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Ecological site YX244X00A202

Arctic Mountain Valley Floodplains

Last updated: 5/28/2025
Accessed: 09/20/2026

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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): 244X–Northern Brooks Range Mountains

Major Land Resource Area (MLRA) 244X includes the steep, rugged, high mountains and narrow valleys on the northern side of the Brooks Range. This remote wildland is sparsely populated and is approximately 14,525 square miles (37,615 square kilometers). The transition to the Arctic climate is the break into MLRA 244X from the surrounding subartic MLRAs. Elevation ranges from about 1,969 feet (600 meters) to 8,570 feet (2,613 meters) at the summit of Mount Igikpak. The major rivers are the Kongakut, Aichilik, Jago, Canning, Ivishak, Ribdon, Atigun, Anaktuvuk, and Killik Rivers. They drain to the Colville River and Arctic Ocean.

Except for the highest peaks, the steep upper ridges, and some unglaciated valleys, glacial ice during the Early and Middle Pleistocene covered the MLRA. By the Late Pleistocene, only the highest valleys and mountains remained glaciated. Periglacial features (gelifluction lobes, polygons, and stripes) and fluvial deposits are common on terraces and gentle slopes. Glacial deposits overlay stratified sedimentary bedrock. This area is in the zone of continuous permafrost. Inclusions of volcanic and igneous rocks occur in the eastern part of the MLRA.

The Brooks Range is characterized by continental arctic climate. The average annual precipitation ranges from 7 to 40 inches (180 to 1,015 millimeters) with an average annual snowfall of 50 to 100 inches (125 to 255 centimeters). The average annual temperature ranges from 8 to 16 degrees Fahrenheit (-13 to -9 degrees C), with freezing temperatures possible any month of the year. Summer temperatures reach 90 to 100 degrees Fahrenheit (32 to 38 degrees Celsius), and winter temperatures drop as low as -75 degrees Fahrenheit (-60 degrees Celsius). The position of this MLRA above the Arctic Circle lends to several days of 24-hour sunlight in June and several sunless days in December.

Freshwater is very limited due to frozen or low flow through long winters. Most domestic use water is from private wells. Aquifers are highly susceptible to contamination from surface activities (septic systems, landfills, and leaking fuel storage tanks).

The dominant soil order in this MLRA is Gelisols. The main soils are Aquiturbels, Histoturbels, Molliturbels, and Haploturbels. These are shallow or moderately deep to permafrost, poorly- to very poorly- drained, and formed in colluvium, slope alluvium, and residuum. Fibristels are shallow or moderately deep to permafrost, very poorly drained, and formed in thick deposits of organic material; in depressions, drainageways, and basins. Miscellaneous areas make up about 75 percent of this MLRA primarily composed of rubble, chutes, rock outcrops, and small glaciers. Lakes make up less than two percent of the area

Low willow, ericaceous shrub scrub, and tussocks are most dominant at lower elevations, with wet sites supporting wet meadows and willow scrub. Dwarf scrub communities (black crowberry, ericaceous shrubs, Dryas, and dwarf willow) are prominent on mountain slopes and ridges with exposed areas dominated by lichens, forbs, sedges, and mosses. As elevation and exposure increase, vegetation disappears and is replaced by rubble, talus, and other miscellaneous areas. This elevational transition is highly variable but roughly occurs at 6,500 feet (Zou et al. 2023) where glaciers also commonly prevail.

Villages use this remote area primarily for subsistence. Mining and prospecting of mineral resources historically occurred. Current disturbance relates to the pipeline and construction of Dalton highway. This disturbance of the fragile permafrost-affected soils is of increasing concern.

LRU notes

No LRUs are developed for this Major Land Resource Area (MLRA). Soils that are within this area are maintained as arctic. Soils corresponding to boreal communities are correlated to the appropriate adjacent MLRA.

Classification relationships

The Brooks Range is the most northerly extension of the Rocky Mountains occurring within the Arctic Mountains province of the Rocky Mountain System.

