Natural Resources
Conservation Service
Ecological site R226XY050AK
Beach Dunes and Ridges (St. George Island)
Accessed: 09/23/2026
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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 is characterized by sand dunes and sandy/gravely beach ridges that run parallel to the coasts of the Bering Sea.
Table 2. Representative physiographic features
Landforms (1) Beach
(2) Dune
(3) Ridge
Elevation 0 – 120 ft Slope 0 – 100 % 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 very deep and well drained. Soils are coarse textured and soil pH is slightly acid. Runoff is very low and permeability is very rapid.
Table 4. Representative soil features
Surface texture (1) Peaty sand
Family particle size (1) Sandy
Drainage class Well drained Permeability class Rapid to very rapid Soil depth 60 – 79 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)6.1 – 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/ Conioselinum chinense var. pacificumCommunity 1.1
Elymus mollis/ Conioselinum chinense var. pacificumSedges and grasses make up 45% and forbs 55% of the composition. Total annual vascular herbage production is 3980 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 1500–2000 American dunegrass LEMOM2 Leymus mollis ssp. mollis 1150–2000 – sedge CAREX Carex 475–500 – red fescue FERU2 Festuca rubra 85–95 – bluegrass POA Poa 40–50 – Forb1 2000–2500 Pacific hemlockparsley COGM Conioselinum gmelinii 1100–1130 – seacoast angelica ANLU Angelica lucida 525–550 – Nootka lupine LUNO Lupinus nootkatensis 475–500 – Tilesius' wormwood ARTI Artemisia tilesii 30–40 – whorled lousewort PEVE Pedicularis verticillata 2–8 – larkspurleaf monkshood ACDE2 Aconitum delphiniifolium 0–5 – boreal yarrow ACMIB Achillea millefolium var. borealis 0–5 – boreal draba DRBO Draba borealis 0–5 – North Pacific draba DRHY Draba hyperborea 0–5 – field horsetail EQAR Equisetum arvense 0–5 – Interpretations
Animal community
This site has very little grazing value for reindeer. Winter forage is low quality and lyme grass is not selected by reindeer and seldom utilized. The site is frequently used for cover from storm winds during winter and for an insect relief area during summer where reindeer take advantage of offshore breezes. This site is generally available for use as a resting area and is one of the more snow free sites in the area.
Recreational uses
Because of the rolling terrain and sandy soils, this site is sometimes used by four wheeler enthusiasts. This site's vegetation does not hold up well to four wheeler traffic, however, and when the soil is exposed the area is succeptible to wind erosion and blow outs.
Wood products
Not applicable
Other products
The lyme grass produced on this site is tall and stout. It has the potential to be used for weaving baskets or other products.
Supporting information
Contributors
David 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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