Print Report

CEGL001121 Rhus trilobata Moist Wet Shrubland

Type Concept Sentence: No Data Available

Common (Translated Scientific) Name: Skunkbush Sumac Moist Wet Shrubland

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This mesic to wet shrubland association is known from western Colorado, Utah and southern Idaho. Rhus trilobata often forms tall, dense, and nearly impenetrable thickets with 30-98% cover. Associated shrubs can sometimes be codominant, but no single species has consistently high cover or constancy across the range of the association. Associated shrubs include Celtis laevigata var. reticulata, Clematis ligusticifolia, Cornus sericea, Ericameria nauseosa, Ribes aureum, Rosa woodsii, Salix exigua, Salix lasiolepis, Salix lutea, Shepherdia argentea, and Toxicodendron rydbergii. Saplings of Populus fremontii, Populus angustifolia, or Salix amygdaloides may be present. Total understory herbaceous cover and diversity are low, and herbaceous species are often confined to shrub canopy gaps. Bromus tectorum and Galium aparine are the most frequently occurring species, but native species such as Elymus canadensis, Equisetum spp., Hordeum jubatum, Muhlenbergia asperifolia, Leymus cinereus, Pascopyrum smithii, and Phragmites australis are sometimes also present. Forb associates include Apocynum cannabinum and Artemisia ludoviciana. Non-native species are common in disturbed stands. Stands occur in both mesic to wet riparian and non-riparian situations. Throughout its range, the association occurs at low to mid elevations (701-1676 in Idaho and 1555-2000 m in Colorado), most often along mid-order to large rivers, but also in narrow canyons of small creeks and intermittent drainages. This association often forms linear bands above the high-water line on steep shorelines, along rocky toeslopes at cliff bases, on benches, and in intermittent arroyos, usually where there is minimal floodplain development. Stands also occur on rocky hillsides in association with springs and seeps emanating from canyon walls. In broad river bottoms, stands occur in the floodplain on second terraces between older Populus spp. forests on upper terraces and Salix exigua shrublands next to the river. In these large floodplains, habitats are in flux with stream meanders, channel downcutting, and sediment deposition; sites where this shrubland persists are generally too dry for the establishment of Populus and Salix spp. Substrates are well-drained, fine silty clay to sandy loam soils overlying coarse alluvium, bedrock or talus.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This association has been quantitatively described from numerous locations: 28 plots and 12 stand observations from southern Idaho (Cole 1995, 1996, Jankovsky-Jones et al. 2001, Hansen and Hall 2002) and a number of plots from western Colorado (e.g., Kittel et al. 1999a). Several riparian communities dominated by, or with high cover of, Rhus trilobata have been documented along the Snake River by Cole (1995, 1996). Due to their degraded stand conditions (indicated by abundant Bromus tectorum) and to inconsistency in the cover and constancy of associated or codominant shrubs, these 4 communities are considered synonymous variants of this more broadly defined Rhus trilobata association. In addition, no diagnostic herbaceous species useful for differentiating between possible Rhus trilobata associations is apparent (Jankovsky-Jones et al. 2001, Hansen and Hall 2002). Rhus trilobata - Salix exigua has been proposed as a different association, but Salix exigua has only moderate constancy in otherwise similar stands sampled from Idaho and Colorado. Although this Rhus trilobata plant association occurs in two distinct wetland settings (riverine and canyon-slope seeps or springs), no other distinct Rhus trilobata associations have been observed in these different settings. Rhus trilobata also occurs as a dominant species in xeric upland stands, especially east of the Continental Divide (Kittel et al. 1999a). These stands are separated by their clearly non-riparian settings and species.

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

Floristics: This plant association is characterized by a dense short-shrub layer dominated by 30-90% cover of Rhus trilobata sometimes forming near monocultures. However, the tall shrub Salix exigua is often present to codominant on mesic sites. Drier sites further from watercourses can have significant amounts of Artemisia tridentata ssp. tridentata, Amelanchier utahensis, or Chrysothamnus linifolius. Other associated shrubs include Artemisia filifolia, Atriplex canescens, Brickellia longifolia, Ericameria nauseosa, Forestiera pubescens, Ribes aureum, Salix lutea, Shepherdia argentea, Toxicodendron radicans, and occasional sapling trees of Populus fremontii, Populus angustifolia, or Salix amygdaloides. In cooler, mesic sites Cornus sericea, Salix ligulifolia (= Salix eriocephala var. ligulifolia), Berberis fendleri, Rosa woodsii, and Clematis ligusticifolia may be present to abundant. The herbaceous layer is relatively sparse (<20% cover) and is composed primarily of graminoids such as Elymus canadensis, Leymus cinereus (= Elymus cinereus), Equisetum spp., Hordeum jubatum, Muhlenbergia asperifolia, Pascopyrum smithii, Phragmites australis, or Sporobolus airoides. Forb associates include Apocynum cannabinum, Artemisia dracunculus, Artemisia ludoviciana, Equisetum hyemale, and Solidago canadensis. Exotic and invasive species are common in disturbed stands and may include Elaeagnus angustifolia, Tamarix ramosissima, Lepidium latifolium, Cirsium arvense, Thinopyrum intermedium, Poa pratensis, Agropyron cristatum, Melilotus officinalis, and Helianthus annuus.

