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G600 Great Basin-Intermountain Ruderal Dry Shrubland & Grassland Group
Type Concept Sentence: 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. Additionally, this group contains shrubland and shrub-steppe that are dominated or codominated by native shrub species (>10% relative cover) with a significant herbaceous understory (>10% absolute cover) that is strongly dominated (>90% relative canopy cover) by exotic herbaceous species.
Common (Translated Scientific) Name: Great Basin-Intermountain Ruderal Dry Shrubland & Grassland Group
Colloquial Name: Great Basin-Intermountain Ruderal Dry Shrubland & Grassland
Hierarchy Level: Group
Type Concept: 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 Alhagi maurorum, Cytisus striatus, Zygophyllum fabago, 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 Agropyron cristatum. Relatively mesic, invasive perennial hay grasses such as Bromus inermis, Dactylis glomerata, and Phleum pratense 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 Acroptilon repens, Cardaria draba, Centaurea calcitrapa, Centaurea diffusa, Centaurea iberica, Centaurea stoebe ssp. micranthos, Centaurea virgata, Euphorbia esula, Hypericum perforatum, Lepidium latifolium, Peganum harmala, or a mixture of other exotic forbs and graminoids. Stands dominated by annuals may be composed of annual grasses such as Bromus arvensis, Bromus hordeaceus, Bromus madritensis, Bromus tectorum, Taeniatherum caput-medusae, or annual forbs, including 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, 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 Artemisia tridentata with a significant herbaceous understory (>10% absolute cover) that is strongly dominated (>90% relative canopy cover) by exotic herbaceous species such as Agropyron cristatum or Bromus tectorum. 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)$$. This group does not include the mesic introduced hay grasses such as Bromus inermis, Dactylis glomerata, and Phleum pratense that have escaped from improved pasture and irrigated meadow to invade montane grasslands. These grasslands are classified in the more temperate ~Western North American Interior Ruderal Grassland & Shrubland Group (G624)$$.
Diagnostic Characteristics: This ruderal shrubland and grassland group occurs in the semi-arid interior western U.S. and includes shrubland, shrub-steppe and grassland stands that are strongly dominated (>90% relative canopy cover) by invasive, exotic species. Additionally, this group contains shrubland and shrub-steppe that is dominated or codominated by native shrub species (>10% relative cover) with a significant herbaceous understory (>10% absolute cover) that is strongly dominated (>90% relative canopy cover) by exotic herbaceous species.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: This group may be difficult to determine from native degraded shrublands and grasslands when non-native species codominate. The test is that the non-native species, especially invasive species, far outweigh (>90% relative cover) native species in abundance and richness, such that a well-trained observer cannot tell what the native counterpart may have been or to do so is only speculation. Dominant and diagnostic semi-arid exotic species Agropyron cristatum can be present to codominant in ~Western North American Interior Ruderal Grassland & Shrubland Group (G624)$$ when codominated by relatively mesic species such as Bromus inermis or exotic forage grasses such as Agrostis stolonifera, Dactylis glomerata, Phleum pratense, and Poa pratensis that are characteristic of more temperate climates.
This group may grade into wetter areas and may have transition zones where mesic forbs intermix with wetter forbs and graminoids found in ~Western North American Ruderal Marsh, Wet Meadow & Shrubland Group (G524)$$. This group does not include the mesic introduced hay grasses such as Bromus inermis, Dactylis glomerata, and Phleum pratense 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)$$.
This group may grade into wetter areas and may have transition zones where mesic forbs intermix with wetter forbs and graminoids found in ~Western North American Ruderal Marsh, Wet Meadow & Shrubland Group (G524)$$. This group does not include the mesic introduced hay grasses such as Bromus inermis, Dactylis glomerata, and Phleum pratense 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)$$.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: This group includes shrubland and shrub-steppe stands that have an open to dense shrub canopy, and annual and perennial grasslands and forblands with an open to dense herbaceous layer.
Floristics: This ruderal shrubland and grassland group includes shrubland and shrub-steppe stands that have an open to dense shrub canopy (>10% absolute cover) that is strongly dominated (>90% relative canopy cover) by invasive, introduced shrub species such as Alhagi maurorum, Cytisus striatus, Zygophyllum fabago, or other exotic shrubs. Additionally, this group includes shrubland and shrub-steppe that is dominated or codominated by native shrub species (>10% relative cover) with a significant herbaceous understory (>10% absolute cover) that is strongly dominated (>90% relative canopy cover) by exotic herbaceous species. Herbaceous layers are composed of either exotic annuals with low cover of perennial species, or high cover of exotic perennials. Also included in this group are open to dense ruderal herbaceous stands without a shrub layer (<10% absolute cover). The herbaceous understory (>10% absolute cover) is strongly dominated (>90% relative canopy cover) by exotic herbaceous species. Herbaceous layers are composed of either exotic annuals with low cover of perennial species (<5% absolute cover), or moderate perennial cover (>10% absolute cover) dominated by of exotic perennials, either graminoids or forbs or a combination. There are relatively few cool, semi-arid perennial graminoids such as Agropyron cristatum (which has frequently been purposefully seeded to prevent soil erosion or provide livestock forage). The relatively mesic, invasive perennial hay grasses such as Bromus inermis, Dactylis glomerata, and Phleum pratense 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 Acroptilon repens, Cardaria draba, Centaurea calcitrapa, Centaurea diffusa, Centaurea iberica, Centaurea stoebe ssp. micranthos, Centaurea virgata, Hypericum perforatum, Lepidium latifolium, Peganum harmala, or a mixture of other exotic forbs and graminoids. Stands dominated by annuals may be composed of annual grasses such as Bromus arvensis (= Bromus japonicus), Bromus hordeaceus, Bromus madritensis, Bromus tectorum, Taeniatherum caput-medusae, or annual forbs, including Bassia scoparia (= Kochia scoparia), Brassica nigra, Centaurea melitensis, Centaurea solstitialis, Crupina vulgaris, Cynoglossum officinale, Descurainia sophia, Erodium cicutarium, Hyoscyamus niger, Isatis tinctoria, Lepidium perfoliatum, Salsola tragus, Sisymbrium altissimum, Taraxacum officinale, or a mixture of other exotic annual forbs and grasses.
