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A4334 Arctic Ericaceous Dwarf-shrub Tundra Alliance
Type Concept Sentence: This alliance is defined by tundra vegetation dominated by dwarf- to low ericaceous shrubs such as Ledum palustre ssp. decumbens, Cassiope tetragona, and Vaccinium vitis-idaea often in combination with abundant bryophytes and lichens in the arctic and subarctic regions of Alaska and Canada.
Common (Translated Scientific) Name: Arctic Ericaceous Dwarf-shrub Tundra Alliance
Colloquial Name: Arctic Ericaceous Dwarf-shrub Tundra
Hierarchy Level: Alliance
Type Concept: This tundra alliance is defined by vegetation dominated by dwarf- to low ericaceous shrubs in the arctic and subarctic regions of Alaska and Canada. The alliance is characterized by high constancy of, and indicated by the presence of, the ericaceous shrubs Ledum palustre ssp. decumbens, Cassiope tetragona, and Vaccinium vitis-idaea. The moss Hylocomium splendens and lichen species in the genus Cladonia may exceed 20% cover. The low shrubs Betula nana, Salix pulchra and dwarf-shrubs Salix phlebophylla and Diapensia lapponica may reach high abundances but do not assume dominance. This alliance is common in semi-protected, mesic sites in the hills and mountains where snow cover is retained. Substrates are acidic to non-acidic; patch size is small to large.
Diagnostic Characteristics: This alliance is defined by tundra vegetation dominated by dwarf- to low ericaceous shrubs in the arctic and subarctic regions of Alaska and Canada.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: The applicability of this group concept in Canada needs critical review. Dwarf-shrub of 40 cm follows the CAVM definition; 20 cm is a very low cutoff, applicable only in flat areas. Once you have any kind of microrelief (which occurs in most of the Arctic), the dwarf-shrubs are taller (M. Raynolds pers. comm. 2012). Viereck et al. (1992) use 20 cm and it is a good cutoff for Alaska, but appears not to be appropriate for the remaining parts of the Arctic (K. Boggs pers. comm. 2012).
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: This alliance is represented by dwarf- to low evergreen and broad-leaved deciduous shrubs with more than 25% cover. Bryophyte and lichen species may exceed 20% cover. Tussocks are not present.
Floristics: This alliance is characterized by high constancy of, and indicated by, the ericaceous shrubs Ledum palustre ssp. decumbens, Cassiope tetragona, and Vaccinium vitis-idaea. The dwarf willow Salix phlebophylla, the low shrubs Betula nana, Salix pulchra, the dwarf-shrub Diapensia lapponica, the graminoids Anthoxanthum monticola ssp. alpinum and Luzula confusa, the mosses Hylocomium splendens and Polytrichum strictum, and lichens from the genus Cladonia (likely Cladonia rangiferina (= Cladina rangiferina), Cladonia arbuscula ssp. mitis (= Cladina mitis), Cladonia stellaris (= Cladina stellaris), Cladonia uncialis (= Cladina uncialis)), and Dactylina arctica are also highly constant. Low shrubs and dwarf willows may reach high abundances but do not assume dominance.
Dynamics: This type is considered to be highly stable. Fire may revert types to a graminoid-dominated system whereas low shrubs may assume dominance with amelioration of site condition (e.g., accumulation of organics, decreased exposure to wind).
Environmental Description: This is a common type on acidic and non-acidic substrates in the hills and mountains of arctic and subarctic Alaska and Canada; circumneutral sites are associated with soils derived from carbonate parent materials and areas of fluvial or wind deposition. Sites are typically mesic and somewhat protected so that snow cover is retained. Slope positions include valleys, north-facing sideslopes, and concave microtopography along summits and ridges.
Geographic Range: This alliance occurs throughout arctic and subarctic Alaska, Canada, and possibly into 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.2.1042070
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 | A4334 Arctic Ericaceous Dwarf-shrub Tundra Alliance | A4334 | 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: > Empetrum nigrum - Arctostaphylos alpina (Crowberry - alpine bearberry) (Bos 1967)
> Vaccinium spp. - Ledum decumbens - Arctostaphylos alpina - Cassiope tetragona (Blueberry - marsh Labrador tea - alpine bearberry) (Hanson 1958)
> II.D.2.a - Bearberry tundra (Viereck et al. 1992)
> II.D.2.b - Vaccinium tundra (Viereck et al. 1992)
= S1, Erect dwarf-shrub tundra (CAVM Team 2003)
> S1.2, S1.3 Erect dwarf-shrub tundra communities 48 and 48 on the Seward Peninsula and Nunivak Island (Raynolds et al. 2006a)
> Vaccinium spp. - Ledum decumbens - Arctostaphylos alpina - Cassiope tetragona (Blueberry - marsh Labrador tea - alpine bearberry) (Hanson 1958)
> II.D.2.a - Bearberry tundra (Viereck et al. 1992)
> II.D.2.b - Vaccinium tundra (Viereck et al. 1992)
= S1, Erect dwarf-shrub tundra (CAVM Team 2003)
> S1.2, S1.3 Erect dwarf-shrub tundra communities 48 and 48 on the Seward Peninsula and Nunivak Island (Raynolds et al. 2006a)
- Boggs, Keith. Personal communication. Ecologist, Alaska Natural Heritage Program, Environment and Natural Resources Institute, University of Alaska, Anchorage.
- Bos, G. N. 1967. Range types and their utilization by muskox on Nunivak Island, Alaska: A reconnaissance study. MSc. thesis, University of Alaska, Fairbanks. 113 pp.
- CAVM Team. 2003. Circumpolar arctic vegetation map (Scale 1:7 500 000). Conservation of Arctic Flora and Fauna (CAFF) Map No. 1, USDI Fish and Wildlife Service, Anchorage, AK.
- 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.
- Hanson, H. C. 1958. Principles concerned in the formation and classification of communities. The Botanical Review 24(2,3):66-125.
- Raynolds, M. K., D. A. Walker, and H. A. Maier. 2006a. Alaska Arctic Tundra Vegetation Map. Scale 1:4,000,000. Conservation of Arctic Flora and Fauna Map No. 2. U.S. Fish & Wildlife Service, Anchorage, AK.
- 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.