Dynamics:  Rhus trilobata is a vigorously sprouting shrub that colonizes well after fires or mechanical disturbance (Padgett et al. 1989). The influence of fire on the Rhus trilobata association in riparian settings is not known. Although the exact response to disturbance is not known, the association is probably resistant to disturbances and minor changes in structure or composition (Hansen and Hall 2002). Exotic species are commonly observed, but they may not always obtain high cover when in competition with Rhus trilobata. The association is probably most sensitive to large-scale environmental changes, such as drying of seeps or springs due to water diversion or clearing for development. Hansen and Hall (2002) suggest that the Rhus trilobata association may represent the potential natural vegetation along narrow floodplains or be a seral state of ~Juniperus scopulorum / Cornus sericea Riparian Woodland (CEGL000746)$$ or ~Populus angustifolia / Rhus trilobata Riparian Woodland (CEGL000652)$$ (Padgett et al. 1989). Fire may help maintain dominance by Rhus trilobata. This shrubland association is considered late-seral by both Kittel et al. (1999a) and Hall and Hansen (1997). Rhus trilobata was observed to rapidly recolonize sandy terraces along the Yampa River once tamarisk was removed.
Environmental Description:  This minor association occurs in mesic, often riparian sites in western Colorado, eastern Utah and southwestern Idaho. Elevation ranges from 700 to 2000 m (2295-6560 feet). These small shrublands are reported from stream and river bottoms and terraces, and upland in mesic swales and on hillslopes below seeps and springs. Along the Yampa, San Miguel, and Dolores rivers, stands often form linear bands on rocky, well-drained benches and toeslopes where it is often confined between the high-water mark of a river and adjacent cliff faces and has access to the high water table. Along the Green River, stands occur in the floodplain on second terraces between older Populus fremontii forests on upper terraces and Salix exigua shrublands next to the river. In large floodplains, habitats are in flux with stream meanders, channel downcutting, and sediment deposition; sites where this shrubland persists are generally too dry for the establishment of Populus and Salix spp. Substrates are variable and range from shallow loamy sand to silt loam over coarse alluvium, boulders or bedrock, to fine silty clay with the depth to groundwater between 2-4 m. Adjacent riparian vegetation includes communities dominated by Schoenoplectus spp., Typha spp., Phragmites australis, Salix exigua, Alnus incana, Betula occidentalis, Populus angustifolia, and Populus fremontii.
Geographic Range: This association is known from western Colorado, Utah and southern Idaho. This minor shrubland association is known from the Yampa, San Miguel and Dolores river basins of the western slope of Colorado, along the Green River in northeastern Utah and Idaho, and the Colorado River in western Colorado and eastern Utah.

Nations: US

States/Provinces:  CO, ID, UT


Confidence Level: High

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 A3799 Skunkbush Sumac - River Hawthorn - Stretchberry Shrubland Alliance A3799 2.C.4.Nb.5.a
Association CEGL001121 Skunkbush Sumac Moist Wet Shrubland CEGL001121 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: ? Celtis laevigata var. reticulata/Rhus trilobata/Bromus tectorum (Cole 1996)
? Rhus aromatica Community Type (Hall and Hansen 1997)
< Rhus trilobata (Basket bush thickets) Provisional Alliance (Sawyer et al. 2009) [37.802.00]
= Rhus trilobata (Kittel et al. 1999b)
? Rhus trilobata-Rosa woodsii/Bromus tectorum (Cole 1996)
? Rhus trilobata-Toxicodendron rydbergii (Cole 1996)
? Salix exigua-Rhus trilobata/Bromus tectorum (Cole 1996)
= Skunkbrush Plant Association (Kittel and Lederer 1993)
Concept Author(s): K.A. Schulz

