This cache is easy to get to and tricky to find. This family-friendly location has a terrific view of the 10 acre Fontana Fen conservation area, a rare wetland praire known as a calcareous fen.
Calcareous fens are a rare and distinctive category of Type 2 wetlands. They are characterized by non-acidic peat soil and dependent on a constant supply of cold, oxygen-poor groundwater rich in calcium and magnesium bicarbonates. This calcium-rich environment supports a plant community dominated by "calciphiles", or calcium-loving species, several of which are listed as endangered, threatened or special concern.
Calcareous fens occur mostly in southern Wisconsin, on sites that are fed by carbonate-enriched groundwater. Most fens are small, covering no more than a few acres, and are often associated and can intergrade with more abundant and widespread wetland communities such as southern sedge meadow, wet prairie, shrub-carr, emergent marsh, and southern tamarack swamp. An accumulation of peat can raise the fen surface to a height of several meters above the adjoining lands.
The diverse fen flora is distinctive, containing many calciphiles of restricted distribution. Common or representative plants include sedges, marsh fern, shrubby cinquefoil, shrubby St. John's-wort, Ohio goldenrod, grass-of-parnassus, twig-rush, brook lobelia, boneset, swamp thistle, and asters. Many fens have a significant number of prairie or sedge meadow components, and some contain plants often associated with bogs, such as tamarack, bog birch and pitcher plant.
Fens occur in several landscape settings, including the bases of morainal slopes, on sloping deposits of glacial outwash, in the headwaters regions of spring runs and small streams, and on the shores of alkaline drainage lakes. Common species are several sedges (Carex sterilis and C. lanuginosa), marsh fern (Thelypteris palustris), shrubby cinquefoil (Potentilla fruticosa), shrubby St. John's-wort (Hypericum kalmianum), Ohio goldenrod (Solidago ohioensis), grass-of-parnassus (Parnassia glauca), twig-rush (Cladium mariscoides), brook lobelia (Lobelia kalmii), boneset (Eupatorium perfoliatum), swamp thistle (Cirsium muticum), and asters (Aster spp.). Some fens have significant prairie or sedge meadow components, and intergrade with those communities.