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Ecological site R030XY161CA
Gypsic Lake 5-7" p.z.
Last updated: 2/24/2025
Accessed: 08/09/2026
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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.
Ecological site concept
This site occurs on dry lake plains and lake terraces. Soils for this site are very deep, coarse-loamy soils derived from lacustrine deposits high in calcium. The entire basin of Mesquite Lake is affected by the limestone mountains surrounding the lakebed.
Please refer to group concept R030XB045CA to view the provisional STM.Associated sites
R030XB114NV SODIC LOAM 3-5 P.Z.
Occurs on adjacent dry lake plain areas.
R030XY160CA Gypsic Terrace 5-7" p.z.
Occurs on adjacent lake terraces with high gypsum soils.
R030XY163CA Loamy Lakeplain 5-7" p.z.
Occurs on adjacent hummock areas.
Similar sites
R030XY013NV SHALLOW SILTY
This site has higher shrub diversity and is lower producing.
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Atriplex confertifolia
Herbaceous Not specified
Physiographic features
This site occurs on dry lake plains and lake terraces.
Table 2. Representative physiographic features
Landforms (1) Lake plain
(2) Lake terrace
Flooding duration Extremely brief (0.1 to 4 hours) to very brief (4 to 48 hours) Flooding frequency Very rare to rare Ponding duration Very brief (4 to 48 hours) to brief (2 to 7 days) Ponding frequency Rare to occasional Elevation 1500 – 3000 ft Slope 0 – 2 % Ponding depth 0 – 1 in Water table depth 80 – 0 in Aspect Aspect is not a significant factor Climatic features
The Mojave Desert experiences clear, dry conditions for a majority of the year. Winter temperatures are mild, summer temperatures are hot, and seasonal and diurnal temperature fluctuations are large. Monthly minimum temperature averages range from 30 to 80 degrees F (-1 to 27 degrees C). Monthly maximum temperature averages range from 60 to 110 degrees F (16 to 43 degrees C) (CSU 2002).
Average annual rainfall is between 2 and 8 inches (50 to 205 millimeters) (USDA 2006). Snowfall is more common at elevations above 4000 feet (1220 meters), but it may not occur every year (WRCC 2002b). The Mojave Desert receives precipitation from two sources. Precipitation falls primarily in the winter as a result of storms originating in the northern Pacific Ocean. The Sierra Nevada and Transverse Ranges create a rain shadow effect, causing little precipitation to reach the Mojave Desert. Sporadic rainfall occurs during the summer as a result of convection storms formed when moisture from the Gulf of Mexico or Gulf of California moves into the region. Summer rainfall is more common and has a greater influence on soil moisture in the eastern Mojave Desert.
Windy conditions are also common in the Mojave Desert, particularly in the west and central Mojave Desert. Spring is typically the windiest season, with winds averaging 10-15 miles per hour (WRCC 2002a). Winds in excess of 25 miles per hour and gusts in excess of 50 miles per hour are not uncommon (CSU 2002).
In the BLM Grazing Allotments Soil Survey (Northeast Part of Mojave Desert Area, CA (CA805)), most areas receive approximately 5 to 7 inches of precipitation annually (WRCC 2002b). At elevations above 4000 feet (1370 meters), average annual precipitation in the form of rain may reach 8 inches or more, and average annual snowfall may reach up to 10 inches (WRCC 2002b).
The data from the following climate stations were used to describe the climate in the BLM Grazing Allotments Soil Survey (station number in parentheses):
Pahrump, NV (265890)
Mountain Pass, CA (045890)
Searchlight, NV (267369)
Red Rock Canyon State Park, NV (266691)
"Maximum monthly precipitation" represents average monthly precipitation at Pahrump, NV.Table 3 Representative climatic features
Frost-free period (average) 240 days Freeze-free period (average) 280 days Precipitation total (average) 10 in BarLineFigure 1. Monthly precipitation range
BarLineFigure 2. Monthly average minimum and maximum temperature
">Influencing water features
Soil features
Soils for this site are very deep, coarse-loamy soils derived from lacustrine deposits high in calcium. The entire basin of Mesquite Lake is affected by the limestone mountains surrounding the lakebed. Permeability is moderate to moderately rapid, and soils are moderately well to well drained. All surface and subsurface fragments are from gypsum crystals. These soils classify as Typic Calcigypsids. The playa and adjacent lake terraces act as sinks for calcium salts, i.e. calcium carbonate and gypsum (a calcium sulfate). Available water capacity is low to moderate.
