Natural Resources
Conservation Service
Ecological site R030XY157CA
Sodic Flat 3-5" p.z.
Last updated: 3/10/2025
Accessed: 03/17/2025
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.
Classification relationships
California Natural Diversity Database, May 2002. List of California terrestrial natural communities recognized by the California Natural Diversity Database – Desert Bush Seepweed shrub.
Sawyer, J.O. and T. Keeler-Wolf. 1995. Manual of California Vegetation – Bush Seepweed Series.
Ecological site concept
This site occurs on nearly level lake plains. The soils that characterize this site are very deep and well drained. These soils are saline and sodic.
Please refer to group concept R030XB025CA to view the provisional STM.
Associated sites
| R030XY156CA |
Sodic Loam 3-5" p.z. Sodic Loam 3-5” P.Z. Occurs on alluvial flats. |
|---|
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Suaeda moquinii |
| Herbaceous |
Not specified |
Physiographic features
This site occurs on nearly level lake plains.
Table 2. Representative physiographic features
| Landforms |
(1)
Lake plain
|
|---|---|
| Flooding duration | Very brief (4 to 48 hours) |
| Flooding frequency | Very rare |
| Ponding duration | Very brief (4 to 48 hours) |
| Ponding frequency | Rare |
| Elevation | 2,580 – 2,800 ft |
| Slope | 2% |
| Ponding depth | 1 – 4 in |
| Water table depth | 60 in |
| Aspect | Aspect is not a significant factor |
Climatic features
The primary air masses affecting California are cold maritime polar air from the Gulf of Alaska and warmer, moist maritime subtropical air from lower latitudes. Occasionally there are invasions of cold continental polar air from northern Canada or the Rocky Mountains. Precipitation in the area results primarily from the passage of cyclones with associated fronts during fall, winter and spring; from closed cyclones in late winter and spring; and from the flow of moist tropical air from the southeast to the southwest quadrant in the summer.
Barstow Fire Station, occurs at a lower elevation and has a long-term record from 1980 to 2002. Twentynine Palms Station, occurs at a lower elevation and has a long-term record from 1948 to 2002. This climate summary is based on data from both locations. Warm, moist winters (35 to 70 degrees F) and hot, dry summers (60 to 105 degrees F) characterize the climate on this site. Mean annual air temperature is 65 to 70 degrees F. The average annual precipitation is 3 to 5 inches, with most falling as rain from December through March. Approximately 20 to 45% of the annual precipitation occurs from July to September as a result of intense, convection storms.
Table 3. Representative climatic features
| Frost-free period (average) | 340 days |
|---|---|
| Freeze-free period (average) | |
| Precipitation total (average) | 5 in |
Figure 1. Monthly average minimum and maximum temperature
Influencing water features
There are no influencing water features associated with this site.
Soil features
The soils that characterize this site are very deep and well drained. These soils are saline and sodic. Available water capacity is very low (due to salinity) and permeability is slow. Effective rooting depth is 60 inches ot more. Water tables are greater than 60 inches.
Soils:
6984702 Calcic Haplosalids-Sodic Haplocalcids complex, 2.8%. Calcic Haplosalids. Johnson Valley OHV Area Soil Survey.
6984730 Calcic Haplosalids-Sodic Haplocalcids-Typic Haplosalids complex, 0-2%. Calcic Haplosalids. Johnson Valley OHV Area Soil Survey.
Table 4. Representative soil features
| Surface texture |
(1) Silty clay loam (2) Sandy loam |
|---|---|
| Family particle size |
(1) Clayey |
| Drainage class | Well drained |
| Permeability class | Slow |
| Soil depth | 60 in |
| Surface fragment cover <=3" | 1 – 5% |
| Available water capacity (0-40in) |
0.3 – 0.6 in |
| Calcium carbonate equivalent (0-40in) |
5 – 15% |
| Electrical conductivity (0-40in) |
20 – 40 mmhos/cm |
| Sodium adsorption ratio (0-40in) |
35 – 160 |
| Soil reaction (1:1 water) (0-40in) |
8.6 – 9.2 |
| Subsurface fragment volume <=3" (Depth not specified) |
1 – 5% |
Ecological dynamics
Please refer to group concept R030XY129CA to view the provisional STM.