Author of Description: K.A. Schulz, C. Murphy, J. Drake and J. Coles

Acknowledgements: No Data Available

Version Date: 08-05-16
  • 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.
  • CNHP Ecology Team [Colorado Natural Heritage Program Ecology Team]. 2001. A classification of the native vegetation of Colorado. Colorado Natural Heritage Program, Colorado State University, Fort Collins.
  • Clark, D., M. Dela Cruz, T. Clark, J. Coles, S. Topp, A. Evenden, A. Wight, G. Wakefield, and J. Von Loh. 2009. Vegetation classification and mapping project report, Capitol Reef National Park. Natural Resource Report NPS/NCPN/NRTR--2009/187. National Park Service, Fort Collins, CO. 882 pp.
  • Cole, N. K. 1995. Cover type map and vegetation classification of the Hagerman study area, southwestern Idaho. Technical appendix E.3.3-A for new license application: Upper Salmon Falls (FERC No. 2777), Lower Salmon Falls (FERC No. 2061), Bliss (FERC No. 1975). Volume 4. Idaho Power Company, Boise ID. 61 pp. plus appendices.
  • Cole, N. K. 1996. Cover type map and vegetation classification of the Shoshone Falls study area, southwestern Idaho. Technical appendix E.3.3-A for new license application: Shoshone Falls (FERC No. 2778), Volume 2. Idaho Power Company, Boise ID. 38 pp. plus appendices.
  • Coles, J., A. Tendick, G. Manis, A. Wight, G. Wakefield, J. Von Loh, and A. Evenden. 2009a. Vegetation classification and mapping project report, Arches National Park. Natural Resource Technical Report NPS/NCPN/NRTR--2009/253. National Park Service, Fort Collins, CO. 544 pp.
  • Coles, J., D. Cogan, D. Salas, A. Wight, G. Wakefield, J. Von Loh, and A. Evenden. 2008a. Vegetation classification and mapping project report, Dinosaur National Monument. Natural Resource Technical Report NPS/NCPN/NRTR-2008/112. National Park Service, Fort Collins, CO. 814 pp.
  • Goodrich, S., and E. Neese. 1986. Uinta Basin flora. Cooperative Project of Ashley National Forest and USDI Bureau of Land Management, Vernal District. USDA Forest Service, Intermountain Region, Ogden, UT. 320 pp.
  • Hall, J. B., and P. L. Hansen. 1997. A preliminary riparian habitat type classification system for the Bureau of Land Management districts in southern and eastern Idaho. Riparian and Wetland Research Program, School of Forestry, University of Montana. Idaho Bureau of Land Management, Technical Bulletin No. 97-11. 381 pp.
  • Hansen, P. L., and J. B. Hall. 2002. Classification and management of the USDI Bureau of Land Management''s riparian and wetland sites in eastern and southern Idaho. Unpublished draft prepared for the Upper Snake River District, Bureau of Land Management, by Bitterroot Restoration, Inc., Corvallis, MT.
  • IDCDC [Idaho Conservation Data Center]. 2002. Unpublished riparian and wetland association occurrence and plot data on file at the Idaho Conservation Data Center, Idaho Department of Fish and Game, Boise, ID.
  • 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).
  • Jankovsky-Jones, M., C. J. Murphy, and C. L. Coulter. 2001. Riparian and wetland plant associations of southwestern Idaho in the Lower Snake River District, Bureau of Land Management. Idaho Conservation Data Center, Idaho Department of Fish and Game, Boise.
  • Kittel, G. M., and N. D. Lederer. 1993. A preliminary classification of the riparian vegetation of the Yampa and San Miguel/Dolores river basins. Unpublished report prepared for Colorado Department of Health and the Environmental Protection Agency by The Nature Conservancy, Colorado Field Office, Boulder.
  • 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.
  • 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.
  • Romme, W. H., K. D. Heil, J. M. Porter, and R. Fleming. 1993. Plant communities of Capitol Reef National Park, Utah. USDI National Park Service, Technical Report NPS/NAUCARE/NRTER-93/02. Cooperative Park Studies Unit, Northern Arizona University. 37 pp.
  • 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.
  • Stevens, J. E., D. S. Jones, and K. J. Benner. 2015. Vegetation classification and mapping project report: Bighorn Canyon National Recreation Area. Natural Resource Report NPS/GRYN/NRR--2015/1070. National Park Service, Fort Collins, CO. 350 pp.
  • Tendick, A., J. Spence, M. Reid, K. Shulz, G. Kittel, K. Green, A. Wight, and G. Wakefield. 2017. Vegetation classification and mapping project report, Glen Canyon National Recreation Area and Rainbow Bridge National Monument. Natural Resource Report NPS/NCPN/NRR—2017/1500. National Park Service, Fort Collins, CO. 1464 pp.
  • Von Loh, J., D. Cogan, K. Schulz, D. Crawford, T. Meyer, J. Pennell, and M. Pucherelli. 2002. USGS-USFWS Vegetation Mapping Program, Ouray National Wildlife Refuge, Utah. USDI Bureau of Reclamation, Remote Sensing and GIS Group, Technical Memorandum 8260-02-03. Denver Federal Center, Denver, CO. 225 pp.
  • Von Loh, J., K. Landgraf, A. Evenden, T. Owens, S. Blauer, and M. Reid. 2007. Vegetation classification and mapping project report, Colorado National Monument. Natural Resource Report NPS/NCPN/NRTR--2007/061. National Park Service, Fort Collins, CO. 564 pp.
  • Welsh, S. L., N. D. Atwood, S. Goodrich, and L. C. Higgins, editors. 1987. A Utah flora. Great Basin Naturalist Memoirs 9. Provo, UT. 894 pp.
  • Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.