands toward a middle-ground, evidence-based consensus on goat grazing. In January, they published their latest findings in Restoration Ecology, which showed that the immediate effects of goat browsing “diverged greatly” from its longer-term effects. According to Larkin, these findings suggest that “goats are most effective as an early ‘knockback’ or maintenance tool for opening up buckthorn-invaded habitats, not as a standalone management strategy.”
Clearing the way
The team tested goat browsing in forests across eastern Minnesota, ranging from open oak savannas to dense hardwood stands. At each site, they compared goat-browsed areas to nearby untreated areas with similar vegetation. They found that goat browsing was most effective at quickly (but temporarily) reducing buckthorn and could ultimately support native diversity—but only if the practice is followed by additional control measures and active restoration efforts.
To mimic how land managers use targeted goat grazing, post-doc Katherine Marchetto, master’s student Sara Nelson, and their collaborators tracked the impact of various herds of 7 to 70 goats. The goat herds were fenced into specific patches and removed after they had eaten roughly 80% of the buckthorn. The team then measured how much vegetation the goats removed and tracked plant communities over time, surveying plots before grazing, immediately after grazing, and annually for up to 3 years.
The initial effect was certainly disruptive to the landscape—goats cleared out much of the vegetation, including native species. However, with repeated targeted goat browsing over multiple years, native plant cover, diversity, and richness generally rebounded and, in some cases, even increased.
As usual, buckthorn proved relentlessly resilient. It rapidly regrew, sometimes becoming even more dense in browsed areas than it had been prior to treatment. This finding highlights that goat grazing alone is not a one-and-done solution, but rather a tool that likely works best when used alongside other management strategies, such as herbicide treatments (especially for resprouts), cutting and mechanical removal, and repeat browsing over multiple years. The findings reinforce that, without sustained follow-up, managers risk entering into a revolving door of knockback, regrowth, and reinvasion.
In this study, goats browsed during the growing season, mostly defoliating leaves. However, the team says goats can strip the bark off buckthorn stems in the fall and winter, potentially killing larger buckthorn trees. Further research, they say, would ideally compare different treatment timings and intensities, including both summer and winter treatments.
The study sites did not include reseeding, and native recovery was modest. The post-disturbance window, just after the goats have opened up an area, is also a crucial time for buckthorn reemergence or invasion by other species, like garlic mustard, as invasive plants can exploit the increased light availability. In Nelson’s 2022 master's thesis, she advocated for adding native seed mixes after buckthorn removal, as well as nudging buckthorn-invaded systems from multiple angles.
“So while goats can help create an opening, managers need to fill that opening with desirable plants,” she says, “and put just as much energy into keeping those plants healthy as they do into keeping buckthorn at bay.”
The road to restoration
Larkin says early conversations about goat grazing ranged from seeing it as a “magic” solution to dismissing it entirely, but their research suggests a more balanced view: “They're not a panacea, but they're also not bad.”
As a plant ecologist with a fascination for these horned herbivores, Larkin says the real buckthorn management shift that needs to take place isn’t even really about goats at all—it’s about shifting the ultimate goal away from just killing buckthorn toward restoring diverse, native ecosystems. Goats are a useful tool, as they can temporarily reduce buckthorn without herbicide and in areas that are hard for humans to access. However, Larkin says, successful restoration is never tied to a single method—it is tied to consistent effort and stewardship.
“Our ultimate goal is restoration,” he says, “and that's a multi-phase, multi-year process that requires a lot of sustained effort. The first phase of that is reducing buckthorn abundance, so that you open up the canopy and have more light available for native species.” Goats are one way to tackle this step, but others include cutting buckthorn, applying herbicide to its stumps, and forestry mowing.
“Once things have opened up and the buckthorn has been reduced enough to create a window of opportunity for native vegetation to be restored, then multiple years of seeding with a grass-heavy seeding mix to promote native plant cover and enable prescribed fire can ultimately shift the system out of that dark, moist, buckthorn-dominated condition,” Larkin says.
“Our context here in Minnesota is ecosystems that were historically much more open, and they've undergone decades of fire suppression and afforestation with buckthorn and with other trees,” says Nelson. The result has been an ecosystem shift. So getting rid of buckthorn is key, but she says, “I see removal of buckthorn as one step in the journey to a functional, diverse plant community.”
By remaining dedicated to this line of inquiry for several years, these experts have embodied the long-term commitment they are urging managers to apply to their lands. And over the course of that time, what once seemed like a simple fix—using goats as a novel, or even charming, solution—gave way to a deeper understanding of the ecological complexity at play, from buckthorn’s life cycle to the long history of changes that have shaped Minnesota’s ecosystems.
“The long-term funding support provided by MITPPC through the Environment and Natural Resource Trust Fund was integral in enabling the longevity of research needed to generate these new insights,” Wolf says.
“This is a really complex thing we’re all trying to do,” says Nelson. “Even though we didn’t find that goats are the magic bullet that fixes the woodland, I think we’ve added a key piece of the puzzle.”
The Minnesota Invasive Terrestrial Plants and Pests Center research is supported by the Environment and Natural Resources Trust Fund, as recommended by the Legislative-Citizen Commission on Minnesota Resources.
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More information
- Goat-grazing for invasive plant control, research project
- Goats can play a role in multi-pronged restoration of buckthorn-invaded woodlands, University of Minnesota Research Brief, 2026
- Concomitant impacts of goat browsing on native vegetation during invasive plant control, Restoration Ecology, 2026
- Meet the Researcher: Katie Marchetto
- Meet the Researcher: Sara Nelson