Print Report
A1110 Atriplex gardneri Low Scrub Alliance
Type Concept Sentence: This dwarf-shrubland alliance has a very sparse to moderately dense cover of dwarf-shrubs that is dominated by Atriplex gardneri and occurs in western Colorado, eastern Utah, and in western and central Wyoming and Montana on mesas, plateaus, plains, low hills and eroded "badlands."
Common (Translated Scientific) Name: Gardner''s Saltbush Low Scrub Alliance
Colloquial Name: Gardner''s Saltbush Low Scrub
Hierarchy Level: Alliance
Type Concept: Stands of this alliance have a very sparse to moderately dense cover of dwarf-shrubs that is dominated by Atriplex gardneri. Artemisia tridentata and Picrothamnus desertorum are codominants in some stands. Many other shrubs and dwarf-shrubs may be present, including Atriplex spp., Krascheninnikovia lanata, Sarcobatus vermiculatus, Suaeda spp., and Tetradymia spinosa. The herbaceous layer, if present, may be dominated by graminoids or forbs. Common species include Achnatherum hymenoides, Eriogonum pauciflorum, Leymus salinus, Monolepis nuttalliana, Pascopyrum smithii, Pleuraphis jamesii, or Xylorhiza venusta. This dwarf-shrubland alliance occurs in western Colorado and eastern Utah, Wyoming and Montana. Stands occur on mesas, plateaus, plains, low hills and eroded "badlands." Sites are nearly flat to moderately steep with moderately deep to deep, usually saline, alkaline soils. Soils are typically fine-textured and often have high erosion rates because of poor infiltration and high runoff. The soil surface is often mostly barren.
Diagnostic Characteristics: Diagnostic of this dwarf-shrubland alliance is the dominance or codominance of Atriplex gardneri on mesas, plateaus, plains, low hills and eroded "badlands."
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: Vegetation cover in this alliance may vary greatly depending on soil chemistry and slope. Some stands could be classified as dwarf-shrublands with 25-60% dwarf-shrub cover (Branson et al. 1976, DeVelice and Lesica 1993, DeVelice et al. 1995). Other stands are in the 3-20% shrub cover range and could be classified in a sparsely vegetated or dwarf-shrub herbaceous alliance (West and Ibrahim 1968, Ibrahim et al. 1972, Baker and Kennedy 1985, Knight et al. 1987, DeVelice and Lesica 1993, DeVelice et al. 1995). In addition, heavy grazing by livestock has impacted some of these stands by nearly eliminating herbaceous species.
There is taxonomic confusion in some of the research done on these vegetation types. Some of the studies report the name Atriplex nuttallii to describe the taxon that is now called Atriplex gardneri, and yet Atriplex nuttallii is still a valid name (Kartesz 1999). Also, Welsh et al. (1987) described six varieties of Atriplex gardneri, most of which are now separate species of Atriplex. Further investigation is needed throughout the range of these taxa to clarify these taxonomic questions. New associations may need to be described or perhaps the concepts of these associations and the alliance need to be broadened to include the other species. DeVelice et al. (1995) have described two new Atriplex gardneri-dominated plant associations that have not yet been included in the U.S. National Vegetation Classification (named by DeVelice et al. (1995) as Atriplex nuttallii / perennial grass and Atriplex nuttallii / Eriogonum pauciflorum). The first plant association is very similar to current plant associations with the herbaceous layer dominated by either Pascopyrum smithii, Pseudoroegneria spicata, or Sporobolus airoides.
There is taxonomic confusion in some of the research done on these vegetation types. Some of the studies report the name Atriplex nuttallii to describe the taxon that is now called Atriplex gardneri, and yet Atriplex nuttallii is still a valid name (Kartesz 1999). Also, Welsh et al. (1987) described six varieties of Atriplex gardneri, most of which are now separate species of Atriplex. Further investigation is needed throughout the range of these taxa to clarify these taxonomic questions. New associations may need to be described or perhaps the concepts of these associations and the alliance need to be broadened to include the other species. DeVelice et al. (1995) have described two new Atriplex gardneri-dominated plant associations that have not yet been included in the U.S. National Vegetation Classification (named by DeVelice et al. (1995) as Atriplex nuttallii / perennial grass and Atriplex nuttallii / Eriogonum pauciflorum). The first plant association is very similar to current plant associations with the herbaceous layer dominated by either Pascopyrum smithii, Pseudoroegneria spicata, or Sporobolus airoides.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: Vegetation in this alliance is dominated by sparse to moderate cover of xeromorphic evergreen dwarf-shrubs (<0.3 m tall). A sparse to moderately dense herbaceous layer that is dominated by perennial graminoids or forbs may be present. Annual forbs and grasses are seasonally present.
Floristics: Stands have a very sparse to moderately dense cover of woody species that is dominated by the halophytic evergreen dwarf-shrub Atriplex gardneri. Some stands are completely dominated by this plant and have very low species diversity. Depending on soil salinity and moisture, other plants may be present. Artemisia tridentata and Picrothamnus desertorum (= Artemisia spinescens) are codominants in some stands. Other shrubs and dwarf-shrubs may include Atriplex spp., Krascheninnikovia lanata, Sarcobatus vermiculatus, Suaeda spp. and Tetradymia spinosa. The herbaceous layer is very sparse to moderately dense. It may be dominated by graminoids such as Achnatherum hymenoides (= Oryzopsis hymenoides), Leymus salinus, Pascopyrum smithii, Pleuraphis jamesii (= Hilaria jamesii), or the by forbs Eriogonum pauciflorum, Monolepis nuttalliana (an annual), or Xylorhiza venusta. Other frequent plants include Allium textile, Aristida spp., Elymus elymoides, Eriogonum inflatum, Lappula spp., Opuntia polyacantha, Plantago patagonica, Poa secunda, Sphaeralcea coccinea, and Sporobolus spp.
