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M118 Atriplex spp. - Ephedra spp. - Eriogonum spp. Intermountain Basins Sparse Vegetation Macrogroup

Type Concept Sentence: This sparsely vegetated macrogroup occurs in a variety of landscapes and a variety of exposed rock and badland substrates the interior western U.S. from the Columbia Plateau south to the Great Basin and Colorado Plateau, and east into Wyoming basins. Characteristic species are variable depending on substrate and other environmental condition and most of the species also occur in non-sparse vegetation macrogroups, although some of the sites with harsh soil properties may have of endemic species.


Common (Translated Scientific) Name: Saltbush species - Joint-fir species - Buckwheat species Intermountain Basins Sparse Vegetation Macrogroup

Colloquial Name: Intermountain Basins Cliff, Scree & Badland Sparse Vegetation

Hierarchy Level:  Macrogroup

Type Concept: This macrogroup consists of landscapes that are sparsely vegetated by vascular plants and are on a variety of rock and badland substrates in the interior western U.S. from the Columbia Plateau south to the Great Basin and Colorado Plateau, east into Wyoming Basins. Species are variable depending on substrate, nutrient availability, and other environmental conditions. Characteristic shrub species in lower elevation semi-desert, lava field, and badland areas include Artemisia tridentata, Atriplex spp., Ephedra spp., Eriogonum spp., Fallugia paradoxa, Grayia spinosa, Psorothamnus spp., Purshia tridentata, Salvia dorrii, and Sarcobatus vermiculatus. Characteristic herbs include species of Achnatherum, Camissonia, Cleome, Eriogonum, and Mentzelia. Characteristic specie of canyon, foothill and lower montane sites include shrubs Artemisia tridentata, Cercocarpus intricatus, Cercocarpus ledifolius, Holodiscus spp., and trees Juniperus occidentalis (Columbia Basin), Juniperus osteosperma, Pinus edulis and Pinus ponderosa (Colorado Plateau), and Pinus monophylla (Great Basin). Most of the species also occur in non-sparse vegetation macrogroups. However, many of the sites have harsh plant growing soil properties such as strongly alkalinity and/or salinity with thin soil or unstable, eroding substrates that limit the abundance and numbers of species that can occur. Some sites have a high number of endemic perennial species. This cool semi-desert type occurs in a variety of sites ranging from low elevation basins to middle elevations foothill and lower montane sites, but does not include higher elevation cool temperate sites in montane and subalpine zones. Landforms include lava fields, cliffs and canyon sides, ridgetops, and rock outcrops on mesas, plateaus, and mountains. Substrates are variable and include sandstone slick rock, shale badlands and volcanic deposits.

Diagnostic Characteristics: Diagnostic characteristics of this lithomorphic macrogroup are near barren or sparsely vegetated rock and badland substrates and its geographic location, which is the intermountain western U.S. However, it is often composed of a mix of woody vegetation, especially shrubs and herbs (particularly cushion plants), although either may be absent on a given site. Characteristic species include Arctostaphylos patula, Artemisia tridentata, Atriplex canescens, Atriplex corrugata, Atriplex gardneri, Artemisia pedatifida, Atriplex confertifolia, Cercocarpus intricatus, Cercocarpus ledifolius, Ephedra spp., Eriogonum corymbosum, Eriogonum heermannii, Eriogonum ovalifolium, Fallugia paradoxa, Glossopetalon spp., Grayia spinosa, Holodiscus spp., Ivesia sp., Juniperus occidentalis, Juniperus osteosperma, Pinus edulis, Pinus monophylla, Pinus ponderosa, Purshia tridentata, Salvia dorrii, and Sarcobatus vermiculatus. Nonvascular species, especially lichens, but also algae, bacteria and mosses, are important on some sites, and biological soil crusts (associations of nonvascular species) can be particularly important and diverse (based on substrate, moisture availability, disturbance, etc.) ( Belnap and Lange 2003).

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This macrogroup is very diverse floristically and so it is difficult to determine indicator species. More diagnostic is the sparse cover of vascular plants and/or presence and sometimes abundance of nonvascular species (e.g., algae, bacteria, bryophytes, lichens, and microfungi).

