Name:
Artemisia frigida / Bouteloua gracilis Dwarf-shrubland
Reference:
Western Ecology Working Group of...
Description:
This dwarf-shrubland is reported from central Colorado, where it is associated with prairie dog towns and heavily grazed pastures in the vicinity of livestock watering ponds. It is located on deeper soils that are typically deposited in drainages, swales (interfluves), and along lower hillslopes. The soil must be of a consistency (silty-clay and clay) that will support burrowing activity in terms of both depth and cohesiveness. Ground cover is typically 60-90% bare soil and small gravel, with the remainder in herbaceous litter. It also occurs at El Malpais National Monument in western New Mexico, primarily in areas of soil formation from deposition and weathering, as well as in kipukas of the oldest lavaflows and occasionally on gentle sideslopes of low hills or on gently rolling plains with alluvium or sandstone substrates. This type is found at elevations ranging from 2100 to 2640 m (6900-8660 feet). The slopes range from 2-7% and are considered moderately well-drained. In prairie dog communities, <i>Artemisia frigida</i> is an increaser under livestock grazing regimes and is evidently unpalatable or less palatable to prairie dogs. The age of the colony determines to what extent <i>Artemisia frigida</i> dominates the site, and the following description covers sites that have been used by prairie dogs for several years. Prairie dog colonies that are densely occupied typically have vegetative cover values less than 40%. The foliar cover for <i>Artemisia frigida</i> ranges from 20-40%, and other dwarf-shrubs (i.e., <i>Ericameria parryi, Chrysothamnus viscidiflorus, Gutierrezia sarothrae, Rosa acicularis</i>, and <i>Solidago</i> sp.) contribute from 5-20% foliar cover on some sites. The most abundant graminoid is <i>Bouteloua gracilis</i>, which is an increaser under light to moderate grazing regimes. <i>Bouteloua gracilis</i> contributes approximately 5-10% foliar cover on sites that are moderate to heavily-grazed. Other graminoids present on established prairie dog towns include <i>Schedonnardus paniculatus, Poa fendleriana</i>, and <i>Nassella viridula</i>. They rarely contribute greater than 5% foliar cover, unless it is a less densely populated colony, then the cover values increase for these species. Forbs generally contribute less than 5% to the foliar cover; those species commonly associated with these disturbed sites include <i>Argentina anserina, Melilotus officinalis</i>, and <i>Achillea millefolium</i>. At El Malpais, <i>Bouteloua gracilis</i> is also the most frequent and abundant species and typically exceeds 25% cover. <i>Elymus elymoides</i> occurs nearly as frequently, though cover is lower. The shrub layer is dominated by the low-growing subshrub <i>Artemisia frigida</i> with around 10% cover. Taller shrubs such as <i>Ericameria nauseosa, Gutierrezia sarothrae</i>, and <i>Tetradymia canescens</i> are common associates, but their cover seldom exceeds 5%. Forbs make up a small proportion of the total cover, but species richness is high with 43 forb species found from sample plots of these grasslands. <i>Eriogonum jamesii</i> and <i>Sphaeralcea coccinea</i> are the most frequently occurring forb species observed. Trees can be scattered in these grasslands but typically occur with less than 10% cover and may include <i>Pinus edulis, Pinus ponderosa, Juniperus scopulorum</i>, and <i>Juniperus monosperma</i>.
Accession Code:
VB.CC.31943.CEGL002782
Plot-observations of this Community Concept:
0
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