One-hundred-thirty goats rented from a ranch in Red Wing are eating their way through a thicket of buckthorn on prized natural land along the Mississippi River owned by Flint Hills Resources.

The goats will roam 8 to 12 acres of the company's property along the Mississippi River known as the Pine Bend Bluffs Natural Area. They will do double duty: As they eat, their hoofs will work native seeds into the ground.

Great River Greening and Friends of the Mississippi River, two nonprofit environmental groups, were hired by Flint Hills to carry out the goat project as part of restoring the land to its natural state. The animals will be monitored daily, accompanied by a guard dog and penned overnight, the company said.

Working bluff land overlooking the Mississippi, the goats have about two weeks of munching to knock back the invasive buckthorn shrub, which crowds out native trees and plants depended upon by native animals, birds and bees.

Goats offer biological control instead of chemical control, and it's a tactic becoming more popular in the Midwest.

Earlier this summer, Great River Greening worked with the city of Mendota Heights to bring in grazing horses to remove dry thatch and restore prairie vegetation in the historic Pilot Knob area.

Flint Hills owns 4,600 acres in and around its Pine Bend Refinery in Rosemount, including 1,000 acres for the refinery itself and some for farming. For the past 13 years, it has been working to restore 1,600 acres along the river to its natural condition, said company spokesman Jake Reint.

Buckthorn was imported from Europe as a shrub to act as a hedge. The Department of Natural Resources considers it a problem because "it out-competes native plants for nutrients, light and moisture, degrades wildlife habitat and threatens the future of forests, wetlands, prairies and other natural habitats.''

The goats are expected to whittle down the buckthorn from 6 feet to 6 inches, making it much easier for humans to finish off the buckthorn next year with herbicide spray.

"Goats obviously have been eating plants a long time and do like to eat woody plants in particular,'' said Karen Schik, ecologist and project manager for the Friends of the Mississippi River. The thought was, "Hey, maybe we can get them to eat this invasive plant we don't like.''

Results have already been demonstrated. The same herd of goats from Goat Peak Ranch in Red Wing was let loose on Department of Natural Resources land in Hastings before coming to the Pine Bend area.

The buckthorn greeting the goats there was an impenetrable wall. When the goats were finished with it, you could see through it, Schik said.

In the 11 years that Great River Greening has managed the Flint Hills land, it has restored a large oak savanna and brought the redheaded woodpecker back to the area just last year, said Wiley Buck, restoration ecologist for the nonprofit organization.

After the goats make their mark, the area will have to be sprayed next tear to kill the buckthorn, Buck said.

The land opened to the goats is not open to the public. It is part of the Pine Bend Natural area, which is home to rare species of plants and to animals and birds.

Laurie Blake • 952-746-3287