Description of the Ecoregions of the United States (Bailey 1983)
100 Polar Domain
120 Tundra Division
M120 Tundra Division - Mountain Provinces
M121 Brooks Range Tundra--Polar Desert Province

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
M173. Feltleaf Willow - Eight-petal Mountain-avens - Tussock Cottongrass
Tundra Macrogroup
G896. Arctic Dwarf-shrub Tundra Group
A4336. Arctic Nonacidic Dwarf Willow Tundra Alliance

LandFire BpS Model/Description Version: Nov. 2024
- 17150 Alaska Arctic Floodplain

Ecological site concept

- This arctic ecological site occurs on floodplains in the Northern Brooks Range MLRA.
- Soils formed in intermixed silty, sandy, and gravelly alluvium.
- Soils are very deep. These gravelly soils lack permafrost in the soil profile.
-Soils flood frequently to occasionally. These poorly and somewhat poorly drained soils have a water table at very shallow to moderate depths during the growing season.
- Vegetation is intermixed patches of scrubland dominated by willow and/or entireleaf mountain-avens and areas with a high water table dominated by wet herbaceous graminoid meadows.

Associated sites

YX244X00A204	Arctic Mountain Valley Terraces Terraces occur along major drainages and are a transitional step up in elevation from the more pronounced floodplains. The shrub-tussock community of the terrace blends down to floodplain vegetation, which does not include dominant tussocks.

YX244X00A204

Arctic Mountain Valley Terraces

Terraces occur along major drainages and are a transitional step up in elevation from the more pronounced floodplains. The shrub-tussock community of the terrace blends down to floodplain vegetation, which does not include dominant tussocks.

Similar sites

YX244X00A111	Arctic Mountain Hummocks The arctic mountain ponds may occur on and will have similar species as wetter portions of the floodplain, especially in concave depressions and along the channel edge.

YX244X00A111

Arctic Mountain Hummocks

The arctic mountain ponds may occur on and will have similar species as wetter portions of the floodplain, especially in concave depressions and along the channel edge.

Table 1. Dominant plant species

Tree	Not specified
Shrub	(1) Salix pulchra (2) Dryas integrifolia
Herbaceous	(1) Chamerion latifolium (2) Lupinus

Legacy ID

R244XY202AK

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Physiographic features

- Occurs on flood plains in the mountains.
- Elevation ranges from 1975 feet to 3400 feet along the edge of the Arctic Foothills.
- Flooding is occasional to frequent for brief or long durations of time. Spring break up is generally linked with flood events. Soils do not pond.
- A very shallow to moderately deep water table occurs (0 to 20 inches) commonly linked to high flow periods.
-Slopes are nearly level. Given the low relief, aspect is not relevant for this ecological site concept.
- Associated with very low to low amounts of runoff to adjacent, downslope ecological sites.

Table 2. Representative physiographic features

Slope shape across	(1) Linear
Slope shape up-down	(1) Linear
Landforms	(1) River valley > Flood plain (2) River valley > Flood plain
Runoff class	Very low to low
Flooding duration	Brief (2 to 7 days) to long (7 to 30 days)
Flooding frequency	Occasional to frequent
Ponding frequency	None
Elevation	1975 – 3400 ft
Slope	0 – 2 %
Water table depth	0 – 20 in
Aspect	Aspect is not a significant factor

Climatic features

Brief, cool summers and long, very cold winters characterize the continental arctic climate. The average annual precipitation throughout most of this area ranges from 15 to 40 inches (380 to 1,015 millimeters). The average annual snowfall is about 50 to 100 inches (125 to 255 centimeters). The average annual temperature ranges from about 8 to 16 degrees F (-13 to -9 degrees C). Freezing temperatures can occur in any month of the year. The Chandalar Shelf DOT climate station is the only station near this MLRA (Major Land Resource Area) and has incomplete data. The station is on the border of the MLRA and is not representative of the climate within MLRA 244X.