Dynamics: Most of the invasive diagnostic species are cool-season (C3) plants such as Agropyron cristatum and Bromus tectorum. Cheatgrass expansion has radically changed fire regimes and vegetation over large areas in the Intermountain West. Cheatgrass invades native vegetation such as big sagebrush shrubland, then produces large amounts of fine fuels that readily carry fire, increasing the number, size and frequency of burns (fire-return interval = 3-5 year) which reduces cover of perennial vegetation and favors dominance by annual grasses (Young and Evans 1978, Zouhar 2003). Crested wheatgrass burns quickly and is therefore less susceptible to damage by fire than some native bunchgrass species that have a thick cespitose growth form. The fire may stay longer in the culms, resulting in heat transfer to the ground and the death of the plant (DePuit 1986). In crested wheatgrass, there is usually little heat transfer into the soil, so the tillers and root system are usually undamaged (DePuit 1986). Thus the more frequent fire regime caused by the introduction of Bromus tectorum also favors the maintenance of Agropyron cristatum over the establishment or survival of native bunchgrasses (S. Rust pers. comm. 2014).
Environmental Description: This interior western U.S. ruderal shrubland and grassland group is found on disturbed dry to mesic, basins, alluvial fans, and foothills elevations (up to 2200 m). Stands can be large areas or narrow strips adjacent to roadsides or under powerlines, in waste places such as abandoned agricultural fields that are no longer irrigated, oil and gas development areas, and other disturbed areas. Climate: This group occurs in the cool, semi-arid, continental, climate found intermountain western U.S. region. Soil/substrate/hydrology: 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. However, it also occurs over vast acres of heavily overgrazed lands in the arid west, where livestock such as cows and horses have broken soil biotic crust, compacted soil and reduced native plant vigor.
Geographic Range: This ruderal group contains disturbed semi-arid grasslands, meadows, shrublands and shrub-steppe found in the interior western U.S. on disturbed dry to mesic, basins, alluvial fans, and foothills elevations (up to 2200 m). Stands do not extend up into the cool, temperate zone in included mountain ranges. This group does not extend south to the warm deserts or east into the Great Plains or west into cismontane California or the west side of the Cascades.
Nations: CA,US
States/Provinces: AZ, CA, CO, ID, MT, ND, NM, NV, OR, SD, SK, UT, WA, WY
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.860755
Confidence Level: Moderate
Confidence Level Comments: No Data Available
Grank: GNA
Greasons: No Data Available
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: No Data Available
- DePuit, E. J. 1986. The role of crested wheatgrass in reclamation of drastically disturbed lands. Pages 323-330 in: K. D. Johnson, editor. Crested wheatgrass: Its values, problems and myths. Symposium proceedings; 1983 October 3-7; Logan, UT. Utah State University, Logan.
- Faber-Langendoen, D., J. Drake, S. Gawler, M. Hall, C. Josse, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, L. Sneddon, K. Schulz, J. Teague, M. Russo, K. Snow, and P. Comer, editors. 2010-2019a. Divisions, Macrogroups and Groups for the Revised U.S. National Vegetation Classification. NatureServe, Arlington, VA. plus appendices. [in preparation]
- Johnson, D. H., and T. A. O''Neil. 2000. Wildlife-habitat relationships in Oregon and Washington. Oregon State University Press, Corvallis. 736 pp.
- Maser, C., J. W. Thomas, and R. G. Anderson. 1984. Wildlife habitats in managed rangelands - the Great Basin of southeastern Oregon: The relationship of terrestrial vertebrates to plant communities and structural conditions. General Technical Report PNW-GTR-172. USDA Forest Service, Pacific Northwest Research Station, Portland, OR. 58 pp.
- Rust, Steve. Personal communication. Ecologist, Conservation Data Center, Idaho Department of Fish and Game, Boise, ID.
- Young, J. A., and R. A. Evans. 1978. Population dynamics after wildfires in sagebrush grasslands. Journal of Range Management 31:283-289.
- Zouhar, K. 2003. Bromus tectorum. In: Fire Effects Information System [Online]. USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). [http://www.fs.fed.us/database/feis/] (accessed 4 December 2013).