Print Report

A0947 Salix exigua Warm Desert Wet Shrubland Alliance

Type Concept Sentence: This alliance covers riparian shrublands of the warm deserts of the southwestern U.S. and adjacent Mexico dominated by Salix exigua. Sites are floodplains, gravel bars and sandbars without tree canopy shading. Stands occur on large braided sandy-bottom rivers and on smaller rockier tributaries.

Common (Translated Scientific) Name: Narrowleaf Willow Warm Desert Wet Shrubland Alliance

Colloquial Name: Narrowleaf Willow - Stretchberry Warm Desert Wet Shrubland

Hierarchy Level:  Alliance

Type Concept: This alliance covers riparian shrublands of the warm deserts of the southwestern U.S. and adjacent Mexico dominated by Salix exigua and/or Salix interior or intermediates between these two taxa. These shrublands are found on open sandbars without tree canopy shading, on larger, well-developed drainages and along larger sandy rivers, or on coarser-textured substrates. The canopy is dominated by a medium to tall (2-5 m) deciduous shrub that is typically many-branched with continuous cover of 60-100%. The herbaceous stratum has sparse to moderate cover, including a variety of pioneering species, such as Glycyrrhiza lepidota and Pascopyrum smithii.

Diagnostic Characteristics: Warm desert washes and riparian areas dominated by Salix exigua.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: No Data Available

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: The canopy is dominated by a tall (2-5 m), broad-leaved deciduous shrub that is typically many-branched with continuous cover of 60-100%. The herbaceous stratum is sparse to moderate cover, including a variety of pioneering species.

Floristics: These riparian shrublands are dominated by Salix exigua (= ssp. exigua var. exigua) (Dorn 1998). The tall-shrub layer has 15-90% cover, ranging in height between 2-5 m. Other willows can occur in the canopy, including Salix lasiolepis, Salix ligulifolia, and Salix monticola, along with Cephalanthus occidentalis, Rosa californica, Rubus armeniacus (= Rubus discolor), and Rubus ursinus. Occasionally, taller emergent trees may occur within the tree subcanopy, including Acer negundo, Alnus rhombifolia, Juglans hindsii, Populus fremontii, Salix gooddingii, Salix laevigata, and Salix lucida. The herbaceous layer varies greatly with as much as 20-35% cover of various graminoid species, including Carex nebrascensis, Carex pellita (= Carex lanuginosa), Equisetum arvense, Muhlenbergia rigens, Panicum bulbosum, Phalaris arundinacea, and Spartina pectinata, as well as a variety of pioneering species, such as Glycyrrhiza lepidota and Pascopyrum smithii (= Agropyron smithii). The forb cover is usually sparse. The understory can be dominated by barren ground or gravel bar.

Dynamics:  This alliance represents an early-seral, primary successional stage on newly deposited sediments that may persist under a regime of repeated fluvial disturbance. Salix exigua is highly adapted to most forms of disturbance and is a prolific sprouter that will reestablish on sites dominated by other disturbance associated species, such as Glycyrrhiza lepidota and Pascopyrum smithii.
Environmental Description:  Stands are associated with annual flooding and inundation and will grow well into the active channel, where it is flooded, even in drier years. Even though flooding is frequent, surface water may not be present for much of the growing season, and the water table is well below the surface. Some stands form large, wide stands on mid-channel islands on larger rivers, or narrow stringer bands on small, rocky tributaries. Stream reaches range widely from moderately sinuous and moderate-gradient reaches to broad, meandering rivers with wide floodplains or broad, braided channels. Many stands also occur within highly entrenched or eroding gullies. Soils of this alliance are typically coarse alluvial deposits of sand, silt and cobbles that are highly stratified with depth from flooding scour and deposition. The stratified profiles consist of alternating layers of clay loam and organic material with coarser sand or thin layers of sandy loam over very coarse alluvium. Occasionally, stands may occur on deep pockets of sand.
Geographic Range: This alliance is found in California, Arizona, New Mexico, Texas, and Mexico.

Nations: MX,US

States/Provinces:  AZ, CA, MXCHH, MXCOA, MXNLE, MXTAM, NM, NV, TX


Confidence Level: Low

Confidence Level Comments: No Data Available
Grank: GNR

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.Nc Southwestern North American Warm Desert Freshwater Marsh & Bosque Division D032 2.C.4.Nc
Macrogroup 2.C.4.Nc.1 Warm Desert Lowland Freshwater Marsh, Wet Meadow & Shrubland Macrogroup M076 2.C.4.Nc.1
Group 2.C.4.Nc.1.b Honey Mesquite - Velvet Mesquite - False Willow species North American Warm Desert Riparian Low Bosque & Shrubland Group G533 2.C.4.Nc.1.b
Alliance A0947 Narrowleaf Willow Warm Desert Wet Shrubland Alliance A0947 2.C.4.Nc.1.b
Association CEGL004115 Subtropical Common Reed Riverbank Wet Meadow CEGL004115 2.C.4.Nc.1.b
Association CEGL005655 Narrowleaf Willow / Barren Warm Desert Wet Shrubland CEGL005655 2.C.4.Nc.1.b
Association CEGL007753 Sandbar Willow / Subtropical Common Reed Wet Shrubland CEGL007753 2.C.4.Nc.1.b
Concept Lineage: A.974 with edits

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: < Salix exigua (Sandbar willow thickets) Alliance (Sawyer et al. 2009) [61.209.00]
= Salix exigua Alliance (Sandbar willow thickets) (Buck-Diaz et al. 2012)
= Salix exigua Shrubland Alliance (Keeler-Wolf and Evens 2006)
= Salix exigua Shrubland Alliance (Evens et al. 2014)
? Plains and Great Basin Riparian Wetlands (Brown 1982a)
Concept Author(s): D. Culver, G. Kittel and A. Klein, in Faber-Langendoen et al. (2013)

Author of Description: G. Kittel

Acknowledgements: No Data Available

Version Date: 09-26-14
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