Natural Resources
Conservation Service
Ecological site DX034A02X176
Very Shallow
Pinedale Plateau
(VS PP)
Last updated: 2/19/2025
Accessed: 05/31/2026
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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.
MLRA notes
Major Land Resource Area (MLRA): 034A–Cool Central Desertic Basins and Plateaus
Major Land Resource Area (MLRA) 34A, Cool Central Desertic Basins and Plateaus, consists of approximately 21 million acres in Wyoming, Colorado and Utah, it consists of 10 Land Resource Units (LRU). These units are divisions of the MLRA based on geology, landscape, common soils, water resources and plant community potentials. The elevation ranges from approximately 5600 feet (1700 m) along the Green River in UT and CO to approximately 9500 feet (2900 m) near Jeffrey City, WY. Annual precipitation ranges from 7 to 16 inches (177 to 406 mm), with the driest areas in the Green River and Great Divide Basins and the wettest areas in northern Carbon County, Southeast Fremont County and Albany County. There is a seasonal weather pattern that trends west to east, with more winter precipitation in the west and more spring/summer in the east, illustrated by diminishing amounts of Big Sagebrush in the eastern part of the MLRA.
LRU notes
The Pinedale Plateau LRU is in the upper Green River Drainage from Pinedale, Wyoming at the north working southward to Farson, Wyoming and easterly to South Pass, Wyoming. It is situated between the Wyoming Range and Wind River Range largely in Sublette County with some areas in Lincoln County, northern Sweetwater County, and a small portion of Fremont County. The total area of this LRU is approximately 1,210,000 acres. It shares a boundary with MLRA 46-Northern Rocky Mountain Foothills (proposed for the foothills of western Wyoming).
This LRU is dominated by the New Fork Tongue of the Wasatch formation, a large artesian aquifer that is estimated to hold large amounts of water with relatively quick recharge (Martin 1996). It is also home to the Lance Formation, a cretaceous strata that is part of the Mesaverde Group, which holds large amounts of hydrocarbons, giving way to one of the largest on shore natural gas fields (Jonah Field) (Bowker et al 2000). The soils in the Pinedale Plateau are dominated by older Alfisols with thick argillic and calcic horizons and younger deep alluvial soils along drainage ways and in river bottoms. Salts are not a major influence in the Pinedale Plateau compared to the adjacent Green River Basin LRU but do occur, including sodium, calcium carbonate, and other soluble salts. Soils are tied closely to their parent geology but are more developed and older so typically do not have bedrock contact within six feet.
This LRU has an aridic ustic soil moisture regime and frigid (bordering on cryic) soil temperature regime. The precipitation pattern is bimodal with a slight spikes in the spring and fall. Winter temperatures are cold allowing snow to accumulate and stay until spring. This lends perfectly to cool season grasses and forbs to flourish, also allowing big sagebrush to establish and dominate the landscape. The mean annual soil temperatures are between 36 to 40 degrees Fahrenheit (2.2 to 4.4 degrees Celsius) and average precipitation is between 9 and 12 inches (230 to 305 mm) annually. Elevations of this LRU range between 6500 and 7500 feet (1980 to 2280 m).Classification relationships
Relationship to Other Established Classification Systems
National Vegetation Classification System (NVC):
3 Semi-Desert
3.B.1 Cool Semi-Desert Scrub & Grassland
3.B.1.Ne Western North American Cool Semi-Desert Scrub & Grassland Division
M118 Intermountain Basins Cliff, Scree and Badland Sparse Vegetation Macrogroup
G570 Intermountain Basins Cliff, Scree and Badland Sparse Vegetation Group
A4052 Intermountain Shale Badlands Cold Desert Sparse Vegetation Alliance
CEGL001667 Pseudoroegnaria spicata/Eriogonum brevicaule Sparse Vegetation Association
Ecoregions (EPA):
Level I: 10 North American Deserts
Level II: 10.1 Cold Deserts
Level III: 10.1.4 Wyoming BasinEcological site concept
This site not does receive any additional water.
