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Ecological site R241XY131AK

Arctic Tussock Loamy Frozen Slopes

Last updated: 5/29/2025
Accessed: 10/20/2025

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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): 241X–Seward Peninsula Highlands

The Seward Peninsula Highlands (MLRA 241X) occurs in Western Alaska, along the southernmost reaches of Land Resource Region Y, which has an arctic climate and occurs in the zone of continuous permafrost. This MLRA is approximately 13,700 square miles across the central Seward Peninsula. The terrain is defined by broad and extensive rolling hills and plains and solitary groups of rugged mountains expanding from sea level to a high point of 4,714 feet on Mount Osborn. Flood plains systems are common but generally narrow. The MLRA 241X watershed drains into Kotzebue Sound and the Chukchi Sea to the north and the Bering Sea to the West. Major rivers include the Buckland, Kiwalik, Serpentine, Agiapuk-American, Kougarok, and Kuzitrin Rivers. The area is mostly undeveloped wild land that is sparsely populated. Residents use this remote area primarily for subsistence hunting, fishing, and gathering. The largest communities in this predominantly inland MLRA are along the coast and include Teller and Brevig Mission. Reindeer herding is a profitable enterprise and many areas of this MRLA are used for reindeer graze and subsistence activities. Parts of this MLRA were mined for gold during the Nome gold rush. Several mines still operate within this boundary (USDA, 2022). Federally managed lands in this MLRA include parts of the Selawik National Wildlife Refuge and parts of Bering Land Bridge National Preserve.

Geology and Soils

MLRA 241X was mostly unglaciated during the late Pleistocene. Glaciers were present during the middle and early Pleistocene in scattered areas such as the York Mountains in the west, the Kiglauik Mountains to the south, and the Upper Kiwalik River drainage. The present-day landscape is mantled with loess, colluvium, and slope alluvium (USDA, 2022). Modified glacial moraines are evident in areas of past glacial activity. Bedrock material is a mix of rock types, with areas of sedimentary, volcanic and igneous throughout the MLRA. Bedrock is at or near the surface in most upland areas of this MLRA, which is reflected in soil development and vegetative patterns.

This MLRA is in the zone of continuous permafrost. Frozen soils are common across the landscape, though may be absent from high energy systems on floodplains, around lakes and on gravelly, well drained soils. Permafrost is generally shallow to moderately deep (10 to 40 inches) that results in a restrictive layer that perches water and creates poorly to very poorly drained soils. Alongside these permafrost soils (Gelisols), other common soil orders include soils with little to no development in the Entisol and Inceptisol orders. Periglacial features are common and include solifluction lobes, polygonal ground, and thermokarst pits (USDA, 2022). Non-soil areas (rock outcrop, riverwash, and surface water) make up approximated five percent of the MLRA surface.

Climate

Climate is predominantly continental arctic, with brief, cool summers and long, cold winters. Maritime conditions, where summer temperatures are moderated by the proximity to open water, persist through the summer along the Bering Sea coast. Mean annual precipitation is 10 to 15 inches in the north and west, increasing to 20 to 40 inches in the mountainous areas in the south and east (USDA, 2022). Mean annual temperatures ranges from 20 to 26 degrees Fahrenheit (PRISM, 2018; SNAP, 2014).

Vegetation

Vegetation is mainly influenced by climate, site, and soil characteristics such as temperature-degree days, elevation, exposure to wind, soil depth, and soil hydrology. Dwarf scrublands are present across most of the upland, with vegetation further restricted on shallow soils. Lower elevations generally support more developed soils, and host willow-sedge scrublands, mixed ericaceous shrub scrublands, and herbaceous graminoid meadows. Tussock tundra is ubiquitous across much of the poorly drained, low-sloped landforms across the MRLA. Wetland communities dominate in closed depressions and drainages (USDA, 2022).

LRU notes

There are currently no Land Resource Areas (LRUs) delineated or described in MLRA 241X. There is potential for two or more LRUs along a climatic break between the lowlands and low-elevation hills of the north and west, and the higher, mountainous regions more prevalent in the south and east. However, vegetation and land management may not differ between these areas, as soils and vegetation are already restricted by cold annual temperatures even at low elevations.

