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Ecological site VX226X00A103

Aleutian Coastal Beach and Dune Complex

Last updated: 6/14/2025
Accessed: 12/05/2025

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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.

MLRA notes

Major Land Resource Area (MLRA): 226X–Aleutian Islands-Western Alaska Peninsula

MLRA 226X is the only MLRA in the Aleutian Alaska Region. It makes up about 5,190 square miles (13,450 square kilometers). The chain of islands includes west of Unimak Island to Attu Island, the Pribilof Islands, and the Sanak Islands. Characteristics and weather patterns of the far western end of the Alaska Peninsula is being included in this MLRA. It is bordered on the south by the Pacific Ocean and on the north by the Bering Sea (the Pribilof Islands are bordered on all sides by the Bering Sea). The coastline is complex, with many prominent headlands, sea cliffs, and narrow, steep-walled bays. Elevation ranges from sea level to more than 4,000 feet (1,220 meters) on many of the islands. Islands drain into the North Pacific and the Bering Sea by numerous short, steep-gradient rivers and streams. Lakes make up less than 2 percent of the area.

Geology
This MLRA includes more than 50 volcanoes, with an estimated 27 with activity since the 1950s. Volcanic rocks and unconsolidated deposits from the Quaternary and Tertiary period overlie a submarine ridge of Tertiary sedimentary rocks. Glacial ice once covered the eastern part of the area to approximately Umnak Island. West of Umnak, only the upper elevations were glaciated. Glaciers account for only 1.5 percent, occurring on the highest volcanoes. Volcanic activity has mantled most of the area with thick deposits of silty volcanic ash, sandy and gravelly cinders, and volcanic rubble. Lower elevations have areas of glacial influenced landforms. Recent coastal and fluvial deposits occur in scattered areas along the coast and on flood plains.

Water
Precipitation is adequate for crops generally. Permanent mountain streams feed most of the MLRA. The surface water generally is suitable for all uses. The ground water used in this MLRA is primarily from unconsolidated river valley sediments and bedrock aquifers. Iron is commonly high in the ground water, causing staining and precipitate in pipes. Wells are shallow with constant recharge by freshwater (rainfall and runoff); and are highly susceptible to contamination from runoff. The intrusion of seawater can be a problem along the coast.

Soils
The dominant soil orders in this MLRA are Andisols and Histosols. Miscellaneous areas (cinder land, rock outcrop, water, riverwash, and beaches) make up about 45 percent of this MLRA. The main soils are: Cryofibrists are poorly drained or very poorly drained and formed in thick deposits of organic material, along the margins of streams and lakeshores.
Tsammana series, Andic Dystrocryepts, Aquandic Dystrocryepts and Vitrandic Dystrocryepts are coarse marine sediments underlain by volcanic deposits. Zolotoi series and other Haplocryands are shallow to deep, well drained to excessively drained, and formed in moderately thick or thick deposits of silty to sandy volcanic ash and coarse sandy to gravelly cinders over basalt bedrock. Polovina series and other Vitricryands are shallow to deep, well drained to excessively drained, and formed in moderately thick or thick deposits of silty to sandy volcanic ash and coarse sandy to gravelly cinders over basalt bedrock.

Biological Resources
Higher elevation vegetation consists of a mosaic of dwarf shrub scrub and lower elevations are wet and dry grasslands. Peatland vegetation consists of low ericaceous shrub scrub. No naturally occurring forests occur on the islands. Aleutian shield fern, Steller sea lion, and the Aleutian Canada goose are currently listed as threatened or endangered. The area is an important winter habitat and nesting habitat for waterfowl and a variety of other birds. Some of the eastern islands support small herds of caribou.

Land Use
Commercial fishing is the primary enterprise, with fur seal harvesting for pelts and meat, Reindeer herding, and small cattle herds. Subsistence hunting, fishing, and gathering are critical for local residents. The major resource concerns are water erosion and mass wasting of soils. Overgrazing by reindeer has impacted vegetation and introduction of rats, dogs, cats, and foxes has severely impacted the nesting bird populations.

