|Sphagnum moss - Red cottongrass|
|Sphagnum spp. - Eriophorum russeolum|
|n = 4|
|III.A.3.k. Subarctic Lowland Sedge-Moss Bog|
|Ecosystem: Relict Drainageway / Lakebed, Kettle|
On the Kenai lowlands, the Sphagnum moss - red cottongrass community is included in Rosenberg’s (1986) red cottongrass (Eriophorum russeolum) – round sedge (Carex rotundata) type, but we separate that community into both a red cottongrass and a round sedge type. Wilson and Underwood (1979. in Viereck, et. al., 1992) describe a similar red cottongrass – white cottongrass (Eriophorum scheuchzeri) type for Kodiak Island. The sphagnum - red cottongrass type is rare on the Kenai; was “undersampled” on the Cooper River Delta (Boggs, 2000), and was not found on neighboring Chugach National Forest (DeVelice et. al., 1999).
Four sites were sampled, two on floating mats at lake margins in kettles, one of which is a human created lake, and two in a hydrologically altered (by road construction) relict glacial drainageway near Kenai. This type is probably related to disturbance, and may not represent a stable community on a time scale of decades.
This is one of the only communities (along with the Sphagnum - leatherleaf and Spahgnum - round sedge 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.
A continuous sphagnum (Sphagnum spp.) mat supports sparse plant cover, dominated by red cottongrass. Bog rosemary (Andromeda polifolia), boreal bog sedge (Carex magellanicaand bog cranberry (Vaccinium oxycoccosare all present in trace amounts. Bluejoint grass (Calamagrostis canadensisand marsh fivefinger (Comarum palustreare often present, also in trace amounts.
The organic mat is thick and depth to the water table variable. The pH is very strongly to extremely acid (4.5). All four sites examined are jurisdictional wetlands.
Table 1. Summary of plant frequency and average cover for plants occurring
in more than 50% of plots .
|Wetland Indicator Status|
|Calamagrostis canadensis||0.8||1.3||FAC||FAC, OBL|
|Contact: Mike Gracz Kenai Watershed Forum PO Box 15301 Fritz Creek, AK 99603 907-235-2218||
Alaska Natural Heritage Program
and Natural Resource Institute
707 A Street, Suite 101
Anchorage, Alaska 99501
04 May 2007 10:04