Classification relationships

Alaska Vegetation Classification:
Mesic graminoid herbaceous (III.A.2 - level III) / Tussock tundra (III.A.2.d - level IV)
(Viereck et al., 1992)

BioPhysical Settings: 6816942 – Alaska Arctic Tussock Tundra - Infrequent Fire
(LANDFIRE biophysical settings, 2009)

Seward Rangesites:
60 – Lichen (Tussock Tundra)
(SCS, 1984; Swanson et al., 1985)

Ecological site concept

Ecological Site characteristics:
• Associated with a tussock tundra community with high lichen ground cover in the reference plant community
• Occurs on gently sloping arctic hill and plain slopes
• Soils contain permafrost and are very poorly drained
• Ponding occurs and is reflected in the facultative to obligate wetland vegetation
• Fire is the major disturbance in the reference state and is responsible for one distinct post-fire community.
• Repeating hummock mounds are common periglacial features on the described landform. These are represented by an alternate state.

Associated sites

R241XY130AK	Arctic Scrub Loamy Warm Hillslopes This ecological site describes a productive birch-mixed ericaceous scrubland on warm slopes.
R241XY134AK	Arctic Scrub Loamy Hillslopes This ecological site is a low ericaceous shrub and sedge scrubland without tussocks on hills and plains.

R241XY130AK

Arctic Scrub Loamy Warm Hillslopes

This ecological site describes a productive birch-mixed ericaceous scrubland on warm slopes.

R241XY134AK

Arctic Scrub Loamy Hillslopes

This ecological site is a low ericaceous shrub and sedge scrubland without tussocks on hills and plains.

Similar sites

R241XY134AK	Arctic Scrub Loamy Hillslopes R241XY134AK has drier soils that support an ericaceous-sedge scrubland on slopes. Circle features are common. Cottongrass may be present but does not support a tussock tundra.

R241XY134AK

Arctic Scrub Loamy Hillslopes

R241XY134AK has drier soils that support an ericaceous-sedge scrubland on slopes. Circle features are common. Cottongrass may be present but does not support a tussock tundra.

Table 1. Dominant plant species

Tree	Not specified
Shrub	(1) Ledum palustre ssp. decumbens (2) Vaccinium vitis-idaea
Herbaceous	(1) Eriophorum vaginatum (2) Carex bigelowii

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Physiographic features

This site occurs on arctic hills and plains. Elevation ranges from 100 to 1000 feet above sea level. Slope gradients are negligible to gentle (0 to 6 percent), and this ecological site occurs on all aspects. A water table is present throughout the growing season. Ponding occurs in the reference state.

Repeating earth hummock mounds are common periglacial microfeatures. They can be mounded well above the surrounding vegetation. Mounds have unique site and soil properties that result in a mosaic of vegetation.

Table 2. Representative physiographic features

Slope shape across	(1) Linear (2) Concave
Slope shape up-down	(1) Linear (2) Concave
Hillslope profile	(1) Footslope
Landforms	(1) Hills > Hill (2) Plains > Plain (3) Plains > Plain > Turf hummock (4) Plains > Plain > Mound
Runoff class	Negligible to low
Flooding frequency	None
Ponding duration	Long (7 to 30 days)
Ponding frequency	Frequent
Elevation	100 – 1,000 ft
Slope	6%
Ponding depth	24 in
Water table depth	Not specified
Aspect	W, NW, N, NE, E, SE, S, SW

Table 3. Representative physiographic features (actual ranges)

Runoff class	Negligible to medium
Flooding frequency	None
Ponding duration	Long (7 to 30 days)
Ponding frequency	None to frequent
Elevation	20 – 2,610 ft
Slope	14%
Ponding depth	24 in
Water table depth	Not specified

Climatic features

The Arctic climate of this ecological site includes short, cool growing seasons and long, cold winters. Mean annual temperature at sea level is about 22 degrees Fahrenheit in the coastal village of Wales. Approximately 35 percent of total precipitation occurs during the growing season months of June through August. Across the MLRA, snowfall ranges from 40 to 100 inches (USDA-NRCS, 2022).

