Three dozen goats joined the Itasca State Park resource management team last summer as an innovative tool for controlling spotted knapweed, an invasive nonnative weed. Introduced to North America from Europe in the 1800s, knapweed is a big problem because it crowds out native vegetation and robs native animals of food and shelter.
Itasca State Park resource manager Becky Marty wanted to keep knapweed from spreading in the park, but she didn't want to use herbicides near the Mississippi River. So she found an alternative: goats.
"It's an extremely sensitive area, so we have to treat it with a lot of respect," Marty says. "We're trying an alternative to herbicides. Park visitors really like the idea of goats eating our problem while we're protecting the watershed."
Last year the goats were put out to pasture during the peak of the first flowering of knapweed, then returned for the second bloom in August. In between those times, park staff spread native grass seeds in the area.
"To our surprise and delight, the goats preferred the spotted knapweed over other forbs and grasses," Marty says.
Marty admits goats are not going to solve the problem completely, because the weed's tiny seeds will continue to be distributed in the park by remaining plants as well as by visitors who inadvertently bring them in on car tires and shoes. Goats also won't work in areas with a lot of native plants, since they will eat other plants besides knapweed.
But, she says, goats are a solid step toward reducing knapweed and helping native plants reclaim this sensitive area.
Mary Hoff, freelance science writer