Table 3 Representative climatic features

Frost-free period (characteristic range)	20-60 days
Freeze-free period (characteristic range)	10-50 days
Precipitation total (characteristic range)	20-30 in
Frost-free period (actual range)
Freeze-free period (actual range)
Precipitation total (actual range)	10-40 in
Frost-free period (average)	40 days
Freeze-free period (average)
Precipitation total (average)

Characteristic range

Actual range

Bar

Line

Figure 1. Monthly precipitation range

Characteristic range

Actual range

Bar

Line

Figure 2. Monthly minimum temperature range

Characteristic range

Actual range

Bar

Line

Figure 3. Monthly maximum temperature range

Bar

Line

Figure 4. Monthly average minimum and maximum temperature

Figure 5. Annual precipitation pattern

Figure 6 Annual average temperature pattern

Climate stations used

(1) CHANDALAR SHELF DOT [USC00501497], Southerly North Slope Bo, AK

Influencing water features

This ecological site is associated with river and stream channels. Floodplains experience flooding disturbances. These disturbances affect this ecological site via erosion, deposition, and post-flood ponding.

Wetland description

This ecological site is classified as a riverine wetland under the Hydrogeomorphic (HGM) classification system (Smith et al. 1995; USDA-NRCS 2008).

Soil features

- Soils formed in alluvium.
- Rock fragments cover 0 to 10 percent of the soil surface.
- These mineral soils typically have no organic cap. The surface mineral horizons are silt loams or sandy loams.
- Subsurface rock fragments range between 30 and 60 percent or more of the soil profile by volume.
- Soils are very deep. Strongly contrasting textural stratification is a restriction that occurs at very shallow to moderate depths. Permafrost does not occur in the soil profile.
- The pH of the soil profile ranges from very strongly acidic to neutral.
- Soils are considered poorly and somewhat poorly drained.

The Arctic Mountain Valley Floodplains ecological site is correlated to three soils components: arctic scrub-gravelly low flood plains, arctic scrub-loamy flood plains, and
arctic wet meadow-loamy flood plains. Soils are classified as Entisols in the great groups Aquents, Fluvents, and Orthents.

This Major Land Resource Area (MLRA) is remote and difficult to reach and has not had soil verification completed. The information was obtained using the STATSGO soils information, a class 5 soils product. When opportunity presents to collect data in this MLRA, this Provisional Ecological Site will be updated.

Table 4. Representative soil features

Parent material	(1) Alluvium
Surface texture	(1) Silt loam (2) Sandy loam
Family particle size	(1) Sandy-skeletal (2) Loamy over sandy or sandy-skeletal
Drainage class	Poorly drained to somewhat poorly drained
Permeability class	Moderately rapid
Depth to restrictive layer	2 – 35 in
Soil depth	60 in
Surface fragment cover <=3"	Not specified
Surface fragment cover >3"	0 – 10 %
Available water capacity (0-40in)	1.9 – 3.8 in
Soil reaction (1:1 water) (0-10in)	5 – 6.5
Subsurface fragment volume <=3" (0-40in)	25 – 45 %
Subsurface fragment volume >3" (0-40in)	5 – 15 %

Table 5. Representative soil features (actual values)

Drainage class	Not specified
Permeability class	Not specified
Depth to restrictive layer	0 in
Soil depth	0 in
Surface fragment cover <=3"	0 %
Surface fragment cover >3"	0 %
Available water capacity (0-40in)	1.1 – 3.8 in
Soil reaction (1:1 water) (0-10in)	5 – 7.6
Subsurface fragment volume <=3" (0-40in)	25 – 55 %
Subsurface fragment volume >3" (0-40in)	5 – 20 %

Ecological dynamics

Floodplains are scoured by glacial melt and snow melt, most often during spring break up, and are commonly associated with braided systems. Gravel bars are intermixed with loamy and silty alluvial deposits. Flooding and areas of localized high-water tables creates a mosaic of wetlands and drier flats with dwarf shrubs. Willows (Salix spp.), mountain avens (Dryas spp.), sedges (Carex spp.), and cottongrass (Eriophorum spp.) are dominant in this complex community.

