Print Report
CEGL000955 Ambrosia dumosa / Pleuraphis rigida Dwarf-shrubland
Type Concept Sentence: No Data Available
Common (Translated Scientific) Name: Burrobush / Big Galleta Dwarf-shrubland
Colloquial Name: No Data Available
Hierarchy Level: Association
Type Concept: This is a sparse, desert sand dune association. It occurs on active to partially stabilized desert sand dunes in the northern Sonoran Desert and Mojave Desert, between 88 and 1300 m (290-4200 feet) of elevation. Ambrosia dumosa and Pleuraphis rigida codominate, though a number of other dune-adapted, shrubby perennial plants may occur. Occasionally common are Ephedra trifurca, Croton californicus, Croton wigginsii, Eriogonum deserticola, and Psorothamnus emoryi. Cover of shrubs and Pleuraphis rigida together varies from 5-20% depending on slope aspect and dune activity. Diagnostic species include Abronia villosa var. villosa, Dicoria canescens and the rare taxa Chamaesyce platysperma, Croton wigginsii, Eriogonum deserticola, Helianthus niveus ssp. tephrodes, Palafoxia arida var. gigantea, and Psorothamnus emoryi. Additional rare species that may be found include Stephanomeria schottii, Pholisma sonorae and Triteleiopsis palmeri. This association contains a high number of ephemeral forbs; in the Gran Desierto dunes, ephemerals comprise up to 63.5% of the flora. Ephemeral forbs include Dimorphocarpa pinnatifida, Dicoria canescens, Lupinus arizonicus, and Oenothera deltoides.
Diagnostic Characteristics: No Data Available
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: Floristic assemblages of sand dunes of the American Southwest have been demonstrated to be dissimilar to each other (Bowers 1984). The Algodones and Gran Desierto dunes were the most similar in a pair-by-pair analysis of eight floras. These dunes have a large floristic component of Sonoran and Sonoran-Mojavean species (51% and 48%, respectively).
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available
Floristics: This is a desert sand dune association with sparse vegetation. The facultatively drought-deciduous shrub Ambrosia dumosa codominates with the rhizomatous perennial grass Pleuraphis rigida (= Hilaria rigida). A number of other shrubby perennial plants also can occur, many of them considered "half-shrubs" or perennial forbs with woody bases and roots (a dune adaptation). Occasionally common are Ephedra trifurca, Croton californicus, Croton wigginsii, Eriogonum deserticola, Larrea tridentata, Lycium andersonii, Opuntia basilaris, Cylindropuntia echinocarpa, Penstemon thurberi, Psorothamnus emoryi, and Viguiera parishii. Cover of shrubs and Pleuraphis rigida together varies from 5% to roughly 25%, depending on the degree of dune activity and aspect of the dune slope (Evens et al. 2012, 2014). Perennial forbs such as Baileya multiradiata, Eriogonum inflatum, Machaeranthera canescens, and Mirabilis laevis var. villosa may be present to abundant in more stabilized sites (Evens et al. 2012, 2014). An important feature of this association is the high proportion of ephemeral forbs; in the Gran Desierto dunes, ephemerals comprise 63.5% of the flora (Felger 1980). Ephemeral forbs in this association include Abronia villosa, Dimorphocarpa pinnatifida, Dicoria canescens, Lupinus arizonicus, and Oenothera deltoides. This association has a relatively large number of rare sand dune endemic species associated with it; most of them are currently global conservation-ranked G2 or G3. These include Chamaesyce platysperma, Croton wigginsii, Helianthus niveus ssp. tephrodes, Palafoxia arida var. gigantea, Pholisma sonorae, Stephanomeria schottii, and Triteleiopsis palmeri. Other associated species include Achnatherum hymenoides, Camissonia spp., Caulanthus cooperi, Chaenactis fremontii, Chaenactis stevioides, Cryptantha spp., Machaeranthera canescens, Malacothrix glabrata, and Nemacaulis denudata (Evens et al. 2012, 2014). Invasive exotic annuals Bromus rubens, Erodium cicutarium, and Schismus spp. may be present to abundant in disturbed stands (Evens et al. 2012).
Dynamics: No Data Available
Environmental Description: This association is found on active to partially stabilized sand dunes, between 88 and roughly 1300 m (290-4200 feet) elevation, in the Sonoran Desert and Mojave Desert in California. Climate is hot and dry, although nights with temperatures below freezing do occur during winter (Evens et al. 2012, 2014). The dunes typically receive less than 15 cm of precipitation annually, most of it occurring during winter and early spring. Dune sands constantly bury or expose plants growing in them, creating a loose and unstable substrate for plant growth. Additionally, dune sands are low in nutrients. They do retain precipitation, with little runoff or evaporation, and may be constantly moist below the surface, making them the most mesic of desert habitats. Substrates are primarily eolian sand but include alluvial sand near drainages.
Geographic Range: This association is restricted to dunes in the Mojave and Sonoran deserts in southwestern Arizona, southeastern California, and the northwestern Sonoran state of Mexico. Only three of the seven dune fields in this region are likely to provide suitable habitat. The area of suitable habitat within the range is probably less than 100 square miles.
