BIOLOGICAL CONTROL + FIRE
Sometimes invasive species can be controlled with biological agents, including livestock, insects, and other organisms.
One example is the use of livestock to eat invasive plants. Some plants can be controlled or weakened through repeated grazing or browsing by goats, sheep, cattle, or other domestic animals. There are many factors to consider when using livestock for invasive species control, including the possibility that the livestock may eat desirable plants. Learn more about using livestock to control invasive plants here.
Insects are often used for biological control. One popular example in Wisconsin involves purple loosestrife, an invasive wetland plant. Beetle species from the genus Galerucella were imported to control purple loosestrife. The beetles feed almost exclusively on purple loosestrife, so they aren't a threat to native species. The Galerucella beetles can control loosestrife populations for years. If you or your organization are interested in raising a releasing loosestrife beetles, more information can be found here.
Research is ongoing to find specific biological control agents for other invasive plant species.
Image from Paul Skawinski
Image from commons.wikimedia.org
Fire can be a helpful tool to control invasive species. Many (but not all) invasive plants are killed or weakened by fire. Some native plants, especially prairie species, respond well to prescribed fire. Prescribed burns are usually performed in early spring. Low-intensity fire reduces competition between plants, returns nutrients to the soil, and stimulates seedling growth.
If you are considering prescribed fire for your property, consult with experts. Safe use of fire requires considerable planning, and usually requires a permit. Reach out to the Wisconsin DNR, nature centers, colleges or tech schools, environmental consultants, or your local fire department for help planning and executing a prescribed burn. Organizations usually charge a fee for services related to prescribed fire.
While prescribed fire can help control invasive plants on a large scale, there are also small-scale uses of fire. Some land managers use large propane torches to spot-treat invasive plants. Invasive seedlings and saplings are exposed to intense heat from the torch and are weakened or killed. This method must also be performed carefully to prevent any fires from spreading out of control.