Print Report

CEGL001201 Salix exigua / Equisetum arvense Wet Shrubland

Type Concept Sentence: No Data Available

Common (Translated Scientific) Name: Narrowleaf Willow / Field Horsetail Wet Shrubland

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This shrubland is a riparian tall-shrub vegetation type that grows on sediment bars and channel edges at middle elevations in mountains of the northwestern U.S. In eastern Idaho and western Wyoming stands of this type generally are found at elevations below 2160 m (7100 feet) and are bordered by other riparian shrublands or by Picea engelmannii forests, while stands in eastern Oregon are found between 914 and 1323 m (3000-4340 feet) next to Pinus ponderosa, Pseudotsuga menziesii, or Abies grandis forests. Soils are cobbly in the lower horizons but may contain virtually no coarse fragments in the surface horizon. The shrub layer is dense, 1 to 2 m (3-6.5 feet) tall, and dominated by Salix exigua or Salix melanopsis, and sometimes contains small amounts of other shrubs. The herbaceous undergrowth contains substantial amounts of Equisetum arvense or Calamagrostis canadensis. Stands of this type depend on floods that create new sediment bars for their establishment, but they have been little affected by recent flooding beyond deposition of small amounts of sediment. Stands of this association are distinguished from stands of other Salix exigua or Salix melanopsis associations by the presence of at least 5% canopy cover of Equisetum arvense or at least 25% canopy cover of Calamagrostis canadensis in the undergrowth.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This association is defined as a PNV vegetation type. If it were renamed as a dominance type, the species would include Salix exigua and Salix eriocephala. This association apparently has been named explicitly only from western Wyoming and eastern Idaho by Youngblood et al. (1985a), but stands of other associations from other places might be placed into it, i.e., the Salix exigua / Eleocharis palustris - Schoenoplectus americanus Association of Oregon, the Salix / Equisetum species Association of eastern Washington, and the Salix exigua Community Type of Montana. While the authors of some of these types may include Salix melanopsis (= Salix exigua ssp. melanopsis) in their associations, in the U.S. National Vegetation Classification, Salix melanopsis-dominated communities should be placed into separate plant associations and alliance(s).

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available

Floristics: The shrub layer is dense, 1 to 2 m (3-6.5 feet) tall, and dominated by Salix exigua or Salix melanopsis, and sometimes contains small amounts of other shrubs. The herbaceous undergrowth contains substantial amounts of Equisetum arvense or Calamagrostis canadensis. According to Youngblood et al. (1985a), stands of this type depend on floods that create new sediment bars for their establishment, but they have been little affected by recent flooding beyond deposition of small amounts of sediment. Stands of this association are distinguished from stands of other Salix exigua or Salix melanopsis associations by the presence of at least 5% canopy cover of Equisetum arvense or at least 25% canopy cover of Calamagrostis canadensis in the undergrowth.

Dynamics:  Salix exigua and Salix melanopsis become established on bare sediments (Youngblood et al. 1985a, Padgett et al. 1989, Hansen et al. 1995 ). Once established, the shrubs sprout from the roots (Hansen et al. 1995, Crowe and Clausnitzer 1997, Kovalchik 2001, Crowe et al. 2004) and recover from many forms of disturbance (Hansen et al. 1995). Development of the Equisetum arvense-dominated undergrowth apparently requires a reduction in flood frequency or severity after the shrubs become established (Youngblood et al. 1985a). Long periods of only minor flooding may result in replacement of these stands with other willow types (Youngblood et al. 1985a, Hansen et al. 1995) or cottonwood woodlands (Kittel et al. 1999b, Crowe et al. 2004 [Salix melanopsis Association]). Consequently, stands of this association seem to require flooding that creates bare sediment bars for willow establishment and then a reduction in flooding for the development of the undergrowth, and possibly to be seral to other riparian vegetation types. The vulnerability of the undergrowth in these stands to changes in composition with disturbance and speed with which the undergrowth recovers apparently have not been assessed.
Environmental Description:  This shrubland is a riparian tall-shrub vegetation type that grows on sediment bars and channel edges at middle elevations in mountains of the northwestern U.S. In eastern Idaho and western Wyoming (Youngblood et al. 1985a) stands of this type generally are found at elevations below 2160 m (7100 feet) and are bordered by other riparian shrublands or by Picea engelmannii forests, while stands in eastern Oregon (Crowe and Clausnitzer 1997) are found between 914 and 1323 m (3000-4340 feet) next to Pinus ponderosa, Pseudotsuga menziesii, or Abies grandis forests. Soils are cobbly in the lower horizons but may contain virtually no coarse fragments in the surface horizon.
Geographic Range: The geographic range is assumed to include the mountains of far western Wyoming, the mountains of Idaho, and the mountains of eastern Oregon and Washington.

