Natural Resources
Conservation Service
Ecological site R237XY210AK
Western Alaska Maritime Scrubland Gravelly Flood Plains
Last updated: 7/23/2020
Accessed: 11/13/2024
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): 237X–Ahklun Mountains
The Ahklun Mountains Major Land Resource Area (MLRA 237) is in western Alaska (fig. 2). This MLRA covers approximately 14,555 square miles, and it includes the mountains, hills, and valleys of the Kilbuck Mountains in the north and the Ahklun Mountains in the south. Except for the Kilbuck Mountains and the highest ridges of the Ahklun Mountains, the MLRA was extensively glaciated during the Pleistocene (Kautz et al., 2004). Today, a few small glaciers persist in mountainous cirques (Gallant et al., 1995). The present-day landscape and landforms reflect this glacial history; glacial moraines and glacial drift cover much of the area (USDA-NRCS, 2006). The landscape of the MLRA is primarily defined by low, steep, rugged mountains cut by narrow-to-broad valleys. Flood plains and terraces of varying sizes are common at the lower elevations in the valley bottoms. Glacially carved valleys host many lakes. Togiak Lake is one of the largest lakes in the region. It is 13 miles long and about 9,500 acres in size. Major rivers include the Goodnews, Togiak, Kanektok, Osviak, Eek, and Arolik Rivers. Where the Goodnews and Togiak Rivers reach the coast, the nearly level to rolling deltas support numerous small lakes.
This MLRA has two distinct climatic zones: subarctic continental and maritime continental (fig. 3). The high-elevation areas are in the subarctic continental zone. The mean annual precipitation is more than 75 inches, and the mean annual air temperature is below about 27 degrees F (-3 degrees C) in extreme locations. The warmer, drier areas at the lower elevations are in the maritime continental zone. The mean annual precipitation is 20 to 50 inches, and the mean annual air temperature is about 30 to 32 degrees F (-0.2 to 1.2 degrees C) (PRISM). This climatic zone is influenced by both maritime and continental factors. The temperatures in summer are moderated by the open waters of the Bering Sea, and the temperatures in winter are more continental due to the presence of ice in the sea (Western Regional Climate Center, 2017). The seasonal ice reaches its southernmost extent off the coast of Alaska in Bristol Bay (Alaska Climate Research Center, 2017). The western coast of Alaska is also influenced by high winds from strong storms and airmasses in the Interior Region of Alaska (Hartmann, 2002).
The Ahklun Mountains MLRA is principally undeveloped wilderness. Federally managed lands include the Togiak and Alaska Maritime National Wildlife Refuges. The MLRA is sparsely populated, but it has several communities, including Togiak, Manokotak, Twin Hills, and Goodnews Bay. Togiak is the largest village. It has a population of approximately 855, most of which are Yup’ik Alaska Natives (U.S. Census Bureau, 2016). Major land uses include subsistence activities (fishing, hunting, and gathering) and wildlife recreation (USDA-NRCS, 2006; Kautz et al., 2004).
Ecological site concept
Ecological site R237XY210AK is on low flood plains confined by steep escarpments or mountainsides. The site is subject to frequent (more than 50 times in 100 years), very brief periods (4 to 48 hours) of flooding. The associated soils are moderately well drained. The reference state has two community phases related to flooding. An alternate state is related to beaver activity.
The reference plant community is open tall scrubland (fig. 1; Viereck et al., 1992) that consists dominantly of facultative or obligate wetland species. The community is dominantly dense willows such as tealeaf willow (Salix pulchra), Barclay’s willow (S. barclayi), grayleaf willow (S. glauca), and Bebb willow (S. bebbiana) and an understory of hydrophilic, shade-tolerant shrubs, graminoids, and forbs. These include Canadian burnet (Sanguisorba canadensis), shrubby cinquefoil (Dasiphora fruticosa), field horsetail (Equisetum arvense), and bluejoint (Calamagrostis canadensis).
Associated sites
R237XY212AK |
Western Alaska Maritime Scrubland Silty Flood Plains Ecological site R237XY210AK is dominantly on low flood plains throughout the Ahklun Mountains area. Other ecological sites on flood plains are distinguished by differences in elevation, disturbance, associated soils, and the type and amount of plants. These sites include R237XY211AK, R237XY212AK, and F237XY216AK. Ecotonal plant communities that have characteristics from more than one ecological site are in areas where these sites abut. |
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R237XY226AK |
Western Alaska Maritime Grassland Peat Flood Plains, Depression Ecological site R237XY226AK is in depressions of flood plains and is associated with site R237XY210AK. Ecotonal plant communities that have characteristics from more than one ecological site are in areas where these sites abut. |
R237XY211AK |
Western Alaska Maritime Scrubland Loamy Flood Plains Ecological site R237XY210AK is dominantly on low flood plains throughout the Ahklun Mountains area. Other ecological sites on flood plains are distinguished by differences in elevation, disturbance, associated soils, and the type and amount of plants. These sites include R237XY211AK, R237XY212AK, and F237XY216AK. Ecotonal plant communities that have characteristics from more than one ecological site are in areas where these sites abut. |
Similar sites
R237XY212AK |
Western Alaska Maritime Scrubland Silty Flood Plains Several ecological sites in the Ahklun Mountains area support a reference plant community characterized as willow scrubland. Although these sites may have plant communities similar to those of site R237XY210AK, the sites are differentiated by the soils, disturbance regimes, and reference state communities. Site R237XY212AK is on broad flood plains that are subject to a different frequency and duration of flooding than are the flood plains of site R237XY210AK. These broad flood plains also are associated with different soils. Ecotonal plant communities that have characteristics from more than one ecological site are in areas where these sites abut. |
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F237XY216AK |
Boreal Woodland Loamy Flood Plains Several ecological sites in the Ahklun Mountains area support a reference plant community characterized as willow scrubland. Although these sites may have plant communities similar to those of site R237XY210AK, the sites are differentiated by the soils, disturbance regimes, and reference state communities. Site F237XY216AK is correlated to different soils and is subject to a different disturbance regime. The reference plant community in this site is noticeably different than that of site R237XY210AK. Ecotonal plant communities that have characteristics from more than one ecological site are in areas where these sites abut. |
R237XY211AK |
Western Alaska Maritime Scrubland Loamy Flood Plains Several ecological sites in the Ahklun Mountains area support a reference plant community characterized as willow scrubland. Although these sites may have plant communities similar to those of site R237XY210AK, the sites are differentiated by the soils, disturbance regimes, and reference state communities. Site F237XY211AK is correlated to different soils and is subject to a different disturbance regime. The reference plant community in this site is noticeably different than that of site R237XY210AK. Ecotonal plant communities that have characteristics from more than one ecological site are in areas where these sites abut. |
Figure 1. The reference plant community is an open tall scrubland. Very dense willow is in some areas.
Table 1. Dominant plant species
Tree |
Not specified |
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Shrub |
(1) Salix pulchra |
Herbaceous |
(1) Calamagrostis canadensis |
Click on box and path labels to scroll to the respective text.
Ecosystem states
T1A | - | Beaver dam building |
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R2A | - | Removal of dam (hypothetical) |
State 1 submodel, plant communities
1.1A | - | More frequent, longer periods of flooding |
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1.2A | - | Less frequent, shorter periods of flooding |