Circumpolar reedgrass – Pacific silverweed  
Calamagrostis deschampsioides – Argentina egedii  
n = 1
III.A.3.h.  Halophytic Grass Wet Meadow
Ecosystem: Tidal


Cicumpolar reedgrass - Pacific silverweed has not been described for Alaska, although it fits well into Viereck, et. al.’s (1992) “Halophytic Grass Wet Meadow” class. 

The single circumpolar reedgrass (Calamagrostis deschampsioides) – pacific silverweed (Argentina egedii) site visited, and perhaps the only one on the lowlands, occurs along Bridge Access Road in Kenai, at the edge of tidal influence, at the mouth of the Kenai River.  

Circumpolar reedgrass, along with Lyngbye’s  sedge (Carex lyngbyei) overtops an open pacific silverweed groundcover.  Arctic daisy (Dendranthema arcticum), beach lovage (Ligusticum scoticum), largeflower speargrass, (Poa eminens) and seaside arrowgrass (Triglochin maritimum) along with a few other herbs, are scattered throughout the site.  

The water table was 15 centimeters below the surface.  A 26 cm thick buried organic layer lies below tidally deposited silt.  The western Kenai shoreline subsided during the 1964 earthquake and then probably rebounded some (Combellick, 1997), so this type may be seral.  Only the highest tides of the year, and storm surges, flood the area.  The pH was measured at nearly neutral (6.4).  This is a jurisdictional wetland.   

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
Calamagrostis deschampsioides 1.0 35.0 FACW FACW
Argentina egedii 1.0 20.0 np
Carex lyngbyei   1.0 10.0 OBL OBL
Dendranthema arcticum 1.0 2.0 FACW FACW
Poa eminens 1.0 1.0 FAC FAC
Triglochin maritimum 1.0 1.0 OBL OBL
Ligusticum scoticum 1.0 1.0 FAC FAC
Moehringia lateriflora 1.0 0.5 FAC UPL, FAC
Carex pluriflora 1.0 0.5 OBL OBL
Galium trifidum 1.0 0.5   FACU FACU, FAC
np- not present on the wetland indicator status list.


 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