Natural Resources
Conservation Service
Ecological site R030XD006CA
Abandoned Fan
Accessed: 03/29/2024
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 Description:
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 Description:
This Land Resource Unit (designated by ‘XD’) is found on the eastern side of California. Elevations range from 400 to 2200 feet on average, but may be found up to 3600 feet on southern exposures. Precipitation ranges from 1 to 6 inches per year, but averages between 2-4 inches. This LRU is characterized primarily by the extreme aridity, hot temperatures, hyperthermic soil temperatures and low stature of widely spaced vegetation. Temperatures can reach over 110 degrees Fahrenheit for several weeks in July and August. Summer precipitation falls between July and September, ranging from 20-33% in the form of rain, and winter precipitation falls starting in November and ends between February and March, ranging from 56-70%, also mostly in the form of rain. Vegetation is primarily small, widely-spaced, low-producing creosote bush (Larrea tridentata), burrobush (Ambrosia dumosa), and brittlebush (Encelia farinosa).
Ecological Site Concept –
This ecological site occurs on gently sloping alluvial fans and fan aprons at elevations of 670 to 2620 feet. Soils are very deep, and are composed of layers of sand, coarse sand and loamy sand with varying amounts of gravel and cobbles. This ecological site tends to occupy distal fan positions, far from sources of run-on, and this site typically has no sheet-flow from flash-flooding events.
Production reference value (RV) is 67 pounds per acre, and ranges from 21 to 191 pounds per acre depending on annual precipitation and annual forb production. Vegetation is sparse, and dominated by low-statured creosote bush (Larrea tridentata). A hyperthermic climate with deep sandy soils with no additional run-on from sheet flooding drives the vegetation community of this ecological site. The deep-rooted creosote bush is the only shrub capable of tolerating the extremely arid conditions.
The data in the following sections is from major (15% of mapunit or greater) components only.
Classification relationships
Mojave Creosote Bush (Holland, 1986)
Larrea tridentata Shrubland Alliance (Sawyer et al. 2009).
Associated sites
R030XD039CA |
Coarse Gravelly Fans This ecological site is found on adjacent occasionally flooded alluvial fans. Creosote bush (Larrea tridenata), burrobush (Ambrosia dumosa) and brittlebush (Encelia farinosa) are dominant. |
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R030XD004CA |
Low-Production Hyperthermic Hills This ecological site is found on steep sideslopes of adjacent fan remnants. Sparse vegetation is dominated by creosote bush (Larrea tridentata). |
R030XD008CA |
Hyperthermic Sandhill This ecological site is found on adjacent sandhills. Big galleta (Pleuraphis rigida) and creosote bush (Larrea tridentata) are dominant. |
R030XD014CA |
Hyperthermic Sandy Plains This ecological site is found on adjacent semi-active sandsheets. Big galleta (Pleuraphis rigida) is dominant. |
R030XD015CA |
Hyper-Arid Fans This ecological site is found on adjacent fan aprons with rare surface flooding. Creosote bush (Larrea tridentata) and burrobush (Ambrosia dumosa) dominate. |
R030XD025CA |
Hyperthermic Sandsheets This ecological site is found on adjacent sandsheets. Creosote bush (Larrea tridentata) and big galleta (Pleuraphis rigida) dominate. |
R030XD042CA |
Hyperthermic Shallow To Moderately Deep Fan Remnants This ecological site is found on adjacent very stable fan remnants. Creosote bush (Larrea tridentata) is dominant. |
R030XY001CA |
Occasionally Flooded, Hyperthermic, Diffuse Ephemeral Stream This ecological site is found on adjacent occasionally flooded drainageways. Creosote bush (Larrea tridentata) and Schott's dalea (Psorothamnus schottii) dominate. |
R030XY092NV |
DESERT PATINA This ecological site is found on adjacent fan remnants with desert pavement surface. Very sparse vegetation is dominated by creosote bush (Larrea tridentata). |
Similar sites
R030XD042CA |
Hyperthermic Shallow To Moderately Deep Fan Remnants This ecological site occurs on very stable fan remnants with a high degree of soil horizon development. It has lower production and shrub density. |
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R030XD015CA |
Hyper-Arid Fans This ecological site occurs on landform positions receiving more surface flooding. This site is more productive, shrub density is higher, and burrobush (Ambrosia dumosa) is co-dominant with creosote bush (Larrea tridentata). |
Table 1. Dominant plant species
Tree |
Not specified |
---|---|
Shrub |
(1) Larrea tridentata |
Herbaceous |
(1) Plantago ovata |
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