|Sphagnum moss - Round sedge|
|Sphagnum spp. - Carex rotundata|
|n = 8|
|III.A.3.j. Subarctic Lowland Sedge Bog|
|Ecosystem: Relict Lakebed / Drainageway, Kettle, Depression|
The sphagnum moss - round sedge community described here is similar to Rosenberg’s (1986) red cottongrass (Eriophorum russeolum) – round sedge (Carex rotundata) community, found around the mouth of the Kenai River, and sometimes has a red cottongrass component. We sampled a larger area with more plots, so are able to discriminate two types, a sphagnum moss (Sphagnum spp.) – round sedge community and the sphagnum moss – red cottongrass community described elsewhere in this document.
Found on well-developed peatlands over relict lakebeds, this is one of the only communities (along with the Sphagnum - leatherleaf community) 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.
Thick sphagnum mats with sparse vegetation cover dominated by round sedge and a few other taxa such as bog rosemary (Andromeda polifolia), bog cranberry (Vaccinium oxycoccos) and round sundew (Drosera rotundifolia) characterize this type.
The organic horizon is at least one meter thick. The water table can be close to the surface, but it was nearly a meter (36”) below the surface at one site. The pH is strongly to very strongly acid (average = 4.8). 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|
|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 10:03