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): 242X–Northern Seward Peninsula-Selawik Lowlands

The Northern Seward Peninsula-Selawik Lowlands (MLRA 242X) includes the mosaic of coastal lowlands, river deltas, gently sloping uplands, and isolated hills and low mountains along the northern Seward Peninsula and in the lower Selawik Basin at the head of Kotzebue Sound. To the east, the area extends to the lower slopes of the Purcell Mountains, Zane Hills, and Sheklukshuk Range. MLRA 242X makes up 8,445 square miles. Lakes, ponds, and saturated soils occur throughout most of this area. The MLRA is mostly undeveloped wildland and is sparsely populated. It is in the zone of continuous permafrost.

Land ownership:
MLRA 242X encompasses the northernmost portion of the Bering Land Bridge National Preserve, the westernmost portion of Cape Krusenstern National Monument, and the majority of the Selawik National Wildlife Refuge.

The Bering Land Bridge National Preserve is located on the Seward Peninsula. The preserve is one of the most remote protected areas in the United States. The preserve is used by native Alaskans for subsistence hunting and is home to several archaeological sites. The preserve is around 2.6 million acres.

The Cape Krusenstern National Monument is located in northwestern Alaska, bordering the Chukchi Sea. Beach ridges within the monument safeguard evidence of 5,000 years of occupation by the Inupiat people, and more than 9,000 years of human occupation (NPS 2025). The Inupiat people maintain subsistence camps within the monument to this day. The monument is around 650,000 acres in size.

The Selawik National Wildlife Refuge is locating in the Waring Mountains of northwestern Alaska and comprises a transitional zone marking the opening of boreal forests into Arctic tundra (USFWS 2025). Selawik Refuge is an important migratory and wintering habitat for the Western Arctic Caribou Herd, one of four herds found across Arctic Alaska. The refuge is around 2.1 million acres, with 240,000 of that set aside as federally designated wilderness.

The majority of MLRA 242X is private lands or those managed by the USFWS, NPS, BLM, and State of Alaska. The USFWS manages 1,604,744 acres, around 36 percent of the MLRA. The National Park Service manages 1,350,544 acres, around 30 percent of the MLRA. The BLM manages 606,464 acres, around 14 percent of the MLRA. The State of Alaska has a patent on 55,675 acres of the MLRA, around 1 percent of the MLRA. Much of the MLRA is within Alaska Native allotments or patents around 832,328 acres, or 19 percent of the MLRA.

Climate:
The arctic climate of MLRA 242X is characterized by brief, cool summers and long, very cold winters. The average annual precipitation ranges from 11 to 12 inches. Average annual snowfall ranges from about 40 to 100 inches. The average annual temperature ranges from 18 to 25 degrees Fahrenheit. The average freeze-free period is between 98 to 104 days.

Geology:
The western part of this MLRA was unglaciated during the Pleistocene Epoch. Most of the eastern part was covered by glacial ice originating in the Waring Mountains and Brooks Range to the north. Sediments across the vast majority of the area consist of fine textured, Holocene and Pleistocene deltaic and fluvial deposits on coastal lowlands, Holocene fluvial deposits on flood plains and stream terraces, and mixed colluvium and slope alluvium on mountain foot slopes. The underlying bedrock geology consists primarily of stratified sedimentary rocks and volcanic rocks of Cretaceous, Tertiary, and Quaternary age.

Soils:
The dominant soil orders in this MLRA are Gelisols, with Histosols and Entisols covering a comparatively minor extent in coastal or estuarine zones. These Gelisols are shallow or moderately deep to permafrost and are typically poorly to very poorly drained. Miscellaneous (non-soil) areas make up about 25 percent of this MLRA. The most common are water and beaches.

Gelisols are soils that have permafrost within 100 cm of the soil surface and/or have gelic materials within 100 cm of the soil surface and have permafrost within 200 cm. Gelic materials are mineral or organic soil materials that have evidence of cryoturbation (frost churning) and/or ice segregation in the active layer (seasonal thaw layer) and/or the upper part of the permafrost (NRCS 2024). The common suborders of Gelisols within this MLRA are Turbels, Histels, and Orthels.

The Histels have thick accumulations of surface organic material and are associated with high-center polygons. The Orthels and Turbels have comparably thinner surface organic material and occur on high floodplains, stream terraces, low-center polygons, and the slopes of hills and plains. Turbels show signs of cryoturbation while Orthels do not.

Histosols have a high content of organic matter and no permafrost. Most are saturated year-round, but a few are freely drained. The most common suborder of Histosols in this MLRA are Fibrists. Fibrists are wet, slightly decomposed Histosols. Most of the soils support natural vegetation of widely spaced small trees, shrubs, forbs, and grasses and grass-like plants (NRCS 2025).

Entisols are soils that show little or no evidence of pedogenic horizon development and in this MLRA are associated with recently deposited sediments. The most common suborder of Entisols in this MLRA are Aquents, which are widely distributed throughout this MLRA. They are common in low lying estuarine areas bordering the Chukchi Sea and Kotzebue Sound.

