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Warm Desert Dry Wash

EVT 9654North American Warm Desert Wash Shrubland

CES302.755GNRShrubRiparian

Summary

This ecological system is restricted to intermittently flooded washes or arroyos that dissect bajadas, mesas, plains and basin floors throughout the warm deserts of North America. Although often dry, the intermittent fluvial processes define this system, which are often associated with rapid sheet and gully flow. This system occurs as linear or braided strips within desert scrub-or desert grassland-dominated landscapes. The vegetation of desert washes is quite variable, ranging from sparse and patchy to moderately dense, and typically occurs along the banks, but may occur within the channel. The woody layer is typically intermittent to open and may be dominated by shrubs and small trees such as Acacia greggii, Brickellia laciniata, Baccharis sarothroides, Chilopsis linearis, Fallugia paradoxa, Hymenoclea salsola, Hymenoclea monogyra, Juglans microcarpa, Olneya tesota, Parkinsonia florida, Prosopis spp., Psorothamnus spinosus, Prunus fasciculata, Rhus microphylla, Salazaria mexicana, or Sarcobatus vermiculatus. Common upland shrubs such as Larrea tridentata and Ambrosia dumosa are often present along the edges of these washes. In Texas, woody species found in and adjacent to these washes include Acacia greggii, Baccharis salicifolia, Brickellia laciniata, Celtis laevigata var. reticulata, Chilopsis linearis, Dasylirion leiophyllum, Fallugia paradoxa, Fraxinus greggii, Juglans microcarpa, Juglans microcarpa, Leucaena retusa, Prosopis glandulosa, Rhus microphylla, and Salix gooddingii. Taller species may form a sparse canopy over the shorter shrubs. In addition, shrubs from the adjacent upland, such as Larrea tridentata, Viguiera stenoloba, Flourensia cernua, and Juniperus pinchotii may be commonly encountered.

Source: NatureServe Explorer

Vegetation

The vegetation of desert washes is typically characterized by an open layer of shrubs and small trees such as Acacia greggii, Brickellia laciniata, Baccharis sarothroides, Baccharis salicifolia, Chilopsis linearis, Dasylirion leiophyllum, Fallugia paradoxa, Fraxinus greggii, Hymenoclea salsola, Hymenoclea monogyra, Juglans microcarpa, Leucaena retusa, Olneya tesota, Parkinsonia florida, Prosopis spp., Psorothamnus spinosus, Prunus fasciculata, Rhus microphylla, Salazaria mexicana, or Sarcobatus vermiculatus. In addition, shrubs from the adjacent uplands may be commonly encountered. Vegetation cover ranges from sparse and patchy to moderately dense, and typically occurs along the banks, but may occur within the channel. Taller species may form a sparse canopy over the shorter shrubs.

Source: NatureServe Explorer

Environment

This ecological system is restricted to flashy, intermittently flooded, often dry washes and arroyos that dissect bajadas, mesas, plains and basin floors throughout the warm deserts of North America.

Source: NatureServe Explorer

Dynamics

Intermittent fluvial processes such as rapid sheet and gully flow define this system.

Source: NatureServe Explorer

Distribution

This system is restricted to intermittently flooded washes or arroyos that dissect bajadas, mesas, plains and basin floors throughout the warm deserts of North America.

Source: NatureServe Explorer

Ecologically Associated Plant Species

Plant species that characterize this ecosystem type, organized by vegetation stratum. These are species ecologically associated with the ecosystem, not confirmed present in any specific area.

Tree canopy

Chilopsis linearis, Juglans microcarpa, Olneya tesota, Parkinsonia florida, Prosopis glandulosa

Shrub/sapling (tall & short)

Acacia greggii, Baccharis sarothroides, Baccharis sergiloides, Fallugia paradoxa, Larrea tridentata, Pluchea sericea, Prunus fasciculata, Psorothamnus spinosus, Rhus microphylla, Salazaria mexicana, Sarcobatus vermiculatus

Short shrub/sapling

Ambrosia dumosa, Brickellia laciniata, Hymenoclea monogyra, Hymenoclea salsola

Source: NatureServe Ecological System assessment

Ecologically Associated Animals (5)

Animal species ecologically associated with this ecosystem type based on NatureServe assessment. These are species whose habitat requirements overlap with this ecosystem, not confirmed present in any specific roadless area.