Soils:
o are not saline or saline-sodic
o are typically very shallow (less than 10 inches deep) to lithic or paralithic bedrock.
o are not strongly or violently effervescent in the surface mineral layer within top 10 inches (25 cm)
o have surface textures that usually range from fine sandy loam to clay loam in the top 4 inches (10 cm) surface mineral layer with clay content less than 35%
o have slopes that range from 15-45 percent
Climate:
aridic ustic moisture regime (ustic bordering on aridic)
frigid (bordering on cryic) temperature regimeAssociated sites
DX034A02X162 Shallow Loamy Pinedale Plateau (SwLy PP)
Soils are slightly deeper (shallow) with different species composition and higher plant production potential.
DX034A02X122 Loamy Pinedale Plateau (Ly PP)
Soils are deeper (moderately deep to deep) with different species composition and higher plant production potential.
DX034A02X150 Sandy Pinedale Plateau (Sy PP)
Soils are deeper (moderately deep to deep) with coarser soil surface textures (sandy loam) and higher plant production potential.
DX034A02X112 Gravelly Pinedale Plateau (Gr PP)
Soils are deeper (moderately deep to deep) with higher amounts of coarse fragments on the soil surface that are typically rounded (gravels) compared to angular (channers) on the Very Shallow site. The Gravelly site has different species composition and higher plant production potential.
Similar sites
R034AY276WY Very Shallow Foothills and Basins West (VS)
Previous version of this site, but applied to a larger geographic area.
R034AY176WY Very Shallow Green River and Great Divide Basins (VS)
Similar site with drier climate and lower plant production potential found in the adjacent Green River Basin LRU.
Table 1. Dominant plant species
Tree Not specified
Shrub Not specified
Herbaceous (1) Pseudoroegneria spicata
Legacy ID
R034AC176WY
Physiographic features
This site occurs in intermontane basin landscapes on hill, hillslope and ridge landforms (see following definitions). The slopes typically range from 15 to 45 percent, but can occur from 0 to greater than 60 percent. This site occurs on all aspects.
Landscape Definitions:
intermontane basin–A generic term for wide structural depressions between mountain ranges that are partly filled with alluvium and called "valleys" in the vernacular.
Landform Definitions:
hills -- A landscape dominated by hills and associated valleys. The landform term is singular (hill).
hillslope -- A generic term for the steeper part of a hill between its summit and the drainage line, valley flat, or depression floor at the base of the hill.
ridge -- A long, narrow elevation of the land surface, usually sharp crested with steep sides and forming an extended upland between valleys. The term is used in areas of both hill and mountain relief.Table 2. Representative physiographic features
Landforms (1) Intermontane basin > Hill
(2) Hillslope
(3) Ridge
Flooding frequency None Ponding frequency None Elevation 6500 – 7500 ft Slope 15 – 45 % Aspect Aspect is not a significant factor Climatic features
Annual precipitation ranges from 9 to 12 inches per year. Wide fluctuations may occur in yearly precipitation and result in more below average years than those with above average precipitation. Temperatures show a wide range between summer and winter and between daily maximums and minimums. This is predominantly due to the high elevation and dry air, which permits rapid incoming and outgoing radiation. Cold air outbreaks in winter move rapidly from northwest to southeast and account for extreme minimum temperatures. Much of the precipitation accumulation (45 percent) comes in the winter in the form of snow (October to April). The wettest month is May (1.69 inches). The dominant plants (sagebrush and cool season grasses) are well adapted to these conditions. Daytime winds are generally stronger than nighttime and occasional strong storms may bring brief periods of high winds with gusts to more than 50 miles per hour. The growing season is short (less than 60 day) and cool. Critical growth period: primary growth typically occurs between May and June.
Growth of native cool-season plants begins in April and continues to approximately early August. Some green-up of cool-season plants usually occurs in September with adequate fall moisture.
