Print Report

CEGL001604 Deschampsia cespitosa - Danthonia californica Marsh

Type Concept Sentence: No Data Available


Common (Translated Scientific) Name: Tufted Hairgrass - California Oatgrass Marsh

Colloquial Name: Tufted Hairgrass Valley Prairie Grassland

Hierarchy Level:  Association

Type Concept: This is a moderately tall, bottomland grassland association. It occupies flat, valley bottom landscapes, generally with little topographic relief. Hummocks are common and important in some of the prairies and absent in others. Soils are usually fine-grained pluvial clays, moderately permeable to impermeable, with a high winter and spring water table. Mild, wet winters and hot, dry summers are typical. In its range in western Oregon and Washington, the large pre-settlement extent of the prairie was maintained by annual burning by Native Americans. The cessation of burning and the introduction of domestic livestock produced marked changes in these prairies. The dominant species are the tall perennial bunchgrass Deschampsia cespitosa and the shorter rhizomatous perennial Danthonia californica. Other common native graminoid species include Poa secunda, Festuca idahoensis ssp. roemeri, Agrostis exarata, Juncus patens, Koeleria macrantha, and Carex species. Common native forbs include Camassia quamash, Montia linearis, Symphyotrichum chilense, Delphinium nuttallii ssp. ochroleucum, Epilobium brachycarpum, Achillea millefolium, Sisyrinchium bellum, Madia spp., and Eriophyllum lanatum. Some areas are characterized by camas blooms in the spring. In low swales which are always found in this type, the species Juncus spp., Hordeum brachyantherum, Beckmannia syzigachne, Alopecurus geniculatus, Eleocharis acicularis, and Veronica scutellata can dominate. Common (often dominant) non-native species in less pristine sites include Holcus lanatus, Bromus arvensis, Poa pratensis, Poa compressa, Agrostis stolonifera, Phleum pratense, Dactylis glomerata, Cynosurus cristatus, Aira caryophyllea, Daucus carota, Hypochaeris radicata, Hypericum perforatum, Rumex acetosella, Geranium dissectum, and Senecio jacobaea. Shrubs include Spiraea douglasii, Rosa gymnocarpa and the non-native Rosa rubiginosa.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: No Data Available

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

Physiognomy and Structure: No Data Available

Floristics: This is a lush herbaceous association, dominated by perennial graminoids, which as a group typically have over 100% cover. The densely tufted grass Deschampsia cespitosa is dominant with 60-70% cover, and grows 1-2 m in height. Several other perennial graminoids can be important, such as Juncus spp., Eleocharis spp., Poa secunda, and Danthonia californica. Other common native graminoid species include Poa secunda, Festuca idahoensis ssp. roemeri, Agrostis exarata, Juncus patens, Koeleria macrantha (= Koeleria nitida), and Carex species. Common native forbs include Camassia quamash, Montia linearis, Symphyotrichum chilense (= Aster chilensis), Delphinium nuttallii ssp. ochroleucum (= Delphinium ochroleucum), Epilobium brachycarpum, Achillea millefolium, Sisyrinchium bellum, Madia spp., and Eriophyllum lanatum. Some areas are characterized by camas blooms in the spring. In low swales which are always found in this type, the species Juncus spp., Hordeum brachyantherum, Beckmannia syzigachne, Alopecurus geniculatus, Eleocharis acicularis, and Veronica scutellata can dominate. Common (often dominant) non-native species in less pristine sites include Holcus lanatus, Bromus arvensis (= Bromus japonicus), Poa pratensis, Poa compressa, Agrostis stolonifera, Phleum pratense, Dactylis glomerata, Cynosurus cristatus, Aira caryophyllea, Daucus carota, Hypochaeris radicata, Hypericum perforatum, Rumex acetosella, Geranium dissectum, and Senecio jacobaea. Shrubs include Spiraea douglasii, Rosa gymnocarpa and the non-native Rosa rubiginosa (= Rosa eglanteria). Perennial forbs typically contribute 20-30% cover and include such species as Galium trifidum, Veronica scutellata, Potentilla gracilis, Prunella vulgaris, and Camassia spp. In the spring months, species of Camassia are very abundant and dominate the visual aspect of this association. Several introduced species are abundant in stands of this association, including the broad-leaved, deciduous shrub Rosa rubiginosa (15-25% cover) and the perennial grass Holcus lanatus (30-40% cover). The broad-leaved, deciduous tree Fraxinus latifolia is a native species that invades stands of this grassland when fires are suppressed.

Dynamics:  No Data Available

Environmental Description:  This valley prairie association occurs in the interior valleys of western Oregon. Proximity to the Pacific coast is modified by the coastal mountain ranges to the west. Winters are mild and wet, but summers are hot and dry. Roughly 80% of the annual precipitation (average of 100 cm) falls during October through May, primarily as rain. The persistent, low-intensity rains result in soil saturation and flooding of low-lying valley bottoms. These valleys are flat-bottomed and characterized geologically as incised valleys filled by deep alluvial materials, over which silts and clays have been deposited. Topographically, these are broad, alluvial flats separated by groups of low hills. Elevations range from 50 to 140 m (160-450 feet), and the low relief has resulted in the rivers being slow-flowing and meandering. This association occurs in old valley bottom river oxbows or bottomland swamp and lake remnants. The soils are derived from heavy clays overlain by thin silt deposits, and horizonation is typically depositional rather than developmental. There is often an abrupt transition from silt loam textures of the surface horizon to clay in the deeper horizons, with a resulting high water-holding capacity and poor drainage. The sites are seasonally flooded, but dry out for up to 4 months, typically from late July to early October.