Table 4. Representative climatic features

Frost-free period (characteristic range)	60-90 days
Freeze-free period (characteristic range)	50-80 days
Precipitation total (characteristic range)	14-16 in
Frost-free period (actual range)	50-90 days
Freeze-free period (actual range)	40-80 days
Precipitation total (actual range)	10-18 in
Frost-free period (average)	75 days
Freeze-free period (average)	65 days
Precipitation total (average)	15 in

Characteristic range

Actual range

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Figure 1. Monthly precipitation range

Characteristic range

Actual range

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Figure 2. Monthly minimum temperature range

Characteristic range

Actual range

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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

Influencing water features

This ecological site is not influenced by wetland or riparian water features. Precipitation and snow melt are the main sources of water for this ecological site.

Wetland description

This ecological site may be classified as a slope wetland under the Hydrogeomorphic (HGM) classification system (Smith et al. 1995; USDA-NRCS 2008). A shallow water table is present in the reference state throughout the year.

Soil features

Soils in the reference state are Gelisols formed primarily on eolian deposits atop alluvium or till (Soil Survey Staff, 2013). Soils are wet and very poorly drained. Rock fragments are absent from the surface. The organic cap is between 9 and 11 inches. Soils are very deep. Permafrost is moderately deep, and strongly contrasting textural stratification is moderately deep when present. Subsurface rock fragment volume is generally low or absent. Soil pH is extremely to moderately acidic.

Soils in the alternate state are highly organic Hemistels (Soil Survey Staff, 2013). Repeating mound features have unique soil properties distinct from the reference state. Microtopography creates a mosaic of well drained highs and very poorly drained lows.

Table 5. Representative soil features

Parent material	(1) Eolian deposits (2) Till (3) Organic material
Surface texture	(1) Peat (2) Mucky peat
Drainage class	Very poorly drained
Permeability class	Moderate
Depth to restrictive layer	17 – 29 in
Soil depth	60 in
Surface fragment cover <=3"	1%
Surface fragment cover >3"	5%
Available water capacity (0-40in)	8.7 – 11.9 in
Soil reaction (1:1 water) (0-10in)	3.9 – 5.4
Subsurface fragment volume <=3" (0-60in)	Not specified
Subsurface fragment volume >3" (0-60in)	Not specified

Table 6. Representative soil features (actual values)

Drainage class	Not specified
Permeability class	Not specified
Depth to restrictive layer	12 – 40 in
Soil depth	Not specified
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 Seward Peninsula Highlands MLRA (MLRA 241X) is in the arctic where the harsh climate limits the composition and structure of plant communities. This area has cool, short summers and long, cold winters. Trees are mostly restricted to the most eastern areas of the MLRA. The expansive tundra is comprised of a mosaic of shrubs, sedges, moss, and lichen.

This ecological site describes a tussock community with various shrubs on plains and hills. Vegetation is restricted by cold temperature, permafrost, and ponding. Vegetation is typically comprised of facultative to facultative wet species. Hydrologically driven processes result in microfeatures such as polygonal ground and frost heaving (Landfire, 2009).

Fire is the major natural disturbance on this ecological site. The fire cycle may range from 50 to 600 years (Landfire, 2009). Fire dynamics in the Arctic region are poorly understood and are likely to vary within and between Arctic regions (Landfire, 2009). This disturbance is responsible for one unique post-disturbance community. Post-fire community composition depends on fire factors such as frequency and severity. Slight to moderate fires may only burn surface vegetation, leaving the wet organic horizon intact. A severe fire burns the insulating organic layer, causing permafrost to drop in the soil profile. Soil drainage improves and less hydric species colonize. Alder may colonize from nearby flood plains. As the organic horizon thickens, permafrost rises, the soil becomes wetter, and the community shifts back to community 1.1.

Frozen mounds are described by an alternate state in this ecological site. Factors such as soil texture, surface heat transfer, and freezing depth are responsible for mound formation (Peterson and Krantz, 2003). Mounds create a repeating microtopography with drier soils at mound tops and wetter soils in inter-mound lows. The variability of soil wetness, exposure, and microclimates creates various niches that results in increased species diversity.

