Sphagnum moss - Leatherleaf
Sphagnum spp. - Chamaedaphne calyculata  
n = 5
II.C.2.e. Ericaceous Shrub Bog
Ecosystem: Relict Drainageway, Depression, Floating Island

Working in the bottomland bogs of the Fairbanks area, Mary Calmes (1976, in Viereck, et. al., 1992) describes a nominally similar leatherleaf (Chamaedaphne spp.) willow (Salix spp.) - sedge (Carex spp.) type, that is the closest published description to what is found on the Kenai Lowlands.

Sphagnum moss (Sphagnum spp.) - leatherleaf (Chamaedaphne calycuta) communities are found on floating islands or mats, usually near the edges of lakes, although one site was in a functionally similar locale along a relict glacial drainageway merging with a relict lakebed near the edge of a floating mat.  Another site was in a hydrologically altered position near a road.  All sites are located on the northern peninsula, and leatherleaf is uncommon south of Soldotna.  

This is one of the only communities (along with the Sphagnum - round sedge and Sphagnum - Red cottongrass 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.

Sphagnum moss - leatherleaf communities are characterized by a thick peat mat with sparse vegetation cover.  A woodland density of leatherleaf overtops trace amounts of sundew (Drosera rotundifolia), bog rosemary Andromeda polifolia) and bog cranberry (Vaccinium oxycoccos).  

Histosols are present, with organic mats almost always over one meter thick (40).  The water table is always less than a foot (30 cm) from the surface.  The lowest pH recorded in the project area, 3.8, was found at one site, and the average of the four sites measured was very strongly acid (4.7), although at one site measured, near a drainageway, was moderately acid (5.7).  All sites visited are 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
Chamaedaphne calyculata   1.0 17.0 FAC FAC
Betula nana 0.8 0.9 FAC FAC, OBL
Dwarf shrubs
Vaccinium oxycoccos 1.0 1.8 OBL OBL
Andromeda polifolia 1.0 1.1 OBL OBL
Drosera rotundifolia 1.0 0.7 OBL OBL
Eriophorum russeolum   0.8 3.9 FACW FACW
Carex aquatilis   0.6 1.5 OBL OBL
Sphagnum spp. 0.8 98.8
Open water 0.6 0.5      


 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 10:03