Research on eliminating buckthorn in MN by introducing competitive plants.

MN Impact: University researchers work to break buckthorn’s cycle of invasion

May 27, 2020

Issue

Buckthorn is an invasive, non-native plant species that affects countless acres and wallets in Minnesota. In North America, it often forms thickets that can impede hunters, hikers, and wildlife moving through the forest and is especially successful at outcompeting native plants in shady conditions.

What has been done

Due to its status as a noxious weed, buckthorn management recommendations are plentiful, but many are struggling with the time and cost needed for multi-year post-management strategies that keep buckthorn at bay.

With the “Cover It Up” project, University researchers at the Minnesota Invasive Terrestrial Plants and Pests Center aim to improve Minnesota’s forest health by breaking the cycle of invasion by revegetating with dense native plant cover to shade out buckthorn after removal—a technique that has been successfully used in prairie restoration.

Results

The researchers have discovered that buckthorn seedlings need a certain threshold of light to survive. If light availability drops to 3-4 percent throughout the spring, summer and fall, it's enough to prevent buckthorn growth. Additionally, some native species have shown promise in helping to suppress regrowth including: wild grasses, flowering herbs and young trees, but researchers stress geography and planting conditions play a key role in determining the right mix of native species.

Results so far suggest that revegetation can suppress buckthorn, but researchers now need to explore how to scale it and apply it across various conditions. For phase two of the project, the team is expanding their reach via a citizen science program that, with the public’s help, will allow them to carry out experiments in woodland areas across the state.

Ultimately, this work could change the way we think about buckthorn management—by helping Minnesota land managers save significant time and money in their long-term restoration efforts—along with improving the overall health of Minnesota’s forests.