Natural Resources
Conservation Service
Ecological site R030XY038CA
Flooded Gravelly Fans
Last updated: 10/21/2024
Accessed: 11/21/2024
General information
Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.
Figure 1. Mapped extent
Areas shown in blue indicate the maximum mapped extent of this ecological site. Other ecological sites likely occur within the highlighted areas. It is also possible for this ecological site to occur outside of highlighted areas if detailed soil survey has not been completed or recently updated.
MLRA notes
Major Land Resource Area (MLRA): 030X–Mojave Basin and Range
MLRA statement:
Major Land Resource Area (MLRA) 30, Mojave Desert, is found in southern California, southern Nevada, the extreme southwest corner of Utah and northwestern Arizona within the Basin and Range Province of the Intermontane Plateaus. The climate of the area is hot (primarily hyperthermic and thermic; however at higher elevations, generally above 5000 feet, mesic, cryic and frigid) and dry (aridic). Elevations range from below sea level to over 12,000 feet in the higher mountain areas found within the MLRA. Due to the extreme elevational range found within this MLRA, land resource units (LRUs) were designated to group the MLRA into similar land units.
LRU notes
"XY" LRU:
This LRU is found throughout the Mojave Desert MLRA. This LRU designation is set aside for ecological sites that are ubiquitous throughout the MLRA. These sites are driven by environmental or chemical features that override the climatic designations of the other LRU’s or are atypical compared to the surrounding landscape. Common overriding XY characteristics within this MLRA include: ephemeral streams subject to flash flood events, riparian areas or other water features, and soils with strong chemical influence (Na, Ca, etc).
Ecological site concept
This ecological site occurs on channeled, rarely flooded alluvial fans and fan aprons that are within the transitional zone between thermic and hyperthermic soil temperatures. This site has rare sheet flood events. Soils are very deep sands with very gravelly to extremely gravelly modifiers. Flooding, gravelly soils, a channeled topography, and a transitional climate support a diverse shrub mixture, co-dominated by Schott’s dalea (Psorothamnus schottii), creosote bush (Larrea tridentata) and desertsenna (Senna armata).
Data ranges in the physiographic data, climate data, water features, and soil data sections of this Ecological Site Description are based on major and minor components.
This site is part of provisional group concept R030XB103NV.
Associated sites
R030XB005NV |
Arid Active Alluvial Fans This ecological site is on adjacent fan remnants with thermic soil temperatures, creosote bush, burrobush, and Mojave yucca are present. |
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R030XB186CA |
Mid Size Thermic To Hyperthermic Ephemeral Stream This ephemeral stream is in drainageways with occasional to frequent flooding, and catclaw acacia is common. |
R030XD002CA |
Desert Pavement This is a hyperthermic desert pavement ecological site present on nearby stable fan remnants. |
R030XD015CA |
Hyper-Arid Fans This ecological site is on adjacent alluvial fans, which receive less intense flooding and creosote bush and burrobush are dominant. |
R030XY001CA |
Occasionally Flooded, Hyperthermic, Diffuse Ephemeral Stream This ephemeral stream is in drainageways and inset fans with occasional flooding and Schott's dalea and creosote bush are present. |
R030XY092NV |
DESERT PATINA This ecological site is on thermic desert pavement, on stable fan remnants with sparse creosote bush. |
Similar sites
R030XY001CA |
Occasionally Flooded, Hyperthermic, Diffuse Ephemeral Stream This ephemeral stream ecological site is in drainageways with occasional flooding, and lacks desertsenna and other species. |
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R030XY128CA |
Broad, Gravelly, Hyperthermic Ephemeral Stream This ecological site has a large braided drainageway with an active channel dominated by burrobrush. Desert lavender is common and smoketree is occasionally present. |
R030XB192CA |
Very Rarely Flooded, Warm Thermic Fan Piedmonts This flooded alluvial fan has more jojoba and Schott's dalea is absent. It is generally at higher elevations, with cooler temperatures. |
Table 1. Dominant plant species
Tree |
Not specified |
---|---|
Shrub |
(1) Larrea tridentata |
Herbaceous |
(1) Pectocarya recurvata |
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