Fall 1998

Misnamed — a bog or a fen?

Porter County, Indiana

It's a misnomer: there's no bog at Cowles Bog. Named in honor of Henry Cowles, the University of Chicago professor whose studies of plant succession among the Indiana Dunes helped develop ecology as a science, Cowles Bog is actually a fen — a related and equally unique wetland community. But the area was misnamed years ago, and the name stuck.

Cowles Bog, part of the Indiana Dunes National Lakeshore, is a remnant of the marsh system that once stretched from where the city of Gary is today all the way to Michigan City. Most of these wetlands were filled in years ago for the massive industries established in northern Indiana. But several spectacular sites — including Cowles Bog — have been preserved and are now administered by the National Park Service.

The core of the Cowles Bog area is a marsh surrounding a small fen. There a stand of tamaracks and white pines grows on a floating mat of peat moss. A constant flow of lime-rich water from springs beneath the mat makes this a fen rather than a bog.

The fen itself is off-limits to the public, because of its sensitivity and the deep muck that visitors would have to traverse to reach it. But you may catch glimpses of it from the three-mile trail that circles the marsh. From the southern leg, look across the marsh for a stand of conifers. The Park Service plans to build markers along the trail to make the fen easy to identify.

The Cowles Bog area offers hikers a view of pristine beach habitat, black oak savanna, and a lowland forest of red maple and yellow birch. Starting near the guardhouse at the northeastern part of the site, the trail passes through a marshy area and over a boardwalk. This is the red maple forest, with damp-loving yellow and paper birches, trees rare in the Chicago region. Many cinnamon ferns also grow here. The trail occasionally passes white and red pines, markers of the area's past. Pines were once common in this area, before almost every one was logged. Along higher, sandier ground, the trail passes through a healthy oak savanna.

A spur off the loop trail leads over the back dunes, dominated by black oak. Once a savanna, the area became overgrown with brush after more than 30 years of fire suppression. In recent years the Park Service has begun conducting prescribed burns again, and the dunes are slowly being restored to native savanna.

The spur continues past interdunal ponds and over the front dunes. After a steep climb, the trail drops to the beach. Swimming is allowed here, though not officially encouraged, as no lifeguards are on duty. The wetlands of Cowles Bog are home to a variety of salamanders and other herps; a large chorus of frogs croaks all spring and summer. The area's many habitats attract a great variety of birds, including Virginia rails, green and great blue herons, Eastern wood-pewees, and several species of hawks. Fall and spring migrations bring an even wider variety.

Autumn is an especially dramatic time of year, as the thick stands of trees turn bright colors. If your timing is right, you may get a glimpse of the fen's tamaracks cloaked in bright yellow. Directions Take I-94 east into Indiana. Exit at US 20; head east about 1.5 miles to the intersection with Mineral Springs Rd. Turn north (left). Go straight at the intersection with Dunes Hwy; just over the RR tracks is the first of two parking areas for Cowles Bog. The second is farther north, to the right of the Dune Acres entrance station. Bikes are not allowed on the trails.

— Chris Larson