Tall cottongrass Livid sedge
Eriophorum angustifolium Carex livida  
n = 3
III.A.3.j.  Subarctic Lowland Sedge Bog Meadow
Ecosystem: Relict Lakebed, Depression, Kettle


Working at the mouth of the Kenai River, Rosenberg (1986) describes this relatively common Kenai lowland type, and in Anchorage wetlands, Hogan and Tande (1983) delineate a similar livid sedge (Carex livida) buckbean (Menyanthes trifoliata) type.  Otherwise, livid sedge types are not described in the literature, and the plant is not listed at all in the Chugach forest (DeVelice, et. al., 1999) and Copper River (Boggs, 2000) classifications.  Tall cottongrass (Eriophorum angustifolium) communities are primarily described as tundra types in the Alaska Vegetation Classification (Viereck, et.al., 1992).

Tall cottongrass - livid sedge is widespread and more common than the low number of plots sampled indicates.  It occurs on relict glacial lakebeds where some degree of groundwater flow has created a strang-flark complex (low peat ridges, a meter or two high alternating with elongate pools (or flarks) oriented perpendicular to groundwater flow).  Northwest of the Kenai airport lies a particularly well-developed strang-flark complex.    Tall cottongrass - livid sedge frequently occupies the edges of flarks where it exhibits low overall cover.  

Tall cottongrass and livid sedge are emergent (rooted under standing water) in about equal quantities, with lower amounts of English sundew (Drosera anglica) and sometimes moor rush (Juncus stygius).  On low hummocks, or at the edge of the flark, tufted bulrush (Trichophorum caespitosum) and bog rosemary (Andromeda polifolia) are found, sometimes with sweetgale (Myrica gale).

Peat is usually over one meter thick, but often not over 160 cm.  The water table is above the surface, or sometimes just below it.  pH averages a moderately acid 5.6.  All sites qualify as 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
Myrica gale1,2 0.7 2.3 OBL OBL
Andromeda polifolia 1.0 0.8 OBL OBL
Eriophorum angustifolium   1.0 7.3 OBL OBL
Carex livida   1.0 6.3 OBL OBL
Drosera anglica 1.0 2.0 OBL OBL
Trichophorum caespitosum   1.0 1.0 OBL OBL
Juncus stygius 0.7 0.5 OBL OBL
Open water 1.0 38.5
1,2 Plant with known morphological and physiological adaptation for occurrence in wetlands (USACE, 1987)


 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 09:40