Soil survey area - Map unit symbol - Component
CA805 - 4765 - Typic CalcigypsidsTable 4. Representative soil features
Surface texture (1) Gypsiferous sandy loam
Family particle size (1) Loamy
Drainage class Moderately well drained to well drained Permeability class Moderate to moderately rapid Soil depth 60 – 80 in Surface fragment cover <=3" 30 – 60 % Surface fragment cover >3" Not specified Available water capacity
(0-40in)2 – 6 in Calcium carbonate equivalent
(0-40in)5 – 20 % Electrical conductivity
(0-40in)0 – 8 mmhos/cm Sodium adsorption ratio
(0-40in)0 – 2 Soil reaction (1:1 water)
(0-40in)7.8 – 8.4 Subsurface fragment volume <=3"
(Depth not specified)45 – 90 % Subsurface fragment volume >3"
(Depth not specified)Not specified Ecological dynamics
Please refer to group concept R030XB045CA to view the provisional STM.
The dominant species on this ecological site is shadscale (Atriplex confertifolia). Shadscale often occurs in nearly pure stands (Stubbendieck et al. 2003), and is not known to have specific edaphic requirements (Simonin 2001). It occurs on both gypsum and non-gypsum substrates (Meyer 1986), and also on saline and alkaline soils (Hodgkinson 1987).
Gypsum is thought to affect plant growth more as a physical restriction rather than a chemical one, particularly at the seedling stage (Meyer 1986).The large amount of gypsum crystals on this ecosite make it difficult for many species to establish. A wide range of tolerance to different growing conditions (Simonin 2001) and its ability to root where large gypsum crystals are present (Groff 1997) may have facilitated growth of shadscale in this ecosite.
The dominance of shadscale on this ecosite may be related to its position in the landscape. Shadscale is thought to be less drought tolerant than other commonly associated species (Simonin 2001). This ecosite is at a low point in the landscape, and water drains to this position. Coupled with shadscale’s tolerance of the edaphic conditions at this location, this may encourage shadscale growth over that of other minor species on this ecosite.
Biological soil crusts—slow-growing complexes of fungi, lichen, moss, and cyanobacteria—may contribute up to 35% of the cover on this ecosite. They indicate site stability and recover slowly following disturbance (Belnap and Lange 2001). They moderate several processes that occur in the desert such as water and wind erosion (Belnap and others 2001). They act like a living mulch and slow evaporative water loss. They also affect soil fertility by increasing the available nitrogen in the soil. By occupying spaces between shrubs, biological soil crusts limit the establishment of invasive species that change disturbance regimes. The presence of biological soil crusts on this ecosite suggest that disturbance on this ecosite historically was not severe.
Wildfire has historically been rare in desert ecosystems due to low and widely spaced fuels. Red brome (Bromus rubens) and Mediterranean grass (Schismus arabicus) are present in small amounts on this ecosite. The high surface cover of gypsum crystals likely prevents rapid spread of these opportunistic species. However, the destruction of gypsum crystals by recreational vehicles, mining, or other disturbances will create bare soil surfaces in which these species may readily establish. Higher biomass production during years of high rainfall may create a more continuous, easily ignitable fuel source. Over time, sufficient biomass may build up and increase the risk that a fire will carry through the ecosite. Tamarisk (Tamarix ramosissima) is also present on this ecosite.State and transition model
More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective textEcosystem states
State 1 submodel, plant communities
State 1
ShadscaleCommunity 1.1
ShadscaleThe interpretive plant community is the reference plant community prior to European colonization.
This community is dominated by shadscale (Atriplex confertifolia). Other species present in small amounts are, iodine bush (Allenrolfea occidentalis), fourwing saltbush (Atriplex canescens), western honey mesquite (Prosopis glandulosa var. torreyana), desert princesplume (Stanleya pinnata), and Mojave seablite (Suaeda moquinii).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 97 195 290 Forb 3 5 10 Total 100 200 300 Table 6. Ground cover
Tree foliar cover 0% Shrub/vine/liana foliar cover 10-40% Grass/grasslike foliar cover 0-0% Forb foliar cover 0-0% Non-vascular plants 0% Biological crusts 10-40% Litter 0% Surface fragments >0.25" and <=3" 0-0% Surface fragments >3" 0% Bedrock 0% Water 0% Bare ground 50-90% Table 7. Canopy structure (% cover)
Height Above Ground (ft) Tree Shrub/Vine Grass/
GrasslikeForb <0.5 – 5-10% – – >0.5 <= 1 – 30-60% – – >1 <= 2 – 20-40% – 0-1% >2 <= 4.5 – – – – >4.5 <= 13 0-1% – – – >13 <= 40 – – – – >40 <= 80 – – – – >80 <= 120 – – – – >120 – – – – Additional community tables
Table 8. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Shrub/Vine1 Perennial Shrubs 97–290 shadscale saltbush ATCO Atriplex confertifolia 87–260 – fourwing saltbush ATCA2 Atriplex canescens 3–9 – Mojave seablite SUMO Suaeda moquinii 3–9 – iodinebush ALOC2 Allenrolfea occidentalis 2–6 – honey mesquite PRGL2 Prosopis glandulosa 1–3 – desert princesplume STPI Stanleya pinnata 1–3 – Forb2 annual forbs 3–10 Forb, annual 2FA Forb, annual 3–10 – Interpretations
Animal community
Shadscale is an important forage species for both wildlife (Howard 2003) and livestock (Sampson and Jesperson 1963). Animals feed on the foliage and fruit, particularly during the winter when other forage is scarce. Uncontrolled grazing may reduce cover, but spine-like branches limit utilization.
