Natural Resources
Conservation Service
Ecological site R236XY129AK
Subarctic Low Scrub Peat Coastal Plains
Last updated: 2/13/2024
Accessed: 09/17/2026
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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): 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
Alaska Vegetation Classification:
Open low scrubland (II.C.2 - level III) / Sweetgale-graminoid bog (II.C.2.j- level IV)
(Viereck et al., 1992)Ecological site concept
This ecological site is on coastal plain tidal marshes. Site elevation is at or near sea level. Slopes are nearly level. Site hydrology, as influenced by aquic soil conditions, a very shallow water table, and flooding and ponding shape the vegetation on this landform. Further, brackish water intrusion also affects the species found on this site.
The reference state supports two communities. The reference plant community is characterized as an open low scrubland (Viereck et al., 1992). It is composed of a mix of hydrophytic shrubs species with facultative to obligate wetland graminoids and forbs throughout. The presence of surface water is a strong indicator of this site on the coastal plain complex. Lower lying areas on this site are commonly wetter, and support more herbaceous species and less shrubs than the reference plant community.Associated sites
R236XY133AK Subarctic Graminoid Loamy Tidal Coastal Plains
Both sites are part of the coastal plain complex. R236XY129AK defines the tidal marshes. Brackish water influences the vegetation. The soil in this site supports a thick organic layer comprised of fibric material, which isn’t found in R236XY133AK. R236XY133AK is found at slightly higher positions on the coastal plain.
R236XY135AK Western Alaska Maritime Scrub Loamy Plains, Coastal
Both sites are on the coastal plain complex. R236XY135AK is associated with Entisols on plain talfs. They lack the organic material associated with soils correlated to R236XY129AK. R236XY135AK supports less hydrophytic species, as the soil is better drained and it does not support a water table throughout the growing season.
R236XY170AK Subarctic Graminoid Loamy Coastal Plain Rises
Both sites are part of the coastal plain complex. R236XY170AK describes the driest areas of the complex, where less hydrophytic vegetation is dominant. Flooding is rare, ponding is absent, and there is no water table present throughout most of the year.
Similar sites
R236XY135AK Western Alaska Maritime Scrub Loamy Plains, Coastal
Both sites are on the coastal plain complex. Both sites are associated with aquic soils and support a mix of facultative wet to obligate wetland species. This site supports a thick, organic soil which is not found in R236XY135AK. Vegetation is also different as this site is under greater influence from brackish water incursion and salt spray.
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Myrica gale
(2) Betula nanaHerbaceous (1) Comarum palustre
(2) Carex lyngbyei
