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A3166 Acacia constricta - Acacia neovernicosa Thornscrub Alliance
Type Concept Sentence: Chihuahuan Desert thornscrub occurring on lower foothills of mountains and piedmont hills and ridges. Vegetation is characterized by 1- to 2-m tall, open to moderately dense shrub canopies dominated by Acacia constricta, Acacia neovernicosa, or less commonly Acacia schottii, either in nearly pure stands at middle elevations, or in mixed stands with Larrea tridentata and other desertscrub species at lower elevations. The herbaceous layer is generally sparse; however, grasses may grow abundantly, especially at higher elevation sites.
Common (Translated Scientific) Name: Whitethorn Acacia - Viscid Acacia Thornscrub Alliance
Colloquial Name: Whitethorn Acacia - Viscid Acacia Thornscrub
Hierarchy Level: Alliance
Type Concept: This Chihuahuan Desert thornscrub alliance is found from Trans-Pecos Texas and New Mexico to southeastern Arizona and adjacent Mexico. The vegetation is characterized by 1- to 2-m tall, open to moderately dense shrub canopies (10-70% cover) dominated by Acacia constricta, Acacia neovernicosa, or less commonly Acacia schottii. It may occur in nearly pure stands of Acacia at middle elevations, but generally the shrub layer is very diverse. Other characteristics shrubs include Aloysia wrightii, Atriplex canescens, Dasylirion wheeleri, Ericameria laricifolia, Flourensia cernua, Parthenium incanum, Prosopis glandulosa, and Yucca baccata. The herbaceous layer is generally sparse; however, grasses such as Achnatherum eminens, Bouteloua curtipendula, Muhlenbergia porteri, and a few shortgrass species may grow abundantly, especially at higher elevation sites. At middle elevations, grasses are more patchy, often found growing under shrubs. At lower elevations, Larrea tridentata and other Chihuahuan desert scrub species intermix. Cacti such as Cylindropuntia imbricata, Opuntia phaeacantha, and Mammillaria spp. are also common. Characteristic forbs species include Eriogonum abertianum, Bahia absinthifolia, or Acourtia nana. Stands occur on lower foothills of mountains and piedmont hills and ridges at elevations from 1280-1930 m. Soils on the footslopes of hills are coarse loamy and shallow, while those on hills and ridges are clayey and shallow, covered by rocky colluvium. Parent materials are typically derived from limestone or less commonly on calcareous sandstone and other substrates.
Diagnostic Characteristics: This Chihuahuan Desert thornscrub alliance is characterized by 1- to 2-m tall, open to moderately dense shrub canopies (10-70% cover) dominated by Acacia constricta, Acacia neovernicosa, or less commonly Acacia schottii. Other associated shrub species include Aloysia wrightii, Atriplex canescens, Dasylirion wheeleri, Ericameria laricifolia, Flourensia cernua, Parthenium incanum, Prosopis glandulosa, and Yucca baccata. The herbaceous layer is generally sparse. Characteristic grass species include Achnatherum eminens, Bouteloua curtipendula, and Muhlenbergia porteri. Characteristic forbs species include Eriogonum abertianum, Bahia absinthifolia, or Acourtia nana.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: Acacia neovernicosa is closely related to and may hybridize with Acacia constricta and Acacia schottii. The three species occur in similar habitats, but Acacia constricta is most typical along the Rio Grande in gravelly soils, and Acacia schottii is most common on gypsiferous soils (Diamond 1993). More survey and classification work are needed to fully characterize this alliance.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: Vegetation in this alliance has a sparse to dense short-shrub layer dominated by xeromorphic deciduous shrubs with a sparse to moderate graminoid layer dominated by medium-tall grasses (<1 m tall). Forbs are very sparse.
Floristics: The vegetation is characterized by 1- to 2-m tall, open to moderately dense shrub canopies (10-70% cover) dominated by Acacia constricta, Acacia neovernicosa, or less commonly Acacia schottii. It may occur in nearly pure stands of Acacia at middle elevations, but generally the shrub layer is very diverse. Other characteristics shrubs include Aloysia wrightii, Atriplex canescens, Dasylirion wheeleri, Ericameria laricifolia, Flourensia cernua, Parthenium incanum, Prosopis glandulosa, and Yucca baccata. The herbaceous layer is generally sparse; however, grasses such as Achnatherum eminens (= Stipa eminens), Bouteloua curtipendula, Muhlenbergia porteri, and a few shortgrass species may grow abundantly, especially at higher elevation sites. At middle elevations, grasses are more patchy, often found growing under shrubs. At lower elevations, Larrea tridentata and other Chihuahuan desert scrub species intermix. Cacti such as Cylindropuntia imbricata (= Opuntia imbricata), Opuntia phaeacantha, and Mammillaria spp. are also common. Characteristic forbs species include Eriogonum abertianum, Bahia absinthifolia, or Acourtia nana.