Fire history documentation is sparse for wet sites in the high arctic. In general, this ecological site does not burn. However, fine fuels are present, and this ecological site may burn under certain conditions such as prolonged drought. Further investigation into fire dynamics on this ecological site are warranted.

Community shifts in this ecological site are dependent on shifts in site hydrology. The communities represented by the state and transition model are distinguished by soil wetness or drainage class. Areas with shallow water tables, such as depressions, are restricted by soil ponding. Changes to the water table are often gradual across floodplains, and ecotonal communities are prevalent. Further research and information are pending on the successional communities and disturbance regimes of floodplain communities.

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 State

State 1 submodel, plant communities

1.1. Tealeaf Willow - Entireleaf Mountain-avens/ Dwarf Fireweed - Lupine

1.2. Cottongrass - Sedge

CP 1.1A	-	Increase water table
CP 1.2B	-	Decrease water table

State 1
Reference State

There are two plant communities within the reference state. Flooding is the main form of disturbance. The reference plant community supports vegetation that can be characterized as closed low willow shrub (Viereck et al 1994).

All plant communities associated with this ecological site have limited data, so the state-and-transition model is provisional.

Dominant plant species

bog blueberry (Vaccinium uliginosum), shrub
white arctic mountain heather (Cassiope tetragona), shrub
entireleaf mountain-avens (Dryas integrifolia), shrub
willow (Salix), shrub
lupine (Lupinus), other herbaceous

Community 1.1
Tealeaf Willow - Entireleaf Mountain-avens/ Dwarf Fireweed - Lupine

The reference community 1.1 is synonymous with the Alaska Arctic Flood Plain described by the Landfire BpS model (LandFire 2009). Vegetation in this community varies depending on specific site characteristics such as soil drainage and flood strength and frequency. This community normally undergoes annual flooding. Major plant groups include low and dwarf shrubs, along with often diverse forbs and graminoids.

Dominant plant species

entireleaf mountain-avens (Dryas integrifolia), shrub
tealeaf willow (Salix pulchra), shrub
dwarf fireweed (Chamerion latifolium), other herbaceous
lupine (Lupinus), other herbaceous

Figure 7. Annual production by plant type (representative values) or group (midpoint values)

Community 1.2
Cottongrass - Sedge

This community is associated with protected depressions or locations with high ground water. Flood frequency is reduced and species diversity is increased. Community 1.2 is characterized as a graminoid herbaceous community. The dominant plant species are cottongrasses (Eriophorum spp.) and sedges (Carex spp.)(Landfire, 2024).

Dominant plant species

Northwest Territory sedge (Carex utriculata), grass
tall cottongrass (Eriophorum angustifolium), grass
water sedge (Carex aquatilis), grass

Figure 8. Annual production by plant type (representative values) or group (midpoint values)

Pathway CP 1.1A
Community 1.1 to 1.2

A shift in hydrologic dynamics that raises the water table will cause a shift in vegetation. A shallow water table through the growing season will support hydrophytic, facultative wet to obligate wetland species.

Pathway CP 1.2B
Community 1.2 to 1.1

A shift in hydrologic dynamics that lowers the water table will cause a shift in vegetation. If this hydrologic shift coincides with the movement of a flood channel, vegetation and soil may be eroded and new gravel bars may be created.

