Invalid Unit Specified
CEGL002685 Populus deltoides (ssp. wislizeni, ssp. monilifera) / Salix exigua Riparian Woodland

The U.S. National
Vegetation Classification
Type Concept Sentence:
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Common (Translated Scientific) Name: (Rio Grande Cottonwood, Plains Cottonwood) / Narrowleaf Willow Riparian Woodland
Colloquial Name:
Hierarchy Level: Association
Type Concept: This is a lowland riparian association known from the Rio Grande, Pecos and Canadian river drainages of central and eastern New Mexico and probably elsewhere in northern New Mexico. It also occurs in the Great Plains of Colorado, North Dakota, Nebraska, Oklahoma, South Dakota, and Texas, and in the Colorado Plateau of Utah and Colorado. This association occurs in wide river corridors that have low-gradient and primarily sandy/gravelly beds (becoming cobbly with increasing gradients). Elevations range from 1380-1980 m (4525-6500 feet). The type is most often found proximal to perennial rivers on low sidebars and streambanks near stream bankfull levels (discharge ratios close to 1). Occasionally, it can be found within the active channel or nearby. Because of its low position, the type is flooded frequently (average recurrence interval is 5 years). Most soils are young and undeveloped Entisols, and soils within the active channel are classified as riverwash. Soils tend to be well-drained sands with mixtures of cobbles and gravels throughout the profile. Most soils tend to be moist or wet within 1 m, at least during seasonal high water. In some soils, moisture indicators are found at greater depths. This association is dominated by relatively young stands of Populus deltoides that form open to moderately open overstories (25-50 % cover) with thickets of Salix exigua in the understory. Baccharis salicina is often well-represented to abundant and may codominate. Herbaceous cover is abundant, particularly among graminoids, and numerous (23) native wetland indicators can be present, such as Schoenoplectus pungens, Scirpus microcarpus, Eleocharis palustris, Juncus arcticus ssp. littoralis, Juncus longistylis, Juncus tenuis, Glyceria striata, Carex aquatilis, Carex oreocharis, Carex scoparia, Carex stipata, Equisetum arvense, and Equisetum laevigatum. Overall herbaceous diversity is high (90 species) and still predominantly native in composition (66 species or 73%).
Diagnostic Characteristics: No Data Available
Rationale for Nominal Species or Physiognomic Features:
Classification Comments: Initially developing on exposed depositional sandbars, this mid-successional community type depends on periodic flooding for maintenance and growth, even when well-established. As sediments and debris become trapped among the woody stems, the bar becomes more stable. In this community type, the cottonwoods overtop the shrubby willows. Because the willows are limited to lower riverside bars or cutoff channels, the community type eventually changes as the trees develop into mature forests on higher terraces without the willow understory. Historically, when cottonwoods eventually died from old age or were removed in high-energy flood events, they were replaced by new, young trees. For this cycle to occur under regulated conditions, flows should mimic the natural flood regime as closely as possible.

Hink and Ohmart (1984) describe a cottonwood/coyote willow mapping unit with four structural sub-types for the middle Rio Grande. Dick-Peddie (1993) refers to a Populus fremontii / Salix exigua / Mesic Grass - Forb vegetation type as part of a Floodplains-Plains Riparian group that is probably inclusive of this type. This association is similar to Populus deltoides - (Salix amygdaloides) / Salix (exigua, interior) Floodplain Woodland (CEGL000659) reported from the Great Plains states.
Similar NVC Types:
Populus deltoides - (Salix amygdaloides) / Salix (exigua, interior) Floodplain Woodland, note: reported from the Great Plains states.
Populus angustifolia / Salix exigua Riparian Woodland, note:
Physiognomy and Structure: No Data Available
Floristics: This type is dominated by relatively young stands of Populus deltoides that form open to moderately open overstories (10-50% cover) with thickets of Salix exigua in the understory. Stands in the Colorado Plateau may include Populus x acuminata in the canopy. Baccharis salicina is often well-represented to abundant and may codominate with Salix in some parts of the range. Herbaceous cover is abundant, particularly among graminoids, and numerous (23) native wetland indicators can be present, such as Schoenoplectus pungens (= Scirpus pungens), Scirpus microcarpus, Eleocharis palustris, Juncus arcticus ssp. littoralis (= Juncus balticus), Juncus longistylis, Juncus tenuis, Glyceria striata, Carex aquatilis, Carex oreocharis, Carex scoparia, Carex stipata, Equisetum arvense, and Equisetum laevigatum. Invasive exotic species can also be prevalent, such as Agrostis gigantea, Agrostis stolonifera, Poa pratensis, and Melilotus officinalis. Overall herbaceous diversity is high (90 species) and still predominantly native in composition (66 species or 73%).
Dynamics: The presence of Salix exigua indicates that the water table is relatively high and the site floods at least occasionally. As the community become isolated from the water table and flood frequency diminishes, Salix exigua disappears, to be replaced by species such as Distichlis spicata, Sporobolus airoides, Rhus trilobata, Ericameria nauseosa, and Artemisia tridentata ssp. tridentata.
