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A4186 Psorothamnus fremontii - Psorothamnus polydenius Desert Wash Scrub Alliance
Type Concept Sentence: Dominant and characteristic shrubs include Psorothamnus fremontii, Psorothamnus arborescens, or Psorothamnus polydenius. Other shrubs that are often present include Ambrosia dumosa and Larrea tridentata. The alliance is found in desert areas of Arizona, California and Nevada where it occurs primarily in alluvial fans, dry washes, lower slopes, and sand dunes, and often occurs in sites that experience disturbance from flooding to shifting substrates.
Common (Translated Scientific) Name: Fremont''s Smokebush - Nevada Smokebush Desert Wash Scrub Alliance
Colloquial Name: Smokebush Desert Wash Scrub
Hierarchy Level: Alliance
Type Concept: The alliance forms an open shrub layer. Dominant and characteristic shrubs include Psorothamnus fremontii, Psorothamnus arborescens, or Psorothamnus polydenius. Other shrubs that are often present include Ambrosia dumosa and Larrea tridentata. The emergent tree layer is sparse if present, and the herbaceous layer is sparse to open. Herbs that are often present include Sphaeralcea ambigua. Commonly associated nonvascular plants include cryptogamic crust. The alliance is found in desert areas of Arizona, California and Nevada. It occurs primarily in alluvial fans, dry washes, lower slopes, and sand dunes, and often occurs in sites that experience disturbance from flooding to shifting substrates. Elevations range from approximately 390 to 1610 m. Soils are derived from a variety of substrates including alluvium, dune sand, volcanic, and sedimentary rock, and soil textures are sand to sandy loam.
Diagnostic Characteristics: This alliance is characterized by an open shrub layer with Psorothamnus fremontii, Psorothamnus arborescens, or Psorothamnus polydenius, which can be dominant or codominant in the shrub layer. The overall shrub cover ranges from 2 to 28% cover.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: No Data Available
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: The alliance forms an open shrub layer, and shrub cover ranges from 2 to 28% cover. The tree layer is sparse if present, and the herb layer is sparse to open. Nonvascular plants are typically sparse to open.
Floristics: Characteristic shrubs include Psorothamnus spp., including Psorothamnus fremontii, Psorothamnus arborescens, or Psorothamnus polydenius, which are either dominant or codominant in the shrub layer. Those shrubs often present include Ambrosia dumosa and Larrea tridentata, and sometimes present is Hymenoclea salsola. The tree layer is typically absent or sparse in cover. The herbaceous layer typically or often includes Sphaeralcea ambigua, and sometimes includes Cryptantha spp., Bromus rubens, and Eriogonum inflatum. Commonly associated nonvascular plants include cryptogamic crust.
Dynamics: Psorothamnus spp. appear adapted to disturbance, including alluvial, colluvial and eolian (shifting-sand) movement.
Environmental Description: Stands occur in various settings, including alluvial fans, dry washes, lower mountain slopes, and sand dunes at lower elevations. Stands in Death Valley included Psorothamnus polydenius as the dominant, often found on sandy dunes in Eureka Valley and the Saline Range, or on steep eroding slopes of the Last Chance Range and Saline Range. Rare stands of Psorothamnus arborescens occur in Death Valley in upper washes and pediment that receives sheetflow in winter. Stands in Lake Mead National Recreation Area with Psorothamnus fremontii occur along sand dunes, in washes, and along alluvial fans and slopes with intermittent drainages in a variety of locations.
Geographic Range: The alliance is found in desert areas of Arizona, California and Nevada. Its occurrence in Mexico is unknown.
Nations: US
States/Provinces: AZ, CA, NV, UT
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.943943
Confidence Level: Low
Confidence Level Comments: No Data Available
Grank: G4?
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.7 North American Warm-Desert Xeric-Riparian Scrub Macrogroup | M092 | 3.A.2.Na.7 |
| Group | 3.A.2.Na.7.a Desert-willow - Apache Plume - Desert Almond Desert Wash & Colluvial Slope Group | G541 | 3.A.2.Na.7.a |
| Alliance | A4186 Fremont''s Smokebush - Nevada Smokebush Desert Wash Scrub Alliance | A4186 | 3.A.2.Na.7.a |
| Association | CEGL001353 Nevada Smokebush / Indian Ricegrass Shrubland | CEGL001353 | 3.A.2.Na.7.a |
| Association | CEGL005154 Fremont''s Smokebush Wash Shrubland | CEGL005154 | 3.A.2.Na.7.a |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: = Psorothamnus (arborescens, fremontii, polydenius) Shrubland Alliance (Evens et al. 2014)
- 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.
- 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.