Water sedge / Marsh fivefinger
Carex aquatilis / Comarum palustre
n = 3
IIA(3)c,f: Wet Sedge Herb Meadow Tundra, Subarctic Lowland Sedge Wet Meadow
Ecosystem: Relict Drainageway, Riparian

Water sedge (Carex aquatilis) communities are well described for Alaska.  A water sedge / marsh fivefinger (Comarum palustre) community is described as ”wet sedge herb meadow tundra” in the Vegetation of Alaska (Viereck, et al 1992).  Since tundra (underlain by permafrost) is absent on the Kenai lowlands, “subarctic lowland sedge wet meadow” is probably a more appropriate classification for Kenai water sedge communities.  A water sedge type with low marsh fivefinger representation is described in Chugach National Forest (DeVelice et. al., 1999), and on the Copper River a marsh fivefinger type is described (Boggs, 2000), although water sedge is not identified as occurring in any plots there.

 The three water sedge / marsh fivefinger sites we measured are along larger, slow moving watercourses on the central Peninsula.  One was adjacent to the Moose River, the other two along Soldotna and Salamatof Creeks.  Both these creeks are modern underfit streams occupying larger relict glacial drainageways. 

An open stand of water sedge tops regular, but scattered marsh fivefinger.  Open water is abundant, and sometimes water horsetail (Equisetum fluviatile) is common.  Occasionally, tealeaf willow (Salix pulchra) is encountered.

A thick organic layer is present, averaging 117 centimeters; on the Moose River this layer is probably a floating mat when the river level is high.  Standing water is present in between the sedge tussocks, and ranges from 7 cm deep to 7 cm below the surface.  pH in slightly acidic, averaging 6.3.  All three sites sampled 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


f  Average Cover    Alaska National
Salix1 pulchra   0.7 2.3 np
Carex aquatilis   1.0 32.7 OBL OBL
Comarum palustre 1.0 13.3 OBL OBL
Equisetum fluviatile 0.7 3.5 OBL OBL
Calamagrostis canadensis 0.7 0.5 FAC FAC, OBL
Open water 0.7 95.0
np- not present on the wetland indicator status list.
1 Plant with known morphological 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 09:37