Environmental Description: This community occurs in wide river corridors that have low-gradient and primarily sandy/gravelly beds (becoming cobbly with increasing gradients). Elevations range from 1380 to 1980 m (4525-6500 feet). The type is most often found proximal to perennial rivers on low sidebars and streambanks near stream bankfull levels (discharge ratios close to 1). Occasionally, it can be found within the active channel or nearby, or at the base of pour-offs in slickrock canyons. Because of its low position, the type is flooded frequently (average recurrence interval 5 years). Most soils are young and undeveloped Entisols, and soils within the active channel are classified as riverwash. Soils tend to be well-drained sands with mixtures of cobbles and gravels throughout the profile. Most soils tend to be moist or wet within 1 m, at least during seasonal high water. In some soils, moisture indicators are found at greater depths.
Geographic Range: This association is found in the Rio Grande, Pecos and Canadian river drainages of central and eastern New Mexico and probably elsewhere in northern New Mexico. It also occurs in the Great Plains of Colorado, North Dakota, Nebraska, Oklahoma, South Dakota, and Texas, as well as the Colorado Plateau of Colorado and Utah.
Nations: US
States/Provinces: AZ, CO, ND, NE, NM, OK, SD, TX, UT
US Forest Service Ecoregions (1994/1995)
Domain Name:
Division Name:
Province Name: Southwest Plateau and Plains Dry Steppe and Shrub Province
Province Code: 315    Occurrence Status: Confident or certain
Section Name: Upper Rio Grande Basin Section
Section Code: 331J     Occurrence Status: Confident or certain
US Forest Service Ecoregions (2007)
Domain Name:
Division Name:
Province Name: Southwest Plateau and Plains Dry Steppe and Shrub Province
Province Code: 315    Occurrence Status: Confident or certain
Section Name: Sacramento-Manzano Mountains Section
Section Code: M313B     Occurrence Status: Confident or certain
Omernik Ecoregions:
Confidence Level: Low
Confidence Level Comments:
Grank: G3
Greasons: This lowland riparian association is restricted to scattered stands along the Rio Grande and Pecos rivers (and their tributaries) in New Mexico, where plants, particularly trees and shrubs, have access to an active ground water table. The number of high-quality occurrences is not likely to exceed 25 in number, because as with many riparian zone communities in the Southwest, impacts over the past 150 years from livestock use, agricultural conversion, urbanization, recreational use, exotic tree and shrub invasion, and the alteration of hydrological regimes have led to extensive fragmentation and loss of this community. Viable occurrences are mostly found along unregulated rivers where periodic flooding and sustained maintenance flows lead to successful reproduction and establishment of native riparian species. In the Southwest, such unregulated rivers are few, hence this community still is threatened, and declines continue, suggesting a rank of G3. Should declines continue the rank might need to be raised to G2.
Concept Lineage:
Predecessors:
Obsolete Names:
Obsolete Parents:
Synonomy: < Populus fremontii / Salix exigua / Mesic Grass - Forb Vegetation Type (Dick-Peddie 1993)
= Plains Cottonwood/Coyote Willow CT (Muldavin et al. 2000a)
? cottonwood/coyote willow mapping unit (Hink and Ohmart 1984)
Concept Author(s): E. Muldavin et al. (2000a)
Author of Description: E. Muldavin et al. (2000a) and J. Coles
Acknowledgements:
Version Date: 07Feb2006
References:
  • CNHP [Colorado Natural Heritage Program]. 2006-2017. Tracked natural plant communities. Colorado Natural Heritage Program, Colorado State University, Fort Collins. [https://cnhp.colostate.edu/ourdata/trackinglist/plant_communities/]
  • 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.
  • Coles, J., A. Tendick, J. Von Loh, G. Bradshaw, G. Manis, A. Wight, G. Wakefield, and A. Evenden. 2010. Vegetation classification and mapping project report, Black Canyon of the Gunnison National Park. Natural Resource Technical Report NPS/NCPN/NRTR--2010/361. National Park Service, Fort Collins, CO.
  • Coles, J., J. Von Loh, A. Evenden, G. Manis, G. Wakefield. and A. Wight. 2008c. Vegetation classification and mapping project report, Natural Bridges National Monument. Natural Resource Technical Report NPS/NCPN/NRTR--2008/077. National Park Service, Fort Collins, CO. 390 pp.
  • Dick-Peddie, W. A. 1993. New Mexico vegetation: Past, present, and future. University of New Mexico Press, Albuquerque. 244 pp.
  • Hink, V. C., and R. D. Ohmart 1984. Middle Rio Grande Biological Survey. Final report. Submitted to U.S. Army Corps of Engineers, Contract No. DAC W47-81-C-0015. Albuquerque, NM.
  • 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.
  • Muldavin, E., Y. Chauvin, P. Neville, T. Neville, L. Arnold, P. Arbetan, and A. Fettes. 2012b. A vegetation classification and map: Pecos National Historical Park. Natural Resource Technical Report NPS/SOPN/NRTR--2012/601. National Park Service, Fort Collins, CO.
  • Salas, D. E., D. Wegner, and C. Bolen. 2010a. Vegetation classification and distribution mapping report: Navajo National Monument. Natural Resource Technical Report NPS/SCPN/NRTR--2010/298. National Park Service, Fort Collins, CO. 160 pp.
  • Von Loh, J., G. Wakefield, A. Wight, A. Evenden, and J. Coles. 2008. Vegetation classification and mapping project report, Hovenweep National Monument. Natural Resource Report NPS/NCPN/NRTR--2008/092. National Park Service, Fort Collins, CO. 328 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.
  • Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.