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Invasive species, whether plants or animals, can devastate local ecosystems—think of the invasive weeds eroding Texas habitats. In Minnesota, buckthorn (Rhamnus cathartica) has long threatened native forests, prompting foresters and park managers to battle its spread for centuries.
Introduced as an ornamental plant in the late 1800s, buckthorn’s rapid growth and hardiness turned it into a formidable invasive. It forms dense thickets that eclipse native plants and disturb wildlife corridors. Conventional removal—cutting, herbicides—often falls short because of its deep root system and seed bank that can remain dormant for years.
Recent research brings fresh optimism. Dr. Michael Schuster of the University of Minnesota’s Forest Resources Department has spent decades examining buckthorn. Together with colleagues, he compiled a practical guide for land managers, revealing that the plant’s toughest opponent may be native species thriving in Minnesota’s own landscapes.
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Minnesota’s native grasses and wildflowers can outcompete buckthorn, which gains a critical advantage by retaining leaves into late fall. By removing mature buckthorn and rapidly establishing fast‑growing natives such as Virginia wildrye, managers can shade out the invasive, cutting off the late‑season light it relies on.
“It’s a race against time,” Dr. Schuster told the Minnesota Star Tribune. “When we quickly establish a dense grass layer, we can shade buckthorn just as it needs light most.”
Schuster’s latest work also underscores the power of controlled burns. One challenge of fire is the lack of fuel where buckthorn has been removed, but native grasses fill that gap. The grasses not only reduce light but also provide ideal fuel for prescribed burns that suppress buckthorn regrowth. In one study, a year after burning, plots seeded with native grass showed a 72% reduction in buckthorn coverage compared to unseeded areas.
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In May 2024, Dr. Schuster and his team published a comprehensive guide to help land managers tackle buckthorn infestations. Developed through years of field research, the guide synthesizes best practices for forest understory restoration and promotes biodiversity—the very thing buckthorn eliminates.
When buckthorn takes hold, it creates a ‘green desert’: a perpetual hedge that offers little diversity,” Schuster explained to the Star Tribune. “Our guide provides actionable steps—seed native species, time prescribed burns, and monitor regrowth—to restore understories and rebuild biodiversity.”
Biodiversity underpins resilient ecosystems. Recent climate studies of tropical forests reveal alarming shifts that threaten biodiversity near the equator, underscoring the urgency of restoration efforts. Such losses echo broader climate challenges and can spark extraordinary conservation initiatives, such as the effort to revive the Tasmanian tiger.