LRU notes

MLRA 226X, although very size-limited, contains very complex and dynamic weather patterns driven by the Pacific air currents on the southern exposure of the islands, and the Bering Sea to the north. The mixing or colliding of these two systems, creates very dramatic and intense storm systems that batter the islands. Weather variables from the Pacific to the Bering Sea, extent from west to east, as well as the extreme elevational gradient moving from sea level to Alpine life zone lends to a community diversity that is difficult to describe across an MLRA extent. Land Resource Units (LRUs) will need to be developed for this MLRA, as more extensive soils survey mapping is completed.

Classification relationships

Alaska-Aleutian province of the Pacific Mountain System.

USFS Description of Ecoregions of the United States
100 Polar Domain
120 Tundra Division
126 Bering Tundra (Southern) Province
M120 Tundra Division - Mountain Province
M127 Aleutian Oceanic Meadow--Heath Province
(USFS, 1994)

United States National Vegetation Classification
C04. Polar & High Montane Scrub, Grassland & Barrens Class
S12. Temperate to Polar Alpine & Tundra Vegetation Subclass
F031. Polar Tundra & Barrens Formation
D044. Arctic Tundra & Barrens Division
(USNVC, 2019)

LandFire BpS Model/Description Version: Nov. 2024
- 17090 North American Arctic-Subarctic Coastal Dune and Beach
(Landfire, 2009)

Ecological site concept

- Occurs on dunes and marine terraces
- Soils resulting from tidal flow, and eolian sand and silt movement along the coastline.
- Soils are affected by salt and fresh water at different rates, creating a diverse community.
- No water table is associated with this site, no ponding expected.
- Flooding is none to rare, lower tidal flats have the influence of the daily tides.
- Fine surface and subsurface gravels and cobbles, with few areas of boulder fields (block fields or fell fields).
- Vegetation is somewhat sparse on newer and more active tidal and dune locations, but vegetation cover increases with landform age and stability.
- Plant community is characterized by a salt-tolerant forb and grass dominated early successional community, then a higher diversity of grass and forbs develop on the second stage or more established beaches and dunes. And finally, the mature sites will have a dwarf-shrub stringers intermixed with the grass and forb established communities.

Associated sites

VX226X00A104	Aleutian Riparian and Lake Shore Complex The tidal flats, beaches, and dunes, are interwoven with the streams, rivers, and lowland wetlands that comprise the drainage complex ecological site. The water table driven components of the beaches and dunes will correlate to the drainage complex.

VX226X00A104

Aleutian Riparian and Lake Shore Complex

The tidal flats, beaches, and dunes, are interwoven with the streams, rivers, and lowland wetlands that comprise the drainage complex ecological site. The water table driven components of the beaches and dunes will correlate to the drainage complex.

Similar sites

VX226X00A110	Aleutian Eolian Plains and Hills The eolian plains and hills ecological site is the upland equivalent to the beach and dunes. The landforms are stabilized and have had more development time to establish an upland community type. The tidal and harsh coastal winds are not the major influence. A low shrub/scrub tundra is the major composition for this upland site.

VX226X00A110

Aleutian Eolian Plains and Hills

The eolian plains and hills ecological site is the upland equivalent to the beach and dunes. The landforms are stabilized and have had more development time to establish an upland community type. The tidal and harsh coastal winds are not the major influence. A low shrub/scrub tundra is the major composition for this upland site.

Table 1. Dominant plant species

Tree	Not specified
Shrub	(1) Arctostaphylos rubra (2) Betula nana
Herbaceous	(1) Leymus mollis (2) Cochlearia groenlandica

Legacy ID

R226XY103AK

Download full description

Physiographic features

This site occurs on dunes and relatively flat, moist beach ridges and marine terraces associated with ocean shores. These landscape positions are not flooded or ponded by tides but are influenced by salt spray. The water table is from 9 to 24 inches below the soil surface throughout the growing season. Slopes range from 2 to 5 percent and elevations are 10 to 80 feet above sea level.

