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A4335 Arctic Acidic Dwarf Willow Tundra Alliance
Type Concept Sentence: This tundra alliance is defined as dwarf-shrub vegetation dominated by prostrate willow species found on exposed sites in the arctic and subarctic regions of Alaska and Canada.
Common (Translated Scientific) Name: Arctic Acidic Dwarf Willow Tundra Alliance
Colloquial Name: Arctic Acidic Dwarf Willow Tundra
Hierarchy Level: Alliance
Type Concept: This tundra alliance is dominated by dwarf willow shrubs and is commonly found on exposed sites in the arctic and subarctic regions of Alaska and Canada. The alliance is indicated by the dwarf willows Salix reticulata, Salix polaris, Salix rotundifolia, and Salix phlebophylla. Characteristic species include the dwarf-shrubs Dryas octopetala and Cassiope tetragona, the graminoids Carex bigelowii and Arctagrostis latifolia, the forb Petasites frigidus, and the lichens Flavocetraria cucullata and Thamnolia vermicularis. The erect shrub Salix pulchra is constant at low cover. This is a small-patch type developing in shallow, well-drained soils on non-acidic substrates underlain by permafrost.
Diagnostic Characteristics: This alliance is defined as tundra vegetation dominated by prostrate willow species found in the arctic and subarctic regions of Alaska, Canada, and possibly Greenland. Erect shrubs and trees provide less than 25% cover.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: This vegetation is not currently well-documented in the NVC, and this description has been adapted from the Willow Dwarf Shrub Tundra described by Viereck et al. (1992). Further information from Raynolds et al. (2006a) should be used to clarify a more arctic expression of this group. Type is similar to low willow shrubs, but is <40 cm high. It could perhaps be combined with former North American Arctic & Subarctic Ericaceous Dwarf-Shrub Tundra Group (G367), which is now treated as ~Arctic Ericaceous Dwarf-shrub Tundra Alliance (A4334)$$. Martha Raynolds (pers. comm. 2012) stated: This group occurs in very small patches on the landscape, but it is a very distinctive group, and can be well-defined floristically. This group is too small to be mapped at the circumpolar scale. Snowbed communities are described on the back on the Alaska Tundra map (Raynolds et al. 2006a). Review of these issues with Canada is needed.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: This alliance is represented by a sparse to open cover of broad-leaved, cold-deciduous dwarf-shrubs dominated by prostrate willow species. Erect shrubs and trees provide less than 25% cover.
Floristics: This alliance is characterized by high constancy of the dwarf willows Salix reticulata and Salix rotundifolia, as well as the dwarf-shrubs Dryas octopetala and Cassiope tetragona. The erect shrub Salix pulchra is constant at low cover. The graminoids Carex bigelowii and Arctagrostis latifolia, the forb Petasites frigidus, and the lichens Flavocetraria cucullata and Thamnolia vermicularis also have high constancy. The alliance is indicated by the dwarf willows Salix reticulata, Salix polaris, and Salix rotundifolia, the forbs Petasites frigidus, Tephroseris atropurpurea ssp. frigida, and Polygonum bistorta var. plumosum, the sedges Carex bigelowii, Eriophorum angustifolium, Eriophorum vaginatum, Luzula confusa, and Luzula arctica, the horsetail Equisetum arvense, and bryophytes which are likely to include Tomentypnum nitens, Hylocomium splendens, Aulacomnium and Dicranum species.
Dynamics: Sites appear to be stable. Changes in exposure or drainage are likely drivers of successional change.
Environmental Description: This tundra alliance is common in the arctic and subarctic regions of Alaska, Canada and possibly extending to Greenland. It most commonly occurs along exposed slopes, ridges, polygon summits and stabilized dunes but may also develop in wetter areas of late-lying snow, high-alpine drainage channels and solifluction lobes. Soils are shallow and well-drained in exposed sites; however, a thin organic mat may develop in moist and mesic settings. This is a small-patch type developing on non-acidic substrates underlain by permafrost.
Geographic Range: This alliance is common in the arctic and subarctic regions of Alaska, Canada and possibly extending to Greenland.
Nations: CA,GL?,IS,NO,RU,US
States/Provinces: AK, LB?, MB, NT?, NU?, QC?, YT?