Mammals (1)

Common Name	Scientific Name	G-Rank
Little Pocket Mouse	Perognathus longimembris	G5

Reptiles (3)

Common Name	Scientific Name	G-Rank
Zebra-tailed Lizard	Callisaurus draconoides	G5
Desert Horned Lizard	Phrynosoma platyrhinos	G4
Common Side-blotched Lizard	Uta stansburiana	G5

Amphibians (1)

Common Name	Scientific Name	G-Rank
Red-spotted Toad	Anaxyrus punctatus	G5

Source: NatureServe Ecological System assessment

Component Associations (79)

Plant community associations that occur within this ecological system. Associations are the finest level of the U.S. National Vegetation Classification (USNVC) and describe specific, repeating assemblages of plant species. Each association represents a distinct community type that may be found where this ecosystem occurs.

Name	G-Rank
Acacia greggii - (Ambrosia eriocentra, Salvia dorrii) Desert Wash Shrubland		NatureServe
Acacia greggii - Eriogonum fasciculatum Desert Wash Shrubland		NatureServe
Acacia greggii - Larrea tridentata - Hymenoclea salsola Desert Wash Shrubland		NatureServe
Acacia greggii - Parkinsonia microphylla Shrubland	G4	NatureServe
Acacia greggii - Prunus fasciculata Desert Wash Shrubland		NatureServe
Acacia greggii - Viguiera parishii Desert Wash Shrubland		NatureServe
Acacia greggii Wash Shrubland		NatureServe
Ambrosia eriocentra - Brickellia spp. Sparse Desert Wash		NatureServe
Baccharis emoryi Wet Shrubland		NatureServe
Baccharis salicifolia / Muhlenbergia rigens Wet Shrubland		NatureServe
Baccharis sarothroides - Baccharis salicifolia Wet Shrubland		NatureServe
Baccharis sarothroides - Parkinsonia microphylla Wet Shrubland		NatureServe
Baccharis sergiloides Wet Shrubland		NatureServe
Bebbia juncea Shrubland		NatureServe
Brickellia laciniata - Hymenoclea monogyra Shrubland		NatureServe
Brickellia longifolia Shrubland		NatureServe
Chilopsis linearis / (Ambrosia eriocentra, Salvia dorrii) Desert Wash Scrub		NatureServe
Chilopsis linearis / Brickellia laciniata Scrub		NatureServe
Chilopsis linearis / Ericameria paniculata Desert Wash Scrub		NatureServe
Chilopsis linearis / Hymenoclea salsola Desert Wash Scrub		NatureServe
Chilopsis linearis / Prunus fasciculata Desert Wash Scrub		NatureServe
Chilopsis linearis Shrubland		NatureServe
Encelia virginensis Shrubland		NatureServe
Ephedra californica - Hymenoclea salsola Desert Wash Shrubland		NatureServe
Ephedra trifurca Desert Wash Shrubland		NatureServe
Ericameria paniculata Desert Wash Shrubland		NatureServe
Ericameria paniculata - Hymenoclea salsola Desert Wash Shrubland		NatureServe
Eriogonum fasciculatum Desert Wash Shrubland		NatureServe
Fallugia paradoxa Colorado Plateau Desert Wash Shrubland		NatureServe
Fallugia paradoxa Grand Canyon Desert Wash Shrubland		NatureServe
Grayia spinosa - Lycium andersonii Shrubland	G5	NatureServe
Grayia spinosa - Lycium pallidum Shrubland	G5	NatureServe
Hymenoclea monogyra Thicket Shrubland		NatureServe
Hymenoclea salsola - (Ambrosia eriocentra) Shrubland		NatureServe
Hymenoclea salsola - Eriogonum fasciculatum Desert Wash Shrubland		NatureServe
Hymenoclea salsola - Larrea tridentata Desert Wash Shrubland		NatureServe
Hymenoclea salsola - Salazaria mexicana Shrubland		NatureServe
Hymenoclea salsola Wash Shrubland		NatureServe
Hyptis emoryi Shrubland		NatureServe
Isocoma acradenia Wet Shrubland		NatureServe
Juglans microcarpa / Cladium mariscus Flooded Scrub Woodland		NatureServe
Juglans microcarpa Scrub		NatureServe
Juglans microcarpa / Sorghastrum nutans Flooded Scrub Woodland		NatureServe
Keckiella antirrhinoides - Prunus fasciculata Desert Wash Shrubland		NatureServe
Larrea tridentata - Encelia farinosa - Bebbia juncea Desert Shrubland		NatureServe
Lepidospartum latisquamum Shrubland		NatureServe
Lepidospartum squamatum Wet Shrubland [Placeholder]
Panicum bulbosum - Alopecurus aequalis Grassland		NatureServe
Panicum bulbosum - Lycurus phleoides Grassland		NatureServe
Prosopis glandulosa / Atriplex canescens Ruderal Shrubland	GNA	NatureServe
Prosopis glandulosa - Atriplex spp. Shrubland		NatureServe
Prosopis glandulosa / Bouteloua curtipendula - Nassella leucotricha Woodland	G3	NatureServe
Prosopis glandulosa / Bouteloua eriopoda Ruderal Shrub Grassland	GNA	NatureServe
Prosopis glandulosa / Bouteloua gracilis Ruderal Shrubland	GNA	NatureServe
Prosopis glandulosa / Mixed Grasses Ruderal Shrubland		NatureServe
Prosopis glandulosa / Muhlenbergia porteri Ruderal Shrubland	GNA	NatureServe
Prosopis glandulosa / Sporobolus airoides Shrubland		NatureServe
Prosopis glandulosa var. glandulosa / Exotic Grass Ruderal Shrubland	GNA	NatureServe
Prosopis glandulosa var. torreyana Wet Scrub		NatureServe
Prosopis glandulosa Wet Scrub		NatureServe
Prosopis pubescens Wet Scrub		NatureServe
Prosopis velutina - Acacia greggii Ruderal Shrubland		NatureServe
Prosopis velutina / Celtis laevigata var. reticulata Wet Scrub		NatureServe
Prosopis velutina / Mimosa dysocarpa Ruderal Shrubland		NatureServe
Prunus eremophila Desert Wash Shrubland		NatureServe
Prunus fasciculata - Ambrosia eriocentra Desert Wash Shrubland		NatureServe
Prunus fasciculata - (Purshia stansburiana, Viguiera reticulata) Desert Wash Shrubland		NatureServe
Prunus fasciculata - Rhus trilobata Desert Wash Shrubland		NatureServe
Prunus fasciculata Shrubland		NatureServe
Psorothamnus fremontii - Ambrosia dumosa Desert Wash Shrubland		NatureServe
Psorothamnus spinosus / Acacia greggii - (Hyptis emoryi) Desert Wash Shrubland		NatureServe
Psorothamnus spinosus / Hymenoclea salsola - (Bebbia juncea, Ephedra californica) Desert Wash Scrub		NatureServe
Psorothamnus spinosus Shrubland		NatureServe
Rhus microphylla / Bouteloua curtipendula Shrubland	GNR	NatureServe
Salix gooddingii / Baccharis emoryi Riparian Woodland		NatureServe
Salvia dorrii Desert Wash Shrubland		NatureServe
Sapindus saponaria - Juglans major Scrub		NatureServe
Senna armata - Hymenoclea salsola Desert Wash Shrubland		NatureServe
Viguiera reticulata Shrubland		NatureServe

