Fall 2004

Phantom Savanna
Nature returns to the Middlefork,
home of a rare remnant savanna

Top: Restored wetlands and prairie blending into savanna and oak woods. Blue-winged teal feed in the marsh but nest well out in the prairie — to avoid the predators that frequent wetland edges. Great-spangled fritillary butterflies are powered by the nectar of abundant savanna flowers. The green heron lives in the marsh but nests in trees. Photos: Landscape by Mike MacDonald/www.ChicagoNature.com; Blue-winged teal by by Art Morris/BIRDS AS ART; Fritillary butterfly by Rob Curtis/The Early Birder; Green heron by Ed Reschke. See more photos before, during, and after restoration of Middlefork Savanna.

By Don Parker

The land talks quietly at first. It doesn't advertise, though the long views across the valley are magnificent. But stand still. A muskrat will plop into the water behind you. An egret will push into the air and glide behind a screen of thick, gnarled oaks. Then, a bluebird. A green heron. A dragonfly. A turtle. The longer you stay, the more happens and the louder it gets.

About 20 years ago, at the edge of an open farm field in Lake Forest, Illinois, along the channelized Middle Fork of the North Branch of the Chicago River, ecologists discovered the last high-quality tallgrass savanna in the region. It covered only about 30 acres, but it quickly became a magnet for conservationists, who began to pull together resources and organizations to purchase the surrounding land. By 2000, fueled with funds from public referenda and backed by a broad partnership, the Lake County Forest Preserves had protected Middlefork Savanna, a 576-acre fragment of rare ecosystems amid the fast-growing communities of southeastern Lake County. Lake Forest Open Lands Association acquired additional land, bringing the total protected to around 700 acres.

Conservationists spoke excitedly of this "phantom ecosystem." A decade before its discovery, no one had even believed that oak savannas existed. There was prairie and there was woodland, but the open woods between them was considered merely a melding of the two, not a unique ecosystem of its own. Yet here in Middlefork lived plants that were nearly absent in prairies and woods. Ecologists suddenly had a real-life, landscape-scale blueprint of how diverse this ecosystem could be.

To date, more than 300 plant species have been identified at the site. "The savanna almost defies definition in that it is both wet and dry, both sunny and shaded," says Nick Huber, restoration ecologist for Lake County Forest Preserves.

The fire-dependent savanna owes much of its existence to the railroad. "Middlefork was so remote that every summer, trains belching cinder would set fire to it," says Stephen Christy of the Lake Forest Open Lands Association. The area was well contained by wetlands, "so mostly they just let it burn."

In 1998, Forest Preserve crews began to remove invasive vegetation, and in 2000, they took out miles of drain tiles. "It was extremely rewarding to observe plants, fish, frogs, and birds immediately inhabiting the hydrologically restored wetlands," says Huber. Biologists have recorded shorebirds in the marshes, warblers in the savanna, even bald eagles. Extensive surveys also have reported yellow lady slippers, scarlet painted cups, and rare walking sticks and butterflies.

Since 2000, nearly 300 volunteers from surrounding communities have gravitated to this place. "We put in 137,000 wetland plants out here the first summer," says Denis Bohm, site steward. "We had a lot of public support and a lot of help from volunteers to do that: people from Abbott Labs, high school groups, and Cub Scout packs. A lot of people got muddy." The hikers, bikers, and joggers that use Middlefork's 3.5-mile trail system may never fully appreciate the work that has gone into this place. But stewards restoring savannas across Chicago Wilderness, not to mention the savanna creatures they're bringing back, owe a debt of gratitude to Middlefork Savanna — simply for surviving.

Related Articles:

Rebirth of the Oak Woods

Middlefork Savanna Expands

Case Study of Middlefork from 1993 Midwest Oak Savanna Conferences