|Bluejoint - Field horsetail|
|Calamagrostis canadensis - Equisetum arvense|
|n = 36|
|III.A.2.b. Bluejoint -Herb|
|Ecosystem: Discharge Slope, Riparian|
Bluejoint (Calamagrostis canadensis) – field horsetail (Equisetum arvense) is not well documented in the Alaskan literature. A new category, (III.A.3.x) “Subarctic Lowland Grass Wet Meadow (or Fen)” is warranted. Its closest fit, the “III.A.2. Mesic Gaminoid Herbaceous” in the Alaska Vegetation Classification (Viereck et. al. 1992) is not appropriate, as Bluejoint filed horsetail is typically wetter than mesic on the Kenai lowlands. Saturated bluejoint stands are common on the lowlands and warrant a new Alaska Vegetation class.
Boggs (2000) describes a similar Bluejoint / Marsh fivefinger (Comarum palustre) type, on the Copper River, but only half of those plots contain field horsetail. On Chugach National Forest, the type described here probably falls between two types they document: the pure field horsetail (with low, inconsistent bluejoint cover) and the pure bluejoint (with about 1/3 of those plots with field horsetail) (DeVelice, et. al., 1999).
Bluejoint - field horsetail communities are common on foot and toeslopes near the coast all over the lowlands, but especially at the base of the Homer bluffs. A few sites are located in appropriate landscape positions in the Caribou Hills. This type can be an indicator of human-generated disturbance.
Bluejoint cover is dense, and tall field horsetail is typically abundant just under the bluejoint (mostly the more robust Calamagrostis canadensis ssp. langsdorfii). Fireweed (Chamerion angustifolium, typically the robust ssp. circumvagum) is a common associate. Sites with thick organic mats (up to 160 cm) tend to have less field horsetail; sites with high water tables have more.
The presence of this type does not necessarily indicate a
wetland. Organic horizon thickness and depth to water table vary tremendously
(3-160 cm and 15-145 cm where measured, respectively);
of the 36 locales visited would probably qualify 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.
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.
|STARICHKOF||5||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|
|Calamagrostis canadensis||1.0||84.4||FAC||FAC, OBL|
|Equisetum arvense||1.0||41.8||FAC*||FAC*, FACW-|
|Chamerion angustifolium||0.7||15.7||FACU||FACU, 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 09:37