Sphagnum moss - Red cottongrass
Sphagnum spp. - Eriophorum russeolum 
n = 4
III.A.3.k. Subarctic Lowland Sedge-Moss Bog
Ecosystem: Relict Drainageway / Lakebed, Kettle

On the Kenai lowlands, the Sphagnum moss - red cottongrass community is included in Rosenberg’s (1986) red cottongrass (Eriophorum russeolum) – round sedge (Carex rotundata) type, but we separate that community into both a red cottongrass and a round sedge type.  Wilson and Underwood (1979. in Viereck, et. al., 1992) describe a similar red cottongrass – white cottongrass (Eriophorum scheuchzeri) type for Kodiak Island.  The sphagnum - red cottongrass type is rare on the Kenai; was “undersampled” on the Cooper River Delta (Boggs, 2000), and was not found on neighboring Chugach National Forest (DeVelice et. al., 1999).

Four sites were sampled, two on floating mats at lake margins in kettles, one of which is a human created lake, and two in a hydrologically altered (by road construction) relict glacial drainageway near Kenai.  This type is probably related to disturbance, and may not represent a stable community on a time scale of decades. 

This is one of the only communities (along with the Sphagnum - leatherleaf and Spahgnum - round sedge communities) on the Kenai lowlands that can indicate ombrotrophic bog development.  An ombrotrophic bog is a peatland that has built a sufficiently thick sphagnum layer to perch a precipitation- derived groundwater lens above the local groundwater table.  These perched lenses are theoretically very poor in nutrients, since the groundwater in them is entirely derived from precipitation, unlike the local groundwater table, which is flowing with some contact with the mineral soil below.

A continuous sphagnum (Sphagnum spp.) mat supports sparse plant cover, dominated by red cottongrass Bog rosemary (Andromeda polifolia), boreal bog sedge (Carex magellanicaand bog cranberry (Vaccinium oxycoccosare all present in trace amounts.  Bluejoint grass (Calamagrostis canadensisand marsh fivefinger (Comarum palustreare often present, also in trace amounts.  

The organic mat is thick and depth to the water table variable.  The pH is very strongly to extremely acid (4.5).  All four sites examined are jurisdictional wetlands.

Table 1.  Summary of plant frequency and average cover for plants occurring in more than 50% of plots.

        Wetland Indicator Status



 Average Cover

  Alaska National
Dwarf shrubs
Adored polifolia 1.0 0.6 OBL OBL
Vaccinium oxycoccos 1.0 0.6 OBL OBL
Eriophorum russeolum   1.0 2.4 FACW FACW
Carex magellanica 1.0 0.6 OBL OBL
Calamagrostis canadensis   0.8 1.3 FAC FAC, OBL
Comarum palustre 0.8 0.5 OBL OBL
Sphagnum spp. 1.0 97.5      


 Introduction and Key to Plant Communities  

Introduction and Key to Ecosystems

    Kenai Hydric Soils    Map Unit Summary    Methods   Glossary

Contact: Mike Gracz
Kenai Watershed Forum 
PO Box 15301
Fritz Creek, AK  99603
The Alaska Natural Heritage Program
Environment and Natural Resource Institute
University of Alaska, Anchorage
707 A Street, Suite 101
Anchorage, Alaska  99501

04 May 2007 10:04