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A2663 Leymus condensatus Coastal Grassland Alliance

Type Concept Sentence: This alliance consists of grasslands dominated or codominated by Leymus condensatus with a mix of native and non-native species. These occur in central and southern coastal areas of California.

Common (Translated Scientific) Name: Giant Wildrye Coastal Grassland Alliance

Colloquial Name: Giant Wildrye Coastal Grassland

Hierarchy Level:  Alliance

Type Concept: This alliance consists of grasslands dominated or codominated by Leymus condensatus with a mix of native and non-native species. Other species include Avena fatua, Brassica nigra, Bromus diandrus, Centaurea melitensis, Hirschfeldia incana, and Malacothrix saxatilis. Emergent trees, such as Juglans californica and Quercus agrifolia, or shrubs, such as Artemisia californica, Baccharis salicifolia, and Salvia leucophylla, may be present at low cover. Herbs are <3 m in height, and the canopy cover is open to intermittent. These grasslands occur in central and southern coastal areas of California. Habitats are somewhat steep, often northerly slopes at low elevations. Soils are loams.

Diagnostic Characteristics: Grasslands dominated or codominated by Leymus condensatus.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: Based on the Sawyer et al. (2009) alliance of the same name and much of the material is drawn from their description. The alliance occurs sporadically throughout central and southern coastal California, but few surveys exist. The alliance tends to be short-lived because oak trees and shrubs of the coastal sage scrub, including Artemisia californica, Eriogonum cinereum, Hazardia squarrosa, Malacothamnus fasciculatus, Salvia leucophylla, and Sambucus nigra, take over the grass stands in time.

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: Grasslands dominated by rhizomatous perennial graminoids that are <3 m in height, and the canopy cover is open to intermittent.

Floristics: This alliance consists of grasslands dominated or codominated by Leymus condensatus with a mix of native and non-native species. Other species include Avena fatua, Brassica nigra, Bromus diandrus, Centaurea melitensis, Hirschfeldia incana, and Malacothrix saxatilis. Emergent trees, such as Juglans californica and Quercus agrifolia, or shrubs, such as Artemisia californica, Baccharis salicifolia, and Salvia leucophylla, may be present at low cover.

Dynamics:  The alliance tends to be short-lived because the reproduction of Leymus condensatus is stimulated by fire, but it is fairly quickly taken over by native shrubs of the coastal sage scrub zone following fire. Keeley (2002) has suggested that Leymus condensatus was one of the species whose abundance was maintained by Native American burning. In the Santa Monica Mountains, Leymus does occur after fires; however, it may persist independently of fire in areas of human disturbance and urban runoff, or in areas of coastal sage scrub where natural slumping and seepage occur.
Environmental Description:  Habitats are somewhat steep, often northerly slopes at low elevations. Soils are loams.
Geographic Range: The alliance occurs sporadically throughout central and southern coastal California, but few surveys have been conducted.

Nations: US

States/Provinces:  CA


Confidence Level: Moderate

Confidence Level Comments: No Data Available
Grank: G3

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.3 Purple Needlegrass - Harvest Brodiaea - Rusty Popcorn-flower Native Grassland Macrogroup M045 2.B.1.Na.3
Group 2.B.1.Na.3.b Purple Needlegrass - California Melicgrass - Giant Wildrye Grassland Group G496 2.B.1.Na.3.b
Alliance A2663 Giant Wildrye Coastal Grassland Alliance A2663 2.B.1.Na.3.b
Association CEGL002883 Giant Wildrye Grassland CEGL002883 2.B.1.Na.3.b
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: = Elymus condensatus Coastal Grassland Alliance (Rodriguez et al. 2017)
= Leymus condensatus (Giant wild rye grassland) Alliance (Sawyer et al. 2009) [41.265.00]
= Leymus condensatus Herbaceous Alliance (CNPS 2017) [41.265.00]
< Native Grassland (#42100) (Holland 1986b)
Concept Author(s): G. Kittel after Sawyer et al. (2009)

Author of Description: M.S. Reid

Acknowledgements: No Data Available

Version Date: 12-18-14
  • AIS [Aerial Information Systems, Inc.]. 2007. Santa Cruz Island photo interpretation and mapping classification report. Unpublished report to The Nature Conservancy, Redlands, CA.
  • CNPS [California Native Plant Society]. 2015-2017. A manual of California vegetation [online]. California Native Plant Society, Sacramento, CA. [http://vegetation.cnps.org/].
  • 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.
  • 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.
  • Keeler-Wolf, T., and J. Evens. 2006. Vegetation classification of the Santa Monica Mountains National Recreation Area and environs in Ventura and Los Angeles counties, California. A report submitted to National Park Service, Santa Monica Mountains National Recreation Area by California Department of Fish and Game, Wildlife and Habitat Data Analysis Branch and The California Native Plant Society, Vegetation Program, Sacramento, CA.
  • Keeley, J. E. 2002. Native American impacts on fire regimes of the California coastal ranges. Journal of Biogeography 29:303-320.
  • Rodriguez, D., K. G. Sikes, T. Keeler-Wolf, G. Kittel, J. Curtis, C. Curley, and J. Evens. 2017. Vegetation classification of Channel Islands National Park. Report to the National Park Service, Fort Collins, CO.
  • 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.
  • Sproul, F., T. Keeler-Wolf, P. Gordon-Reedy, J. Dunn, A. Klein, and K. Harper. 2011. Vegetation classification manual for western San Diego County. AECOM, California Department of Fish and Game, San Diego Area Governments.