All data is based on the 30-year average from 1981-2010.Table 3 Representative climatic features
Frost-free period (characteristic range) 30-70 days Freeze-free period (characteristic range) 50-80 days Precipitation total (characteristic range) 10-10 in Frost-free period (actual range) 20-70 days Freeze-free period (actual range) 50-90 days Precipitation total (actual range) 10-10 in Frost-free period (average) 40 days Freeze-free period (average) 60 days Precipitation total (average) 10 in Characteristic rangeActual rangeBarLineFigure 1. Monthly precipitation range
Characteristic rangeActual rangeBarLineFigure 2. Monthly minimum temperature range
Characteristic rangeActual rangeBarLineFigure 3. Monthly maximum temperature range
BarLineFigure 4. Monthly average minimum and maximum temperature
Figure 5. Annual precipitation pattern
Figure 6 Annual average temperature pattern
Climate stations used
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(1) BOULDER REARING STN [USC00480951], Boulder, WY
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(2) CORA [USC00482054], Cora, WY
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(3) PINEDALE [USC00487260], Pinedale, WY
">Influencing water features
There are no influencing water features.
Wetland description
N/A
Soil features
The soils of this site are very shallow (less than 10 inches) and formed in slope alluvium, colluvium and residuum derived from interbedded sandstone and shale, sedimentary rock and siltstone. There is high variability, with areas of exposed bedrock as well as pockets of moderately deep soil, but the soil depth concept is shallow.
Surface and subsurface textures are fine sandy loam to light clay loam. Rock fragments are typically channery or flaggy (angular) and may be present at the surface with outcropping bedrock, increasing in volume with depth to lithic or paralithic contact. These soils are well-drained and have slow to moderate permeability.
The soil moisture regime is aridic ustic (ustic bordering on aridic) and the soil temperature regime is frigid bordering on cryic.
Major Soil Series correlated to this site include: Brickner and Polaris
Representative soil taxonomy:
Loamy-skeletal, mixed, superactive, frigid Lithic Haplustalfs
Loamy, mixed, superactive, frigid, shallow Aridic CalciusteptsTable 4. Representative soil features
Parent material (1) Slope alluvium – sandstone and shale
(2) Colluvium – sedimentary rock
(3) Residuum – sandstone and shale
(4) Slope alluvium – siltstone
Surface texture (1) Fine sandy loam
(2) Channery, very channery, flaggy sandy loam
(3) Gravelly loam
(4) Channery, very channery, flaggy sandy clay loam
Family particle size (1) Loamy-skeletal
Drainage class Well drained Permeability class Slow to moderate Depth to restrictive layer 4 – 10 in Soil depth 4 – 10 in Surface fragment cover <=3" 10 – 50 % Surface fragment cover >3" 0 – 5 % Available water capacity
(0-40in)0.8 – 2.4 in Calcium carbonate equivalent
(0-10in)0 – 10 % Electrical conductivity
(0-10in)0 – 2 mmhos/cm Sodium adsorption ratio
(0-10in)Not specified Soil reaction (1:1 water)
(0-10in)7.4 – 8.4 Subsurface fragment volume <=3"
(0-10in)0 – 40 % Subsurface fragment volume >3"
(0-10in)0 – 20 % Ecological dynamics
A State-and-Transition Model (STM) diagram is depicted in this section. Narrative descriptions of each state, transition, plant community phase, and pathway are found after the model in this document. This diagram is based on available experimental research, field observations, professional consensus, logical extrapolations, and interpretations. While based on the best available information, the STM will change over time as knowledge of ecological processes increases. Although there is considerable qualitative experience supporting the pathways and transitions within the State-and-Transition Model, no quantitative information exists that specifically identifies threshold parameters between reference states and degraded states in this ecological site. For information on STMs, see the following citations: Bestelmeyer et.al. 2003, Bestelmeyer et.al. 2004, Bestelmeyer and Brown 2005, Briske et.al. 2008, and Stringham et,al. 2003.
Plant community composition within the same ecological site has a natural range of variability across the LRU due to the naturally occurring variability in weather, soils, and aspect. The biological processes on this site are complex; therefore, representative values are presented in a land management context. The species lists are representative and are not botanical descriptions of all species occurring, or potentially occurring, on this site. They are not intended to cover every situation or the full range of conditions, species, and responses for the site.