Hydrological functions
This ecological site occurs in low positions in the landscape, and water from adjacent areas will drain toward this area.
Recreational uses
Off-highway vehicle use occurs on this ecosite, the impacts of which may be severe. Cover of shadscale may be reduced by vehicle trampling. Gypsum crystals will likely be destroyed. The gypsum crystals on this site protect the surface soil structure, so destruction of this natural barrier will loosen the surface soil. The biological crusts that protect the soil surface are also fragile, easily damaged, and very slow to recover following a disturbance. Destruction of either soil surface stabilizer will likely lead to greater potential for wind erosion on this site.
Other products
Gypsum mining is planned for soils within this ecosite. Mining will destroy large areas of this site. There will be increased wind erosion from this area as the soil surface will be loose and large areas of soil will be exposed.
Supporting information
Inventory data references
Species composition of this ecosite was estimated in Spring and Fall 2005 using 3 Range Inventory Worksheets (NV-ECS-1) . Productivity was sampled on 29 June 2005 using one double-weight sampling transect (SCS Range 417) at the type locality.
Type locality
Location 1: San Bernardino County, CA UTM zone N UTM northing 3953178 UTM easting 627406 Latitude 35° 42′ 51″ Longitude 115° 35′ 29″ General legal description The type site is located near the center of Mesquite Lake. Other references
Belnap, J., J.H. Kaltenecker, R. Rosentreter, J. Williams, S. Leonard, D. Eldridge. 2001. Biological Soil Crusts: Ecology and Management. Technical Reference 1730-2. U.S. Department of the Interior, Bureau of Land Management and U.S. Geological Survey. Available: http://www.blm.gov/nstc/library/pdf/CrustManual.pdf. Accessed 5 October 2006.
Belnap, J. and O.L. Lange. 2001. Structure and functioning of biological soil crusts: a synthesis. In: Ecological Studies, Vol. 150. Belnap, J. and O.L. Lange (eds.). 2001. Biological Soil Crusts: Structure, Function, and Management. Springer-Verlag Berlin Heidelberg. pp. 471-479.
California State University (CSU) Desert Studies Center. 2002. Desert Climate. CSU Desert Studies Center, Soda Springs, CA. Online. http://biology.fullerton.edu/facilities/dsc/zz_climate.html. Accessed 28 November 2006.
Groff, Dale. 1997. Characteristics of gypsum soils in arid landscapes. Hortus West 8(1):10-52.
Meyer, S.E. 1986. The ecology of gypsophile endemism in the Eastern Mojave Desert. Ecology 67(5):1303-1313.
Rundel, P.W. and A.C. Gibson. 1996. Ecological communities and processes in a Mojave Desert ecosystem: Rock Valley, Nevada. Cambridge University Press, New York. 369pp.
Sampson, A.W. and B.S. Jesperson. 1963. California range brushlands and browse plants. Publication 4010. Division of Agriculture and Natural Resources, University of California.
Simonin, Kevin A. 2001. Atriplex confertifolia. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ [ 2006, November 15].
Stubbendieck, James, Stephan L. Hatch, and L. M. Landholt. 2003. North American Wildland Plants. A Field Guide. University of Nebraska Press, Lincoln, Nebraska. xiv + 501 pp.
United States Department of Agriculture (USDA), Natural Resources Conservation Service. 2006. Land Resource Regions and Major Land Resource Areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296.
Western Regional Climate Center (WRCC). 2002a. Average wind speeds by state (1992-2002). Desert Research Institute, Reno, NV. Online. http://www.wrcc.dri.edu/htmlfiles/westwind.final.html. Accessed 28 November 2006.
Western Regional Climate Center (WRCC). 2002b. Western U.S. Climate Historical Summaries [Online]. Desert Research Institute, Reno, NV. Online. http://www.wrcc.dri.edu/Climsum.html. Accessed 28 November 2006.
Locator map image generated using TopoZone.com © 1999-2004 Maps a la carte, Inc. - All rights reserved.
Contributors
Heath M. McAllister, Steven R. Perkins, Allison Tokunaga
Approval
Sarah Quistberg, 2/24/2025
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 08/09/2026 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
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Presence of water flow patterns:
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Number and height of erosional pedestals or terracettes:
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Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
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Number of gullies and erosion associated with gullies:
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Extent of wind scoured, blowouts and/or depositional areas:
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Amount of litter movement (describe size and distance expected to travel):
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Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
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Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
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Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
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Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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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:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
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Average percent litter cover (%) and depth ( in):
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Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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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:
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Perennial plant reproductive capability:
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