The information in this Ecological Dynamics section, including the state-and-transition model (STM), was developed based on professional experience and a review of available scientific literature. As a result, all possible scenarios or plant species may not be included. Key indicator plant species, disturbances, and ecological processes are described to inform land management decisions.

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

2. Mound State

T1A	-	Frost heave mound formation
R2A	-	Mound collapse

State 1 submodel, plant communities

1.1. Ledum palustre ssp. decumbens - Vaccinium vitis-idaea / Eriophorum vaginatum - Carex bigelowii

1.2. Eriophorum vaginatum - Carex bigelowii / Chamerion angustifolium

1.1A	-	Fire
1.2A	-	Fire recovery

State 2 submodel, plant communities

2.1. Empetrum nigrum - Ledum palustre ssp. decumbens / Carex bigelowii

State 1
Reference State

This reference state is developed and characterized using available vegetation models, most notably United States Department of Agriculture - Soil Conservation Service range surveys (SCS, 1984; Swanson et al., 1985). The reference state describes two distinct vegetative communities under a fire cycle regime. Along with a fire regime, soil wetness, caused by water perched by permafrost, is the major factor influencing vegetation. There is no indication of an alternate grazing state on this site. Targeted data collection may be able to address whether grazing or browsing in the reference state result in an alternate state.

Dominant plant species

marsh Labrador tea (Ledum palustre ssp. decumbens), shrub
lingonberry (Vaccinium vitis-idaea), shrub
cloudberry (Rubus chamaemorus), shrub
bog blueberry (Vaccinium uliginosum), shrub
tussock cottongrass (Eriophorum vaginatum), grass
Bigelow's sedge (Carex bigelowii), grass

Community 1.1
Ledum palustre ssp. decumbens - Vaccinium vitis-idaea / Eriophorum vaginatum - Carex bigelowii

This community is a tussock tundra (Viereck et al., 1992). Major plant groups are tall and medium graminoids, and low and dwarf shrubs (Swanson et al., 1985). Shrubs grow on and in-between tussocks. Moss is prevalent throughout the spaces between tussocks. Lichens growth both on the moss and tussocks. Tabular data for this community is from the 1984 Seward range site publication (SCS, 1984), with supplemental information from Swanson et al. (1985).

Forest understory. Live lichen and moss annual production cannot be measured accurately due to a lack of information on growth rates and/or slow annual growth rates. Lichen and moss biomass data below refers to total biomass, while vascular plants biomass refers to annual production.

Dominant plant species

marsh Labrador tea (Ledum palustre ssp. decumbens), shrub
lingonberry (Vaccinium vitis-idaea), shrub
bog blueberry (Vaccinium uliginosum), shrub
dwarf birch (Betula nana), shrub
cloudberry (Rubus chamaemorus), shrub
tussock cottongrass (Eriophorum vaginatum), grass
Bigelow's sedge (Carex bigelowii), grass
field horsetail (Equisetum arvense), other herbaceous
greygreen reindeer lichen (Cladina rangiferina), other herbaceous
(Flavocetraria cucullata), other herbaceous
island cetraria lichen (Cetraria islandica), other herbaceous
reindeer lichen (Cladina mitis), other herbaceous

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

Table 7. Annual production by plant type

Plant type	Low (lb/acre)	Representative value (lb/acre)	High (lb/acre)
Moss	890	2485	5340
Lichen	850	995	1140
Shrub/Vine	280	310	340
Grass/Grasslike	180	200	220
Forb	50	55	60
Total	2250	4045	7100

Table 8. Ground cover

Tree foliar cover	0%
Shrub/vine/liana foliar cover	12-25%
Grass/grasslike foliar cover	6-12%
Forb foliar cover	6-12%
Non-vascular plants	25-75%
Biological crusts	0%
Litter	6-12%
Surface fragments >0.25" and <=3"	0%
Surface fragments >3"	0%
Bedrock	0%
Water	0%
Bare ground	0-6%

Community 1.2
Eriophorum vaginatum - Carex bigelowii / Chamerion angustifolium

This community has generally been burned within the last 15 years (Landfire, 2009). It is comprised of extant species present pre-burn, as well as fast-growing colonizing herbaceous species. Major plant groups are tall and medium graminoids, and medium and low forbs (Landfire, 2009). Ground cover varies based on burn severity and time since burn, but usually supports mosses, lichens, herbaceous litter, and water.

