Berlin Fen

State Natural Area (No. 207)

Location: Green Lake County. T17N-R13E, Section 12 W½SW¼NW¼. 22 acres.

Access: From the intersection of State Highways 49 and 91 in Berlin, go east on 91 2 miles, then south on Willard Road 0.25 mile to the northwest corner of the tract. The site lies east of Willard Road and north of the Green Lake County Trail.

Description: Berlin Fen contains two mound fens, the smaller on the south side near the abandoned railroad trail and the larger covering nearly the entire northern portion of the site. The mounds are dome-shaped piles of wet calcareous peat and have unique combinations of plants. The larger mound is dominated by shrubby cinquefoil and chairmaker's rush while the smaller mound is dominated by prairie grasses. Throughout the main mounds are areas of marl rivulets and pools, which harbor a very unusual flora including special concern species slender bog arrow-grass (Triglochin palustris) with grass-of-parnassus, bladderwort, and large populations of pitcher plant. Preliminary studies suggest that sedge wren, common yellowthroat, and savanna and clay-colored sprarrows breed here. Berlin Fen is owned by the DNR and was designated a State Natural Area in 1986.