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CEGL001729 Ayenia microphylla / Bouteloua eriopoda Shrub Grassland
Type Concept Sentence: No Data Available
Common (Translated Scientific) Name: Dense Ayenia / Black Grama Shrub Grassland
Colloquial Name: No Data Available
Hierarchy Level: Association
Type Concept: This is a very poorly known desert grassland association. It is reported from one study in south-central Arizona, near Tucson, in a region known for its low annual precipitation and extreme summer heat. The one reported stand of the type occurred on an ungrazed mesa top at an elevation ranging from 1050 to 1080 m (3450-3550 feet). The mesa is composed of basalts, and the entire mesa top was bouldery and cobbly. The stand sampled is associated with clay loam soils, and caliche was found at a depth of 15-30 cm (6-12 inches). This association is composed of a moderate abundance of the perennial bunchgrass Bouteloua eriopoda intermixed with the dwarf-shrub Ayenia microphylla. A sparse layer of taller shrubs and small trees is also present; species include Fouquieria splendens, Parkinsonia microphylla, Lycium berlandieri, Opuntia spp., and Larrea tridentata. Forbs include Allionia incarnata.
Diagnostic Characteristics: No Data Available
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: This type is known from only one study, conducted on the top of a mesa that is presumed to have been isolated from domestic livestock grazing. The type is probably valid, but has been unconfirmed in other literature. Given the very few locations remaining in southern Arizona that have not been grazed, it is not surprising that the association is unreported from other sources. Further inventory efforts should be made for this (and other) remnant desert grassland vegetation types.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available
Floristics: No Data Available
Dynamics: No Data Available
Environmental Description: No Data Available
Geographic Range: Presently known only from one location in south-central Arizona, near Tucson. The distribution of Ayenia microphylla includes western Texas, southern Arizona and northern Mexico, so it is possible the association occurs over this larger area as well.
Nations: US
States/Provinces: AZ
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.689741
Confidence Level: Low
Confidence Level Comments: No Data Available
Grank: G1G2
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.3 Black Grama - Bullgrass - Tobosa Grass Chihuahuan Semi-Desert Grassland Macrogroup | M087 | 3.A.2.Na.3 |
| Group | 3.A.2.Na.3.a Black Grama - Chino Grama - Bush Muhly Semi-Desert Grassland Group | G490 | 3.A.2.Na.3.a |
| Alliance | A3204 Black Grama - Chino Grama Piedmont Desert Grassland Alliance | A3204 | 3.A.2.Na.3.a |
| Association | CEGL001729 Dense Ayenia / Black Grama Shrub Grassland | CEGL001729 | 3.A.2.Na.3.a |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: = Bouteloua-Ayenia Association (Ferguson 1950)
- 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.
- Ferguson, C. W. 1950. An ecological analysis of lower Sonoran zone relic vegetation in southcentral Arizona. Unpublished thesis. University of Arizona, Tucson. 41 pp.
- Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.