Dominant plant species

tussock cottongrass (Eriophorum vaginatum), grass
Bigelow's sedge (Carex bigelowii), grass
bluejoint (Calamagrostis canadensis), grass
polargrass (Arctagrostis), grass
fireweed (Chamerion angustifolium), other herbaceous

Pathway 1.1A
Community 1.1 to 1.2

Fire is the major disturbance on this site. Mean fire return intervals vary and may range from 50 years to greater than 600 years (Landfire, 2009). Fire typically burns the insulating layer of herbaceous litter, mosses and lichens. Soils thaw and create conditions where quickly growing forbs and graminoids colonize and intermix with surviving plants.

Pathway 1.2A
Community 1.2 to 1.1

Fire recovery occurs regularly quickly. Fire typically burns the insulating layer of herbaceous litter, mosses and lichens. Soils thaw, but typically stabilize or return to prefire conditions within ten years (Racine et al., 1987). Cottongrass spreads and shrubs recolonize and spread from surviving rootstock or via seed.

State 2
Mound State

This state is characterized using available vegetation models, most notably United States Department of Agriculture - Soil Conservation Service range surveys (SCS, 1984; Swanson et al., 1985). This alternate state describes a scrub community across frost heaved mounds. The conditions required for this microfeature to develop are not fully understood. Available water, an insulating organic horizon and an absence of fire are suspected to be factors needed for the necessary ice cores to form and for mounds to develop.

Dominant plant species

black crowberry (Empetrum nigrum), shrub
marsh Labrador tea (Ledum palustre ssp. decumbens), shrub
lingonberry (Vaccinium vitis-idaea), shrub
bog blueberry (Vaccinium uliginosum), shrub
cloudberry (Rubus chamaemorus), shrub
Bigelow's sedge (Carex bigelowii), grass
tussock cottongrass (Eriophorum vaginatum), grass

Community 2.1
Empetrum nigrum - Ledum palustre ssp. decumbens / Carex bigelowii

This community is characterized as a crowberry tundra (Viereck et al., 1992). Major plan groups are low and dwarf shrubs, and medium and dwarf graminoids. This community is recognized by the repeating pattern of mounds across the landform.

Dominant plant species

black crowberry (Empetrum nigrum), shrub
marsh Labrador tea (Ledum palustre ssp. decumbens), shrub
bog blueberry (Vaccinium uliginosum), shrub
lingonberry (Vaccinium vitis-idaea), shrub
cloudberry (Rubus chamaemorus), shrub
Bigelow's sedge (Carex bigelowii), grass
tussock cottongrass (Eriophorum vaginatum), grass

Transition T1A
State 1 to 2

Mounds develop when ice cores form under an insulating layer of organics. Ice cores pull in surrounding water via capillary action and push the overlying vegetation upwards. This process can only be initiated in ideal conditions. The normal fire regime typically favors cottongrasses. The absence of a fire disturbance can allow low shrubs to dominate (Landfire, 2009; Racine et al., 1987), which adds to the insulating effect.

Restoration pathway R2A
State 2 to 1

Collapse of the ice core within the frost heave mound results in a return to a tussock tundra community. Frost heave mounds collapse when the insulating organic layer is no longer sufficient. This can be due to natural dieback of the moss layer due to overgrowth of the ice core. Fire can also remove the organic layer and melt the ice core. The post-mound collapse community composition will be dependent on the method of mound collapse, with fire leading to community 1.2, and natural die-back leading to either community 1.1 or 1.2.

