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G524 Poa pratensis - Conyza canadensis - Cirsium arvense Ruderal Marsh, Wet Meadow & Shrubland Group
Type Concept Sentence: This group contains wet meadows dominated by non-native species such as Agrostis gigantea, Agrostis stolonifera, Alopecurus pratensis, Conyza canadensis, Cirsium arvense, Sonchus spp., Lactuca serriola, Phalaris arundinacea, Phragmites australis ssp. australis, Poa palustris, and/or Poa pratensis that occur in the same physical settings as native wet meadows found throughout the western U.S., Canada and Mexico.
Common (Translated Scientific) Name: Kentucky Bluegrass - Canadian Horseweed - Canada Thistle Ruderal Marsh, Wet Meadow & Shrubland Group
Colloquial Name: Western North American Ruderal Marsh, Wet Meadow & Shrubland
Hierarchy Level: Group
Type Concept: This group contains disturbed wet meadows found in lowland, montane and subalpine elevations, occasionally reaching into the lower edges of the alpine elevations (sea level to 3600 m) throughout the western U.S., Canada and Mexico. Vegetation is dominated by non-native species such as Agrostis gigantea, Agrostis stolonifera, Alopecurus pratensis, Bromus inermis, Conyza canadensis, Cirsium arvense, Sonchus spp., Lactuca serriola, Phalaris arundinacea, Phragmites australis ssp. australis, Poa bulbosa, Poa palustris, and Poa pratensis. Native species may be present but are so low in abundance that the original native plant association is impossible to determine. These can be wet meadows, wet emergent marshes, coastal backwater dunes, sloughs, open wet depressions, basins and flats with low-velocity surface and subsurface flows. They can be large meadows in montane or subalpine valleys, or occur as narrow strips bordering ponds, lakes, and streams, and along toeslope seeps. They are typically found on flat areas or gentle slopes, but may also occur on subirrigated sites with slopes up to 10%. Sites are usually seasonally wet, often drying by late summer, and many occur in a tension zone between perennial wetlands and uplands, where water tables fluctuate in response to long-term climatic cycles. They may have surface water for part of the year, but depths rarely exceed a few centimeters. Soils are mostly mineral and show typical hydric soil characteristics such as low chroma and redoximorphic features; some areas may have high organic content as inclusions or pockets. Due to disturbance, soils may be compacted.
Diagnostic Characteristics: Wet graminoid and forb meadow or marsh dominated by non-native species.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: This group may be difficult to tease apart from its native counterpart. The test is that the non-native species far outweigh native species in abundance and richness, such that a well-trained observer cannot tell what the native counterpart may have been or to do so is only speculation. This group does not include actively managed irrigated hay meadows that have been historically seeded. Those belong under ~7 Agricultural & Developed Vegetation Class (CCL01)$$.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: Herbaceous wet meadow dominated by perennial herbs introduced to North America.
Floristics: Vegetation of this group is dominated by non-native species such as Agrostis gigantea, Agrostis stolonifera, Alopecurus pratensis, Bromus inermis, Conyza canadensis, Lactuca serriola, Cirsium arvense, Iris pseudacorus, Phalaris arundinacea, Phragmites australis, Poa bulbosa, Poa palustris, Poa pratensis, Poa trivialis, and Scirpus cyperinus. Native species may be present but are so low in abundance that the original native plant association is impossible to determine. Floristic information was compiled from Whitson et al. (1996), Rondeau (2001), Faber-Langendoen et al. (2008), and Sawyer et al. (2009).
Dynamics: This group is a product of disturbance such as continuous heavy grazing by domestic livestock, soil disturbance/compactions, significant change in hydrologic regime, invasion after natural disturbance such as fire, floods or landslides, and are a combination of infestation by non-native invasive plants, and by diminished or lack of competition by native plants.
Environmental Description: Soil/substrate/hydrology: These wet meadows occur in open wet depressions, basins and flats with low-velocity surface and subsurface flows. They can be large meadows in montane or subalpine valleys, or occur as narrow strips bordering ponds, lakes, and streams, and along toeslope seeps. They are typically found on flat areas or gentle slopes, but may also occur on subirrigated sites with slopes up to 10%. Sites are usually seasonally wet, often drying by late summer, and many occur in a tension zone between perennial wetlands and uplands, where water tables fluctuate in response to long-term climatic cycles. Some sites occur under an agricultural management regime of seasonal sheet irrigation for grazing or haying purposes, and may bear no resemblance to historical types of the area. They may have surface water for part of the year, but depths rarely exceed a few centimeters. Soils are mostly mineral and show typical hydric soil characteristics such as low chroma and redoximorphic features; some areas may have high organic content as inclusions or pockets. Due to disturbance, soils may be compacted.
This group occurs in the same environmental settings as ~Vancouverian-Rocky Mountain Montane Wet Meadow & Marsh Group (G521)$$, ~Vancouverian Freshwater Wet Meadow & Marsh Group (G517)$$, and ~Arid West Interior Freshwater Marsh Group (G531)$$.
This group occurs in the same environmental settings as ~Vancouverian-Rocky Mountain Montane Wet Meadow & Marsh Group (G521)$$, ~Vancouverian Freshwater Wet Meadow & Marsh Group (G517)$$, and ~Arid West Interior Freshwater Marsh Group (G531)$$.
Geographic Range: This group is found throughout the entire western U.S., Canada and Mexico.
Nations: CA,MX,US
States/Provinces: AB, AZ, BC, CA, CO, ID, MB, MT, MXCHH, MXCOA, MXNLE, MXSON, MXTAM, ND, NE, NM, NV, OK, OR, SD, SK, TX, UT, WA, WY
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.857308
Confidence Level: Low
Confidence Level Comments: No Data Available
Grank: GNA
Greasons: No Data Available
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: No Data Available
- Buck-Diaz, J., S. Batiuk, and J. M. Evens. 2012. Vegetation alliances and associations of the Great Valley ecoregion, California. California Native Society, Sacramento, CA. [http://cnps.org/cnps/vegetation/pdf/great_valley_eco-vegclass2012.pdf]
- Faber-Langendoen, D., J. Drake, S. Gawler, M. Hall, C. Josse, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, L. Sneddon, K. Schulz, J. Teague, M. Russo, K. Snow, and P. Comer, editors. 2010-2019a. Divisions, Macrogroups and Groups for the Revised U.S. National Vegetation Classification. NatureServe, Arlington, VA. plus appendices. [in preparation]
- Faber-Langendoen, D., J. Rocchio, P. Comer, G. Kudray, L. Vance, E. Byers, M. Schafale, C. Nordman, E. Muldavin, G. Kittel, L. Sneddon, M. Pyne, and S. Menard. 2008a. Overview of Natural Heritage methodology for ecological Element Occurrence ranking based on ecological integrity assessment methods. Draft for Network review. NatureServe, Arlington, VA.
- Rondeau, R. 2001. Ecological system viability specifications for Southern Rocky Mountain ecoregion. First edition. Colorado Natural Heritage Program, Colorado State University, Fort Collins, CO. 181 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.
- Whitson, T. D., L. C. Burrill, S. A. Dewey, D. W. Cudney, B. E. Nelson, R. D. Lee, R. Parker. 2000. Weeds of the West. The Western Society of Weed Science in cooperation with the Western United States Land Grant Universities, Cooperative Extension Services. University of Wyoming, Laramie. 630 pp.