Common (Translated Scientific) Name: Western Interior Riparian Forest & Woodland Group

Colloquial Name: Western Interior Riparian Forest & Woodland

Hierarchy Level: Group

Type Concept: This group consists of riparian woody vegetation. Dominant trees may include Acer negundo, Celtis laevigata var. reticulata, Cephalanthus occidentalis, Fraxinus velutina, Juglans major, Platanus wrightii, Populus deltoides ssp. wislizeni, Populus deltoides ssp. monilifera, Populus fremontii, Platanus racemosa, Quercus lobata, Salix amygdaloides, Salix gooddingii, Salix laevigata, Sapindus saponaria, and Washingtonia filifera. Dominant shrubs include Alnus oblongifolia, Baccharis salicifolia, Prunus spp., Salix exigua, Salix lasiolepis, Shepherdia argentea, and Vitis californica. Other dominants on serpentine substrates include Aquilegia eximia, Carex serratodens, Cirsium fontinale, Hesperocyparis sargentii, Frangula californica ssp. tomentella, Mimulus glaucescens, Mimulus guttatus, Packera clevelandii, Salix breweri, Solidago spp., Stachys albens, and Umbellularia californica. The variety of plant associations within this group reflects elevation, stream gradient, floodplain width, and flooding events. It also includes springs, seeps, and perennial and intermittent streams and riparian areas found on serpentine substrates. These are disturbance-driven systems that require flooding, scour and deposition for germination and maintenance. Periodic flooding and associated sediment scour are necessary to maintain growth and reproduction of vegetation. Flooding regimes have been significantly altered in all but a few tributaries that support this group. This group occurs throughout lowlands of the interior west, including southwest warm and cool deserts and Mediterranean California, generally below about 1800 m (6000 feet) elevation. Known occurrences include the following rivers and their tributaries: Colorado, Gila, Pecos, Rio Grande, Sacramento, San Joaquin, Santa Cruz, Salt, San Pedro, Truckee, Snake and others.

Diagnostic Characteristics: This group is wide-ranging in the western U.S. and occurs in the warm desert regions (Sonoran and Mojave) of the southwestern U.S. and adjacent Mexico, Mediterranean California, and the cool desert interior in riparian corridors along perennial and seasonally intermittent streams and spring-fed depressions. Diagnostic tree species trees include Juglans major, Platanus racemosa, Platanus wrightii, Populus deltoides ssp. monilifera, Populus deltoides ssp. wislizeni, Populus fremontii, Salix amygdaloides, Salix laevigata, and Washingtonia filifera. Shrubs are rich and varied. Stands are always adjacent to streams or their floodplains and have been observed to follow narrow tributaries. Seasonal flooding and soil saturation by a rising water table are necessary to maintain growth and reproduction of vegetation.

Rationale for Nominal Species or Physiognomic Features:

Classification Comments: This group combines warm southwestern deserts with cool interior lower elevation rivers, and occurs from sea level, but does not include montane elevations.

Similar NVC Types:
G510 Interior West Ruderal Riparian Forest & Scrub, note:
G541 Warm Semi-Desert Shrub & Herb Dry Wash & Colluvial Slope, note:
G533 North American Warm Desert Riparian Low Bosque & Shrubland, note:

Physiognomy and Structure: Open to closed woodlands of tall cold-deciduous trees and shrubs, forming linear bands following stream and river courses and alluvial floodplains. Herbaceous undergrowth is variable depending on the amount of shading in the overstory.