Geographic Range: The center of distribution of this type is the Willamette Valley of Oregon. Scattered remnants are found in southwestern Washington and to the south in the interior valleys of the Klamath Mountain ecoregion. It has not reported in northern California, nor in the intermountain valleys east of the Cascades.

Nations: US

States/Provinces:  OR, WA




Confidence Level: Moderate

Confidence Level Comments: No Data Available

Grank: G2

Greasons: No Data Available


Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available

Synonomy: = Deschampsia caespitosa - Danthonia californica (McCain and Christy 2005) [3 plots]
= Deschampsia caespitosa - Danthonia californica Association (Christy 2004)
? Deschampsia caespitosa - Danthonia intermedia Association (Crowe et al. 2004)

Concept Author(s): M.S. Reid

Author of Description: M.S. Reid and J. Titus

Acknowledgements: No Data Available

Version Date: 12-20-93

  • 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.
  • Christy, J. A. 2004. Native freshwater wetland plant associations of northwestern Oregon. Oregon Natural Heritage Information Center, Oregon State University, Portland, OR.
  • Connelly, K. P. 1989. Ecological effects of fire in bottomland Willamette Valley prairies, with special emphasis on Lomatium bradshawii and Erigeron decumbens, two rare endemic plants. Study plan and progress report. The Nature Conservancy, Oregon Field Office, Portland. 35 pp.
  • Connelly, K. P., and J. B. Kauffman. 1991. Ecological effects of fire in Willamette Valley wetland prairies with special emphasis on Lomatium bradshawii and Erigeron decumbens, two rare endemic plants. Unpublished report, on file at the Oregon Natural Heritage Program, Portland, OR. 45 pp.
  • Crowe, E. A., B. L. Kovalchik, and M. J. Kerr. 2004. Riparian and wetland vegetation of central and eastern Oregon. Oregon Natural Heritage Information Center, Institute for Natural Resources, Oregon State University, Portland. 473 pp. [http://oregonstate.edu/ornhic/ publications.html]
  • Johannessen, C. L., W. A. Davenport, A. Millet, and S. McWilliams. 1971. The vegetation of the Willamette Valley. Annals of the Association of American Geographers 61:286-302.
  • Kagan, J. 1983. Willamette Valley wetlands and wet prairies. Bulletin of the Native Plant Society of Oregon 16:12.
  • Kagan, J. S. 1980. The biology of Lomatium bradshawii (Apiaceae), a rare plant of Oregon. Unpublished thesis, University of Oregon, Eugene.
  • Kagan, J. S., J. A. Christy, M. P. Murray, and J. A. Titus. 2004. Classification of native vegetation of Oregon. January 2004. Oregon Natural Heritage Information Center, Portland. 52 pp.
  • Kauffman, J. B., and K. P. Connelly. 1989. Ecological effects of fire in Willamette Valley Prairies: Effects on rare and endangered plants and ecosystems. Progress report 1. Unpublished report to the U.S. Army Corps of Engineers, on file at The Nature Conservancy, Oregon Field Office, Portland, OR.
  • Lippert, B. E., and D. L. Jameson. 1964. Plant succession in temporary ponds of the Willamette Valley, Oregon. American Midland Naturalist 71:181-197.
  • McCain, C., and J. A. Christy. 2005. Field guide to riparian plant communities in northwestern Oregon. Technical Paper R6-NR-ECOL-TP-01-05. USDA Forest Service, Pacific Northwest Region, Portland. 357 pp.
  • Moir, W., and P. Mika. 1972. Prairie vegetation of the Willamette Valley, Benton County, Oregon. Unpublished report on file at the Pacific Northwest Forest and Range Experiment Station, Forestry Science Laboratory, Corvallis, OR. 29 pp. + appendices.
  • Savonen, C. 1988. Historical wetlands of the west Eugene study area. Lane Council of Governments, Eugene, OR. 10 pp.
  • Titus, J. H., J. A. Christy, D. Vander Schaaf, J. S. Kagan, and E. R. Alverson. 1996. Native wetland, riparian, and upland plant communities and their biota in the Willamette Valley, Oregon. Report to the Environmental Protection Agency, Region X, Seattle, WA. Willamette Basin Geographic Initiative. Oregon Natural Heritage Program, The Nature Conservancy, Portland, OR.
  • WNHP [Washington Natural Heritage Program]. 2018. Unpublished data files. Washington Natural Heritage Program, Department of Natural Resources, Olympia, WA.
  • Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.
  • Wilson, M. V., K. P. Connelly, and L. E. Lantz. 1993. Plant species, habitat, and site information for Fern Ridge Reservoir. A component of the project to develop management guidelines for native wetland communities. Report to Army Corps of Engineers and Soil Conservation Service. Oregon State University. 64 pp. plus figures.