Print Report

A2066 Poa macrantha - Leymus mollis - Festuca rubra Sand Dune Grassland Alliance

Type Concept Sentence: This alliance represents upland, native herbaceous coastal sand dune communities found from central Washington south to Point Reyes near San Francisco characterized by the perennial grasses and forbs Artemisia campestris, Festuca rubra, Leymus mollis, Lupinus littoralis, and Poa macrantha.


Common (Translated Scientific) Name: Seashore Bluegrass - American Dunegrass - Red Fescue Sand Dune Grassland Alliance

Colloquial Name: Seashore Bluegrass - American Dunegrass - Red Fescue Sand Dune Grassland

Hierarchy Level:  Alliance

Type Concept: This alliance represents upland, native herbaceous coastal sand dune communities found from central Washington south to Point Reyes near San Francisco. These herbaceous areas are characterized by the perennial grasses and forbs Artemisia campestris, Festuca rubra, Leymus mollis, Lupinus littoralis, and Poa macrantha. They are typically open and only slightly stabilizing their substrates, although the Festuca rubra communities can occur on partially stabilized dunes. They are restricted to coastal areas, generally within 2 km of the ocean, although some extensive dune areas such as those at Oregon Dunes National Recreation Area can extend inland up to 10 km. Elevation ranges from sea level to 200 m (0-600 feet). Aspect varies and the dunes can move seasonally. These grasslands occur on sand substrates, ranging from low foredunes along the ocean, coastal plains, and giant, often moving dunes.

Diagnostic Characteristics: Communities of the Pacific Northwest where the sand dune-adapted species Artemisia campestris, Festuca rubra, Leymus mollis, Lupinus littoralis, and Poa macrantha are the dominant species.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: These are dry coastal dune communities dominated by native grasses. Historically, dune vegetation would have been open and sparse in places with shifting sands. These remnant, open, natural dune habitats are present at Cape Disappointment, Fort Stevens, and Sunset Beach/Yeon in small patches. Large remnants of these natural systems are found at Oregon Dunes National Recreation Area and in Arcata, California. Most dunes are now almost entirely covered by non-native beachgrasses (Ammophila spp.), dramatically altering dune dynamics.

Similar NVC Types: No Data Available
note: No Data Available

Physiognomy and Structure: These communities typically contain a mixed herbaceous layer of graminoids and forbs of sparse to moderate cover (10-60%).

Floristics: This alliance represents upland, native herbaceous coastal sand dune communities. These herbaceous areas are characterized by the perennial grasses and forbs Artemisia campestris, Festuca rubra, Leymus mollis, Lupinus littoralis, and Poa macrantha. They are typically open and only slightly stabilized, although the Festuca rubra communities can be partially stabilized. These stabilized meadows rarely persist, as they are rapidly invaded by Arctostaphylos uva-ursi, Gaultheria shallon, Vaccinium ovatum, and other typical dune shrubs, followed by Argentina egedii, Fragaria chiloensis, Glehnia littoralis, Lathyrus japonicus, Lathyrus littoralis, Pinus contorta var. contorta, and Polygonum paronychia. Many remaining stands of this alliance are small remnants, many in poor condition because of the widespread conversion to ruderal vegetation dominated by non-native or planted graminoids, including extensive plantings of Leymus mollis and non-native beachgrasses Ammophila arenaria and Ammophila breviligulata, or non-native invasive shrubs such as Cytisus scoparius and Ulex europaeus.

Dynamics:  Stands in this open native, dune grassland alliance are generally seral, as they are rapidly invaded by Arctostaphylos uva-ursi, Gaultheria shallon, Vaccinium ovatum, and other typical dune shrubs, followed by Pinus contorta var. contorta. Dune processes, such as blowouts, create new habitat for this community. A combination of non-native sand-binding plant introductions and a significant reduction of sand input due to extensive dams on major rivers has altered natural conditions and threatened most examples of this alliance (Kagan et al. 2012).

Environmental Description:  This alliance represents upland, native herbaceous coastal sand dune communities found from central Washington south to Point Reyes near San Francisco. They are restricted to coastal areas, generally within 2 km of the ocean, although some extensive dune areas such as at Oregon Dunes National Recreation Area can extend inland up to 10 km. Elevation ranges from sea level to 200 m (0-600 feet). Aspect varies and the dunes can move seasonally. Sand represents the substrate, ranging from low foredunes along the ocean, coastal plains, and giant, often moving dunes.

Geographic Range: This alliance is found from central Washington south to Point Reyes near San Francisco, California.

Nations: CA,US

States/Provinces:  BC, CA, OR, WA




Confidence Level: Moderate

Confidence Level Comments: No Data Available

Grank: GNR

Greasons: No Data Available


Concept Lineage: A.1236, A.1243, A.1333, A.1355, A.1648, A.2503.

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available

Synonomy: ? Leymus mollis (Sea lyme grass patches) Alliance (Sawyer et al. 2009) [41.260.00]

Concept Author(s): J. Kagan and G. Kittel, in Faber-Langendoen et al. (2013)

Author of Description: K.A. Schulz and M.E. Hall

Acknowledgements: No Data Available

Version Date: 09-26-14

  • 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.
  • Kagan, J. S., E. M. Nielsen, M. D. Noone, J. C. van Warmerdam, L. K. Wise, G. Kittel, and C. Copass. 2012. Lewis and Clark National Historic Park vegetation classification and mapping project report. Natural Resource Report NPS/NCCN/NRR--2012/597. 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.