Natural Resources
Conservation Service
Ecological site R226XY033AK
Dwarf Shrub Tundra (AK653 St Paul Island)
Accessed: 09/16/2026
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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
Occurs on gently sloping broad summits of hills near the coast. There are a few rock outcrops and incipient drainage ways.
Table 2. Representative physiographic features
Landforms (1) Hill
Elevation 200 – 250 ft 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) 20 in BarLineFigure 1. Monthly precipitation range
BarLineFigure 2. Monthly average minimum and maximum temperature
">Influencing water features
Soil features
Soils are moderately deep and well drained. Textures are medium and soil pH is slightly acid to neutral. Runoff is low and permeability is rapid to moderately rapid.
Table 4. Representative soil features
Surface texture (1) Medial fine sandy loam
Family particle size (1) Sandy
Drainage class Well drained Permeability class Rapid to moderately rapid Soil depth 20 – 40 in Surface fragment cover <=3" Not specified Surface fragment cover >3" Not specified Available water capacity
(0-40in)4.5 – 4.7 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 – 7.3 Subsurface fragment volume <=3"
(Depth not specified)Not specified Subsurface fragment volume >3"
(Depth not specified)Not specified Ecological dynamics
Shrubs make up about 45% of the composition, forbs about 50% and grasses and sedges 5% of the composition. Total annual vascular herbage production is 1130 pounds/acre. Total live lichen biomass is 2,000 pounds/acre.
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
Lupinus nootkatensis/Salix arcticaCommunity 1.1
Lupinus nootkatensis/Salix arcticaShrubs make up about 45% of the composition, forbs about 50% and grasses and sedges 5% of the composition. Total annual vascular herbage production is 1130 pounds/acre. Total live lichen biomass is 2,000 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 (%) Shrub/Vine1 490–510 northern willow SAAR6 Salix arctophila 295–305 – netleaf willow SARE2 Salix reticulata 95–105 – black crowberry EMNI Empetrum nigrum 95–105 – Grass/Grasslike1 85–95 spike trisetum TRSP2 Trisetum spicatum 70–80 – red fescue FERU2 Festuca rubra 10–20 – common woodrush LUMU2 Luzula multiflora 0–5 – bluegrass POA Poa 0–5 – shortstalk sedge CAPO Carex podocarpa 0–5 – Forb1 500–600 Nootka lupine LUNO Lupinus nootkatensis 395–405 – boreal yarrow ACMIB Achillea millefolium var. borealis 95–105 – whorled lousewort PEVE Pedicularis verticillata 20–30 – larkspurleaf monkshood ACDE2 Aconitum delphiniifolium 0–5 – Langsdorf's lousewort PELAL5 Pedicularis langsdorffii ssp. langsdorffii 0–5 – thymeleaf saxifrage SASE7 Saxifraga serpyllifolia 0–5 – moss campion SIAC Silene acaulis 0–5 – sweetflower rockjasmine ANCH Androsace chamaejasme 0–5 – seacoast angelica ANLU Angelica lucida 0–5 – boreal sagebrush ARAR9 Artemisia arctica 0–5 – purple wormwood ARGL8 Artemisia globularia 0–5 – bittercress CARDA Cardamine 0–5 – Bering chickweed CEBE2 Cerastium beeringianum 0–5 – arctic stitchwort MIAR3 Minuartia arctica 0–5 – Lapland poppy PALA9 Papaver lapponicum 0–5 – boreal draba DRBO Draba borealis 0–5 – field horsetail EQAR Equisetum arvense 0–5 – Ross' avens GERO2 Geum rossii 0–5 – Hornemann's willowherb EPHOB Epilobium hornemannii ssp. behringianum 0–1 – Pacific hemlockparsley COGM Conioselinum gmelinii 0–1 – arctic cinquefoil PONA6 Potentilla nana 0–1 – Interpretations
Animal community
This is a high value winter grazing site for reindeer due to the exposed windswept hill summits and easily accessible forage. Willows growing on this site have high forage value and are preferred by reindeer during winter and early spring months. Reindeer will tend to concentrate on this site which is very sensitive to grazing.
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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