Additional community tables

Table 6. Community 1.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)
Shrub/Vine
1				–
	tealeaf willow	SAPU15	Salix pulchra	–	–
	willow	SALIX	Salix	–	–
	entireleaf mountain-avens	DRIN4	Dryas integrifolia	–	–
	white arctic mountain heather	CATE11	Cassiope tetragona	–	–
	bog blueberry	VAUL	Vaccinium uliginosum	–	–
	red fruit bearberry	ARRU	Arctostaphylos rubra	–	–
Forb
2				–
	lupine	LUPIN	Lupinus	–	–
	springbeauty	CLAYT	Claytonia	–	–
	dwarf fireweed	CHLA13	Chamerion latifolium	–	–

Table 7. Community 1.2 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)
Grass/Grasslike
1				–
	tall cottongrass	ERAN6	Eriophorum angustifolium	–	–
	cottongrass	ERIOP	Eriophorum	–	–
	Northwest Territory sedge	CAUT	Carex utriculata	–	–
	longawn sedge	CAMA11	Carex macrochaeta	–	–
	water sedge	CAAQ	Carex aquatilis	–	–
Shrub/Vine
2				–
	dwarf birch	BENA	Betula nana	–	–
	marsh Labrador tea	LEPAD	Ledum palustre ssp. decumbens	–	–
	black crowberry	EMNI	Empetrum nigrum	–	–
	bog blueberry	VAUL	Vaccinium uliginosum	–	–
	tealeaf willow	SAPU15	Salix pulchra	–	–
	leatherleaf	CHCA2	Chamaedaphne calyculata	–	–
	beauverd spirea	SPST3	Spiraea stevenii	–	–
	manzanita	ARCTO3	Arctostaphylos	–	–
	lingonberry	VAVI	Vaccinium vitis-idaea	–	–
Moss
3				–
	sphagnum	SPHAG2	Sphagnum	–	–
	splendid feather moss	HYSP70	Hylocomium splendens	–	–
	polytrichum moss	POLYT5	Polytrichum	–	–
Lichen
4				–
Forb
5				–
	horsetail	EQUIS	Equisetum	–	–
	purple marshlocks	COPA28	Comarum palustre	–	–
	ragwort	SENEC	Senecio	–	–

Interpretations

Animal community

The Brooks Range is an important big-game area in Alaska. Mammals common to the area include brown bear, black bear, wolf, caribou, and Dall sheep. The smaller mammals include marmot, red fox, Arctic fox, wolverine, ground squirrel, lemming, and pika. The Brooks Range is an important resting area for migrating waterfowl and songbirds during summer. Raptors prominent in many areas include golden eagles, marsh hawks, gyrfalcons, and snowy and other open country owls.

Hydrological functions

This ecological site undergoes annual flooding. Areas with shallow water tables and surface ponding, such as depressions, are defined by wetland species.

Recreational uses

This remote area is used for sport hunting and other kinds of wildland recreation. Visitors use air taxi, guiding, and outfitting companies operating out of the major Alaska communities.

Wood products

Wooded areas reside just outside of the Major Land Resource Area.

Other products

This remote area is primarily used for subsistence hunting, fishing, and gathering.

Supporting information

Inventory data references

No on-site data is available. 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

C. Racine, R. Jandt, C. Meyers, and J. G. Dennis. 2004. Tundra fire and vegetation change
along a hillslope on the Seward Peninsula, Alaska, USA. Arctic, Antarctic, and Alpine Research. Environmental Science, Online. 1–10.
Viereck, L.A., C. T. Dyrness, A. R. Batten, and K. J. Wenzlick. 1992. The Alaska vegetation classification. U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station General Technical Report PNW-GTR-286..
Zou, L. and et al. 2023. Assessing the upper elevational limits of vegetation growth in global
high-mountains.

Other references

Higuera, Philip E., Melissa L. Chipman, Jennifer L. Barnes, Michael A. Urban, and Feng Sheng Hu. 2011. Variability of Tundra Fire Regimes in Arctic Alaska: Millennial-Scale Patterns and Ecological Implications. Ecological Applications 21, no. 8: 3211–26.

Joly, K., F. S. Chapin, and D. R. Klein 2010. Winter habitat selection by caribou in relation to lichen abundance, wildfires, grazing, and landscape characteristics in northwest Alaska. Ecoscience 17:321-333.