The interpretive plant community for this site is the historic climax plant community. This site occurs on dry lake beds which are intermittently flooded. The historic site potential is characterized by a low, open shrubland dominated by Mojave seablite (Suaeda moquinii). Few other species occur. Perennial grasses and forbs are scarce. Annuals are seasonally present. Potential vegetative composition is approximately 5% grasses, 5% forbs, and 90% shrubs. This site is stable in this condition.
This site is characterized by low productivity with little plant diversity. Disturbance would allow for the introduction of non-native annuals such as cheatgrass (Bromus tectorum) and Russian thistle (Salsola tragus).
State and transition model
More interactive model formats are also available.
View Interactive Models
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Ecosystem states
State 1 submodel, plant communities
State 1
Mojave seablite
Community 1.1
Mojave seablite
Figure 2. Sodic Flat
The interpretive plant community for this site is the historic climax plant community. This site occurs on dry lake beds which are intermittently flooded. The historic site potential is characterized by a low, open shrubland dominated by Mojave seablite (Suaeda moquinii). Few other species occur. Perennial grasses and forbs are scarce. Annuals are seasonally present. Potential vegetative composition is approximately 5% grasses, 5% forbs, and 90% shrubs. This site is stable in this condition. This list of plants and their relative proportions are based on near normal years. Fluctuations in species composition and relative production may change from year to year dependent upon abnormal precipitation or other climatic factors. The historic climax plant community has been determined by study of rangeland relict areas or other protected areas and historical accounts.
Figure 3. Annual production by plant type (representative values) or group (midpoint values)
Table 5. Annual production by plant type
| Plant type | Low (lb/acre) |
Representative value (lb/acre) |
High (lb/acre) |
|---|---|---|---|
| Shrub/Vine | 67 | 133 | 225 |
| Forb | 4 | 9 | 13 |
| Grass/Grasslike | 4 | 8 | 12 |
| Total | 75 | 150 | 250 |
Table 6. Ground cover
| Tree foliar cover | 0% |
|---|---|
| Shrub/vine/liana foliar cover | 1-5% |
| Grass/grasslike foliar cover | 1% |
| Forb foliar cover | 1% |
| Non-vascular plants | 0% |
| Biological crusts | 0% |
| Litter | 0% |
| Surface fragments >0.25" and <=3" | 0% |
| Surface fragments >3" | 0% |
| Bedrock | 0% |
| Water | 0% |
| Bare ground | 0% |
Table 7. Soil surface cover
| Tree basal cover | 0% |
|---|---|
| Shrub/vine/liana basal cover | 0% |
| Grass/grasslike basal cover | 0% |
| Forb basal cover | 0% |
| Non-vascular plants | 0% |
| Biological crusts | 0% |
| Litter | 5-10% |
| Surface fragments >0.25" and <=3" | 1-5% |
| Surface fragments >3" | 0% |
| Bedrock | 0% |
| Water | 0% |
| Bare ground | 70-90% |
Table 8. Canopy structure (% cover)
| Height Above Ground (ft) | Tree | Shrub/Vine | Grass/ Grasslike |
Forb |
|---|---|---|---|---|
| <0.5 | – | – | – | – |
| >0.5 <= 1 | – | – | 1-2% | – |
| >1 <= 2 | – | – | – | 1-2% |
| >2 <= 4.5 | – | 5-15% | – | – |
| >4.5 <= 13 | – | – | – | – |
| >13 <= 40 | – | – | – | – |
| >40 <= 80 | – | – | – | – |
| >80 <= 120 | – | – | – | – |
| >120 | – | – | – | – |
Figure 4. Plant community growth curve (percent production by month). CA3010, Mojave Seablite. Growth begins in early spring; flowering occurs from July to September..
