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All the United States Iowa Elkader Fern Ridge Unit
AO Edited

Fern Ridge Unit

This tiny site in Iowa, part of a patchwork national wildlife refuge, is home to ancient flora and fauna.

Elkader, Iowa

Added By
Gemma Tarlach
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The dominance of ferns reveals the fragile mini-ecosystem on the north slope of Fern Ridge.   Gemma Tarlach/Atlas Obscura
The dominance of ferns reveals the fragile mini-ecosystem on the north slope of Fern Ridge.   Gemma Tarlach/Atlas Obscura
The trail from the road to a glimpse of the Ice Age refugium that makes Fern Ridge special.   Gemma Tarlach/Atlas Obscura
A small kiosk at the southwestern corner of the unit provides information for visitors.   Gemma Tarlach/Atlas Obscura
From the southwest approach, Fern Ridge looks like just another hill.   Gemma Tarlach/Atlas Obscura
Water from a spring bubbles directly out of the base of the cliff and into Dry Mill Creek on the north edge of the unit.   Gemma Tarlach/Atlas Obscura
From the road to the north, visitors can glimpse a steep cliff that’s off-limits.   Gemma Tarlach/Atlas Obscura
A close-up of the water bubbling right out of the limestone cliff.   Gemma Tarlach/Atlas Obscura
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In northeastern Iowa’s Clayton County, a gravel road passes Elkader Airport and curves around a hillside. There’s a small kiosk with a map informing visitors they’ve reached the Fern Ridge Unit of the Driftless Area National Wildlife Refuge, managed by the U.S. Fish & Wildlife Service. But this is not your typical wildlife refuge, and Fern Ridge, while it may look identical to other slopes rising up from the surrounding farmland, is not your typical hillside.

The Driftless Area National Wildlife Refuge is a patchwork of small parcels totaling less than 1,000 acres scattered across this corner of Iowa and, just across the Mississippi River, neighboring Wisconsin. The refuge takes its name from the larger Driftless Area, which also includes slivers of northwest Illinois and southeast Minnesota. This Upper Midwest region is both scenic and scientifically significant: As glaciers descended from the north on and off over the last several million years, they somehow missed this spot. As a result, the landscape hasn’t been flattened and instead is full of steep hills and ravines. There’s no glacial drift, the rocky debris left in a glacier’s wake, hence the name “Driftless.”

A lack of glaciation is only part of what makes Fern Ridge and other units in the refuge special, however. Fern Ridge includes a north-facing slope and, nearby, a steep cliff—both are home to flora and fauna that are either extinct elsewhere or exist only far to the north. Made of limestone, the Fern Ridge landscape features a sinkhole and numerous fractures in the rock that allow water to accumulate and, during winter, freeze. The chilled air then escapes via ice vents that, on north-facing parts of the site that don’t receive direct sunlight, create a cool microclimate. It’s here in what researchers call an Ice Age refugium that the northern monkshood plant (Aconitum noveboracense) and other endangered or threatened species are able to survive.

Most of Fern Ridge is open to the public, though a map shows areas off-limits to protect the fragile Ice Age environment. You can follow a trail that leads gently uphill, past the off-limits slope on the western side of the unit, but visitors must take care not to venture off it and damage the fragile ecosystem that has persisted for thousands of years. A spring bubbles directly out of the rock at the base of the protected cliff on the north side of the unit, but enjoy the view from the nearby bridge: The land to the west is privately owned and there is no public access to the spring.

Related Tags

Geology Wildlife Flora Fauna Endangered Animals Hiking Animals Plants

Know Before You Go

Fern Ridge unit is open to the public year-round, including to hunters during deer and turkey season; visitors should be aware of the hunting season windows and exercise appropriate caution. Areas marked in red on the Fish & Wildlife Service map of the unit are off-limits at all times to protect the fragile ecosystem and the federally-listed endangered and threatened species that it supports. Land surrounding the unit is privately owned and not open to the public.

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gemmatarlach

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May 19, 2021

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Fern Ridge Unit
Elkader, Iowa, 52043
United States
42.842889, -91.369412
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