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A.1577 | EcoArt 2002
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Name: A.1577
Reference: EcoArt 2002
Description: Plant associations in this alliance are typically found well above treeline in high mountains of the interior Pacific Northwest and Rocky Mountains. The climate is cold and snowy with severe winds, snow abrasion, and a short growing season. Annual precipitation ranges from 75 cm in the Rocky Mountains to over 250 cm in the Cascades. The vegetation occurs on dry, exposed mountain ridges where snow blows off or melts relatively early. Elevations range from 1700-2400 m in the Cascades up to 3600 m in the Rocky Mountains. Soils are composed of varied parent materials, including granitics, limestone, and basalt, but are usually young and skeletal. Frost boiling and needle ice formation are common disturbances. Plant associations in this alliance form a distinctive fell-field type on dry ridges above treeline with coarse, frost-heaved soils. The depauperate dwarf-shrub communities are dominated by ~Dryas octopetala$, and have few forb and graminoid species in the understory. ~Minuartia obtusiloba$ is the most characteristic forb species in both Cascade and Rocky Mountain stands. ~Carex rupestris$ is important and may be codominant in some stands in the Rockies. Other common herbaceous associates across the range include ~Sedum lanceolatum, Lupinus sellulus var. lobbii, Danthonia intermedia, Festuca brachyphylla$, and ~Luzula spicata$. Adjacent vegetation is usually ~Tsuga mertensiana$ (in the Cascades), ~Pinus albicaulis, Larix lyallii$, or ~Abies lasiocarpa$ krummholz, dry alpine grasslands, sedge wetlands, or bare rock and ice. 
Accession Code: VB.CC.1332.A1577
Plot-observations of this Community Concept: 0
      Party Perspective according to: NatureServe (organization)
Perspective from: 26-Nov-1997 to: 17-Mar-2005
     
  • status: accepted
  • Community's Parent: V.A.8.N.c
  • This Community's Level: Alliance
  • This Community's Children: [none]
Names:   Scientific: DRYAS OCTOPETALA DWARF-SHRUB HERBACEOUS ALLIANCE
  Code: A.1577
  Common: Eight-petal Mountain-avens Dwarf-shrub Herbaceous Alliance
(convergence) and Synonyms:
(undetermined) Dryas octopetala Dwarf-shrub Herbaceous Alliance