Print Report

A3831 Kalmia microphylla - Cassiope mertensiana - Dryas drummondii Wet Dwarf-shrubland Alliance

Type Concept Sentence: This alliance includes dwarf-shrubland wetlands dominated by Kalmia microphylla, Cassiope mertensiana, and/or Dryas drummondii in the subalpine and alpine elevations of western North American mountains.

Common (Translated Scientific) Name: Alpine Laurel - Western Moss-heather - Drummond''s Mountain-avens Wet Dwarf-shrubland Alliance

Colloquial Name: Alpine Laurel - Moss-heather - Mountain-avens Wet Dwarf-shrubland

Hierarchy Level:  Alliance

Type Concept: These dwarf-shrubland wetlands are dominated by Kalmia microphylla, Cassiope mertensiana, and/or Dryas drummondii. Other ericaceous shrubs are usually present. The herbaceous layer is typically dominated by graminoids, of which Carices usually predominate. Mesic forbs are usually scattered through the graminoid matrix. This alliance is found at subalpine and alpine elevations (1700-4000 m) of western North American mountains. Stands occur in cold and snowy places such as meadows, snowbeds, lake margins, low-gradient depressions, and areas with hummocky topography. Soils are frigid. Water tables are often at or near the surface for much of the growing season. Some stands occur on point bars and stream terraces having well- to rapidly drained cobbly soils.

Diagnostic Characteristics: High-altitude, dwarf-shrublands dominated by Kalmia microphylla, Cassiope mertensiana, and/or Dryas drummondii on saturated soils.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: These three former alliances (A.2629, A.1089, A.1096) often form continuous interdigitated mosaics.

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: Dwarf and low-growing, mainly evergreen shrubs with perennial graminoids and forbs beneath the shrub layer and in openings in the canopy.

Floristics: This dwarf-shrubland if often formed of nearly pure stands of Kalmia microphylla, Cassiope mertensiana, and/or Dryas drummondii. However, equally often there are a variety of other associated shrubs, including Arctostaphylos uva-ursi, Ledum glandulosum, Phyllodoce breweri, Phyllodoce empetriformis, Salix arctica, and Vaccinium spp. The herbaceous layer is a matrix of graminoids, mostly Carices such as Carex aquatilis, Carex canescens, Carex nigricans, Carex paysonis, Carex pellita (= Carex lanuginosa), Carex scirpoidea, and Carex scopulorum, but others include Danthonia intermedia, Deschampsia cespitosa, Juncus drummondii, and Phleum alpinum. Scattered in amongst the matrix of graminoids are several forbs, such as Caltha leptosepala, Chamerion latifolium, Dodecatheon spp., Epilobium spp., Gentiana spp., Geum rossii, Oxytropis sericea, Pedicularis groenlandica, Potentilla diversifolia, and Symphyotrichum spathulatum (= Aster occidentalis).

Dynamics:  Frost heaving tends to create subtle changes in microtopography that allow coexistence of various wetland species. Livestock trampling can cause rutting and headcut erosion in these habitats, leading to drying and invasion of upland species. Kalmia microphylla is poisonous to livestock and is probably not grazed, but the forb and graminoid components of these communities may be heavily utilized.
Environmental Description:  This dwarf-shrub alliance occurs on alpine tundra and is also found in the montane to lower subalpine zones, ranging in elevation from 1000 m in the northern mountains to 4000 m in the southern extent. The alliance occurs in snowbed habitats, or areas that accumulate snow in the winter and release snow slowly during the growing season. The vegetation is often located on solifluction lobes, which receive moisture from upslope, subsurface drainage. Consequently, soils are cold and nearly saturated for most of the growing season, derived from bedrock, aggraded alluvium, from metamorphic or igneous rock, usually high in organic matter, and strongly acidic. Soils can be well- to rapidly drained cobbly soils or on acidic peat soils but are usually saturated with water most of the year, with pH ranging from 5.8-6.2. Soil texture tends to be variable. These communities can be associated with hummocky topography, which provides a juxtaposition of saturated and somewhat drained microhabitats. The water table is often at or near the surface for much of the growing season and due to the cold, soil organic decomposition is slow.
Geographic Range: This alliance is found through high elevations of western North American mountains.

Nations: CA,US

States/Provinces:  AB, BC, CA, CO, ID, MT, NV, OR, UT, WA, WY


Confidence Level: Low

Confidence Level Comments: No Data Available
Grank: GNR

Greasons: No Data Available
Type Name Database Code Classification Code
Class 2 Shrub & Herb Vegetation Class C02 2
Subclass 2.C Shrub & Herb Wetland Subclass S44 2.C
Formation 2.C.4 Temperate to Polar Freshwater Marsh, Wet Meadow & Shrubland Formation F013 2.C.4
Division 2.C.4.Nb Western North American Temperate Freshwater Marsh, Wet Meadow & Shrubland Division D031 2.C.4.Nb
Macrogroup 2.C.4.Nb.5 Sitka Alder - Booth''s Willow / Northwest Territory Sedge Montane Marsh, Wet Meadow & Shrubland Macrogroup M893 2.C.4.Nb.5
Group 2.C.4.Nb.5.c White Marsh-marigold - Black Alpine Sedge - Alpine Laurel Subalpine-Alpine Snowbed, Wet Meadow & Dwarf-shrubland Group G520 2.C.4.Nb.5.c
Alliance A3831 Alpine Laurel - Western Moss-heather - Drummond''s Mountain-avens Wet Dwarf-shrubland Alliance A3831 2.C.4.Nb.5.c
Association CEGL001396 Western Moss-heather / Payson''s Sedge Wet Dwarf-shrubland CEGL001396 2.C.4.Nb.5.c
Association CEGL001402 Alpine Laurel / Black Alpine Sedge Wet Dwarf-shrubland CEGL001402 2.C.4.Nb.5.c
Association CEGL001403 Alpine Laurel / Mountain Sedge Wet Dwarf-shrubland CEGL001403 2.C.4.Nb.5.c
Association CEGL005834 Drummond''s Mountain-avens / Dwarf Fireweed Wet Dwarf-shrubland CEGL005834 2.C.4.Nb.5.c
Concept Lineage: A.2629, A.1089, A.1096

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: > Cassiope mertensiana (White mountain heather heath) Provisional Alliance (Sawyer et al. 2009) [91.126.00]
? Cassiope mertensiana/Carex paysonis Community Type (Cooper et al. 1997)
> Cassiope mertensiana Provisional Dwarf Shrubland Alliance (CNPS 2017) [91.126.00]
> Kalmia microphylla (Alpine laurel heath) Provisional Alliance (Sawyer et al. 2009) [45.406.00]
> Kalmia microphylla Provisional Dwarf Shrubland Alliance (CNPS 2017) [45.406.00]
Concept Author(s): G. Kittel, in Faber-Langendoen et al. (2013)

Author of Description: G. Kittel

Acknowledgements: No Data Available

Version Date: 09-26-14
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