Common (Translated Scientific) Name: Fourwing Saltbush - American Tarwort Lowland Basin Scrub Group
Colloquial Name: Chihuahuan Desert Lowland Basin Scrub
Hierarchy Level: Group
Type Concept: This desert scrub group occurs extensively as open-canopied shrublands in the alkaline, often somewhat saline basins and lowlands in the Chihuahuan Desert. It commonly includes stands dominated by Atriplex canescens or Flourensia cernua, but under more saline conditions, Allenrolfea occidentalis, Sarcocornia utahensis, Suaeda moquinii, or other halophytic plants may be present to codominant. The widespread, invasive Prosopis glandulosa may also be present to dominant in these lowland sites. While sites are often barren in the inter-shrub spaces, others can have high graminoid cover dominated by Sporobolus airoides, Pleuraphis mutica, Scleropogon brevifolius, or Distichlis spicata. It occurs as extensive open-canopied shrublands of lowland, often somewhat saline basins in the Chihuahuan Desert. Stands often occur on alluvial flats and around playas, as well as in floodplains along the Rio Grande and Pecos River, possibly also extending into the San Simon of southeastern Arizona. Substrates are generally fine-textured, often saline soils.
Diagnostic Characteristics: These open-canopied shrublands are dominated by saltbush or other saline habitat species with characteristic species of the Chihuahuan Desert such as Flourensia cernua. The widespread, invasive Prosopis glandulosa may also be present to dominant in these lowland sites, typically with saline or alkaline indicators in the herbaceous layer such as Sporobolus airoides, Pleuraphis mutica, or Distichlis spicata.
Rationale for Nominal Species or Physiognomic Features: Atriplex canescens represents the typical saltbush-dominated nature of this group, and Flourensia cernua is a Chihuahuan Desert species that is characteristic of lowland desert basins. Prosopis glandulosa is widespread and invasive in the Chihuahuan Desert so is not included in the name.
Classification Comments: This warm-season group is similar to Intermountain Shadscale - Saltbush Scrub Group (G300) and shares dominant saltbush species and some widespread herbaceous species. The presence of Chihuahuan Desert indicator species will floristically distinguish these groups.
Similar NVC Types:
G300 Intermountain Shadscale - Saltbush Scrub, note:
Physiognomy and Structure: These shrublands have a sparse to moderately dense, short-shrub canopy with 10-40% cover and less than <1 m tall. The herbaceous layer has variable cover ranging from sparse (<10% cover) to fairly dense (>50% cover) and is often patchy. It is usually dominated by perennial graminoids especially bunch grasses with low cover of forbs.
Floristics: This group includes extensive open-canopied shrublands most commonly dominated by Atriplex canescens or Flourensia cernua, but under more saline conditions, Allenrolfea occidentalis, Sarcocornia utahensis, Suaeda moquinii, Tidestromia carnosa, or other halophytic plants may be present to codominant. The widespread, invasive Prosopis glandulosa may also be present to dominant in these lowland sites. Graminoid species may include Sporobolus airoides, Panicum obtusum, Pleuraphis mutica, Scleropogon brevifolius, or Distichlis spicata at varying densities. Occasional riparian species may be present near watercourses, such as Prosopis pubescens or Populus deltoides ssp. wislizeni.
Dynamics: No Data Available
Environmental Description: This group includes extensive open-canopied shrublands of lowland, often somewhat saline basins in the Chihuahuan Desert. Stands often occur on alluvial flats and around playas, as well as in floodplains along the Rio Grande and Pecos River, possibly also extending into the San Simon of southeastern Arizona. Sites are flat to gently sloping with slopes up to 3%. Elevation ranges from 1000-1300 m (3300-4300 feet). Substrates are generally fine-textured, often saline soils (silts, clay loams and clays) but may include moderately coarse-textured alluvium in the floodplains. Water tables are generally shallow but fluctuate within reach of deep-rooted plants, and in most places are high enough that salts accumulate on the surface of the soil.
Geographic Range: This group occurs in saline basins in the Chihuahuan Desert. Stands often occur around playas and on alluvial flats, as well as in floodplains along the Rio Grande and Pecos River, possibly also extending into the San Simon of southeastern Arizona.
Nations: MX, US
States/Provinces: AZ, MXCH, MXCO, MXDU, MXNU, MXSO, NM, TX
|US Forest Service Ecoregions (2007)|
Southwest Plateau and Plains Dry Steppe and Shrub Province
Confident or certain
White Mountains-San Francisco Peaks-Mogollon Rim Section
Confident or certain
Omernik Ecoregions: 22:P, 22g:P, 22m:P, 23:P, 23a:P, 23b:P, 23e:P, 23f:P, 24:P, 24a:P, 24b:P, 24c:P, 24d:P, 24e:P, 24f:P, 24g:P, 24h:P, 26:P, 26h:P, 26o:P, 26q:P, 30:P, 30d:P, 31:P, 31b:P, 79:P, 79a:P, 79b:P, 79e:P, 81:P, 81k:P, 81l:P
Confidence Level: Low
Confidence Level Comments:
Synonomy: = Chihuahuan Desertscrub, Saltbush Series - 153.27 (Brown et al. 1979)
Concept Author(s): D.E. Brown, C.H. Lowe, and C.P. Pase (1979)
Author of Description: K.A. Schulz and E. Muldavin
Acknowledgements: E. Muldavin
Version Date: 05Nov2015
- Brown, D. E., C. H. Lowe, and C. P. Pase. 1979. A digitized classification system for the biotic communities of North America with community (series) and association examples for the Southwest. Journal of the Arizona-Nevada Academy of Science 14:1-16.
- Brown, D. E., editor. 1982a. Biotic communities of the American Southwest-United States and Mexico. Desert Plants Special Issue 4(1-4):1-342.
- Burgess, T. L., and D. K. Northington. 1977. Desert vegetation of the Guadalupe Mountains region. Pages 229-243 in: R. H. Wauer and D. H. Riskind, editors. Transactions of the symposium on the biological resources of the Chihuahuan Desert region, United States and Mexico. USDI National Park Service. Transaction Proceedings Series No. 3. Washington, DC.
- Dick-Peddie, W. A. 1993. New Mexico vegetation: Past, present, and future. University of New Mexico Press, Albuquerque. 244 pp.
- 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]
- Muldavin E., G. Bell, et al. 2002a. Draft ecoregional conservation assessment of the Chihuahuan Desert. Pronatura Noreste. 87 pp.
- Muldavin, E., Y. Chauvin, and G. Harper. 2000b. The vegetation of White Sands Missile Range, New Mexico: Volume I. Handbook of vegetation communities. Final report to Environmental Directorate, White Sands Missile Range. New Mexico Natural Heritage Program, University of New Mexico, Albuquerque. 195 pp. plus appendices
- NHNM [Natural Heritage New Mexico]. No date. Unpublished data on file. Natural Heritage New Mexico, University of New Mexico, Albuquerque.
- Shreve, F., and I. L. Wiggins. 1964. Vegetation and flora of the Sonoran Desert. Stanford University Press, Stanford, CA. 840 pp.