Additional community tables

Table 9. Community 1.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production (lb/acre)	Foliar cover (%)
Undefined
1	Vascular Plants			510–620
Shrub/Vine
2	Shrub			280–340
	marsh Labrador tea	LEPAD	Ledum palustre ssp. decumbens	110–130	–
	bog blueberry	VAUL	Vaccinium uliginosum	35–45	–
	lingonberry	VAVI	Vaccinium vitis-idaea	30–40	–
	dwarf birch	BENA	Betula nana	25–30	–
	black crowberry	EMNI	Empetrum nigrum	15–20	–
	Alaska bog willow	SAFU	Salix fuscescens	10–12	–
	resin birch	BEGL	Betula glandulosa	6–7	–
	white arctic mountain heather	CATE11	Cassiope tetragona	2	–
	tealeaf willow	SAPU15	Salix pulchra	2	–
	red fruit bearberry	ARRU	Arctostaphylos rubra	2	–
	bog rosemary	ANPO	Andromeda polifolia	0–1	–
	netleaf willow	SARE2	Salix reticulata	1	–
	small cranberry	VAOX	Vaccinium oxycoccos	0–1	–
	alpine azalea	LOPR	Loiseleuria procumbens	1	–
Grass/Grasslike
3	Grass/Grasslike			180–220
	tussock cottongrass	ERVA4	Eriophorum vaginatum	130–160	–
	Bigelow's sedge	CABI5	Carex bigelowii	45–50	–
	water sedge	CAAQ	Carex aquatilis	15–20	–
Forb
4	Forb			50–60
	cloudberry	RUCH	Rubus chamaemorus	55–65	–
	field horsetail	EQAR	Equisetum arvense	2	–
	arctic sweet coltsfoot	PEFR5	Petasites frigidus	1	–
	starwort	STELL	Stellaria	1	–
Lichen
5	Live lichen biomass			850–1140
	greygreen reindeer lichen	CLRA60	Cladina rangiferina	270–365	–
		FLCU	Flavocetraria cucullata	160–215	–
	cup lichen	CLADO3	Cladonia	120–160	–
	reindeer lichen	CLMI60	Cladina mitis	100–130	–
	island cetraria lichen	CEIS60	Cetraria islandica	95–125	–
	reindeer lichen	CLAR60	Cladina arbuscula	75–100	–
	cup lichen	CLGR13	Cladonia gracilis	20–25	–
	cup lichen	CLUN60	Cladonia uncialis	5–7	–
	whiteworm lichen	THSU60	Thamnolia subuliformis	4–6	–
	star reindeer lichen	CLST60	Cladina stellaris	3	–
	Lichen	2LICHN	Lichen	1	–
		FLNI	Flavocetraria nivalis	1	–
Moss
6	Moss			890–5340

Interpretations

Animal community

This site supports a relatively large number of small mammals, such as lemmings, voles, shrews and the tundra hare. The needs of a large variety of these small herbivores and insectivores can be met by the diversity of microhabitats found on this site. Well developed tussocks provide islands of relative warmth and dryness for small mammals preferring such conditions, while species adapted to use moist or wet food or terrain for food and cover can find suitable conditions between the tussocks and among the depressions created by frost heaving. Cottongrass, sedges, and forbs provide small bird and mammal herbivores with a variety of seeds, shoots, stems, and other nutritious plant parts, and with sources of insects, for feeding young, building fat reserves, or strong food for winter. Where small birds and mammals are abundant, so are their predators; red fox, least weasel, pomarine jaeger, snowy owl, rough-legged hawk and other predators feed on small mammals, birds, and/or the eggs and nestlings. Large herbivores, especially caribou, may feed on the variety of plant foods on this site, especially in winter and early spring when the lush growth of lichens represent the most abundant and nutritious forage seasonally available.

Recreational uses

This site is used for snowmobiling, dogsledding, hunting for caribou and ptarmigan and trapping of red fox. It has potential for sightseeing and photography since the general area includes canyons, rock formations, lakes, lava beds, and hot springs, besides the wildlife and plant communities. Some low bush cranberry and blueberry picking is also found on this site.

Wood products

No wood products available from this site.

Other products

Grazing

This site is a good winter range and due to the fragile characteristics of lichen this site should not be used for any other season. Grasses, sedges, and the new growth of shrubs provide good forage during the early part of the season. Water and salt are fairly accessible on this site.

Supporting information

Inventory data references

Vegetative communities and transitions are described using existing models and expert knowledge. There are no vegetation inventory data points in NASIS associated with this ecological site.

