|Sitka alder / Shieldfern|
|Alnus viridis ssp. sinuata
/ Dryopteris expansa
|IIB(1)b: Closed Tall Alder Shrub|
|Ecosystem: Discharge Slope|
Sitka alder (Alnus viridis ssp. sinuata) types are widespread and variable in Alaska (Viereck et al 1992), but a shieldfern (Dryopteris expansa) understory has not been previously described in the literature.
Sitka Alder / sheildfern is uncommon. It usually is found on steep back- and footslopes near the coast.
Tall Sitka alder (greater than 2 meters) and shieldfern cover are nearly complete (95-100%). Bluejoint grass (Calamagrostis canadensis) is present at about 20% cover. Field horsetail (Equisetum arvense), red elderberry (Sambucus racemosa), and arctic starflower (Trientalis europea) are common associates.
This can be an upland type. The water table was at 150 centimeters at the one site where it was measured. However, redoximorphic features (soil evidence that the water table is seasonally high) were found closer than 30 cm from the surface at two sites. At the one nearly level location (on the toeslope of a steep gully), along the coast between Clam Gulch and Ninilchik, a 150 cm thick organic layer was measured, with redox features at 12 cm. Four of the nine plots sampled could be classified as jurisdictional wetlands.
Table 1. Frequency of occurrence and hydric status of soil series named at NRCS holes. Bold type indicates soils on the NRCS Alaska hydric soils list.
|Soil Series||n||Hydric Criteria number|
Table 2. Summary of plant frequency and
average cover for plants occurring in more than 50% of plots .
|Wetland Indicator Status|
|Alnus viridis ssp. sinuata||1.0||98.3||FAC||FAC, FACW*|
|Dryopteris expansa||1.0||61.7||FACU||FACU, FACW
|Calamagrostis canadensis||1.0||19.7||FAC||FAC, OBL|
|Equisetum arvense||1.0||3.2||FAC*||FAC*, FACW-|
|Trientalis europaea||1.0||1.7||FAC||FAC*, FAC
|Equisetum sylvaticum||0.7||7.8||FACU||FACU, FACW
|Gymnocarpium dryopteris||0.7||3.8||FACU||UPL, FAC|
|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 09:36