Natural Resources
Conservation Service
Ecological site R226XY058AK
Rocky Shrub Tundra (Upland) (AK653 St Paul Island)
Accessed: 10/07/2026
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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 rocky inland areas. This site is similar to, and frequently associated with Dwarf Shrub Tundra (Upland) site. Rock outcroppings are interspersed throughout the site.
Table 2. Representative physiographic features
Landforms (1) Hill
Elevation 120 – 500 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 shallow to moderately deep and moderately well to well drained. Soils are stony and cobbly and medium textured. Soil pH is slightly acid. Runoff is very low and permeability is moderately rapid.
Table 4. Representative soil features
Surface texture (1) Extremely stony silt loam
(2) Cobbly
Family particle size (1) Loamy
Drainage class Moderately well drained to well drained Permeability class Moderately rapid Soil depth 10 – 40 in Surface fragment cover <=3" Not specified Surface fragment cover >3" Not specified Available water capacity
(0-40in)4.2 – 4.4 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
Salix arctica/Achillea borealisCommunity 1.1
Salix arctica/Achillea borealisShrubs make up about 40% of the composition, forbs about 45% and grasses and sedges about 15% of the composition. Total annual vascular herbage production is1800 pounds/acre. Total live lichen biomass is 5000 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 550–600 northern willow SAAR6 Salix arctophila 370–380 – black crowberry EMNI Empetrum nigrum 85–100 – arctic willow SAAR27 Salix arctica 90–100 – Grass/Grasslike1 300–320 showy sedge CASP5 Carex spectabilis 95–105 – alpine timothy PHAL2 Phleum alpinum 90–100 – Bering Sea sedge CAMIN Carex microchaeta ssp. nesophila 45–55 – spike trisetum TRSP2 Trisetum spicatum 25–35 – arctic bluegrass POARA2 Poa arctica ssp. arctica 5–15 – bluegrass POA Poa 0–10 – red fescue FERU2 Festuca rubra 2–10 – polargrass ARCTA Arctagrostis 5–10 – common woodrush LUMU2 Luzula multiflora 2–8 – American dunegrass LEMOM2 Leymus mollis ssp. mollis 0–5 – Forb1 900–1000 boreal yarrow ACMIB Achillea millefolium var. borealis 320–330 – Nootka lupine LUNO Lupinus nootkatensis 165–175 – seacoast angelica ANLU Angelica lucida 100–125 – Bering chickweed CEBE2 Cerastium beeringianum 60–75 – Pacific hemlockparsley COGM Conioselinum gmelinii 20–25 – field horsetail EQAR Equisetum arvense 15–25 – Macoun's poppy PAMA5 Papaver macounii 10–20 – boreal draba DRBO Draba borealis 10–20 – sweetflower rockjasmine ANCH Androsace chamaejasme 5–15 – larkspurleaf monkshood ACDE2 Aconitum delphiniifolium 5–15 – Tilesius' wormwood ARTI Artemisia tilesii 5–15 – field sagewort ARCAB4 Artemisia campestris ssp. borealis var. borealis 0–10 – Hornemann's willowherb EPHOB Epilobium hornemannii ssp. behringianum 0–10 – captiate valerian VACA3 Valeriana capitata 0–10 – cloudberry RUCH Rubus chamaemorus 3–8 – northern starwort STCA Stellaria calycantha 0–5 – starwort STELL Stellaria 0–5 – Aleutian violet VILA6 Viola langsdorffii 0–5 – whorled lousewort PEVE Pedicularis verticillata 0–5 – tall Jacob's-ladder POAC Polemonium acutiflorum 0–5 – arctic raspberry RUARS Rubus arcticus ssp. stellatus 0–5 – mountain harebell CALA7 Campanula lasiocarpa 0–5 – boreal sagebrush ARAR9 Artemisia arctica 0–5 – Danish scurvygrass COGR6 Cochlearia groenlandica 0 – Lichen1 0–5 whiteworm lichen THAMN3 Thamnolia 0–5 – Interpretations
Animal community
This is a winter high-value grazing site for reindeer. Salix spp. growing on this site is high forage and preference value during winter and winter-spring months. Reindeer will tend to concentrate on this site which is very sensitive to grazing. Herders need to use caution when moving reindeer through these areas. Herding techniques need to be subtle because crowding the reindeer and causing them to mill may result in hoof injuries and broken legs.
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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