Table 2. Representative physiographic features

Landforms	(1) Island > Beach (2) Beach terrace (3) Dune (4) Strand plain
Runoff class	Negligible to low
Flooding frequency	None to occasional
Ponding frequency	None
Elevation	10 – 80 ft
Slope	2 – 5%
Water table depth	9 – 24 in
Aspect	W, NW, N, NE, E, SE, S, SW

Table 3. Representative physiographic features (actual ranges)

Runoff class	Not specified
Flooding frequency	None to very frequent
Ponding frequency	Not specified
Elevation	100 ft
Slope	16%
Water table depth	Not specified

Climatic features

The climate is similar to that on the arctic coastal plain, except Islands are impacted by the tides, air movement, and storms influenced by the Pacific Ocean and Bering Sea, and really no inland influence. Winters are less severe than those on the coastal plain, with temperature ranges of 18 to 27 degrees F (10 to 15C), as compared to a 54 degrees F (30C) range on the coastal plain. The climate is characterized by fog and rain, with the amount of precipitation varying little from month to month. Annual precipitation varies from 21 in (530 mm) to more than 78 in (2,000 mm) across all islands. The higher elevations average 46 to 58 inches per year, with smaller islands receiving less precipitation than larger islands. Winds are often severe on the islands. Pacific Ocean water moving northward through the straits between the islands produces complex mixing with Bering Sea water, including upwelling. The Pribilof Islands in the Bering Sea are the southern limit of the arctic ice pack in winter (USDA-NRCS 2022). Weather information below is captured by climate stations located at Dutch Harbor and Cold Bay. The location of these stations represents only a small segment of the dynamic climate across this chain of islands.

Table 4. Representative climatic features

Frost-free period (characteristic range)	78-92 days
Freeze-free period (characteristic range)	122-136 days
Precipitation total (characteristic range)	46-58 in
Frost-free period (actual range)	75-95 days
Freeze-free period (actual range)	119-139 days
Precipitation total (actual range)	43-61 in
Frost-free period (average)	85 days
Freeze-free period (average)	129 days
Precipitation total (average)	52 in

Characteristic range

Actual range

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Figure 1. Monthly precipitation range

Characteristic range

Actual range

Bar

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Figure 2. Monthly minimum temperature range

Characteristic range

Actual range

Bar

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Figure 3. Monthly maximum temperature range

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Figure 4. Monthly average minimum and maximum temperature

Figure 5. Annual precipitation pattern

Figure 6. Annual average temperature pattern

Climate stations used

(1) DUTCH HARBOR [USC00502587], Unalaska, AK
(2) COLD BAY AP [USW00025624], Cold Bay, AK

Influencing water features

No water table is associated with the Volcanic landforms. Runoff from this site does feed into the aquifers and streams influencing lower elevation landforms.

Wetland description

No wetlands classified within this ecological site. The associated tidal marshes and depressions on the flats as well as drainages from the beaches and dunes are correlated to the Drainage Complex ecological site.

Soil features

Soils are derived from beach sands and windblown silts and sands at times deposited over residuum.
Soils are typically very deep without restriction. On occasion, soils contact bedrock at moderate to deep depths.
Soils are well drained.
Soils are coarse textured with areas of organic material on the surface, although very sporadic.
Soil pH is slightly acid.

Common Soils:
Tsammana sand
Lukanin sand
Histic Cryaquepts
Typic Cryaquents
Vitrandic Dystrocryepts

Table 5. Representative soil features

Parent material	(1) Eolian deposits (2) Marine deposits (3) Grassy organic material (4) Alluvium – scoria (5) Residuum
Surface texture	(1) Fine sandy loam (2) Sand (3) Peaty
Family particle size	(1) Sandy
Drainage class	Well drained to excessively drained
Permeability class	Rapid to very rapid
Depth to restrictive layer	Not specified
Soil depth	60 in
Surface fragment cover <=3"	Not specified
Surface fragment cover >3"	Not specified
Available water capacity (0-40in)	1.6 – 8.4 in
Soil reaction (1:1 water) (0-10in)	5.1 – 6.5
Subsurface fragment volume <=3" (0-60in)	5 – 11%
Subsurface fragment volume >3" (0-60in)	35%

Table 6. Representative soil features (actual values)

Drainage class	Not specified
Permeability class	Not specified
Depth to restrictive layer	39 – 60 in
Soil depth	39 – 60 in
Surface fragment cover <=3"	Not specified
Surface fragment cover >3"	Not specified
Available water capacity (0-40in)	Not specified
Soil reaction (1:1 water) (0-10in)	Not specified
Subsurface fragment volume <=3" (0-60in)	Not specified
Subsurface fragment volume >3" (0-60in)	Not specified

Ecological dynamics

The tidal flats, beaches, and dunes are transitional in nature with time and with distance from the tide level. Dunes will stabilize over time as they are further from the tidal movement, or when there is optimal development in cover to allow soils to develop. Influence of tidal spray, sporadic over wash from high tides, as well as overland flow from uplands that will bring in a mix of sediments, as well as salt and fresh water.