Floristics: The vegetation is a mix of riparian woodlands dominated by trees and tall arborescent shrubs. Dominant trees include Acer macrophyllum, Acer negundo, Alnus rhombifolia, Alnus rubra, Celtis laevigata var. reticulata, Cephalanthus occidentalis, Fraxinus velutina, Juglans major, Platanus racemosa, Platanus wrightii, Populus deltoides ssp. wislizeni, Populus deltoides ssp. monilifera, Populus fremontii, Pseudotsuga menziesii, Quercus agrifolia, Quercus lobata, Salix amygdaloides, Salix gooddingii, Salix laevigata, Salix lasiolepis, Sapindus saponaria, and Washingtonia filifera. Shrub dominants include Alnus oblongifolia, Baccharis salicifolia, Prunus spp., Salix exigua, Salix geyeriana, Salix lasiolepis, and Vitis californica. Other dominants on serpentine substrates include Aquilegia eximia, Carex serratodens, Cirsium fontinale, Hesperocyparis sargentii (= Cupressus sargentii), Frangula californica ssp. tomentella (= Rhamnus tomentella), Mimulus glaucescens, Mimulus guttatus, Packera clevelandii (= Senecio clevelandii), Salix breweri, Solidago spp., Stachys albens, and Umbellularia californica. These are disturbance-driven systems that require flooding, scour and deposition for germination and maintenance. Exotic species that may be present include Ailanthus altissima, Eucalyptus spp., and Tamarix spp., and herbs such as Arundo donax.

Dynamics: Vegetation is dependent upon annual or periodic flooding and associated sediment scour and/or annual rise in the water table for growth and reproduction. Permanent subsurface water is required to maintain Washingtonia filifera. Salinity is low in the root zone, but increases near the surface where evaporation leaves salt accumulations. Reproduction of Washingtonia filifera is limited by water supply, surface salinity, rainfall, and fire. Fan palms are fire-tolerant, while the understory species are not, and fires open up the understory allowing palm seedlings to establish. Removal of the understory also decreases competition for water. There are currently 24 known occurrences of Washingtonia filifera in Arizona, Nevada, and California (Sawyer et al. 2009).

Environmental Description: Stands occur on streambanks and floodplains. The variety of plant associations within this group reflects elevation, stream gradient, floodplain width, and flooding events. It also includes springs, seeps, and perennial and intermittent streams on serpentine substrates.

Geographic Range: The group occurs throughout Mediterranean California, California's Central Valley, the southern Coast Ranges of Oregon, the lower valleys of Nevada and southern Idaho and the Colorado Plateau south into the canyons and desert valleys of the Sonoran and Mojave deserts of southwestern United States and adjacent Mexico. Specifically, it is known in California, southern Oregon, Nevada, Utah, Colorado, southern Arizona, New Mexico, adjacent Mexico (Baja California, Baja California del Sur, Chihuahua), and western Texas. Elevation ranges from sea level up to 1800 m.