Both percent species composition by weight and percent cover are used in this ESD. Most observers find it easier to visualize or estimate percent cover for woody species (trees and shrubs). Foliar cover is used to define plant community phases and states in the State-and-Transition Model. Cover drives the transitions between communities and states because of the influence of shade and interception of rainfall. Species composition by dry weight remains an important descriptor of the herbaceous community and of site productivity as a whole and includes both herbaceous and woody species. Calculating Similarity Index requires data on species composition by dry weight.
Not all managers will choose the Reference Plant Community as the management goal. Other plant communities may be desired to meet land management objectives. This is valid as long as the rangeland health attributes assessment departures are none to slight or slight to moderate from the Reference State as described in the Range Health Reference sheet.
A resource concern risk assessment and dominant resource concerns are provided for each Land Use, State, and Plant Community Phase based on NRCS resource concern and planning criteria used to determine resource treatment levels during the conservation planning process. A resource concern is a resource condition that does not meet the minimum accepted levels established by planning criteria as shown in Section III of the NRCS Field Office Technical Guide (https://efotg.sc.egov.usda.gov/#/).
• Low risk means a low probability for the category of resource concerns and additional assessment is typically not necessary.
• Medium risk means that the category of resource concerns could occur, and additional assessment is recommended if the identified resource is a client concern and/or objective.
• High risk means that a resource concern in that category is likely to occur.
The resource categories are: S (soil), W (water), A (air), P (plant), A (animal), E (energy), and H (human). The dominant resource concerns further refine the resource category to a specific resource concern within that category.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
SWAPAEHSWAPAEHT1A - Extreme soil disturbance or catastrophic drought State 1 submodel, plant communities
1.1A - Extreme drought 1.2A - Favorable weather conditions (above normal precipitation) State 2 submodel, plant communities
State 1
Reference
The Reference State consists of one plant community, the Bunchgrass/Mixed Shrub community. This plant community consists of bunchgrasses and a variety of shrub species. Tree species such as juniper or limber pine may be present as a minor component. Forbs are a minor component.
Characteristics and indicators. Dominant bunchgrasses include bluebunch wheatgrass and Indian ricegrass. Vegetation is sparse with high amounts of bare ground. The site can have a variety of shrubs depending on the surface geology and soil surface textures. It is very common to find pockets of deeper soil with bedrock outcropping and scattered shrubs and some trees such as juniper and limber pine. Even though vegetation is very sparse, individual plants may be quite robust as they have less competition for moisture captured in rock fissures. Because of the low amount of effective precipitation on the site, it is vulnerable to bunchgrass die-off events during extreme drought conditions.
Resilience management. This site has moderate resilience due to its aridic ustic (ustic bordering on aridic) soil moisture regime and frigid bordering on cryic temperature regime (Chambers et.al. 2014). Precipitation is typically low, but more effective with cooler temperatures and present when needed during the critical growth period (May through June). The site can usually recover after minor disturbance but is susceptible to delays in recovery during extreme climatic events such as drought. The site has moderately high resistance to invasion by annual grasses because of climate limitations (dry and cold). The site may be susceptible to invasion after extreme disturbance during warmer climatic periods or on southeast aspects and concave microtopography.
Dominant plant species
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bluebunch wheatgrass (Pseudoroegneria spicata), grass
Dominant resource concerns
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Sheet and rill erosion
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Wind erosion
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Classic gully erosion
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Terrestrial habitat for wildlife and invertebrates
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Inadequate livestock water quantity, quality, and distribution
Community 1.1
Bunchgrass and Mixed ShrubThis plant community is well adapted to the Cool Central Desertic Basins and Plateaus climatic conditions. The diversity in plant species allows for high drought resistance. This is a sustainable plant community, but is difficult to re-establish after extreme disturbance.