Nations: MX,US
States/Provinces: AZ, CA, MXSON
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.687442
Confidence Level: Low
Confidence Level Comments: No Data Available
Grank: G2
Greasons: No Data Available
| Type | Name | Database Code | Classification Code |
|---|---|---|---|
| Class | 3 Desert & Semi-Desert Class | C03 | 3 |
| Subclass | 3.A Warm Desert & Semi-Desert Woodland, Scrub & Grassland Subclass | S06 | 3.A |
| Formation | 3.A.2 Warm Desert & Semi-Desert Scrub & Grassland Formation | F015 | 3.A.2 |
| Division | 3.A.2.Na North American Warm Desert Scrub & Grassland Division | D039 | 3.A.2.Na |
| Macrogroup | 3.A.2.Na.4 Saguaro - Organ Pipe Cactus - Burrobush Mojave-Sonoran Semi-Desert Scrub Macrogroup | M088 | 3.A.2.Na.4 |
| Group | 3.A.2.Na.4.e North American Warm Semi-Desert Dune & Sand Flats Group | G675 | 3.A.2.Na.4.e |
| Alliance | A3170 Big Galleta Desert Grassland Alliance | A3170 | 3.A.2.Na.4.e |
| Association | CEGL000955 Burrobush / Big Galleta Dwarf-shrubland | CEGL000955 | 3.A.2.Na.4.e |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: = Ambrosia dumosa / Pleuraphis rigida (Sawyer et al. 2009) [33.060.04]
= Ambrosia dumosa / Pleuraphis rigida Dwarf-shrubland (Keeler-Wolf and Thomas 2000)
= Ambrosia dumosa / Pleuraphis rigida Dwarf-shrubland (Keeler-Wolf et al. 1998a)
= Pleuraphis rigida - Ambrosia dumosa Association (Evens et al. 2012)
= Pleuraphis rigida / Ambrosia dumosa Association (Evens et al. 2014)
< Arid lowland Pleuraphis rigida shrub-steppe (McAuliffe 2016)
= Transect #10. Hilaria rigida, Ambrosia dumosa, Ephedra trifurca codominated (Felger 1980)
= Ambrosia dumosa / Pleuraphis rigida Dwarf-shrubland (Keeler-Wolf and Thomas 2000)
= Ambrosia dumosa / Pleuraphis rigida Dwarf-shrubland (Keeler-Wolf et al. 1998a)
= Pleuraphis rigida - Ambrosia dumosa Association (Evens et al. 2012)
= Pleuraphis rigida / Ambrosia dumosa Association (Evens et al. 2014)
< Arid lowland Pleuraphis rigida shrub-steppe (McAuliffe 2016)
= Transect #10. Hilaria rigida, Ambrosia dumosa, Ephedra trifurca codominated (Felger 1980)
- Bourgeron, P. S., and L. D. Engelking, editors. 1994. A preliminary vegetation classification of the western United States. Unpublished report. The Nature Conservancy, Western Heritage Task Force, Boulder, CO. 175 pp. plus appendix.
- Bowers, J. E. 1984. Plant geography of southwestern sand dunes. Desert Plants 6(1):31-42, 51-54.
- Evens, J. M., D. Roach-McIntosh, and D. Stout. 2012. Vegetation descriptions for Joshua Tree National Park. Unpublished report submitted to USDI, National Park Service, Mojave Desert Inventory and Monitoring Network. California Native Plant Society, Sacramento, CA.
- Evens, J. M., K. Sikes, D. Hastings, and J. Ratchford. 2014. Vegetation alliance descriptions for Lake Mead National Recreation Area, Death Valley National Park and Mojave National Preserve. Unpublished report submitted to USDI National Park Service, Mojave Desert Network Inventory and Monitoring Program. California Native Plant Society, Sacramento, CA.
- Felger, R. S. 1980. Vegetation and flora of the Gran Desierto, Sonora, Mexico. Desert Plants 2(2):87-114.
- Grossman, D. H., K. Lemon Goodin, and C. L. Reuss, editors. 1994. Rare plant communities of the conterminous United States: An initial survey. The Nature Conservancy. Arlington, VA. 620 pp.
- Keeler-Wolf, T., C. Roye, and K. Lewis. 1998a. Vegetation mapping and classification of the Anza-Borrego Desert State Park, California. Unpublished report on file at California Natural Diversity Database, California Department Fish and Game, Sacramento.
- Keeler-Wolf, T., and K. Thomas. 2000. Draft descriptions of vegetation alliances for the Mojave Ecosystem Mapping project. California Natural Diversity Database, California Department of Fish and Game, Sacramento.
- McAuliffe, J. R. 2016. Perennial grass-dominated plant communities of the eastern Mojave Desert region. Desert Plants 32(1):1-90.
- Sawyer, J. O., T. Keeler-Wolf, and J. Evens. 2009. A manual of California vegetation. Second edition. California Native Plant Society, Sacramento CA. 1300 pp.
- Warren, P. L., and A. W. Laurenzi. 1987. Rare plant survey of the Yuma District. Unpublished report prepared for USDI Bureau of Land Management, Yuma, AZ. 61 pp.
- Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.