Foggy rolling in over the fen, with wildflowers and trees in the foreground
Misty Morning: Mist rising at Pickerel Lake Fen © Gerald H. Emmerich, Jr.

Places We Protect

Pickerel Lake Fen Preserve


Pickerel Lake Fen Preserve is largely dominated by oak openings, an extremely rare plant community.

Why You Should Visit

The Nature Conservancy has established its Mukwonago River Watershed project office on 36 acres located on the west side of Pickerel Lake. The land, which includes a portion of Pickerel Lake Fen, a rare wetland type, contains several springs that feed Pickerel Lake and an oak woodland.

The fen itself is located south of Pickerel Lake and is a fragile environment. Please stay on the trails when walking at the preserve.

Why the Conservancy Selected This Site

Fens are among the rarest types of wetlands in North America, including Wisconsin. They are dependent upon natural springs and, as a result, have never been common. Pickerel Lake Fen is tied for first place with Ottawa Lake Fen as the most biologically diverse fen in southeast Wisconsin and is one of the few fens in conservation protection. Several rare or endangered species are also protected at the preserve. Pickerel Lake Fen is dedicated as a State Natural Area.

What the Conservancy Has Done/Is Doing

The Nature Conservancy has owned and managed land at Pickerel Lake Fen Preserve since 1985 when the Emmerich and Muth families donated 38 acres. The Emmerichs also donated a conservation easement on additional land to help protect the calcareous fen.  The Conservancy acquired another 40 acres in 2000 and located its Mukwonago River Watershed project office at the preserve.

Conservancy staff and volunteers, together with local landowners, are using periodic prescribed fires and manual removal to control non-native, invasive species like buckthorn and honeysuckle, which rim the edge of the fen and are slowly advancing on the interior. Left unchecked, they will out-compete the native vegetation and would eventually take over completely.

Pickerel Lake Fen Preserve is located within the Mukwonago River Watershed project area. The Conservancy has an office and staff at the preserve, and we are working cooperatively with many different public and private partners to accomplish the following:

  • Protect the water quality of and natural areas within the Mukwonago River Watershed.
  • Manage our preserves to maintain rare natural communities and provide habitat for fish, mussels, amphibians and reptiles.
  • Work with individuals and organizations concerned with the health of the watershed to help balance watershed protection with human needs and economic health.

What to See

The Conservancy is restoring oak openings at the preserve.  This plant community is extremely rare and is characterized by large burr and white oak trees with a prairie-like understory of grasses and wildflowers.

Of the 150 fish species native to Wisconsin, 59 can be found in the Mukwonago River and nearby Lulu Lake.  Pickerel Lake is home to the starhead topminnow, a rare fish on the state’s endangered species list.

Frogs heard at the preserve include spring peepers, green frogs, leopard frogs, pickerel frogs, and bullfrogs.


For more information about visiting the preserve, please follow the links below:

All of our preserve maps are now georeferenced. You can download an app on your Apple or Android device, and it will allow you to view your location, record GPS tracks, add placemarks and find places.