|Crowberry – Labrador tea|
|Empetrum nigrum – Ledum palustre ssp. decumbens|
|n = 19|
|II.C.2.e. Open Low Ericaceous Shrub Bog|
|Ecosystem: Relict Lakebed / Drainageway, Depression|
This is a common Alaskan type. These dominants can occupy alpine areas where peat is not well developed, but in the Alaska Vegetation Classification (Viereck, et. al., 1992) those communities are classified as ericaceous shrub rather than shrub bog.
On the lowlands, the crowberry (Empetrum nigrum) - Labrador tea (Ledum palustre ssp. decumbens) type is widespread but more common south of Clam Gulch, primarily on relict glacial lakebeds. It is sometimes found on abandoned relict drainageways in locales where peat is deeper.
This community is dominated by a dense low cover of crowberry with abundant Labrador tea on a hummocky mossy peat. Shrub birch (Betula nana) and bog blueberry (Vaccinium uliginosum) are often common to abundant. Cloudberry (Rubus chamaemorus) and the dwarf shrubs lingonberry (Vaccinium vitis-idaea) and bog cranberry (Vaccinium oxycoccos) are often present.
Peat is usually over 1 meter thick. The water table is typically close to the surface, but was greater than a meter deep at three locations. pH was only measured at one site where it was strongly to very strongly acid (5.0). Seventeen of 19 plots visited are jurisdictional wetlands, while the other two are close calls.
These peatlands are curious, the peat depth meets the soils hydric criterion, but sometimes the water table is very deep. Where it is deep, these sites might represent dry years, dry times during the year, or suggest that a longer-term drying trend is prevalent. See the discussion in the depression ecosystem description.
Table 1. Summary of plant frequency and average cover for plants occurring
in more than 50% of plots .
|STARICHKOF||7||1, 2B2, 3|
|1Proposed series, definitely hydric|
Table 2. Summary of plant frequency and average cover for plants occurring in more than 50% of plots.
|Wetland Indicator Status|
|Empetrum nigrum||1.0||51.6||FAC||FACU, FACW
|Ledum palustre ssp. decumbens||1.0||43.2||FACW||FACW
|Betula nana||0.9||25.1||FAC||FAC, OBL
|Vaccinium uliginosum||0.8||11.3||FAC||FACU+, FACW|
|Equisetum arvense||0.6||13.0||FAC*||FAC*, FACW-|
|1 Plant with known morphological adaptation for occurrence in wetlands (USACE, 1987)|
|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 09:39