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.1042080
Confidence Level: Low
Confidence Level Comments: No Data Available
Grank: GNR
Greasons: No Data Available
| Type | Name | Database Code | Classification Code |
|---|---|---|---|
| Class | 4 Polar & High Montane Scrub, Grassland & Barrens Class | C04 | 4 |
| Subclass | 4.B Temperate to Polar Alpine & Tundra Vegetation Subclass | S12 | 4.B |
| Formation | 4.B.2 Polar Tundra & Barrens Formation | F031 | 4.B.2 |
| Division | 4.B.2.Xa Arctic Tundra & Barrens Division | D044 | 4.B.2.Xa |
| Macrogroup | 4.B.2.Xa.2 Feltleaf Willow - Eight-petal Mountain-avens - Tussock Cottongrass Tundra Macrogroup | M173 | 4.B.2.Xa.2 |
| Group | 4.B.2.Xa.2.b Arctic Dwarf-shrub Tundra Group | G896 | 4.B.2.Xa.2.b |
| Alliance | A4335 Arctic Acidic Dwarf Willow Tundra Alliance | A4335 | 4.B.2.Xa.2.b |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: > Salicetea herbaceae - Salix rotundifolia comm. (Walker et al. 1994a)
> Salix arctica - Carex nesophila - Cladina alpestris - Cetraria cucullata (Arctic willow - Bering Sea sedge - reindeer lichen - cetraria lichen) (Klein 1959)
> Salix polaris (Polar willow) (Boggs et al. 2003)
> Salix reticulata - Carex bigelowii - Aulacomnium spp. (Netleaf willow - Bigelow''s sedge - aulacomnium moss) (Jorgenson 1984)
> Salix rotundifolia (Least willow) (Klein 1959)
> II.D.3.a - Willow tundra (dwarf shrub) (Viereck et al. 1992) [Type is described in Alaska as being common in both alpine areas and other windswept tundra settings throughout the state except for southeast Alaska.]
> Syntaxa 6-9 Salix rotundifolia snowbeds (Cooper 1986c)
> Salix arctica - Carex nesophila - Cladina alpestris - Cetraria cucullata (Arctic willow - Bering Sea sedge - reindeer lichen - cetraria lichen) (Klein 1959)
> Salix polaris (Polar willow) (Boggs et al. 2003)
> Salix reticulata - Carex bigelowii - Aulacomnium spp. (Netleaf willow - Bigelow''s sedge - aulacomnium moss) (Jorgenson 1984)
> Salix rotundifolia (Least willow) (Klein 1959)
> II.D.3.a - Willow tundra (dwarf shrub) (Viereck et al. 1992) [Type is described in Alaska as being common in both alpine areas and other windswept tundra settings throughout the state except for southeast Alaska.]
> Syntaxa 6-9 Salix rotundifolia snowbeds (Cooper 1986c)
- Boggs, K. W., S. C. Klein, J. E. Grunblatt, and B. Koltun. 2003. Landcover classes, ecoregions and plant associations of Katmai National Park and Preserve. Natural Resource Technical Report NPS/KATM/NRTR--2003/001. National Park Service, Fort Collins, CO. 274 pp.
- Cooper, D. J. 1986c. Arctic-alpine tundra vegetation of the Arrigetch Creek Valley, Brooks Range, Alaska. Phytocoenologia 14(4):647-555.
- 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.
- Jorgenson, M. T. 1984. The response of vegetation to landscape evolution on glacial till near Toolik Lake, Alaska. Pages 134-142 in: Inventorying forest and other vegetation of the high latitude and high altitude regions. Proceedings of an International Symposium, Society of American Foresters Regional Technical Conference. Fairbanks, AK. Society of American Foresters, Bethesda, MD.
- Klein, D. R. 1959. St. Matthew Island reindeer-range study. Special Scientific Report-Wildlife No. 43. U.S. Fish and Wildlife Service, Washington, DC.
- Raynolds, Martha. Personal communication. Research Biologist, University of Alaska, Fairbanks, AK.
- Viereck, L. A., C. T. Dyrness, A. R. Batten, and K. J. Wenzlick. 1992. The Alaska vegetation classification. General Technical Report PNW-GTR286. USDA Forest Service, Pacific Northwest Research Station, Portland, OR. 278 pp.
- Walker, M. D., D. A. Walker, and N. A. Auerbach. 1994a. Plant communities of a tussock tundra landscape in the Brooks Range Foothills, Alaska. Journal of Vegetation Science 5:843-866.