Common (Translated Scientific) Name: Interior West Ruderal Flooded & Swamp Forest & Woodland Macrogroup
Colloquial Name: Interior West Ruderal Flooded & Swamp Forest & Woodland
Hierarchy Level: Macrogroup
Type Concept: This macrogroup consists of low-elevation riparian areas throughout the southwestern U.S. and into Mexico that are dominated by non-native invasive woody species. Abundant species include Elaeagnus angustifolia, Tamarix chinensis, Tamarix parviflora, and Tamarix ramosissima. Schinus molle, Schinus terebinthifolius, or Myoporum laetum may be present to abundant, but these latter species are not restricted to riparian settings. There are no native species present or, if present, they contribute less than 10% relative cover. Elevation ranges from sea level to above 2000 m (6500 feet). Sites are typically streambanks and benches, floodplains and canyons with permanent, intermittent or temporary waterflow.
Diagnostic Characteristics: Diagnostic tree species trees include Phoenix dactylifera, Tamarix spp. and Elaeagnus angustifolia, along with other exotic woody flora (including non-native stands of Washingtonia filifera) of the region alone or in combination.
Rationale for Nominal Species or Physiognomic Features: The non-native invasive woody species of Tamarix spp. and Elaeagnus angustifolia are widespread and common.
Classification Comments: Many plant communities may trend towards this macrogroup (M298) with the proliferation of exotic woody vegetation, particularly with altered flow regimes and dewatering and xerification of many riparian systems that subsequently affect the regeneration of and competition with native dominants. The amount of natives present helps determine the fine line between classifying the site as a native type, or whether the site has gone beyond the dominance threshold for exotics and is now best placed here (M298). Note that the concept for ruderal macrogroups allows for inclusion of stands where the ground layer is primarily exotic and the overstory consists of generalist or "weedy" native tree species that are clearly outside their typical niche (e.g., stands of Washingtonia filifera outside of its native range are included in this macrogroup); however, these stands are borderline cases, as they may also be "poor" condition expressions of native types. At this time, these stands are not well-described here.
Similar NVC Types:
M036 Interior Warm & Cool Desert Riparian Forest, note: "has lower abundance of exotic overstory dominants, when present."
Physiognomy and Structure: Broad- and narrow-leaved evergreen trees form open- to closed-canopy riparian woodlands with marginal vertical diversity. Stands dominated or codominated by other exotic tree taxa may have multiple canopy layers and more varied/patchy horizontal diversity.
Floristics: Dominant species include Elaeagnus angustifolia, Myoporum laetum, Phoenix dactylifera, Schinus molle, Schinus terebinthifolius, Tamarix africana, Tamarix aphylla, Tamarix aralensis, Tamarix canariensis, Tamarix chinensis, Tamarix gallica, Tamarix parviflora, Tamarix ramosissima, or Ulmus pumila. Also, occurrences of Washingtonia filifera outside of its native range are included in this macrogroup. Salt-cedar habitats tend to support fewer species and individuals than native habitats (Smith and Douglas 1989, Barbour et al. 2007, Sogge et al. 2008, Sawyer et al. 2009).
Dynamics: Vegetation is dependent upon at least occasional rise in the water table. The periodicity of flooding is variable, though many sites are no longer flooded due to upstream impoundments except in extreme runoff or precipitation events. The exotics that now dominate contemporary plant communities do not require the regularity of flooding or degree of soil moisture to regenerate and outcompete native woody taxa. Rising salinity from the lack of flooding in many areas may be another diagnostic feature in settings that increasingly favor tamarisk.
Environmental Description: Elevation ranges from sea level to above 2000 m (6500 feet). Climate: Warm temperate. Soil/substrate/hydrology: Sites are typically alluvial streambanks and floodplains, with slightly alkaline soils and water sometimes heavy in agricultural runoff (Smith and Douglas 1989, Barbour et al. 2007a, Sogge et al. 2008, Sawyer et al. 2009). Stands are adjacent to streams or their floodplains, or along lake/reservoir margins. The periodicity of flooding or inundation is variable, and many sites are no longer flooded due to upstream impoundments except in extreme runoff or precipitation events.
Geographic Range: This macrogroup is found throughout the southwestern U.S. and into Mexico.
Nations: MX, US
States/Provinces: AZ, CA, CO, ID, MT, MXCH, MXCO, ND, NM, NV, OR, SD, UT, WY
|US Forest Service Ecoregions (2007)|
Southwest Plateau and Plains Dry Steppe and Shrub Province
Uinta Mountains Section
Confidence Level: High
Confidence Level Comments:
Concept Author(s): Faber-Langendoen et al. (2014)
Author of Description: G. Kittel and J. Triepke
Version Date: 15Oct2014
- Barbour, M. G., T. Keeler-Wolf, and A. A. Schoenherr, editors. 2007a. Terrestrial vegetation of California, third edition. University of California Press, Berkeley.
- Brotherson, J. D., and D. Field. 1987. Tamarix: Impacts of a successful weed. Rangelands 9(3):110-112.
- 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]
- 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.
- Smith, S. D., and C. L. Douglas. 1989. The ecology of saltcedar (Tamarix chinensis) in Death Valley National Monument and Lake Mead National Recreation Area: An assessment of techniques and monitoring for saltcedar control in the park system. University of Nevada Cooperative National Park Resources Studies Unit Report 041/03, Las Vegas. 63 pp.
- Sogge, M. K., S. J. Sferra, and E. H. Paxton. 2008. Tamarix as habitat for birds: Implications for riparian restoration in the southwestern United States. Restoration Ecology 16(1):145-154.