Jones, B. M., C. A. Kolden, R. Jandt, J. T. Abatzoglou, F. Urban, and C. D. Arp. 2009. Fire behavior, weather, and burn severity of the 2007 Anaktuvuk River Tundra Fire, North Slope, Alaska. Arctic, Antarctic, and Alpine Research 41:309-316.

LANDFIRE. 2009. Alaska Arctic Dwarf-Shrubland - Infrequent Fire. In: LANDFIRE National Vegetation Dynamics Models. USDA Forest Service and US Department of Interior. Washington, DC.

Racine, C. H., L. A. Johnson, and L. A. Viereck. 1987. Patterns of vegetation recovery after tundra fires in northwestern Alaska, U.S.A. Arctic and Alpine Research 19:461-469

Racine, C. H., J. L. Allen, and J. G. Dennis. 2006 Long-term monitoring of vegetation change following tundra fires in Noatak National Preserve, Alaska. NPS/AKRARCN/NRTR-2006/02, Arctic Network of Parks Inventory and Monitoring Program, National Park Service, Alaska Region. U.S. Department of the Interior, Washington, D.C., USA.
Schoeneberger, P.J., and D.A. Wysocki. 2012. Geomorphic Description System, Version 4.2. Natural Resources Conservation Service, National Soil Survey Center, Lincoln, Nebraska.

Schoeneberger, P.J., D.A. Wysocki, E.C. Benham, and W.D. Broderson, editors. 2012. Field book for describing and sampling soils. Version 3.0. U.S. Department of Agriculture, Natural Resources Conservation Service.

Smith, Daniel R., Alan P Ammann, Candy C Bartoldus, and Mark M Brinson 1995. An approach for assessing wetland functions using hydrogeomorphic classification, reference wetlands, and functional indices.

Soil Survey Division Staff. 2017. Soil survey manual. U.S. Department of Agriculture Handbook 18.

USDA-NRCS. 2008. Hydrogeomorphic Wetland Classification System: An Overview and Modification to Better Meet the Needs of the Natural Resources Conservation Service United States Department of Agriculture Staff. Technical Note No. 190-8-76.

United States Department of Agriculture. 2024. Land Resource Regions and Major Land Resource Areas of the United States, the Caribbean, and the Pacific Basin.
(https://www.nrcs.usda.gov/resources/data-and-reports/major-land-resource-area-mlra)

United States Department of Agriculture-Natural Resources Conservation Service. 2016. U. S. General Soil Map (STATSGO2). Web Soil Survey. Available online at http://websoilsurvey.nrcs.usda.gov. Accessed May 8 2024.

Wells, Aaron F., Christopher S. Swingley, Susan L. Ives, Robert W. McNown, and Dorte Dissing; Vegetation classification for northwestern Arctic Alaska using an EcoVeg approach: tussock tundra and low and tall willow groups and alliances; Pages 87–117 in Changcheng Liu, editors. Vegetation Classification and Survey, International Association for Vegetation Science, Online, 2022

Contributors

Marji Patz
Blaine Spellman
Phil Barber

Approval

Blaine Spellman, 5/28/2025

Acknowledgments

Nathan Roe, Ecological Site Specialist in California (Southwest Region) provided the R script and analysis process to summarize data within the NASIS database. Matthew Mayer, Ecological Site Specialist in Wasilla Alaska provided the R script to summarize geospatial data for climate information.

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	09/20/2026
Approved by
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:

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Natural ResourcesConservation Service

Ecological site YX244X00A202

Arctic Mountain Valley Floodplains

Last updated: 5/28/2025 Accessed: 09/20/2026

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General information

MLRA notes

LRU notes

Classification relationships

Ecological site concept

Associated sites

Similar sites

Table 1. Dominant plant species

Legacy ID

Natural Resources
Conservation Service

Last updated: 5/28/2025
Accessed: 09/20/2026