The full scope of vegetative dynamics across this coastal gradient is significant. Once the opportunity to collect vegetation and soils information at a finer scale, the full dynamics of these communities needs to be further developed into individual ecological sites.

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 text

Ecosystem states

1. Reference or Stabilized State

2. Active Movement (Erosion) State

T1a	-	Surface disturbance, erosion, impacts of tidal influence
T2a	-	Time, removal of tidal influence, dune stabilization

State 1 submodel, plant communities

1.1. American Dunegrass/Beach Pea

1.2. Red fruit Bearberry/American Dunegrass

CP1a	-	time and stabilization
CP1b	-	Surface disturbance, ice shear, catastrophic storm event

State 2 submodel, plant communities

2.1. Cochlearia groenlandica/Honckenya peploides/Mertensia maritima

State 1
Reference or Stabilized State

Distance from the active shoreline, tidal influence, and salt spray provides the opportunity for sands and sediments to stabilize with the help of successional vegetative growth. With time and the distance from the erosive effects, dunes and tidal areas mature and develop a strong herbaceous cover. The herbaceous cover allows woody shrub/scrub cover to develop. Although infrequent, fire can be an impact to these communities. Although referenced, no specific information was found on the shifts to these communities.

Dominant plant species

dwarf birch (Betula nana), shrub
red fruit bearberry (Arctostaphylos rubra), shrub
black crowberry (Empetrum nigrum), shrub
American dunegrass (Leymus mollis), grass
red fescue (Festuca rubra), grass
Bering's tufted hairgrass (Deschampsia beringensis), grass
beach pea (Lathyrus japonicus var. maritimus), other herbaceous
boreal yarrow (Achillea millefolium var. borealis), other herbaceous
dwarf fireweed (Chamerion latifolium), other herbaceous

Community 1.1
American Dunegrass/Beach Pea

Dune or plain height and distance from the active tidal action are above high tide and removed from the immediate spray patterns. The evolution of the vegetation pattern shifts to a stabilizing herbaceous community. The first, or most common leading colonizer is American dunegrass. Common species include American dunegrass (Leymus mollis), beach pea (Lathyrus japonicus var. maritimus), boreal yarrow (Achillea millefolium var. borealis), red fescue (Festuca rubra), beach strawberry (Fragaria chiloensis), seaside ragwort (Senecio pseudoarnica), Bering's tufted hairgrass (Deschampsia beringensis), common cowparsnip (Heracleum maximum), and largeflower speargrass (Poa eminens).

Dominant plant species

American dunegrass (Leymus mollis), grass
red fescue (Festuca rubra), grass
Bering's tufted hairgrass (Deschampsia beringensis), grass
largeflower speargrass (Poa eminens), grass
beach pea (Lathyrus japonicus var. maritimus), other herbaceous
beach strawberry (Fragaria chiloensis), other herbaceous
boreal yarrow (Achillea millefolium var. borealis), other herbaceous
seaside ragwort (Senecio pseudoarnica), other herbaceous

Community 1.2
Red fruit Bearberry/American Dunegrass

The older, mature dunes begin to see a dwarf shrub cover that is prominent in stringers behind the mature stands of American dunegrass (Leymus mollis) community. The common woody species in this dwarf shrub community include red fruit bearberry (Arctostaphylos rubra), dwarf birch (Betula nana), and black crowberry (Empetrum nigrum). Herbaceous species include dwarf fireweed (Chamerion latifolium), Lapland cornel (Cornus suecica), beach pea (Lathyrus japonicus var. maritimus), eastern hemlockparsley (Conioselinum chinense), alpine fescue (Festuca brachyphylla), and Jakutsk snowparsley (Cnidium cnidiifolium).

