Bluejoint floating island
Calamagrostis canadensis floating island
n = 1
Ecosystem:  Floating Island


Bluejoint (Calamagrostis canadensis) floating island is a rare type, and not is described in the literature.  It is found floating on Suneva Lake, near Nikiski; small mats are found on Beluga Lake in Homer.  Both lakes were created by humans.  Examination of 1950 and 1996 aerial photographs reveals that “Suneva Lake” was a peatland until a road, built across its outlet stream, backed up drainage, creating the lake.  Several floating islands, including one about 0.5 km2, drift across the lake and lodge along its shoreline.  Beluga Lake was created as an airport in 1939.

The single bluejoint floating island sampled appeared well anchored, consisting of a 65 cm thick organic mat suspended over 32 cm of water.  Other plant communities are present on the island, though bluejoint was the most common type away from the edge.  

At the edge, the most common type is a Sitka sedge (Carex aquatilis var. dives) – western water hemlock (Cicuta douglasii) community.  In the center of the mat, a small leatherleaf (Chamaedaphne calyculata) bog has developed.  

Where bluejoint d is tall and dense (75%), and overtops sparse marsh fivefinger (Comarum palustre).  Scattered, well-developed clumps of silvery sedge (Carex canescens) are scattered amongst the thick bluejoint.  A few buckbean (Menyanthes trifoliata) plants, and the shrubs leatherleaf and bog rosemary (Andromeda polifolia) are found towards the bog, away from the water’s edge.  This type is a jurisdictional wetland.

Table 1.  Summary of plant cover.

        Wetland Indicator Status


f Average Cover    Alaska National
Chamaedaphne calyculata   1.0 0.5 FAC FAC
Calamagrostis canadensis   1.0 75.0 FAC FAC, OBL
Comarum palustre 1.0 3.0   OBL OBL
Carex canescens   1.0 1.0 OBL FACW+, OBL
Carex magellanica 1.0 1.0 OBL OBL
Epilobium palustre 1.0 0.5 OBL OBL
Andromeda polifolia 1.0 0.5 OBL OBL
Menyanthes trifoliata1 1.0 0.5 OBL OBL
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