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| J | F | M | A | M | J | J | A | S | O | N | D |
| 0 | 0 | 5 | 15 | 20 | 30 | 15 | 10 | 5 | 0 | 0 | 0 |
Additional community tables
Table 9. Community 1.1 plant community composition
| Group | Common name | Symbol | Scientific name | Annual production (lb/acre) | Foliar cover (%) | |
|---|---|---|---|---|---|---|
|
Grass/Grasslike
|
||||||
| 1 | Perennial grasses | 1–4 | ||||
| saltgrass | DISP | Distichlis spicata | 1–4 | – | ||
| 2 | Annual grasses | 1–4 | ||||
| Grass, annual | 2GA | Grass, annual | 1–4 | – | ||
|
Forb
|
||||||
| 3 | Perennial forbs | 1–10 | ||||
| Forb, perennial | 2FP | Forb, perennial | 1–10 | – | ||
| desert princesplume | STPI | Stanleya pinnata | 1–4 | – | ||
| 4 | Annual forbs | 1–4 | ||||
| Forb, annual | 2FA | Forb, annual | 1–3 | – | ||
|
Shrub/Vine
|
||||||
| 5 | Dominant shrubs | 155–203 | ||||
| Mojave seablite | SUMO | Suaeda moquinii | 155–203 | – | ||
| 6 | Other shrubs | 1–11 | ||||
| Shrub, evergreen | 2SE | Shrub, evergreen | 1–11 | – | ||
| fourwing saltbush | ATCA2 | Atriplex canescens | 1–5 | – | ||
| cattle saltbush | ATPO | Atriplex polycarpa | 1–5 | – | ||
Interpretations
Animal community
Grazing: This site has limited use for livestock grazing due to low productivity, unsuitable forage, and lack of stockwater. Mojave seablite is considered poor forage for livestock.
Wildlife: This site has low species diversity. Small mammals, coyotes, and black-tailed jackrabbits may occur. Common lizards include western whiptails. Common birds include horned larks and common ravens. Mojave seablite is used by Black-tailed jackrabbits, non-game birds and small mammals, but the degree of utilization is unknown. Shadscale is a desirable shrub for Black-tailed jackrabbits, non-game birds and small mammals.
Hydrological functions
Intermittent flooding occurs after convective summer storms.
Recreational uses
High off-road vehicle usage due to proximity to dry lake beds. Dry lake beds are prime locations for off-highway vehicle use and campsites.
Supporting information
Inventory data references
Line transects: 2 from 7/02 to 8/02 in San Bernardino, California.
NV-ECS:1 8/02 in San Bernardino, California.
Type locality
| Location 1: San Bernardino County, CA | |
|---|---|
| UTM zone | N |
| UTM northing | 3810192 |
| UTM easting | 540049 |
| Latitude | 34° 25′ 56″ |
| Longitude | 116° 33′ 50″ |
| General legal description | Melville Lake, Johnson Valley, California. Elevation 2755 feet. |
Other references
Hickman, J.C. (ed).1993. The Jepson Manual: Higher plants of California. University of California Press, Berkeley, CA.
U.S. Department of Agriculture, NRCS. National Range and Pasture Handbook, September 1997.
U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. 2002. Fire Effects Information System [Online] Available: http://www.fs.fed.us/database/feis/plants)
Western Regional Climate Center, Desert Research Institute, Reno, Nevada (http://www.wrcc.dri.edu/index.html)
Locator map image generated using TopoZone.com © 1999-2004 Maps a la carte, Inc. - All rights reserved.
Contributors
Patti Novak-Echenique, Heath M. McAllister
Approval
Kendra Moseley, 3/10/2025
Rangeland health reference sheet
Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.
| Author(s)/participant(s) | |
|---|---|
| Contact for lead author | |
| Date | 03/11/2025 |
| Approved by | Sarah Quistberg |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
-
Presence of water flow patterns:
-
Number and height of erosional pedestals or terracettes:
-
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
-
Number of gullies and erosion associated with gullies:
-
Extent of wind scoured, blowouts and/or depositional areas:
-
Amount of litter movement (describe size and distance expected to travel):
-
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
-
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
-
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
-
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
-
Functional/Structural Groups (list in order of descending dominance by above-ground annual-production or live foliar cover using symbols: >>, >, = to indicate much greater than, greater than, and equal to):
Dominant:
Sub-dominant:
Other:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
-
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
-
Potential invasive (including noxious) species (native and non-native). List species which BOTH characterize degraded states and have the potential to become a dominant or co-dominant species on the ecological site if their future establishment and growth is not actively controlled by management interventions. Species that become dominant for only one to several years (e.g., short-term response to drought or wildfire) are not invasive plants. Note that unlike other indicators, we are describing what is NOT expected in the reference state for the ecological site:
-
Perennial plant reproductive capability:
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