This ecological system includes extensive open-canopied shrublands of typically saline basins in the Mojave and Sonoran deserts. Stands most often occur around playas and in valley bottoms or basins where evapotranspiration results in saline soils. Substrates are generally fine-textured, saline soils. Vegetation is typically composed of one or more Atriplex species, such as Atriplex canescens or Atriplex polycarpa, along with other species of Atriplex. Species of Allenrolfea, Salicornia, Suaeda, Krascheninnikovia lanata, or other halophytic plants are often present to codominant. In some locations, scattered Yucca brevifolia may occur, but other Mojavean taxa are typically not present. Graminoid species may include Sporobolus airoides or Distichlis spicata at varying densities.
Source: NatureServe Explorer
Vegetation
Vegetation is typically composed of one or more Atriplex species, such as Atriplex polycarpa, Atriplex lentiformis, Atriplex parryi, Atriplex spinifera, Atriplex canescens or Atriplex confertifolia, which is more common in the Great Basin. Associates include of Allenrolfea occidentalis, Lycium andersonii, Salicornia spp., Suaeda spp., Krascheninnikovia lanata, or other halophytic plants that are often present to codominant. Ambrosia dumosa, Larrea tridentata, and other desert scrub may be present on less saline sites and in transitional zones. In some sandy locations, scattered Yucca brevifolia may occur, but other Mojavean taxa are typically not present. Graminoid species may include Sporobolus airoides or Distichlis spicata at varying densities. The floristic description is based on several references, including Brown (1982), MacMahon and Wagner (1985), Barbour and Major (1988), MacMahon (1988), Holland and Keil (1995), Reid et al. (1999), Comer et al. (2003), Thomas et al. (2004), Barbour et al. (2007), Keeler-Wolf (2007), and Sawyer et al. (2009).
Source: NatureServe Explorer
Environment
This ecological system includes extensive open-canopied shrublands in saline basins, near and around washes, lower bajadas and alluvial fans in the Mojave and Sonoran deserts. Stands most often occur around playas and in valley bottoms or basins where evapotranspiration results in saline soils. Substrates are generally fine-textured, saline soils. Adjacent systems include Sonora-Mojave Creosotebush-White Bursage Desert Scrub (CES302.756) and Sonoran Paloverde-Mixed Cacti Desert Scrub (CES302.761) above and North American Warm Desert Playa (CES302.751) below. The environmental description is based on several references, including Brown (1982), MacMahon and Wagner (1985), Barbour and Major (1988), MacMahon (1988), Holland and Keil (1995), Reid et al. (1999), Comer et al. (2003), Thomas et al. (2004), Barbour et al. (2007), Keeler-Wolf (2007), Sawyer et al. (2009), and NatureServe Explorer (2011).
Source: NatureServe Explorer
Dynamics
West (1982) stated that "salt desert shrub vegetation occurs mostly in two kinds of situations that promote soil salinity, alkalinity, or both. These are either at the bottom of drainages in enclosed basins or where marine shales outcrop." Species and communities are apparently sorted out along physical, chemical, moisture, and topographic gradients with Atriplex lentiformis being the most salt-tolerant, often occurring where the water table is close to the soil surface. It is followed by Atriplex polycarpa which has the broadest tolerance (5% salinity to non-saline soils). Atriplex canescens is the least salt-tolerant and often occurs on well-drained, sandy soil (Keeler-Wolf 2007). Atriplex confertifolia occurs on both saline bottomland and dry uplands.
Source: NatureServe Explorer
Threats
The primary land uses that alter the natural processes of this system are associated with livestock grazing and introduction of exotic annual grasses. Excessive grazing stresses the system through soil disturbance, diminishing or eliminating the biological soil crust, altering the composition of perennial species, and increasing the establishment of native disturbance-increasers and annual grasses, particularly Bromus rubens, Bromus madritensis, Bromus tectorum, Schismus spp., and other exotic annual grasses. The introduction of exotic annual grasses has altered many stands by increasing the amount of fine fuels present that can substantially increasing fire frequency and intensity, reducing the cover of fire-sensitive shrubs (Sawyer et al. 2009).
Human development has impacted many locations throughout the ecoregion. High- and low-density urban and industrial developments also have large impacts. For example, residential development has significantly impacted locations within commuting distance to urban areas. Impacts may be direct as vegetation is removed for building sites or more indirectly through natural fire regime alteration, and/or the introduction of invasive species. Mining operations can drastically impact natural vegetation. Road building and power transmission lines continue to fragment vegetation and provide vectors for invasive species.
Source: NatureServe Explorer
Distribution
This system is found in saline basins of the Mojave and Sonoran deserts.
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.
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.
At-Risk Species Associated with this Ecosystem (2)
Species with conservation concern that are ecologically associated with this ecosystem type. G-Rank indicates global conservation status: G1 (critically imperiled) through G5 (secure). ESA status indicates U.S. Endangered Species Act listing.
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.
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
NV
SNR
UT
SNR
Roadless Areas (2)
Inventoried Roadless Areas where this ecosystem is present, identified from LANDFIRE 2024 Existing Vegetation Type spatial analysis. Coverage indicates the proportion of each area occupied by this ecosystem type.
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.