Name:
Artemisia tridentata ssp. vaseyana Shrub Herbaceous Alliance
Reference:
Western Ecology Working Group of...
Description:
This alliance is widespread in mountainous areas across the western U.S. The alliance can form large, continuous stands on mid-elevation mountain slopes and foothills, and can extend above lower treeline as patches within montane or subalpine coniferous forests. Sites are variable and range from flats to steep slopes to ridgetops with deep to shallow rocky soil. The vegetation included in this alliance is characterized by a sparse (<25% cover on average) shrub layer of Artemisia tridentata ssp. vaseyana, but generally high cover of perennial graminoids (>20% total cover). Associated shrubs include Artemisia arbuscula, Artemisia rigida, Ribes cereum, Symphoricarpos oreophilus, Purshia tridentata, Prunus virginiana, Tetradymia canescens, and Amelanchier alnifolia. The herbaceous layer is typically abundant and dominated by perennial graminoids. The most common species is the bunchgrass Festuca idahoensis, or Carex geyeri, a sod-forming sedge. Other locally important species include Pseudoroegneria spicata, Festuca thurberi, Bromus carinatus, Elymus elymoides, Elymus trachycaulus, Koeleria macrantha, Achnatherum occidentale (= Stipa occidentalis), and Poa secunda. Forb canopy cover and species composition are variable; species of Castilleja, Potentilla, Erigeron, Phlox, Astragalus, Geum, Lupinus, and Eriogonum are characteristic, and Balsamorhiza sagittata, Achillea millefolium, Eriogonum umbellatum, Antennaria rosea, and Geranium viscosissimum are common. Trees are uncommon but individuals of Pinus ponderosa, Cercocarpus ledifolius, Populus tremuloides, Juniperus occidentalis, Pinus albicaulis, and Abies lasiocarpa may occasionally occur. Diagnostic of this shrub herbaceous alliance is the relatively sparse Artemisia tridentata ssp. vaseyana shrub layer (<25% cover on average) with an abundant graminoid layer.
Accession Code:
VB.CC.20587.ARTEMISIATRIDEN
Plot-observations of this Community Concept:
0
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