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A1107 Eriogonum microthecum Dwarf-shrubland Alliance
Type Concept Sentence: This minor dwarf-shrubland alliance is dominated by dwarf-shrub Eriogonum microthecum and occurs in portions of the Snake and Imnaha river canyons in Idaho and eastern Oregon and Washington.
Common (Translated Scientific) Name: Slender Buckwheat Dwarf-shrubland Alliance
Colloquial Name: Slender Buckwheat Dwarf-shrubland
Hierarchy Level: Alliance
Type Concept: Vegetation included in this alliance has a sparse woody layer that is dominated by the dwarf-shrub Eriogonum microthecum and occurs in rather fine-scale mosaic patterns. Some stands may have Eriogonum strictum instead of, or in addition to, Eriogonum microthecum. The herbaceous layer is also sparse and composed of a relatively even mix of forbs and grasses. Other characteristic species include forbs, such as Achillea millefolium, Chaenactis douglasii, Erysimum asperum, Oenothera caespitosa, Phacelia heterophylla, Polygonum douglasii, Physaria oregona, and the grass Pseudoroegneria spicata. Moss and lichen are nearly absent, likely because of the instability of the slopes. Exotic species, namely Bromus tectorum, often make up a significant portion of the vegetation cover in these stands. This minor dwarf-shrubland alliance occurs in portions of the Snake and Imnaha river canyons in Idaho and eastern Oregon and Washington. Precipitation primarily occurs in the winter as snow or rain. This moisture is stored in the soil profile and utilized during the typically dry summers. Stands are typically found on highly weathered basalt outcrops in the canyons. Sites are very hot and dry, occurring on moderate to steep slopes with southern or western aspects. Soils are very shallow, coarse-textured, and well-drained with a high percentage of rock fragments. The soil surface has a high cover of pea-sized gravel and sand with cobbles. Parent material is colluvium and residuum derived from a unique, highly fractured, hydrothermally altered basalt lava. Chemically, this substrate is alkaline with low organic matter and high cation-exchange capacity of calcium and soluble sodium.
Diagnostic Characteristics: Largely unvegetated sites (~90%) characterized by nearly sparsely vegetated dwarf-shrublands of portions of the Snake and Imnaha river canyons in Idaho and eastern Oregon and Washington with Eriogonum microthecum as the most consistent dominant. Some stands may have Eriogonum strictum as the dominant species.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: Stands in this alliance may be too sparse to be classified as dwarf-shrublands (Daubenmire 1970, Johnson and Simon 1987).
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: Vegetation in this alliance has sparse to moderately sparse cover of dwarf-shrubs. There is also a sparse cover of perennial forbs. Annual forbs and grasses are seasonally present in small amounts.
Floristics: Vegetation included in this minor alliance has a sparse woody layer (usually less than 0.5 m tall) that is dominated by the dwarf-shrub Eriogonum microthecum. Some stands may have Eriogonum strictum instead of, or in addition to, Eriogonum microthecum. The herbaceous layer is also sparse (typically <10% cover). It is composed of a relatively even mix of forbs and grasses. Other characteristic species include forbs, such as Achillea millefolium, Chaenactis douglasii, Erysimum asperum, Oenothera caespitosa, Phacelia heterophylla, Polygonum douglasii, Physaria oregona, and the grass Pseudoroegneria spicata. Poa bulbosa is common in spring. Moss and lichen are nearly absent, likely because of the instability of the slopes. Exotic species, namely Bromus tectorum, often make up a significant portion of the vegetation cover in these stands.
Dynamics: Stands are restricted to hot/dry, moderately steep slopes with a coarse-textured unstable substrate. The native vegetation is too sparse to carry fire, and the sites are too steep to be accessible to livestock (Daubenmire 1970, Johnson and Simon 1987). The biggest threat is exotic plants that have invaded many stands. Common exotics include annual grasses such as Bromus tectorum, Bromus briziformis, and annual forbs such as Erodium cicutarium, Lactuca serriola, and Holosteum umbellatum. Bromus tectorum is moderately dense on some stands and could possibly be dense enough to carry a fire.