Fire Dynamics and Succession:
Reported fire history in this MLRA spans 1957 to 2021. During this time period, there were 67 recorded fires. The mean fire size was approximately twelve thousand acres. The largest fire was the 1977 AUGUS fire, burning 235,584 acres (AICC 2025). The number of fires that burn in tundra systems are limited by ignitions, prevalence of atmospheric moisture, and fuel moisture content or fuel availability. Fires in the tundra happen less often than in boreal systems (NPS 2024). Fires can be sporadic and widely distributed. The fire return intervals vary widely in tundra systems, from 30 years to over 1,000 years. In the past, fires have burned more frequently on the Seward Peninsula and in the Noatak Valley than in other tundra regions. This is due to slightly warmer and drier conditions and higher amounts of plants and shrubs above ground such as tussock cottongrass (NPS 2024).

There are over 143 million acres of arctic and subarctic tundra in Alaska, most of which is designated in a limited fire management option. A limited fire management option is one of four fire management options outlined in the Alaska Interagency Wildland Fire Management Plan (AICC 2024). A ‘limited’ approach is the most hands-off management option, meaning the fire will be left to behave naturally and fill its natural ecological role (AICC 2024).
Arctic tundra areas are experiencing warmer temperatures and an increase in fire activity over the past twenty years. Climate model forecasts show more warming in the future, particularly in the high northern areas. This could affect the length of the growing season, how well plants and shrubs grow, and rain and snowfall. A longer and more robust growing season could likely impact trends regarding number and intensity of fires in the arctic tundra.

Vegetation dynamics:
Uplands are not common in this MLRA but where present they generally support dwarf scrub dominated by tussock tundra. On shallow, rocky soils and exposed sites, lichens and scattered herbs dominate the ground layer. Bare soil and bedrock generally are extensive. On mesic sites, halophytic sedges and grasses dominate. Depressions, drainageways, and other saturated areas support wet sedge meadows and wet sedge-moss meadows. The vegetation on flood plains consists of a mixture of wet sedge meadows and of tall scrub dominated by various willows and shrub birch.

Vascular and non-vascular plant succession dynamics vary in post-fire environments. Data collected in the footprint of the abnormally severe Anaktuvuk River fire shows that four years after the burn, above-ground net primary productivity of vascular plants was equal in burned and unburned areas, though total live biomass was less (Bret-Harte et al 2013). Graminoid biomass had recovered to unburned levels, but shrubs had not. Most of the vascular plant biomass had resprouted from surviving underground parts. Much greater changes were observed in the biomass and composition of the non-vascular plant community (Bret-Harte et al 2013). Lichen biomass appears to take decades to centuries to recover from the disturbances of fires, particularly under a warming climate (Racine et al 2004).

Tussock cottongrass is the primary tussock forming plant species in arctic tundra. Tussock cottongrass burns easily yet is very hardy. It grows quickly and is very productive, forming a tussock made of fine dead fuels from the previous year. These fine fuels burn quickly and easily. Tundra fires are usually wind driven and move rapidly, burning through years of accumulated tussock grass thatch. The tussock growth protects the cottongrass roots and plant tissues from fire. These plants and shrubs recover and grow vigorously after fire, benefitting from nutrients and warmer soils after a fire (NPS 2024).

Fire impacts soil composition and structure (Li et al 2021). Fires will often partially or completely consume the organic material layer, depending on the severity of the fire. Fire can also impact permafrost. On average, forest fires reduce the permafrost extent by up to 9 to 16 percent and accelerate permafrost thaw by five years. The effects of wildfire on permafrost are much larger in forested areas than in tundra, bogs, and fens (Li et al 2021).

Classification relationships

Landfire Biophysical Settings:
6717060 – Alaska Arctic Wet Sedge Tundra (Landfire 2009)
6717080 – Alaska Arctic Polygonal Ground Shrub-Tussock Tundra (Landfire 2009)

Viereck Communities:
Wet sedge meadow tundra – III.A.3.a (Viereck et al., 1992)
Tussock tundra – III.A.2.d (Viereck et al., 1992)

Ecological site concept

• Arctic climate
• Associated landforms are coastal plains and high- or low- center polygons
• Soils are derived from organic material, silty eolian deposits, and silty cryoturbate
• Low center polygons are considered very poorly drained and pond frequently for very long durations. High center polygons are considered well drained and do not pond or flood.
• Soils have permafrost at 24 inches or strongly contrasting textural stratification at 32 inches
• The reference plant community is characterized as a tussock tundra (Viereck et al., 1992) with the dominant plants being tussock cottongrass, Bigelow’s sedge, dwarf birch, and tealeaf willow or wet sedge meadow tundra with the dominant plants being water sedge and tussock cottongrass (Viereck et al., 1992).

Associated sites

Similar sites

Table 1. Dominant plant species