Dominant plant species

dwarf birch (Betula nana), shrub
red fruit bearberry (Arctostaphylos rubra), shrub
black crowberry (Empetrum nigrum), shrub
American dunegrass (Leymus mollis), grass
alpine fescue (Festuca brachyphylla), grass
dwarf fireweed (Chamerion latifolium), other herbaceous
Lapland cornel (Cornus suecica), other herbaceous
beach pea (Lathyrus japonicus var. maritimus), other herbaceous
eastern hemlockparsley (Conioselinum chinense), other herbaceous
Jakutsk snowparsley (Cnidium cnidiifolium), other herbaceous

Pathway CP1a
Community 1.1 to 1.2

The root system of the herbaceous cover provide stability to the soils allowing bands of dwarf shrubs and other late colonizers to establish in stringers behind the herbaceous cover or on the more protected older edges of the dune ridges and terrace extents. This change is a function of time and stabilization

Pathway CP1b
Community 1.2 to 1.1

Large storm events, ice shear, disturbance of soil surface or loss of woody vegetation, starts the successional process over. The early stabilizers on the dune system will be the first to establish.

State 2
Active Movement (Erosion) State

The coastal beaches, beach dunes, and tidal basins are in a state of active development with the periodic tidal inundation and salt spray as well as the coastal winds that easily transport the loose sands and silts. Small areas of disturbance may initiate small dunes and erosional sites. Over time, without removal of the pressure, these isolated areas can completely de-stabilize a dune field. The time frame is significant, looking at decades to centuries for complete dune destabilization.

Dominant plant species

sand ryegrass (Leymus arenarius), grass
Danish scurvygrass (Cochlearia groenlandica), grass
American dunegrass (Leymus mollis), grass
seaside sandplant (Honckenya peploides), other herbaceous
draba (Draba), other herbaceous
Moss (Moss), other herbaceous
beach pea (Lathyrus japonicus var. maritimus), other herbaceous

Community 2.1
Cochlearia groenlandica/Honckenya peploides/Mertensia maritima

Active development with the periodic tidal inundation and coastal winds and increased disturbance from human activity are major factors that will denude the existing vegetation and start the successional process on the dunes and beaches. The initial community to establish is a forb dominated community that is salt-tolerant. The common species include Danish scurvygrass (Cochlearia groenlandica), seaside sandplant (Honckenya peploides), North pacific draba (Draba hyperborea), and oysterleaf (Mertensia maritima). Areas of soils around beach boulder fields will have grass hummocks of sand ryegrass (Elymus arenarius) form on sandy areas. Patches of darker sands pebbles, and cobbles support racomitrium moss (Racomitrium lanuginosum), schistidium moss (Schistidium apocarpum), and ulota moss (Ulota pyllantha).

Dominant plant species

Danish scurvygrass (Cochlearia groenlandica), grass
sand ryegrass (Leymus arenarius), grass
North Pacific draba (Draba hyperborea), other herbaceous
seaside sandplant (Honckenya peploides), other herbaceous
racomitrium moss (Racomitrium lanuginosum), other herbaceous
schistidium moss (Schistidium apocarpum), other herbaceous
ulota moss (Ulota), other herbaceous

Transition T1a
State 1 to 2

Surface disturbance, erosion, impacts of tidal influence

Transition T2a
State 2 to 1

Time, removal of tidal influence, dune stabilization.

Additional community tables

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

Inventory data references

Very limited data is available and resides more on the coastal zone than the higher volcanics. Information used to build this ecological site was obtained from existing land cover and vegetation maps, literature review, and vegetative summaries from partnering agencies.

References

Hansford T. Shacklette, L. W. Durrell, James A. Erdman, John R. Keith, William M. Klein, Hildur Krog, Herman Persson, H. Skuja, and William A. Weber. 1969. Vegetation of Amchitka Island, Aleutian Islands, Alaska. Geological Survey Professional Paper 648. United States Geological Survey, United States Government Printing Office, Washington : 1969.

