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A4024 Chorizanthe rigida - Geraea canescens Desert Pavement Alliance
Type Concept Sentence: This alliance consists of sparsely vegetated (<2% plant cover) rock outcrops where the most abundant species include Chorizanthe rigida, Eriogonum fasciculatum, Eriogonum inflatum, Geraea canescens, and/or Larrea tridentata. This alliance occurs throughout much of the warm deserts of North America. Habitats are typically flat basins where extreme temperature and wind develop ground surfaces of fine to medium gravel coated with "desert varnish."
Common (Translated Scientific) Name: Devil''s Spineflower - Hairy Desert-sunflower Desert Pavement Alliance
Colloquial Name: Warm Semi-Desert Ephemerally Vegetated Pavement
Hierarchy Level: Alliance
Type Concept: This alliance consists of sparsely vegetated rock outcrops where the most abundant species include Chorizanthe rigida, Eriogonum fasciculatum, Eriogonum inflatum, Geraea canescens, and/or Larrea tridentata. This alliance is composed of unvegetated to very sparsely vegetated (<2% plant cover) landscapes, typically flat basins where extreme temperature and wind develop ground surfaces of fine to medium gravel coated with "desert varnish." This alliance occurs throughout much of the warm deserts of North America. It may surround playas in valley bottoms or near washes and, less commonly, on dissected, eroding alluvial fans. Very low cover of desert scrub species is usually present. However, ephemeral herbaceous species may have high cover in response to seasonal precipitation.
Diagnostic Characteristics: No Data Available
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: Might better be considered a group-level distinction.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: Herbs or shrubs <2 m in height with very sparse (<2%) cover. The tree and shrub layers and nonvascular plants, if present, are sparse.
Floristics: This alliance consists of sparsely vegetated stands with total cover <2% that includes Chorizanthe rigida, Eriogonum fasciculatum, Eriogonum inflatum, Geraea canescens, and/or Larrea tridentata. Very low cover of desert scrub species is usually present. However, ephemeral herbaceous species may have high cover in response to seasonal precipitation.
Dynamics: The germination and abundance of Chorizanthe rigida, Geraea canescens, and related annual herbs vary among years depending on annual precipitation and temperature patterns. Their seeds can persist in seed banks for decades awaiting optimum fall and winter climate conditions. In El Niño years, their abundance can be substantial, covering desert pavement, bajadas, and hills in vibrant green and gold hues.
Environmental Description: Typically flat basins where extreme temperature and wind develop ground surfaces of fine to medium gravel coated with "desert varnish." It may surround playas in valley bottoms or near washes and, less commonly, on dissected, eroding alluvial fans.
Geographic Range: This alliance is found in the warm semi-deserts of North America, including the Mojave, Colorado and Sonoran deserts of Arizona, California, and extending south into Baja California and Sonora, Mexico.
Nations: MX,US
States/Provinces: AZ, CA, MXBCN, MXSON, NV
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.900075
Confidence Level: Low - Poorly Documented
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.6 Ocotillo - Desert-holly - Watson''s Amaranth North American Rock Vegetation Macrogroup | M117 | 3.A.2.Na.6 |
| Group | 3.A.2.Na.6.a Ocotillo - Bear-grass species - Desert-holly Rock Vegetation Group | G569 | 3.A.2.Na.6.a |
| Alliance | A4024 Devil''s Spineflower - Hairy Desert-sunflower Desert Pavement Alliance | A4024 | 3.A.2.Na.6.a |
| Association | CEGL009686 Devil''s Spineflower - Hairy Desert-sunflower Desert Pavement | CEGL009686 | 3.A.2.Na.6.a |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: = Chorizanthe rigida - Geraea canescens Desert Pavement Annual Herbaceous Alliance (Evens et al. 2012)
= Chorizanthe rigida-Geraea canescens Desert Pavement Sparsely Vegetated Alliance (Evens et al. 2014)
= Chorizanthe rigida-Geraea canescens Desert Pavement Sparsely Vegetated Alliance (Evens et al. 2014)
- 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.
- 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.
- Thomas, K. A., T. Keeler-Wolf, J. Franklin, and P. Stine. 2004. Mojave Desert Ecosystem Program: Central Mojave vegetation mapping database. U.S. Geological Survey, Western Regional Science Center. 251 pp.
- VegCAMP and AIS [Vegetation Classification and Mapping Program and Aerial Information Systems, Inc.]. 2013. 2012 California desert vegetation map and accuracy assessment in support of the Desert Renewable Energy Conservation Plan. Unpublished report to California Department of Fish and Wildlife Renewable Energy Program and the California Energy Commission. California Department of Fish and Wildlife, Vegetation Classification and Mapping Program and Aerial Information Systems, Inc.