Natural Resources
Conservation Service
Ecological site R236XY151AK
Subarctic Open Willow Loamy Plain Swales
Last updated: 2/13/2024
Accessed: 12/22/2024
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
Alaska Vegetation Classification:
Open tall scrubland (II.B.2 - level III) / Willow scrubland (II.B.2.a - level IV)
(Viereck et al., 1992)
Ecological site concept
This ecological site is in concave swales on hills and plains. Site elevation is between 450 and 1,820 feet above sea level. Slope gradients are nearly level to strong (0 - 12 percent). Soil hydrology, soil acidity, and microtopography shape the vegetation on this landform. Occasional, brief ponding during the growing season, along with somewhat poorly drained soils with aquic conditions, restricts vegetation to predominantly facultative wet to obligate wetland species.
The reference state supports one stable community. The reference plant community is characterized as an open, tall willow scrubland (Viereck et al., 1992). It is composed of one or more willow species in the overstory with an understory of bluejoint, diverse forbs, and ericaceous shrubs.
Associated sites
| R236XY105AK |
Subarctic Scrub Mosaic Gravelly Hillslopes Both sites are on hills. R236XY151AK describes concave swales features on the shrub hillslopes described by R236XY105AK. |
|---|---|
| R236XY106AK |
Subarctic Dwarf Scrub Dry Loamy Slopes Both sites are on hills and plains. R236XY151AK describes concave swales features on the ericaceous shrub hills and plains described by R236XY106AK. |
Similar sites
| F236XY152AK |
Boreal Forest Volcanic Loamy Swales Both sites are swale features on plains. F236XY152AK is distinguished by its ability to support a boreal forest on its soil. R236XY151AK does not support trees. |
|---|
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Salix pulchra |
| Herbaceous |
(1) Equisetum |
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