Nations: MX, US

States/Provinces: AZ, CA, CO, ID, MXBC?, MXBS, MXCH, MXSO, NM, NV, OR, UT

Omernik Ecoregions: 1:P, 1a:P, 1i:P, 1j:P, 1k:P, 1l:P, 1m:P, 1n:P, 1o:P, 4:P, 4d:P, 4e:P, 4f:P, 4g:P, 4h:P, 5:P, 5a:P, 5b:P, 5c:P, 5d:P, 5e:P, 5f:P, 5g:P, 5h:P, 5i:P, 5j:P, 5l:P, 5m:P, 5n:P, 5o:P, 6:P, 6a:P, 6b:P, 6c:P, 6d:P, 6e:P, 6f:P, 6g:P, 6h:P, 6i:P, 6j:P, 6k:P, 6l:P, 6m:P, 6n:P, 6o:P, 6p:P, 6q:P, 6r:P, 6s:P, 6t:P, 6u:P, 6v:P, 6w:P, 6x:P, 6y:P, 6z:P, 6aa:P, 6ab:P, 6ac:P, 6ad:P, 6ae:P, 6af:P, 6ag:P, 6ah:P, 6ai:P, 6aj:P, 6ak:P, 6al:P, 6am:P, 6an:P, 6ao:P, 6ap:P, 6aq:P, 6ar:P, 7:P, 7a:P, 7b:P, 7c:P, 7d:P, 7f:P, 7g:P, 7h:P, 7j:P, 7k:P, 7l:P, 7m:P, 7n:P, 7o:P, 7p:P, 7q:P, 7r:P, 7s:P, 7t:P, 7u:P, 7v:P, 8:P, 8a:P, 8b:P, 8c:P, 8d:P, 8e:P, 8f:P, 8g:P, 9:P, 9g:P, 9k:P, 9l:P, 9n:P, 9o:P, 9r:P, 9t:P, 13:P, 13a:P, 13b:P, 13c:P, 13d:P, 13e:P, 13f:P, 13g:P, 13h:P, 13j:P, 13k:P, 13l:P, 13p:P, 13q:P, 13s:P, 13t:P, 13u:P, 13v:P, 13w:P, 13x:P, 13y:P, 13z:P, 13aa:P, 13ab:P, 13ac:P, 13ad:P, 13ae:P, 14:P, 14a:P, 14b:P, 14c:P, 14d:P, 14e:P, 14f:P, 14g:P, 14h:P, 14i:P, 14j:P, 14k:P, 14l:P, 14n:P, 14o:P, 14p:P, 19:P, 19f:P, 19g:P, 20:P, 20a:P, 20b:P, 20c:P, 20d:P, 20f:P, 20h:P, 20i:P, 21:P, 21c:P, 21d:P, 21f:P, 21h:P, 22:P, 22d:P, 22g:P, 22i:P, 22j:P, 22k:P, 22l:P, 22m:P, 22n:P, 22o:P, 22p:P, 22q:P, 22r:P, 22s:P, 22t:P, 22u:P, 22v:P, 22w:P, 22x:P, 22y:P, 22z:P, 22aa:P, 23:P, 23a:P, 23b:P, 23c:P, 23e:P, 23f:P, 23h:P, 23j:P, 23k:P, 23l:P, 24:P, 24a:P, 24b:P, 24c:P, 24d:P, 24e:P, 24f:P, 24g:P, 24h:P, 25:P, 25j:P, 25k:P, 26:P, 26h:P, 26q:P, 30:P, 30d:P, 31:P, 31b:P, 78:P, 78a:P, 78d:P, 78f:P, 78g:P, 78i:P, 78j:P, 78k:P, 78l:P, 78m:P, 78n:P, 78o:P, 78p:P, 78q:P, 78r:P, 79:P, 79a:P, 79b:P, 79c:P, 79e:P, 80:P, 80a:P, 80d:P, 80i:P, 80j:P, 81:P, 81a:P, 81b:P, 81c:P, 81d:P, 81e:P, 81f:P, 81g:P, 81h:P, 81i:P, 81j:P, 81k:P, 81l:P, 81m:P, 81n:P, 81o:P, 85:P, 85a:P, 85b:P, 85c:P, 85d:P, 85e:P, 85f:P, 85g:P, 85h:P, 85i:P, 85j:P, 85k:P, 85l:P, 85m:P

Plot Analysis Summary:

Confidence Level: Moderate

Confidence Level Comments:

Grank: GNR

Greasons:

Concept Lineage:

Predecessors:

Obsolete Names:

Obsolete Parents:

Synonomy: >< Quercus lobata (Valley oak woodland) Alliance (Sawyer et al. 2009) [71.040.00]
>< Arizona Cypress: 240 (Eyre 1980)
>< Cottonwood - Willow: 235 (Eyre 1980)
>< Port Orford-Cedar: 231 (Eyre 1980)
< Riparian Woodland (203) (Shiflet 1994) [Serpentine substrates are not specifically mentioned in Shiflet (1994).]

Concept Author(s): G. Kittel, P. Comer and T. Keeler-Wolf in Faber-Langendoen et al. (2015)

Author of Description: G. Kittel

Acknowledgements: Julie Evens, Todd Keeler-Wolf

Version Date: 29Sep2016

References:

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