Other references

Landfire National Vegetation Dynamics Models; USGS; http://www.LANDFIRE.gov/index.php, 2009 (Date accessed)

USDA PLANTS Database; http://plants.usda.gov, 2021

USNVC [United States National Vegetation Classification]. 2019. United States National Vegetation Classification Database, V2.03. Federal Geographic Data Committee, Vegetation Subcommittee, Washington DC. USNVC: http://usnvc.org/

AMUNDSEN, C.C. 1972. Amchitka Bioenvironmental Program: Plant ecology of Amchitka Island, Final Report. Batelle, Columbus Laboratories, under AEC Prime, Contract No. AT(26-l)-171. 27 p.

AMUNDSEN, c.c. and E.E.C. CLEBSCH. 1971. Dynamics of the terrestrial ecosystem vegetation of Amchitka Island, Alaska. Bioscience 21:619-623.

AMUNDSEN, C.C. 1977. Terrestrial plant ecology. Pages 203-226 in M.L. Merritt and R.G. Fuller, eds. The environment of Amchitka Island, Alaska. ERDA TID-26712.

Bailey, R.G. [in prep.] Description of the ecoregions of the United States. 2d ed. Misc. Publ. No. 1391 [rev.]. Washington, DC: U.S. Department of Agriculture, Forest Service. Bailey, Robert G.; Avers, Peter E.; King, Thomas; McNab, W. Henry, eds. 1994. Ecoregions and subregions of the United States (map). Washington, DC: U.S. Geological Survey. Scale 1: 7,500,000; colored. Accompanied by a supplementary table of map unit descriptions compiled and edited by McNab, W. Henry, and Bailey, Robert G. Prepared for the U.S. Department of Agriculture, Forest Service.

BANK, T.B. II. 1951. Botanical and ethnobotanical studies in the Aleutian Islands. I. Aleutian vegetation and Aleut culture. Mich. Acad. Sci., Arts, and Lett. 37:13-30 + 6 plates.

BYRD, G.V. 1984. Vascular vegetation of Buldir Island, Aleutian Islands, Alaska compared to another Aleutian Island. Arctic 37(1):37-48.

Fosberg, Francis Raymond. "Succession and condition of ecosystems." (1967).

Hultén, Eric (1937) Flora of the Aleutian Islands and westernmost Alaska Peninsula with notes on the flora of Commander islands. Stockholm, Thule. 397 pp. 2nd ed. 1960 (series: Flora et vegetation mundi, vol. 1) Weinheim, Cramer. 376 pp.

SHACKLETTE, H.T., L.W. ERDMAN-J.R. KEITH, W.M. KLEIN, H. KROG, H. PERSSON, H. SKUJA, and W.A. WEBER. 1969. Vegetation of Amchitka Island, Aleutian Islands, Alaska. U.S. Geol. Surv. Prof. Pap. 648. 66p.

Swanson, D.J., Lehner, D., Zimmerman, J., and Pauling, D. Range survey of Nunivak Island, Alaska, 1986.

TATEWAKI. M. 1963. Phytogeography of. the islands of the north Pacific Ocean. Pages 23-27 in J.L. Gressitt, ed. Pacific Basin Biogeography. lOth Pacific Science Congress. Bishop Museum Press, Honolulu.

TALBOT, S.S., S.L. TALBOT, and L.R. Walker. 2010. Post-eruption legacy effects and their implications for long-term recovery of the vegetation on Kasatochi Island, Alaska. Arctic, Antarctic, and Alpine Research, Vol. 42, No. 3, pp. 285-296

WALKER., H. 1945. Plants of the Aleutian Islands. Pages 63-;71 in Collins, H.B., Jr., A.H. Clark, and E.H. Walker, eds. The Aleutian Islands: Their people and natural history. Smithsonian Inst. War Background Studies 21, Publ. 3775.

Contributors

Marji Patz
Tyler Annetts

Approval

Blaine Spellman, 6/14/2025

Acknowledgments

Blaine Spellman, Ecological Site Data Quality Specialist and Phil Barber, Ecological Site Specialist within Alaska, for your review and guidance of the PES development. Matt Mayer for assisting with R Scripts on weather, as well as Nathan Roe for assistance with R scripts on site data summaries.

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	06/14/2025
Approved by	Blaine Spellman
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: