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<br />scattered trees. The dominant graminoid is Carex lasiocarpa, and typical associates
<br />include Carex chordorrhiza, Carex limosa, Carex o/igosperma, Rhynchospora alba,
<br />Scirpus cespitosus, and Scheuchzeria palustris. Forbs include Arethusa bulbosa,
<br />Aster borealis, Calopogon tuberosus, Pogonia ophioglossoides, Sarracenia purpurea,
<br />Solidago u/iginosa. The low-shrub layer contains Andromeda polifolia, Betula pumila,
<br />Chamaedaphne calyculata, Larix laricina, Salix discolor, Salix pedicel/aris, and
<br />Vaccinium oxycoccos. The moss layer is virtually continuous, and is dominated by
<br />Sphagnum capillifolium, Sphagnum fuscum, and Sphagnum magellanicum. Diagnostic
<br />features include the dominance of graminoids, particularly Carex lasiocarpa, the
<br />almost continuous layer of Sphagnum peat, and few minerotrophic indicators.
<br />
<br />Rich Fen (MLCCS Code 61460, 61461, and 61462 I Total Acres)
<br />Within the city, nine rich fens were documented, two of these were floating-mat
<br />subtypes found along the margins of small lakes.
<br />
<br />The ground layer of rich fens is dominated by wiregrass sedge (Carex /asiocarpa),
<br />brown sedge (Carex buxbaumii), livid sedge (Carex /ivida), bluejoint grass
<br />Calamagrostis neg/ecta, or bog reed-grass (Calamagrostis inexpansa). Although
<br />generally open communities, Rich Fens may have up to 70% cover of woody shrubs,
<br />especially bog birches, sage-leaved willows, and shrubby cinquefoils. Mosses range
<br />from scarce to abundant in the community. Where mosses are abundant, the
<br />dominant species are species other than sphagnum mosses (Sphagnum spp.).
<br />
<br />Surface waters within the community are slightly acidic to circumneutral (pH 5.8 - 7.8)
<br />with moderate nutrient levels. Rich fen may grade into poor fen but is distinguishable
<br />from poor fen by its higher species diversity and by the more frequent occurrence and
<br />greater abundance of minerotrophic indicator species, including livid sedge (Carex
<br />/ivida), brown sedge (C. buxbaumii), swamp lousewort (Pedicularis lanceolata), spike-
<br />rush (Eleocharis compressa), marsh muhly (Muh/enbergia glomerata), and Kalm's
<br />lobelia (Lobe/ia ka/mii).
<br />
<br />Rich fen occurs in the conifer-hardwood forest and deciduous forest-woodland zones.
<br />There are two geographic sections of rich fen, a Transition Section and a Boreal
<br />Section. In the Boreal Section (i.e. northern Minnesota), rich fen usually occurs on
<br />deep peat and contains characteristically northern species such as bog-rosemary
<br />(Andromeda glaucophylla) and other ericaceous shrubs, the bulrush Scirpus
<br />hudsonianus, and pitcher-plant (Sarracenia purpurea).
<br />
<br />City of Elk River, MN - Natural Resouce Inventory
<br />Bonestroo Natural Resources, September 2004
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