Environmental Description: These sparse dwarf-shrublands occur in portions of the Snake and Imnaha river canyons in Idaho and eastern Oregon and Washington. Elevations range from 230-730 m, and the climate is temperate continental. Mean annual precipitation is approximately 25-30 cm. Precipitation primarily occurs in the winter as snow or rain. This moisture is stored in the soil profile and utilized during the typically dry summers. Stands are typically found on highly weathered basalt outcrops in the canyons. Sites are very hot and dry, occurring on moderate to steep (30-60%) slopes with southern or western aspects. Soils are very shallow (less than 15 cm), well-drained, with a high percentage of rock fragments (approximately 35%) (lithic). Soil texture ranges from gravelly sand to gravelly sandy loam. The soil surface has a high cover of pea-sized gravel and sand (approximately 70%) with cobbles. Parent material is colluvium and residuum derived from a unique, highly fractured, hydrothermally altered basalt lava. Chemically, this substrate is alkaline (pH 7-7.9) with low organic matter and high cation-exchange capacity of calcium and soluble sodium.
Geographic Range: This is a minor alliance found on a limited and unique substrate in the vicinity of the Snake River Canyon at the boundaries of Idaho, Oregon, and Washington states.
Nations: US
States/Provinces: ID, OR, WA
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.899074
Confidence Level: Moderate
Confidence Level Comments: No Data Available
Grank: GNR
Greasons: No Data Available
| Type | Name | Database Code | Classification Code |
|---|---|---|---|
| Class | 3 Desert & Semi-Desert Class | C03 | 3 |
| Subclass | 3.B Cool Semi-Desert Scrub & Grassland Subclass | S11 | 3.B |
| Formation | 3.B.1 Cool Semi-Desert Scrub & Grassland Formation | F033 | 3.B.1 |
| Division | 3.B.1.Ne Western North American Cool Semi-Desert Scrub & Grassland Division | D040 | 3.B.1.Ne |
| Macrogroup | 3.B.1.Ne.2 Little Sagebrush - Black Sagebrush - Scabland Sagebrush Steppe & Shrubland Macrogroup | M170 | 3.B.1.Ne.2 |
| Group | 3.B.1.Ne.2.a Scabland Sagebrush - Buckwheat species Dwarf-shrubland & Steppe Group | G307 | 3.B.1.Ne.2.a |
| Alliance | A1107 Slender Buckwheat Dwarf-shrubland Alliance | A1107 | 3.B.1.Ne.2.a |
| Association | CEGL001737 Slender Buckwheat - Oregon Twinpod Dwarf-shrubland | CEGL001737 | 3.B.1.Ne.2.a |
Concept Lineage: equivalent to A.1107
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: ? Eriogonum microthecum-Physaria oregana habitat type (Daubenmire 1970)
? Eriogonum spp./Physaria oregana Habitat Type (Johnson and Simon 1987)
? Eriogonum spp./Physaria oregana Habitat Type (Johnson and Simon 1987)
- Daubenmire, R. F. 1970. Steppe vegetation of Washington. Washington State University Agricultural Experiment Station Technical Bulletin No. 62. 131 pp.
- Faber-Langendoen, D., J. Drake, M. Hall, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, M. Russo, K. Schulz, L. Sneddon, K. Snow, and J. Teague. 2013-2019b. Screening alliances for induction into the U.S. National Vegetation Classification: Part 1 - Alliance concept review. NatureServe, Arlington, VA.
- Johnson, C. G., Jr., and S. A. Simon. 1987. Plant associations of the Wallowa-Snake Province Wallowa-Whitman National Forest. Technical Paper R6-ECOL-TP-255A-86. USDA Forest Service, Pacific Northwest Region, Wallowa-Whitman National Forest. 399 pp. plus appendices.