$327,000 to develop management tools to limit buckthorn re-colonization following its removal, by identifying cost-effective methods of establishing dense cover of preferred plant species that will suppress buckthorn regeneration.
Winter 2017 update
Common buckthorn is an invasive shrub or small tree that displaces native plants, degrades wildlife habitat, and inhibits human use of forests. In Minnesota alone, millions of dollars are spent each year to remove buckthorn and restore affected areas. However, many efforts to remove buckthorn only yield temporary relief because removing buckthorn creates an ecological vacuum that is often more easily filled by buckthorn than by native species. Cover It Up aims to develop strategies that increase the abundance and diversity of native plants and enhance forests’ ability to prevent buckthorn from coming back after it has been removed. In partnership with over a dozen public, private, and non-profit organizations, we are testing the ability of diverse mixtures of native species to suppress buckthorn in areas where buckthorn has been removed. At each of six experimental sites around Minneapolis/Saint Paul, we seeded large plots with a mixture of 35 grass and wildflower species in February 2017. Since then, we have been monitoring the performance of buckthorn and native species both with and without follow-up herbicide treatment of buckthorn. Additionally, we are monitoring the performance of buckthorn in smaller plots planted with either a mixture of four shrub species, a maple-fir mixture, sedges, or ferns. This work, combined with our monitoring of buckthorn in existing forest experiments, has already characterized how deep shade can slow buckthorn growth, and will provide further insights into the effectiveness of using native plants to suppress buckthorn in the coming years.