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A1203 Cortaderia jubata - Cortaderia selloana Ruderal Grassland Alliance

Type Concept Sentence: This alliance consists of stands dominated by Cortaderia jubata and/or Cortaderia selloana. It occurs primarily in coastal California in disturbed areas, estuaries, inland grasslands, urban areas, and wetlands.

Common (Translated Scientific) Name: Purple Pampas Grass - Uruguayan Pampas Grass Ruderal Grassland Alliance

Colloquial Name: Ruderal Pampas Grass Tussock Grassland

Hierarchy Level:  Alliance

Type Concept: This alliance consists of invading patches of Cortaderia jubata and/or Cortaderia selloana where they are dominant in the herbaceous and shrub layers. Emergent shrubs and trees may be present in low cover. Herbs are <4 m in height, and the canopy cover is open to continuous. It occurs in California at elevations ranging from sea level to 800 m. Habitats are coastal land, disturbed areas, estuaries, grasslands, urban areas, and wetlands. Areas where this alliance thrives receive between 100-200 cm of rain per year. Stands of Cortaderia invade coastal bluff and coastal scrub stands of Artemisia californica, Baccharis pilularis, and Eriogonum fasciculatum. They also invade moist forest stands of Picea sitchensis, Pseudotsuga menziesii, and Sequoia sempervirens, and invade inland riparian stands of herbs and trees in the Central Valley.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: The nominal species of this alliance are exotic and invasive. Stands of Cortaderia invade coastal bluff and coastal scrub stands of Artemisia californica, Baccharis pilularis, and Eriogonum fasciculatum alliances. They grow in moist, open forest stands and infest inland riparian stands in the Great Valley.

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: This tall, temperate bunch grassland forms an open canopy of graminoids less than 4 m in height. An understory of shrubs, or emergent trees (0-10%), may be present.

Floristics: In this invasive herbaceous grassland of California, Cortaderia jubata or Cortaderia selloana are the sole or dominant species in the herbaceous layer. Shrub species present may include Artemisia californica, Eriogonum fasciculatum, and Baccharis pilularis. In disturbed forest areas emergent trees may be present and could include Pseudotsuga menziesii, Sequoia sempervirens, and Picea sitchensis.

Dynamics:  In forested areas the nominal species of this alliance require a disturbance such as logging to open the canopy for invasion to occur. As the forest grows, stands of Cortaderia spp. gradually decline as light levels decrease. In shrub alliances, Cortaderia spp. can be much more persistent and invasive. Seeds are windblown and can germinate under all but the densest shrub canopies. Disturbed shrublands along the outer Coast Ranges can be replaced by virtual monocultures of Cortaderia. These species can increase fire fuel loads and fire intensity, especially in areas already altered by other non-natives with which they commonly grow.
Environmental Description:  This herbaceous alliance of the temperate regions of California invades several shrubland vegetation types and disturbed forest sites. Stands are found on all topographic positions, from sea level to 800 m. Areas where this alliance thrives receive between 100-200 cm of rain per year.
Geographic Range: This alliance occurs in California, primarily in coastal areas.

Nations: US

States/Provinces:  CA


Confidence Level: Low

Confidence Level Comments: No Data Available
Grank: GNA

Greasons: No Data Available
Type Name Database Code Classification Code
Class 2 Shrub & Herb Vegetation Class C02 2
Subclass 2.B Temperate & Boreal Grassland & Shrubland Subclass S18 2.B
Formation 2.B.1 Mediterranean Scrub & Grassland Formation F038 2.B.1
Division 2.B.1.Na Californian Scrub & Grassland Division D327 2.B.1.Na
Macrogroup 2.B.1.Na.90 Wild Oat - Black Mustard - Ripgut Brome Ruderal Grassland, Meadow & Scrub Macrogroup M046 2.B.1.Na.90
Group 2.B.1.Na.90.a Wild Oat - Ripgut Brome Ruderal Grassland, Meadow & Scrub Group G497 2.B.1.Na.90.a
Alliance A1203 Purple Pampas Grass - Uruguayan Pampas Grass Ruderal Grassland Alliance A1203 2.B.1.Na.90.a
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: = Cortaderia (jubata, selloana) (Pampas grass patches) Semi-natural Stands (Sawyer et al. 2009) [42.070.00]
= Cortaderia (jubata, selloana) Semi-Natural Stands (Pampas grass patches) (Buck-Diaz et al. 2012)
= Cortaderia (jubata, selloana) Herbaceous Semi-Natural Alliance (CNPS 2017) [42.070.00]
< Non-native Grassland (#42200) (Holland 1986b)
= Pampas grass series (Sawyer and Keeler-Wolf 1995)
Concept Author(s): J.O. Sawyer et al. (2009)

Author of Description: M.S. Reid

Acknowledgements: No Data Available

Version Date: 12-18-14
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  • CNPS [California Native Plant Society]. 2015-2017. A manual of California vegetation [online]. California Native Plant Society, Sacramento, CA. [http://vegetation.cnps.org/].
  • DiTomaso, J. M., E. Healy, C. Bell, J. Drewitz, and A. Tschohl. 1999. Pampas grass and jubata grass threaten California coastal habitats. Leaflet 99-1, University of California Extension, WeedRIC, and California Exotic Pest Plant Council, Davis, 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.
  • Fuller, T. C. 1976. Pampas grass: Its history as a weed. Fremontia 4:16.
  • Hickson, D., and T. Keeler-Wolf. 2007. Vegetation and land use classification and map of the Sacramento-San Joaquin River Delta. Prepared for the Bay Delta Region, California Department of Fish and Game by the Vegetation Classification and Mapping Program, California Department of Fish and Game, Sacramento. 152 pp. plus appendices.
  • Holland, R. F. 1986b. Preliminary descriptions of the terrestrial natural communities of California. Unpublished report prepared for the California Department of Fish and Game, Nongame-Heritage Program and Natural Diversity Database, Sacramento. 156 pp.
  • Lambrinos, J. G. 2000. The impact of the invasive alien grass Cortaderia jubata (Lemoine) Stapf on an endangered Mediterranean-type shrubland in California. Diversity Distributions 6:217-231.
  • Lambrinos, J. G. 2001. The expansion history of a sexual and asexual species of Cortaderia in California, USA. Journal of Ecology 89:88-98.
  • Lambrinos, J. G. 2002. The variable invasive success of Cortaderia species in a complex landscape. Ecology 83:518-529.
  • Peterson, D. L., and M. J. Russo. 1988. Element stewardship abstract for Cortaderia jubata [online]. The Nature Conservancy, Arlington, VA.
  • 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.
  • Sawyer, J. O., and T. Keeler-Wolf. 1995. A manual of California vegetation. California Native Plant Society, Sacramento. 471 pp.
  • Vaghti, M., and T. Keeler-Wolf. 2004. Suisun Marsh vegetation mapping change detection 2003: A report to the California Department of Water Resources. California Department of Fish and Game-Wildlife Habitat Data Analysis Branch, Sacramento, CA.
  • Walgren, M., L. Andreano, J. Beaulieu, S. Christopher, and C. Jackson. 2005. Resource inventory for Morro Strand State Beach. Unpublished report. California Department of Parks and Recreation, San Luis Obispo, CA.