Similar NVC Types: No Data Available
note: No Data Available

Physiognomy and Structure: This macrogroup may be composed of woody plants, including both trees and shrubs, herbaceous plants, and/or nonvascular plants. Shrubs are especially common and were chosen as indicator species, however, herbs, especially cushion plants, and nonvascular organisms such as mosses or lichens may be more common.

Floristics: This macrogroup consists of sparsely vegetated rock and badland substrates from a variety of landscapes in the interior western U.S. Species are variable depending on substrate and other environmental conditions. Characteristic shrub species in lower elevation semi-desert, lava field, and badland areas include Artemisia tridentata, Atriplex canescens, Atriplex corrugata, Atriplex gardneri, Artemisia pedatifida, Atriplex confertifolia, Ephedra spp., Eriogonum corymbosum, Eriogonum heermannii, Eriogonum ovalifolium, Fallugia paradoxa, Grayia spinosa, Purshia tridentata, Salvia dorrii, and Sarcobatus vermiculatus. Characteristic herbs include species of Achnatherum, Camissonia, Cleome, Eriogonum, and Mentzelia. Characteristic specie of canyon, foothill and lower montane sites include forb Ivesia sp., shrubs Arctostaphylos patula, Artemisia tridentata, Cercocarpus intricatus, Cercocarpus ledifolius, Ephedra spp., Glossopetalon spp., Holodiscus spp., Purshia tridentata, and trees Juniperus occidentalis (Columbia Basin), Juniperus osteosperma, Pinus edulis and Pinus ponderosa (Colorado Plateau), and Pinus monophylla (Great Basin). Shrubs may include Cercocarpus ledifolius, Ephedra spp., Ivesia sp., and. Most of the species also occur in non-sparse vegetation macrogroups. However, some of the sites with harsh soil properties have a high number of endemic perennial species (Welsh 1979, Welsh and Chatterly 1985).

Dynamics:  Following wildfire, various associations which are typically woodland and shrubland will have transitional stages that are sparsely vegetated. However, most stands in this macrogroup are edaphic types and are largely defined by their substrates. Biological soil crusts can improve soil stability and soil fertility, and disturbances such as grazing and non-native species invasion can negatively impact these crusts (Belnap and Eldridge 2003, Belnap et al. 2006).

Environmental Description:  This macrogroup consists of landscapes that are sparsely vegetated by vascular plants on a variety of rock and badland substrates. This cool semi-desert type ranges from low elevation basins to middle elevations foothill and lower montane sites, but does not include higher elevation cool temperate sites in upper montane and subalpine zones. Landforms include lava fields, cliffs and canyon sides, ridgetops, and rock outcrops on mesas, plateaus, and mountains. Substrates are variable and include sandstone slick rock, shale badlands and volcanic deposits such as lava, cinder, ash, tuff and basalt dikes. Some substrates, such as marine shales are strongly alkaline and/or saline which chemically limits plant growth. Active substrates such as scree slopes are difficult sites for plants to grow. Physical properties of substrates may also limit plant growth. Some massive rock substrates lack cracks where vascular plants can root. Badland sites often have heavy clay soils that reduce water infiltration increasing erosion rates and reducing soil moisture for plants.

Geographic Range: This sparsely vegetated macrogroup occurs in the interior western U.S. from the Columbia Plateau south to the Great Basin and Colorado Plateau, east into Wyoming Basins.

Nations: US

States/Provinces:  AZ, CA, CO, ID, MT, NM, NV, OR, UT, WA, WY




Confidence Level: Moderate

Confidence Level Comments: No Data Available

Grank: GNR

Greasons: No Data Available


Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available

Synonomy: >< Littleleaf Mountain-Mahogany (417) (Shiflet 1994)
>< Pinyon - Juniper: 239 (Eyre 1980)

Concept Author(s): Faber-Langendoen et al. (2014)

Author of Description: K.A. Schulz

Acknowledgements: No Data Available

Version Date: 10-15-14

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