Natural Resources
Conservation Service
Ecological site R226XY099AK
Grassy Meadow (AK653 St Paul Island)
Accessed: 11/23/2024
General information
Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
Not specified |
| Herbaceous |
Not specified |
Physiographic features
This site occurs in broad drainage-ways, plains and alluvial fans. This site occurs near the coastal zones and in conjunction with Forb Tundra (Coastal).
Table 2. Representative physiographic features
| Landforms |
(1)
Drainageway
(2) Plain (3) Alluvial fan |
|---|---|
| Elevation | 6 – 24 m |
| Slope | 1 – 10% |
Climatic features
Table 3. Representative climatic features
| Frost-free period (average) | 120 days |
|---|---|
| Freeze-free period (average) | 100 days |
| Precipitation total (average) | 610 mm |
Figure 1. Monthly precipitation range
Figure 2. Monthly average minimum and maximum temperature
Influencing water features
Soil features
Soils are moderately deep to deep and moderately well to somewhat poorly drained. Soil pH is moderately acid. Soils are stony and cobbly, and textures are medium. Runoff is very low and permeability is moderately rapid.
Table 4. Representative soil features
| Surface texture |
(1) Medial silt loam (2) Stony |
|---|---|
| Family particle size |
(1) Loamy |
| Drainage class | Moderately well drained to somewhat poorly drained |
| Permeability class | Moderately rapid |
| Soil depth | 51 – 152 cm |
| Surface fragment cover <=3" | 0% |
| Surface fragment cover >3" | 0% |
| Available water capacity (0-101.6cm) |
14.99 – 15.49 cm |
| Calcium carbonate equivalent (0-101.6cm) |
0% |
| Electrical conductivity (0-101.6cm) |
0 mmhos/cm |
| Sodium adsorption ratio (0-101.6cm) |
0 |
| Soil reaction (1:1 water) (0-101.6cm) |
5.6 – 6 |
| Subsurface fragment volume <=3" (Depth not specified) |
0% |
| Subsurface fragment volume >3" (Depth not specified) |
0% |
Ecological dynamics
State and transition model
More interactive model formats are also available.
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Ecosystem states
State 1 submodel, plant communities
State 1
Elymus arenarius ssp. mollis/Calamagrostis holmii
Community 1.1
Elymus arenarius ssp. mollis/Calamagrostis holmii
Grasses make up 60% and forbs 40% of the composition. Total annual vascular herbage production is 3660 pounds/acre.
Figure 3. Annual production by plant type (representative values) or group (midpoint values)
Additional community tables
Table 5. Community 1.1 plant community composition
| Group | Common name | Symbol | Scientific name | Annual production (kg/hectare) | Foliar cover (%) | |
|---|---|---|---|---|---|---|
|
Grass/Grasslike
|
||||||
| 1 | 2410–2522 | |||||
| American dunegrass | LEMOM2 | Leymus mollis ssp. mollis | 1334–2242 | – | ||
| Holm's reedgrass | CAHO | Calamagrostis holmii | 600–611 | – | ||
| wideleaf polargrass | ARLA2 | Arctagrostis latifolia | 291–308 | – | ||
| arctic bluegrass | POARA2 | Poa arctica ssp. arctica | 129–135 | – | ||
| alpine timothy | PHAL2 | Phleum alpinum | 39–50 | – | ||
| Bering's tufted hairgrass | DEBE2 | Deschampsia beringensis | 22–34 | – | ||
|
Forb
|
||||||
| 1 | 1569–1681 | |||||
| seacoast angelica | ANLU | Angelica lucida | 493–510 | – | ||
| Pacific hemlockparsley | COGM | Conioselinum gmelinii | 286–291 | – | ||
| boreal yarrow | ACMIB | Achillea millefolium var. borealis | 207–213 | – | ||
| Nootka lupine | LUNO | Lupinus nootkatensis | 196–213 | – | ||
| Tilesius' wormwood | ARTI | Artemisia tilesii | 101–112 | – | ||
| larkspurleaf monkshood | ACDEC | Aconitum delphiniifolium ssp. chamissonianum | 73–84 | – | ||
| northern Jacob's-ladder | POBOM | Polemonium boreale ssp. macranthum | 34–39 | – | ||
| northern starwort | STCA | Stellaria calycantha | 17–28 | – | ||
| Aleutian violet | VILA6 | Viola langsdorffii | 11–17 | – | ||
| larkspurleaf monkshood | ACDE2 | Aconitum delphiniifolium | 6–17 | – | ||
| Hornemann's willowherb | EPHOB | Epilobium hornemannii ssp. behringianum | 11–17 | – | ||
| field horsetail | EQAR | Equisetum arvense | 6–17 | – | ||
| Danish scurvygrass | COGR6 | Cochlearia groenlandica | 6–11 | – | ||
| captiate valerian | VACA3 | Valeriana capitata | 6–11 | – | ||
Interpretations
Animal community
Excellent in spring for a short period of time after soils have thawed and snow runoff has percolated down through soil profile. Later on during middle to late summer, the forage is significantly reduced.
Supporting information
Contributors
Swanson
Rangeland health reference sheet
Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.
| Author(s)/participant(s) | |
|---|---|
| Contact for lead author | |
| Date | |
| Approved by | |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
-
Presence of water flow patterns:
-
Number and height of erosional pedestals or terracettes:
-
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
-
Number of gullies and erosion associated with gullies:
-
Extent of wind scoured, blowouts and/or depositional areas:
-
Amount of litter movement (describe size and distance expected to travel):
-
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
-
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
-
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
-
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
-
Functional/Structural Groups (list in order of descending dominance by above-ground annual-production or live foliar cover using symbols: >>, >, = to indicate much greater than, greater than, and equal to):
Dominant:
Sub-dominant:
Other:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
-
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
-
Potential invasive (including noxious) species (native and non-native). List species which BOTH characterize degraded states and have the potential to become a dominant or co-dominant species on the ecological site if their future establishment and growth is not actively controlled by management interventions. Species that become dominant for only one to several years (e.g., short-term response to drought or wildfire) are not invasive plants. Note that unlike other indicators, we are describing what is NOT expected in the reference state for the ecological site:
-
Perennial plant reproductive capability:
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