Name:
Great Basin-Intermountain Ruderal Dry Shrubland & Grassland Group
Reference:
NatureServe Biotics 2019
Description:
This semi-desert interior western U.S. ruderal shrubland and grassland group includes shrubland, shrub-steppe and grassland stands that are strongly dominated (>90% relative canopy cover) by invasive, exotic species. Diagnostic invasive shrubs include <i>Alhagi maurorum, Cytisus striatus, Zygophyllum fabago</i>, or other exotic shrubs. Herbaceous stands include open to dense grasslands and forblands composed of either exotic annual or biennial grasses or forbs with low cover of perennial species (<10% absolute cover) or stands with a significant perennial herbaceous layer (>10% absolute cover) strongly dominated by exotics (>90% relative cover) with or without annuals and biennials present to dominant. There are relatively few cool, semi-arid invasive perennial graminoids such as <i>Agropyron cristatum</i>. Relatively mesic, invasive perennial hay grasses such as <i>Bromus inermis, Dactylis glomerata</i>, and <i>Phleum pratense</i> are typically absent or have low cover and are restricted to mesic microsites as they are more common in higher elevation or higher latitude, temperate climates or relatively mesic sites. Numerous exotic perennial herbaceous species may compose these stands, such as <i>Acroptilon repens, Cardaria draba, Centaurea calcitrapa, Centaurea diffusa, Centaurea iberica, Centaurea stoebe ssp. micranthos, Centaurea virgata, Euphorbia esula, Hypericum perforatum, Lepidium latifolium, Peganum harmala</i>, or a mixture of other exotic forbs and graminoids. Stands dominated by annuals may be composed of annual grasses such as <i>Bromus arvensis, Bromus hordeaceus, Bromus madritensis, Bromus tectorum, Taeniatherum caput-medusae</i>, or annual forbs, including <i>Bassia scoparia, Brassica nigra, Centaurea melitensis, Centaurea solstitialis, Crupina vulgaris, Cynoglossum officinale, Descurainia sophia, Erodium cicutarium, Hyoscyamus niger, Isatis tinctoria, Salsola tragus, Sisymbrium altissimum, Taraxacum officinale</i>, or a mixture of other exotic annual forbs and grasses. Additionally, this group contains semi-desert shrublands and shrub-steppe that are dominated or codominated by native shrub species such as <i>Artemisia tridentata</i> with a significant herbaceous understory (>10% absolute cover) that is strongly dominated (>90% relative canopy cover) by exotic herbaceous species such as <i>Agropyron cristatum</i> or <i>Bromus tectorum</i>. Stands occur in disturbed dry to mesic basins, alluvial fans, and foothills elevations up to 2200 m and are restricted to areas with the cool, semi-arid climate found in the intermountain western U.S. region. Stands can be large areas or narrow strips adjacent to roadsides or under powerlines and other disturbed areas. Soils are mostly mineral and well-drained. Due to disturbance, soils may be compacted. It is an early-successional type that may occur in areas disturbed by fire, grazing or mining. This group may grade into wetter areas and may have transition zones where mesic forbs intermix with wetter forbs and graminoids found in ~Western North American Ruderal Marsh, Wet Meadow & Shrubland Group (G524)$$. This group does not include the mesic introduced hay grasses such as <i>Bromus inermis, Dactylis glomerata</i>, and <i>Phleum pratense</i> that have escaped from improved pasture and irrigated meadow to invade montane grasslands. These grasslands are classified in the more temperate ~Western North American Interior Ruderal Grassland & Shrubland Group (G624)$$.
Accession Code:
urn:lsid:vegbank.org:commConcept:40265-{FE59245C-12D6-4665-AA61-251BF1E71B3F}
Plot-observations of this Community Concept:
0
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