Common (Translated Scientific) Name: Water Sedge - Peatmoss species - Beaksedge species Acidic Fen Alliance

Colloquial Name: Sedge - Sphagnum - Beaksedge Acidic Fen

Hierarchy Level:  Alliance

Type Concept: This alliance consists of herbaceous-dominated acidic fens where the herbaceous canopy is dominated by Carex aquatilis (often var. dives), Carex lenticularis, Carex utriculata, or Schoenoplectus species and includes characteristic fen species such as Carex californica, Comarum palustre, Darlingtonia californica, Deschampsia cespitosa, Drosera rotundifolia, Eleocharis quinqueflora, Eriophorum chamissonis, Calliscirpus criniger, Rhynchospora alba, and Sanguisorba officinalis. Sphagnum moss may be very abundant and contribute more cover than the vascular plants. Shrub species may be present but these generally have cover of <25% and may include Ledum groenlandicum, Lonicera involucrata, Salix hookeriana, Spiraea douglasii, Vaccinium oxycoccos, or Vaccinium uliginosum. This alliance occurs in southern Alaska, coastal British Columbia, Washington and Oregon. Climate is maritime. This vegetation is found in glacial cirques and valleys, often along streams, below seeps, and especially on the edge of beaver ponds. These wetlands have organic soil of peat at least 30 cm thick, with soil/water pH of <5.5. Elevations range from 850-1590 m. Substrates are moderately deep (50-90 cm), silt- or silty clay loam-textured soils with a deep organic horizon (20-50 cm). Parent materials are alluvium or volcanic pumice deposits. These wetlands have a high water table and are seasonally flooded during much of the growing season.

Diagnostic Characteristics: A dominance of herbaceous species of Carex, Eriophorum, or Rhynchospora with high cover of Sphagnum or brown mosses and soil/water pH <5.5.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: Peat wetlands are often mosaics of many plant associations, and may have more acidic associations on elevated hummocks, domes and lawns intermixed with more neutral to even alkaline fen types at lower (microtopographic) elevations. Or the mosaic may be in a pattern of concentric rings of increasing or decreasing pH levels and corresponding plant associations. In addition, as peat grows and changes the rooting zone distance from groundwater, the pH of an association will change and the floristics may take longer to change. Thus, fitting an association into "acidic" or "neutral-alkaline" groups can be problematic. Alliances may be the more appropriate level for the floristic distinction between acidic and alkaline fens.

Similar NVC Types: No Data Available

note: No Data Available