Dynamics: Atriplex gardneri-dominated vegetation is the most saline/drought-tolerant of the Mancos shale plant communities studied by Branson et al. (1976). Although very slow-growing, it can completely dominate these extremely saline sites (Branson et al. 1976). This plant utilizes winter soil moisture, beginning new growth in March when the soils are relatively warm and moist. It flowers in April and by mid-July fruits are shattered (Branson et al. 1976).
Environmental Description: Dwarf-shrublands in this alliance are found on mesas, plateaus, plains, low hills and eroded "badlands" in western Colorado and eastern Utah, and in western and central Wyoming and Montana. Elevation ranges from 1150-2200 m. Climate is temperate and semi-arid. Summers are generally hot and freezing temperatures are common in the winter. Mean annual precipitation ranges from 13-33 cm. In Montana and Wyoming, approximately two-thirds of the annual precipitation falls in spring and early summer. In Colorado and Utah, over half the precipitation occurs in the late-summer monsoons as high-intensity thunderstorms. Sites are nearly flat to moderately steep. Soils are moderately deep to deep, usually saline, moderately alkaline, poorly developed and typically have high erosion rates because of poor infiltration and high runoff. Soil texture is typically fine, but ranges from sandy loam to clay and may be gravelly. Parent material is typically shale, alluvium and bentonite. The soil surface is often mostly barren. In the Badger Wash basin in Colorado, the soil surface has 74% bare ground and 6% litter (Branson et al. 1976).
Geographic Range: Dwarf-shrublands included in this alliance occur on mostly alkaline and barren plains and hills in western Colorado, eastern Utah, and in western and central Wyoming and Montana.
Nations: US
States/Provinces: CO, MT, OR?, SD, UT, WY
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.899076
Confidence Level: Moderate
Confidence Level Comments: No Data Available
Grank: GNR
Greasons: No Data Available
Concept Lineage: equivalent to A.1110
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: ? Atriplex gardnerae association (Ibrahim et al. 1972)
? Atriplex nuttallii Community Type (Cooper et al. 1995)
? Atriplex nuttallii plant community (Branson et al. 1976)
? Atriplex spp. Series (Johnston 1987) [includes Atriplex gardneri/Elytrigia smithii plant association.]
>< Saltbush Desert Shrubland (Knight et al. 1987)
? Atriplex nuttallii Community Type (Cooper et al. 1995)
? Atriplex nuttallii plant community (Branson et al. 1976)
? Atriplex spp. Series (Johnston 1987) [includes Atriplex gardneri/Elytrigia smithii plant association.]
>< Saltbush Desert Shrubland (Knight et al. 1987)
- Baker, W. L., and S. C. Kennedy. 1985. Presettlement vegetation of part of northwestern Moffat County, Colorado, described from remnants. Great Basin Naturalist 45(4):747-777.
- Branson, F. A., R. F. Miller, and I. S. McQueen. 1976. Moisture relationships in twelve northern desert shrub communities near Grand Junction, Colorado. Ecology 57:1104-1124.
- Cooper, S. V., P. Lesica, R. L. DeVelice, and T. McGarvey. 1995. Classification of southwestern Montana plant communities with emphasis on those of Dillon Resource Area, Bureau of Land Management. Montana Natural Heritage Program, Helena, MT. 154 pp.
- DeVelice, R. L., S. V. Cooper, J. T. McGarvey, J. Lichthardt, and P. S. Bourgeron. 1995. Plant communities of northeastern Montana: A first approximation. Montana Natural Heritage Program, Helena, MT. 116 pp.
- DeVelice, R. L., and P. Lesica. 1993. Plant community classification for vegetation on BLM lands, Pryor Mountains, Carbon County, Montana. Unpublished report by Montana Natural Heritage Program, Helena, MT. 78 pp.
- Faber-Langendoen, D., J. Drake, M. Hall, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, M. Russo, K. Schulz, L. Sneddon, K. Snow, and J. Teague. 2013-2019b. Screening alliances for induction into the U.S. National Vegetation Classification: Part 1 - Alliance concept review. NatureServe, Arlington, VA.
- Ibrahim, K. M., N. E. West, and D. L. Goodwin. 1972. Phytosociological characteristics of perennial Atriplex-dominated vegetation of southeastern Utah. Vegetatio 24:13-22.
- Johnston, B. C. 1987. Plant associations of Region Two: Potential plant communities of Wyoming, South Dakota, Nebraska, Colorado, and Kansas. R2-ECOL-87-2. USDA Forest Service, Rocky Mountain Region. Lakewood, CO. 429 pp.
- Kartesz, J. T. 1999. A synonymized checklist and atlas with biological attributes for the vascular flora of the United States, Canada, and Greenland. First edition. In: J. T. Kartesz and C. A. Meacham. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden, Chapel Hill, NC.
- Knight, D. H., G. P. Jones, Y. Akashi, and R. W. Myers. 1987. Vegetation ecology in the Bighorn Canyon National Recreation Area. Unpublished report prepared for the USDI National Park Service and University of Wyoming-National Park Service Research.
- Welsh, S. L., N. D. Atwood, S. Goodrich, and L. C. Higgins, editors. 1987. A Utah flora. Great Basin Naturalist Memoirs 9. Provo, UT. 894 pp.
- West, N. E., and K. I. Ibrahim. 1968. Soil-vegetation relationships in the shadscale zone of southeastern Utah. Ecology 49(3):445-456.