Glacial Ridge: Reconstructing the Prairie

To restore 17,000 acres of prairie at Glacial Ridge, the Conservancy harvested and hand-collected seed from native plants.

“There was a real risk of failure,” recalls Susan Galatowitsch.

Galatowitsch is Professor of Restoration Ecology at the University of Minnesota and has studied the restoration of prairie pothole wetlands. When the Glacial Ridge Project began, she also served on The Nature Conservancy’s Board of Trustees in Minnesota and was skeptical that the project could succeed.

“Starting from cornfields is different than starting from prairie remnants,” says Galatowitsch. Most of Glacial Ridge was agricultural land, bare fields that could quickly fill with weeds if not seeded promptly with prairie plants. This was not the same as taking a patch of prairie, removing the non-native plants and making it bigger.

Conservancy Program Director Brian Winter agrees, explaining, “The task at Glacial Ridge was much more than restoration; it was reconstruction – actually rebuilding a prairie. And we had to start with seed from prairies that closely resembled what was once at Glacial Ridge to create a good match.”

There were many habitats at Glacial Ridge to match: sandy soils at the top of beach ridges created dry prairie, ridge slopes were moister and supported other kinds of plants, and swales between ridges created ephemeral wetlands with different plants at different times of the year. Restoring this much varied topography required finding lots of seed. Restoration projects typically gather seed within 25 to 30 miles of a property. Because Glacial Ridge needed so much seed of so many species, the search extended to 70 miles away.

Seed was gathered throughout the growing season beginning in May and ending in October. Many seeds could be mechanically harvested, but the very fine seeds of some wildflowers had to be collected by hand. Seed also was purchased from nearby commercial growers. The seed was used to create approximately 2,000 acres of new prairie each year. Prescribed burns were an important part of this process – burns helped control non-native plants and also increased seed production in the newly-established prairie plants (an 11-fold increase by some).

Wetlands were also created, most by simply filling in drainage ditches and allowing water to pool naturally. “There were ditches everywhere,” Winter recalls, and filling those ditches created at least 20 new wetlands every year. Eventually, 126 miles of ditches were filled, restoring the hydrology at Glacial Ridge more closely to its original flow. No flooding resulted – the property is so big that its water did not spill onto neighboring lands. And because no drainage ditches were moving water off the land, the Glacial Ridge Project actually decreased the likelihood of flooding downstream.

“The standing water was good for wildlife, but it was not good for tractors,” Clayton Engelstad remembers. Engelstad is one of the many neighbors who worked on the project when he wasn’t farming at home. For eight years, he helped fill ditches at Glacial Ridge, and the tractors would sometimes get stuck. Even so, Engelstad is proud of helping restore Glacial Ridge. “We put it back to what it was like before men starting messing with it,” he said. "The land is now as it should be.”

In all, the Conservancy restored more than 20,000 acres at Glacial Ridge by reconstructing 3,068 acres of wetlands in 258 basins that are now used by waterfowl and planting 17,000 acres of prairie. It is the largest prairie and wetland restoration project ever undertaken in the United States. Where once there were black fields and ditches, there are now miles and miles of grasses and flowers.

Susan Galatowitsch is pleased with the results: “What happened at Glacial Ridge is an absolute success.”