Dynamics: Stands often occur on calcareous substrates such as limestone (Muldavin et al. 2000b). The nitrogen-fixing ability of Acacia neovernicosa allows it to colonize harsh environments well (Muldavin et al. 1998a). Livestock impacts on this shrubland are generally limited because of poor forage potential and rough terrain (Muldavin et al. 1998a).
Environmental Description: Shrublands included in this Chihuahuan Desert alliance occur on lower foothills of mountains, mesas and piedmont hills and ridges in southern New Mexico, western Texas, and southeastern Arizona. Elevation ranges from 1280 to 1930 m. Climate is arid to semi-arid with most of the approximately 20 cm of annual precipitation occurring during monsoon months of July to September. Sites are on moderate to steep slopes mostly on southern aspects. Soils are generally shallow and rocky. In the Tularosa Basin, footslopes of hills and mountains soil are coarse and loamy over shallow bedrock, whereas on colluvial hills and ridges, soils are shallow, well-developed, clayey and covered with colluvium (Muldavin et al. 1998c). Parent materials are typically derived from limestone or less commonly on calcareous sandstone and other substrates. Muldavin et al. (1994a) described a stand growing on a moderately steep, southwestern slope in the Organ Mountains with parent material derived from rhyolite.
Geographic Range: Stands in this Chihuahuan Desert alliance are found on piedmont hills and mountain ridges of the Tularosa Basin east to the Guadalupe Mountains in southern New Mexico, west to southeastern Arizona, and south to Trans-Pecos Texas and the northern Mexico states of Chihuahua, Coahuila and Sonora.
Nations: MX,US
States/Provinces: AZ, MXCHH, MXCOA, MXSON, NM, TX
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.899291
Confidence Level: Low
Confidence Level Comments: No Data Available
Grank: GNR
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.2 Creosotebush - American Tarwort - Mesquite species Chihuahuan Desert Scrub Macrogroup | M086 | 3.A.2.Na.2 |
| Group | 3.A.2.Na.2.a Creosotebush - American Tarwort - Viscid Acacia Chihuahuan Mixed Desert Scrub Group | G288 | 3.A.2.Na.2.a |
| Alliance | A3166 Whitethorn Acacia - Viscid Acacia Thornscrub Alliance | A3166 | 3.A.2.Na.2.a |
| Association | CEGL001341 Viscid Acacia / American Tarwort Shrubland | CEGL001341 | 3.A.2.Na.2.a |
| Association | CEGL001342 Viscid Acacia / Bush Muhly Shrubland | CEGL001342 | 3.A.2.Na.2.a |
Concept Lineage: Old Alliance III.B.3.N.a. Acacia neovernicosa Shrubland Alliance (A.1037), includes all associations, but new alliance is broader containing types dominated by Acacia constricta, Acacia neovernicosa and possibly communities dominated by other upland Acacia spp. that have not been described.
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: No Data Available
- Diamond, D. D. 1993. Classification of the plant communities of Texas (series level). Unpublished document. Texas Natural Heritage Program, Austin. 25 pp.
- 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, 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.
- Muldavin, E., P. Mehlhop, and E. DeBruin. 1994a. A survey of sensitive species and vegetation communities in the Organ Mountains of Fort Bliss. Volume III: Vegetation communities. Report prepared for Fort Bliss, Texas, by New Mexico Natural Heritage Program, Albuquerque.
- Muldavin, E., V. Archer, and P. Neville. 1998a. A vegetation map of the Borderlands Ecosystem Management Area. Final report submitted to USDA Forest Service, Rocky Mountain Experiment Station, Flagstaff, AZ, by the New Mexico Natural Heritage Program, University of New Mexico, Albuquerque, NM. 58 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
- Muldavin, E., and P. Mehlhop. 1992. A preliminary classification and test vegetation map for White Sands Missile Range and San Andreas National Wildlife Refuge, New Mexico. University of New Mexico, New Mexico Natural Heritage Program.
- Muldavin, E., et al. 1998c. Plant community inventory for Fort Bliss. Unpublished report in preparation by the New Mexico Natural Heritage Program, Albuquerque, NM.
- Wentworth, T. R. 1982. Vegetation and flora of the Mule Mountains, Cochise County, Arizona. Journal of the Arizona-Nevada Academy of Science 17:29-44.