Nations: US

States/Provinces:  ID, NM, OR, WA, WY


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.C Shrub & Herb Wetland Subclass S44 2.C
Formation 2.C.4 Temperate to Polar Freshwater Marsh, Wet Meadow & Shrubland Formation F013 2.C.4
Division 2.C.4.Nb Western North American Temperate Freshwater Marsh, Wet Meadow & Shrubland Division D031 2.C.4.Nb
Macrogroup 2.C.4.Nb.5 Sitka Alder - Booth''s Willow / Northwest Territory Sedge Montane Marsh, Wet Meadow & Shrubland Macrogroup M893 2.C.4.Nb.5
Group 2.C.4.Nb.5.a Narrowleaf Willow - Hawthorn species - Stretchberry Rocky Mountain-Great Basin Riparian Shrubland Group G526 2.C.4.Nb.5.a
Alliance A3800 Narrowleaf Willow - Dewystem Willow Shrubland Alliance A3800 2.C.4.Nb.5.a
Association CEGL001201 Narrowleaf Willow / Field Horsetail Wet Shrubland CEGL001201 2.C.4.Nb.5.a
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: < Salix / Equisetum species Association (Kovalchik 2001) [It is unclear whether the Salix / Equisetum species Association in Washington (Kovalchik 2004) contains stands that could be placed into this association.]
>< Salix exigua / Eleocharis palustris - Schoenoplectus americanus Association (Crowe et al. 2004)
= Salix exigua / Equisetum arvense Community Type (Youngblood et al. 1985a)
>< Salix exigua (Crowe and Clausnitzer 1997) [(p.114) This type is a gamish of Salix exigua and Salix melanopsis. Assumes they have stands dominated by Salix exigua and not Salix melanopsis with Equisetum arvense.]
< Salix exigua / Mesic Forb Community Type (Padgett et al. 1989) [Padgett et al. (1989) indicate that the Salix exigua / Equisetum arvense Community Type of Youngblood et al. (1985a) is part of their Salix exigua / Mesic Forb Community Type, but that is unclear from their summary data table and their description.]
< Salix exigua / Mesic Graminoid (Kittel et al. 1999b)
>< Salix exigua Community Type (Hansen et al. 1995) [However, Equisetum arvense is never more than 3% cover.]
Concept Author(s): Western Ecology Group