State Conservation Ranks (5)

Subnational conservation status ranks (S-ranks) assigned by Natural Heritage Programs in each state where this ecosystem occurs. S1 indicates critically imperiled at the state level, S2 imperiled, S3 vulnerable, S4 apparently secure, and S5 secure. An ecosystem may be globally secure but imperiled in specific states at the edge of its range.

State	S-Rank
AZ	SNR
CA	SNR
NM	SNR
NV	SNR
TX	SNR

Methodology and Data Sources

Ecosystem classification: Ecosystems are classified using the LANDFIRE 2024 Existing Vegetation Type (EVT) layer, mapped to NatureServe Terrestrial Ecological Systems via a curated crosswalk. Each EVT is linked to the USNVC (U.S. National Vegetation Classification) hierarchy through pixel-level co-occurrence analysis of LANDFIRE EVT and NatureServe IVC Group rasters across all roadless areas.

Vegetation coverage: Coverage percentages and hectares are derived from zonal statistics of the LANDFIRE 2024 EVT raster intersected with roadless area boundaries.

Ecosystem narratives and community species: Sourced from the NatureServe Explorer API, representing professional ecological assessments of vegetation composition, environmental setting, dynamics, threats, and characteristic species assemblages.

IVC hierarchy: The International Vegetation Classification hierarchy is sourced from the USNVC v3.0 Catalog, providing the full classification from Biome through Association levels.

Component associations: Plant community associations listed as components of each NatureServe Ecological System. Association data from the NatureServe Explorer API.

State ranks: Conservation status ranks assigned by NatureServe member programs in each state where the ecosystem occurs.