5.10. SR 12-20-2004 - Laserfiche WebLink

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present in most Poor Fens as associates of the dominant sedges. Poor Fens have at least 50% cover by sphagnum mosses. and up to 70% cover by shrubs and small trees, most commonly bog birches and stunted tamaracks. Poor Fen occurs on deep peat (>1.0m) that receives minimal nutrient-rich run-off from surrounding uplands. In Minnesota's large patterned peatlands, Poor Fen often is present on sites with water infiltration from adjacent raised bogs. Less frequently, Poor Fen occurs in the interiors of small basins that are relatively isolated from run-off. This is the case for fens in Elk River. The surface water of Poor Fen is Poor Fen example - Eden Prairie, MN slightly acidic (pH 4.1 - 5.9) and nutrient poor ([Ca2+] <13 mg/I). Poor Fen is transitional between Rich Fen and Open Bog and commonly grades into these communities on the landscape. There are four subtypes of Poor Fen, a Sedge Subtype, a Shrub Subtype, a Scrub Tamarack Subtype, and a Patterned Subtype. Kev-based definition: A saturated wetland on peat >0.5m deep where grasses and sedges, such as Carex lasiocarpa, and C. chordorrhiza, are mostly <3mm wide and there is <50% cover by shrubs, including dwarf-shrubs. The community does not occur on the floating mat at the edge of a shallow lake and lacks the complex patterned topography of strings and flarks. The following species are NOT common: Carex livida, C. buxbaumii, Pedicularis lanceolata, Eleocharis compressa, Muhlenbergia glomerata, and Lobelia kalmii. The National Veqetation Classification Svstem description of a more narrowlv defined community is qiven here as well: This graminoid poor fen community is found in the Great Lakes region of the United States and Canada, as well as elsewhere in central Canada, ranging from Ontario to Manitoba, south to Iowa, and east to Illinois. Stands are found in peatlands with low exposure to mineral-rich groundwater, including basin fens, shores above the level of seasonal flooding and larger peatlands. Water hydrology is saturated, and surface water is slightly acidic and nutrient poor. The vegetation is dominated by graminoids, with up to 25 percent shrub cover, and City of Elk River, MN - Natural Resouce Inventory Bonestroo Natural Resources, September 2004 31