Natural Resources
Conservation Service
Ecological site R236XY140AK
Subarctic Tussock Tundra Wet Loamy Plains
Last updated: 2/13/2024
Accessed: 04/28/2024
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): 236X–Bristol Bay-Northern Alaska Peninsula Lowlands
The Bristol Bay-Northern Alaska Peninsula Lowland Major Land Resource Area (MLRA 236) is located in Western Alaska. This MLRA covers approximately 19,500 square miles and is defined by an expanse of nearly level to rolling lowlands, uplands and low to moderate hills bordered by long, mountain footslopes. Major rivers include the Egegik, Mulchatna, Naknek, Nushagak, and Wood River. MLRA 236 is in the zone of discontinuous permafrost. It is primarily in areas with finer textured soils on terraces, rolling uplands and footslopes. This MLRA was glaciated during the early to middle Pleistocene. Moraine and glaciofluvial deposits cover around sixty percent of the MLRA. Alluvium and coastal deposits make up a large portion of the remaining area (Kautz et al., 2012; USDA, 2006).
Climate patterns across this MLRA shift as one moves away from the coast. A maritime climate is prominent along the coast, while continental weather, commonly associated with Interior Alaska, is more influential inland. Across the MLRA, summers are general short and warm while winters are long and cold. Mean annual precipitation is 13 to 50 inches, with increased precipitation at higher elevations and areas away from the coast. Mean annual temperatures is between 30 and 36 degrees F (USDA, 2006).
The Bristol Bay-Northern Alaska Peninsula MLRA is principally undeveloped wilderness. Federally managed land includes parts of the Katmai and Aniakchak National Parks, and the Alaska Peninsula, Becharof, Togiak and Alaska Maritime National Wildlife Refuges. The MLRA is sparsely populated. Principal communities include Dillingham, Naknek, and King Salmon. Commercial fishing in Bristol Bay and the Bering Sea comprises a major part of economic activity in the MLRA. Other land uses include subsistence activities (fishing, hunting, and gathering) and sport hunting and fishing (USDA, 2006).
Classification relationships
laska Vegetation Classification:
Mesic graminoid herbaceous (III.A.2 - level III) / Tussock tundra (III.A.2.d - level IV)
(Viereck et al., 1992)
BioPhysical Settings: 7216280 - Western North American Boreal Low Scrub-Tussock Tundra
(LANDFIRE biophysical settings, 2009)
Ecological site concept
This ecological site is on linear to convex plain talf slopes. Site elevation is between 10 and 960 feet above sea level. Slopes are nearly level gentle (0 – 5 percent). Soil hydrology, low soil pH and a fire regime shape the vegetation on this landform. Soils support aquic conditions, with a water table during the growing season and frequent, brief ponding at the surface.
The reference state supports two communities. The reference plant community is characterized as a tussock tundra (Viereck et al., 1992). It is composed of one or more species of cottongrass (Eriophorum spp.) with low and dwarf shrubs throughout. A post-fire community is comprised of fast-growing colonizing herbaceous species along with extant, surviving cottongrasses and shrubs.
Associated sites
| R236XY109AK |
Subarctic Low Scrub Peat Drainages R236XY109AK is in non-permafrost, concave dips on plains. These organic depressions are features on the plain talfs described by R236XY140AK. |
|---|---|
| R236XY132AK |
Subarctic Dwarf Scrub Dry Loamy Slopes R236XY132AK describes the open low scrubland on convex slopes of rolling plains. These areas are upslope of R2136XY140AK. |
| R236XY131AK |
Subarctic Tussock-Scrub Frozen Plains R236XY131AK describes depressions with permafrost on plains. The vegetation associated with the moderately well-drained soil and the associated frost heaving that occur differentiate it from R236XY140AK |
| R236XY130AK |
Subarctic Scrub Scrub Tundra Loamy Plains and Hills R236XY130AK describes hill toeslopes and plain rises. Slopes are greater than in R236XY140AK and soils are better drained. The vegetation reflects these differences, with no tussocks in R236XK130AK. |
Similar sites
| R236XY130AK |
Subarctic Scrub Scrub Tundra Loamy Plains and Hills These sites are adjacent to each other and the ecotonal areas between them may be large. R236XY130AK is better drained and supports a denser scrubland reference plant community. R236Xy140AK is flatter and has aquic soil conditions, which results in more tussocks and less shrub cover. |
|---|---|
| F236XY171AK |
Subarctic Woodland Loamy Slopes Both sites are on linear plain talfs. F236XY171AK is proximal to Dillingham. Temperatures are warmer, allowing a woodland to develop on the plain talfs. Areas along the Nushagak River corridor are cooler in comparison, and support the tussock-scrub tundra described by R236XY140AK. |
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Ledum palustre subsp. decumbens |
| Herbaceous |
(1) Eriophorum vaginatum |
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Ecosystem states
State 1 submodel, plant communities
| 1.1A | - | Fire |
|---|---|---|
| 1.2A | - | Fire recovery |