External data sources:
The Alaska Vegetation Classification (Viereck et al., 1992)

LANDFIRE Biophysical Settings Models (LANDFIRE Biophysical Settings, 2009)

Ecological site descriptions of the Seward Peninsula (SCS, 1984).

Range survey of the Seward Peninsula reindeer ranges (Swanson et al., 1985)

References

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..

Other references

Kautz, D.R., P. Taber, and S. Nield, editors. 2012. Land Resource Regions and Major Land Resource Areas of Alaska. United States Department of Agriculture, Natural Resources Conservation Service (USDA–NRCS).

LANDFIRE Biophysical Settings. 2009. Biophysical Setting 6816942 – Alaska Arctic Tussock Tundra - Infrequent Fire. In: LANDFIRE Biophysical Setting Model: Map zone 68, [Online]. In: Vegetation Dynamics Models. In: LANDFIRE. Washington, DC: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory; U.S. Geological Survey; Arlington, VA: The Nature Conservancy (Producers). Available: https://www.landfire.gov/national_veg_models_op2.php. Accessed Sept 30, 2024.

Peterson R.A. and W.B. Krantz. 2003. A mechanism for differential frost heave and its implications for patterned-ground formation. Journal of Glaciology. 49(164):69-80. doi:10.3189/172756503781830854

PRISM Climate Group. 2018. “Alaska – average monthly and annual precipitation and minimum, maximum, and mean temperature for the period 1981-2010.” Oregon State University, Corvallis, Oregon. https://prism.oregonstate.edu/projects/alaska.php. Accessed Sept 17, 2024.

Racine C.H., L.A. Jonson and L.A Viereck. 1987. Patterns of vegetation recovery after tundra fires in northwestern Alaska, USA. Arctic and Alpine Research. 19(4), 461-469.

Raynolds, M.K., D.A. Walker and H.A Maier. 2006. Alaska Arctic Tundra Vegetation Map. Scale 1:4,000,000. Conservation of Arctic Flora and Fauna (CAFF) Map No. 2, U.S. Fish and Wildlife Service, Anchorage, Alaska.

Scenarios network for Alaska and arctic planning (SNAP). 2014. “Historical Monthly Temperature – 1km, 1901-2009”. http://ckan.snap.uaf.edu/dataset/. Accessed Sept 17, 2024.

Scenarios network for Alaska and arctic planning (SNAP). 2014. “Historical monthly and derived precipitation products downscaled from CRU TS data via the delta methods – 2km, 1901-2009”. http://ckan.snap.uaf.edu/dataset/. Accessed Sept 17, 2024.

SCS (Soil Conservation Service). 1984. Ecological site descriptions, Seward Peninsula. U.S. Department of Agriculture, Soil Conservation Service, Alaska Field Office, Anchorage.

Soil Survey Staff. 2013. Simplified Guide to Soil Taxonomy. USDA-Natural Resources Conservation Service, National Soil Survey Center, Lincoln, NE.

Swanson, J.D., M. Schuman, and P.C. Scorup. 1985. Range survey of the Seward Peninsula reindeer ranges, Alaska. US Department of Agriculture, Soil Conservation Service.

United States Department of Agriculture, Natural Resources Conservation Service. 2022. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296.

Western Regional Climate Center. 2021. Climate of Alaska. Retrieved from https://wrcc.dri.edu/Climate/narrative_ak.php. Accessed April 9, 2021.

Contributors

Phil Barber
Blaine Spellman
Marji Patz
Steph Schmit
Karin Sonnen

Approval

Blaine Spellman, 5/29/2025

Acknowledgments

The described soil – ecological site correlations described in this document were reviewed during a February 2024 Provisional Ecological Site workshop in Wasilla, AK. Many thanks are given to the NRCS staff who have provided feedback regarding the MLRA 241X ecological site key and ESDs delivered under the PES national initiative.

This ecological site description (ESD) fulfills the requirements of the Provisional Ecological Site (PES) national initiative. This ESD is published to fit current site-soil correlations as they are currently mapped and understood. Further data collection may provide the information to update this ESD from the provisional level to the approved level.

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	06/01/2025
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: