|
|
Sitka alder / Field horsetail |
| Alnus viridis ssp. sinuata / Equisetum arvense | |
| n=3 | |
| IIB(1)b: Closed Tall Alder Shrub | |
| Ecosystem: Discharge Slope |
Variable Sitka alder (Alnus viridis ssp. sinuata)
types are widespread in Alaska.
Boggs (2000) and DeVelice, et. al.
(1999) describe a type similar to the one described here,
although with a Barclay's willow (Salix barclayi)
component not present on the Kenai Lowlands.
Craighead et. al. (1988) describe this type for
extreme northwestern Alaska.
Sitka alder / field horsetail (Equisetum arvense) is found throughout the Kenai Lowlands on foot- and toeslopes, typically at the edges of moderately steep stream valley walls. It is also below the Homer bluffs, at the edge of a tidal lagoon near Nikiski, and along the west slope of the Caribou Hills along toeslopes of larger terraces.
Dense patches of field horsetail with scattered ladyfern (Atyrium felix-femina) occur in the understory. Sometimes thinleaf alder (Alnus incana ssp. tenuifolia) replaces Sitka alder as the overstory dominant. Other plants are sparse, though red elderberry, (Sambucus racemosa) may be common. Bluejoint (Calamagrostis canadensis) may be abundant or absent.
The water table, or evidence of it, is usually around 20 centimeters from the surface. Sometimes a thick organic layer is present (64 cm at one locale). pH ranges from strongly to moderately acid (5.0-6.1 at the three sites measured). Nine of ten of the plots sampled 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.
| Soil Series | n | Hydric Criteria Number |
| BELUGA | 3 |
2B3 |
| KILLEY | 2 |
2B3 |
| SPENARD | 2 |
2B3 |
Table 2. Summary of plant frequency and average cover for plants occurring in more than 50% of plots.
| f | Average Cover | Alaska | National | ||
| Shrubs | |||||
| Alnus viridis ssp. sinuata | 0.8 | 63.4 | FAC | FAC,
FACW* |
|
| Herbs/Graminoids | |||||
| Equisetum arvense | 0.9 | 42.7 | FAC* | FAC*,
FACW- |
|
| Athyrium filix-femina | 0.9 | 4.2 | FAC | FAC, FAC+ | |
| Calamagrostis canadensis | 0.6 | 27.7 | FAC | FAC, OBL |
|
| Impatiens noli-tangere | 0.6 | 24.8 | FACW | FACW |
|
| Urtica dioica ssp. gracilis | 0.6 | 23.5 | FACU | FACU, FACW |
|
| Heracleum maximum | 0.6 | 1.0 | FACU | FACU-, OBL | |
| Moss | 0.8 | 15.3 |
|||
|
|
Introduction and Key to Plant Communities |
 |
| Contact: Mike Gracz Kenai Watershed Forum PO Box 15301 Fritz Creek, AK 99603 907-235-2218 |
The
Alaska Natural Heritage Program
Environment
and Natural Resource Institute
University of
Alaska, Anchorage
707 A Street, Suite 101
Anchorage, Alaska 99501
04 May 2007 09:36 |
