The Pilot Knob open space site, a landmark of Minnesota's beginnings, is set to make it into the books for another historic achievement: It will be the first public urban site in the nation that will use grazing animals to help restore prairie vegetation.

The city of Mendota Heights is using funds left over from a grant from the National Trust for Historic Preservation to bring horses to Pilot Knob to eat nonnative grasses, part of an effort to bring the land back to its historic state as a prairie oak savanna.

"It's pretty intensively managed grazing," said Wiley Buck, restoration ecologist for Great River Greening, the company working with the city on the project. "It removes the thatch, the dead vegetation, and also gets the nitrogen cycle back into balance. These large grazers are just a natural part of the prairie. It really helps with the prairie restoration."

Pilot Knob is a 23-acre site overlooking Hwy. 55. It was a sacred site for Dakota Indians, and it was the place where a treaty was signed ceding 35 million acres of land to the U.S. government more than 160 years ago. That land would become southeastern Minnesota and portions of other states.

It is known to Dakota people as Oheyawahi, "the hill much visited." The land is named Pilot Knob because in the 1800s, when steamboats came into the area, there was a knob at the top of the hill that pilots of the boats used for navigation.

The city of Mendota Heights purchased the land in 2006 and has since worked to bring it back to its historic state. The scenic area is well-known for bird observation and wildlife sightings, along with views of the river valleys, Fort Snelling and downtown Minneapolis. The land is on the east end of the Mendota Bridge, south of Hwy. 55.

The Mendota Heights City Council on April 2 approved a contract with Great River Greening to begin the project. Since then, city leaders and Buck have met with horse owners to talk about preparing the land for the safety of the horses and the public.

Because of its urban setting, the conservation project faces challenges.

"For outstate Minnesota, the standard practice is to partner with a neighboring cattle owner," Buck explained. "We don't have that option in the metro. So transport of the animals is more difficult."

The site also has public trails, so interaction between the public and the animals needs to be monitored, and the horses used will have to be ones that are comfortable around people, dogs, and traffic and airplane noise. The plan is to have owners stay with the horses at all times. Between May and October, about five horses will be on the site for 30 yet-to-be-determined days.

"We are timing the horse grazing to target specific natural resource objectives — time it so they eat a certain grass at a certain time of the year," Buck said.

The city also uses burning and mowing to restore the land — but this will be different. "The prairie plants are adapted to being grazed directly," Buck said. Grazing also results in a "mosaic of different vegetation heights."

"This is another tool in the toolbox," said Jake Sedlacek, assistant city administrator and the project manager for the Pilot Knob open space. "It's an intensive site to get it back to its historic state, for people to come see what the land looked like. It was a holy site — it's a place of significance for Native Americans and settlers. We want to bring it back to what it was."

The grazing areas will be fenced to keep the animals from wandering off.

The next step is to prep the land. Buck and University of Minnesota equine specialists are set to do a walk-through on the site later this month.

"We are going forward with it very slowly and very carefully," Buck said. "All systems are go."

The land was one of 25 Twin Cities historic sites to compete for a grant, and it received $75,000 to remove utility poles and lines that brought electricity to houses formerly on the hill. Left from that money was nearly $26,000, which the city needs to spend before June 30. The funds will go to this project, including fencing, water supply, horse owner recruiting, seeding and maintenance.

"Lots of people drive by [Pilot Knob] every day, but not that many know the story behind it," Sedlacek said. "I think it's cool that we've managed to preserve it … It's an interesting thing that our community has been able to be a part of."

Liala Helal • 952-746-3286