Natural Resources
Conservation Service
Ecological site R226XY055AK
Forb Tundra (Coastal) (AK 653 St Paul Island)
Accessed: 10/04/2026
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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 on nearly level beach terraces and on toe-slopes of rocky uplands adjacent to the coast.
Table 2. Representative physiographic features
Landforms (1) Coastal plain
Elevation 5 – 80 ft Slope 0 – 3 % Climatic features
Table 3 Representative climatic features
Frost-free period (average) 120 days Freeze-free period (average) 100 days Precipitation total (average) 20 in BarLineFigure 1. Monthly precipitation range
BarLineFigure 2. Monthly average minimum and maximum temperature
">Influencing water features
Soil features
Soils are shallow to deep and well drained. Textures are coarse and soil pH is strongly acid to slightly acid. Runoff is very low to low, and permeability is moderately rapid to rapid.
Table 4. Representative soil features
Surface texture (1) Peaty sand
Family particle size (1) Sandy
Drainage class Well drained Permeability class Moderately rapid to rapid Soil depth 10 – 60 in Surface fragment cover <=3" Not specified Surface fragment cover >3" Not specified Available water capacity
(0-40in)2.9 – 3.1 in Calcium carbonate equivalent
(0-40in)Not specified Electrical conductivity
(0-40in)Not specified Sodium adsorption ratio
(0-40in)Not specified Soil reaction (1:1 water)
(0-40in)5.1 – 6.5 Subsurface fragment volume <=3"
(Depth not specified)Not specified Subsurface fragment volume >3"
(Depth not specified)Not specified Ecological dynamics
State and transition model
More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective textEcosystem states
State 1 submodel, plant communities
State 1
Elymus mollis/ Lupinus nootkatensisCommunity 1.1
Elymus mollis/ Lupinus nootkatensisGrasses make up 45% and forbs 55% of the composition. Total annual vascular herbage production is 3300 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 () Foliar cover (%) Grass/Grasslike1 1300–1400 American dunegrass LEMOM2 Leymus mollis ssp. mollis 960–970 – wideleaf polargrass ARLA2 Arctagrostis latifolia 330–340 – bluegrass POA Poa 40–45 – alpine timothy PHAL2 Phleum alpinum 20–25 – Forb1 1730–1750 seacoast angelica ANLU Angelica lucida 530–550 – Pacific hemlockparsley COGM Conioselinum gmelinii 295–305 – Tilesius' wormwood ARTI Artemisia tilesii 240–260 – boreal yarrow ACMIB Achillea millefolium var. borealis 230–240 – Nootka lupine LUNO Lupinus nootkatensis 180–190 – tall Jacob's-ladder POAC Polemonium acutiflorum 85–90 – field horsetail EQAR Equisetum arvense 25–35 – monkshood ACONI Aconitum 30–35 – Aleutian violet VILA6 Viola langsdorffii 15–25 – whorled lousewort PEVE Pedicularis verticillata 15–20 – arctic starflower TREU Trientalis europaea 5–15 – captiate valerian VACA3 Valeriana capitata 0–5 – Interpretations
Animal community
Grasses such as wide leaf polargrass, alpine timothy and bluegrass provide high value reindeer forage spring to fall. These same grasses decline in forage value during the winter at which time their forage value is moderate. Lyme grass is seldom selected by reindeer during spring and summer and is of no value during wimter. The large variety of forbs provides excellent spring and summer forage.
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
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Number and extent of rills:
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Presence of water flow patterns:
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Number and height of erosional pedestals or terracettes:
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Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
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Number of gullies and erosion associated with gullies:
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Extent of wind scoured, blowouts and/or depositional areas:
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Amount of litter movement (describe size and distance expected to travel):
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Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
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Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
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Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
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Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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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:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
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Average percent litter cover (%) and depth ( in):
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Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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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:
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Perennial plant reproductive capability:
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