Author of Description: G.P. Jones and G. Kittel

Acknowledgements: No Data Available

Version Date: 09-27-04
  • 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.
  • Crawford, Rex. Personal communication. Vegetation Ecologist - Eastern WA, Washington Natural Heritage Program, Department of Natural Resources, Olympia, WA.
  • 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]
  • Crowe, E. A., and R. R. Clausnitzer. 1997. Mid-montane wetland plant associations of the Malheur, Umatilla, and Wallowa-Whitman national forests. Technical Paper R6-NR-ECOL-TP-22-97. USDA Forest Service, Pacific Northwest Region, Portland, OR.
  • Erixson, J., D. Cogan, and J. Von Loh. 2011b. Vegetation inventory project report: Lake Roosevelt National Recreation Area. Natural Resource Report NPS/UCBN/NRR--2011/434 National Park Service, Fort Collins, CO.
  • Girard, M., D. L. Wheeler, and S. B. Mills. 1997. Classification of riparian communities on the Bighorn National Forest. R2-RR-97-02. USDA Forest Service, Rocky Mountain Region, Sheridan, WY. 308 pp.
  • Hansen, P. L., R. D. Pfister, K. Boggs, B. J. Cook, J. Joy, and D. K. Hinckley. 1995. Classification and management of Montana''s riparian and wetland sites. Miscellaneous Publication No. 54. Montana Forest and Conservation Experiment Station, School of Forestry, University of Montana. 646 pp. plus posters.
  • IDCDC [Idaho Conservation Data Center]. 2005. Wetland and riparian plant associations in Idaho. Idaho Conservation Data Center, Idaho Department of Fish and Game, Boise. [http://fishandgame.idaho.gov/tech/CDC/ecology/wetland_riparian_assoc.cfm] (accessed 14 June 2005).
  • Jones, G. 1992b. Wyoming plant community classification (Draft). Wyoming Natural Diversity Database, Laramie, WY. 183 pp.
  • Jones, G. P., and G. M. Walford. 1995. Major riparian vegetation types of eastern Wyoming. Submitted to Wyoming Department of Environmental Quality, Water Quality Division. Wyoming Natural Diversity Database, Laramie, WY. 245 pp.
  • 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.
  • Kagan, Jimmy. Personal communication. Coordinator, Oregon Natural Heritage Program, Portland.
  • Kittel, G., E. Van Wie, M. Damm, R. Rondeau, S. Kettler, A. McMullen, and J. Sanderson. 1999b. A classification of riparian and wetland plant associations of Colorado: A user''s guide to the classification project. Colorado Natural Heritage Program, Colorado State University, Fort Collins CO. 70 pp. plus appendices.
  • Kovalchik, B. L. 2001. Classification and management of aquatic, riparian and wetland sites on the national forests of eastern Washington. Part 1: The series descriptions. 429 pp. plus appendix. [http://www.reo.gov/col/wetland_classification/wetland_classification.pdf]
  • Muldavin, E., P. Durkin, M. Bradley, M. Stuever, and P. Mehlhop. 2000a. Handbook of wetland vegetation communities of New Mexico. Volume I: Classification and community descriptions. Final report to the New Mexico Environment Department and the Environmental Protection Agency prepared by the New Mexico Natural Heritage Program, University of New Mexico, Albuquerque.
  • Padgett, W. G., A. P. Youngblood, and A. H. Winward. 1989. Riparian community type classification of Utah and southeastern Idaho. Research Paper R4-ECOL-89-0. USDA Forest Service, Intermountain Forest and Range Experiment Station, Ogden, UT.
  • Rust, Steve. Personal communication. Ecologist, Conservation Data Center, Idaho Department of Fish and Game, Boise, ID.
  • WNDD [Wyoming Natural Diversity Database]. No date. Unpublished data on file. Wyoming Natural Diversity Database, University of Wyoming, Laramie, WY.
  • WNHP [Washington Natural Heritage Program]. 2018. Unpublished data files. Washington Natural Heritage Program, Department of Natural Resources, Olympia, WA.
  • Walford, G. M. 1996. Statewide classification of riparian and wetland dominance types and plant communities - Bighorn Basin segment. Report submitted to the Wyoming Department of Environmental Quality, Land Quality Division by the Wyoming Natural Diversity Database. 185 pp.
  • Walford, G., G. Jones, W. Fertig, S. Mellman-Brown, and K. Houston. 2001. Riparian and wetland plant community types of the Shoshone National Forest. General Technical Report RMRS-GTR-85. USDA Forest Service, Rocky Mountain Research Station, Fort Collins, CO. 122 pp.
  • Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.
  • Youngblood, A. P., W. G. Padgett, and A. H. Winward. 1985a. Riparian community type classification of eastern Idaho-western Wyoming. R4-Ecol-85-01. USDA Forest Service, Intermountain Region, Ogden, UT. 78 pp.