Natural Resources
Conservation Service
Ecological site R236XY163AK
Boreal Herbaceous Loamy Flood Plain Sloughs
Last updated: 2/13/2024
Accessed: 11/21/2024
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.
Figure 1. Mapped extent
Areas shown in blue indicate the maximum mapped extent of this ecological site. Other ecological sites likely occur within the highlighted areas. It is also possible for this ecological site to occur outside of highlighted areas if detailed soil survey has not been completed or recently updated.
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).
Ecological site concept
This boreal ecological site is on concave sloughs on lowland flood plains. Site elevation ranges from sea level to 80 feet. Slopes are nearly level (0 – 3 percent). Soil and site hydrology shape the vegetation on this landform. Flooding is frequent and brief and ponding is frequent and long during the growing season. Soils are poorly drained with aquic conditions that restrict vegetation to obligate wetland species.
The reference state supports one community. The reference plant community is characterized as a wet graminoids herbaceous meadow (Viereck et al., 1992). It is composed of a mix of facultative wet to obligate wetland species, including sedges and diverse forbs.
Associated sites
| R236XY155AK |
Boreal Scrub Loamy Flood Plains, Wet R236XY155AK describes flood plains. The site describe here is in corresponding flood plain sloughs. |
|---|---|
| R236XY172AK |
Boreal Dwarf Scrub Peat Flood Plains Depressions Both sites are on flood plains. R236XY172AK describes dips on flood plains, which can be found near to the sloughs describe by this ecological site. |
Similar sites
| R236XY153AK |
Boreal Willow Silty Low Flood Plains Both sites are on boreal low flood plains. R236XY163AK is in flood plain sloughs. Site and soil hydrology are different between these areas, as are flooding and ponding disturbances. The resulting reference state vegetation and ecological dynamics are different between these flood plain sites. |
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Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Salix pulchra |
| Herbaceous |
(1) Carex rostrata |
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