It is dominated by mid-size cool-season bunchgrasses such as bluebunch wheatgrass and Indian ricegrass. Shrub species are diverse and forbs are a minor component.Dominant plant species
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bluebunch wheatgrass (Pseudoroegneria spicata), grass
Figure 7. 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)Grass/Grasslike 110 193 275 Shrub/Vine 60 105 150 Forb 30 52 75 Total 200 350 500 Table 6. Soil surface cover
Tree basal cover 0% Shrub/vine/liana basal cover 0-0% Grass/grasslike basal cover 0-0% Forb basal cover 0-0% Non-vascular plants 0% Biological crusts 0-0% Litter 10-30% Surface fragments >0.25" and <=3" 10-50% Surface fragments >3" 0-10% Bedrock 0-10% Water 0% Bare ground 30-50% Figure 8. Plant community growth curve (percent production by month). WY34A02Xa , MLRA34A-Pinedale Plateau-all. Forage Production (herbaceous only) Developed by using the Rangeland Analysis Platform (RAP).
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec J F M A M J J A S O N D 1 5 15 24 25 18 9 3 Community 1.2
Rhizomatous Wheatgrass and Mat ForbThis plant community is adapted to the Cool Central Desertic Basins and Plateaus climatic conditions. This plant community is a result of severe drought that causes a die off of mid-size cool-season bunchgrasses. The stand is dominated by rhizomatous wheatgrass with a variety of mat-forming forbs such as short stem buckwheat (Eriogonum brevicaule), Hoods' phlox (Phlox hoodii), and stemless mock goldenweed (Stenotus acaulis).
Once favorable weather conditions return, the site typically shifts to bunchgrass dominance.
Total annual production ranges from 200 to 500 pounds per acre with a Representative Value (RV) of 350 pounds per acre.
Resilience management. The plant community is stable and protected from excessive erosion. The biotic integrity of this plant community is usually intact, however forage value will decrease and wildlife values will shift toward different species. The watershed is functioning.
Dominant plant species
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thickspike wheatgrass (Elymus lanceolatus ssp. lanceolatus), grass
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shortstem buckwheat (Eriogonum brevicaule), other herbaceous
Figure 9. Annual production by plant type (representative values) or group (midpoint values)
Table 7. Annual production by plant type
Plant type Low
(lb/acre)Representative value
(lb/acre)High
(lb/acre)Shrub/Vine 100 175 250 Grass/Grasslike 70 123 175 Forb 30 52 75 Total 200 350 500 Table 8. Soil surface cover
Tree basal cover 0% Shrub/vine/liana basal cover 0-0% Grass/grasslike basal cover 0-0% Forb basal cover 0-0% Non-vascular plants 0% Biological crusts 0-10% Litter 10-30% Surface fragments >0.25" and <=3" 10-50% Surface fragments >3" 0-10% Bedrock 0-10% Water 0% Bare ground 30-50% Figure 10. Plant community growth curve (percent production by month). WY34A02Xa , MLRA34A-Pinedale Plateau-all. Forage Production (herbaceous only) Developed by using the Rangeland Analysis Platform (RAP).
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec J F M A M J J A S O N D 1 5 15 24 25 18 9 3 Pathway 1.1A
Community 1.1 to 1.2Extreme drought causes a die-off of mid-sized, cool-season bunchgrasses. A temporary increase in herbivory due to drought and poor forage conditions may contribute the shift in dominance from bunchgrasses to rhizomatous grasses.
Context dependence.Drought conditions can be short-lived and extreme or moderate to severe and persistent.
Key drivers
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Precipitation (decadal scale)
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Wildlife grazing or browsing
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Livestock grazing or browsing
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Precipitation (annual scale)
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Temperature (annual scale)
Key ecosystem services affected
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Plant biodiversity
Pathway 1.2A
Community 1.2 to 1.1Favorable weather conditions (above average precipitation) contribute to dominance of mid-size cool-season bunchgrasses.
Context dependence.Favorable conditions must occur during spring and conditions must persist to provide adequate soil moisture throughout the early part of the growing season for adequate plant recovery. Conditions must persist into the following growing season for new seedling establishment. Average or below average temperatures during the growing season result in more effective precipitation. Improved forage conditions at a larger scale will reduce herbivory pressure, allowing for accelerated recovery. This site is not often grazed by livestock due to slope, but if livestock access the site, a prescribed grazing plan that allows for plant recovery is critical to this pathway.
Conservation practices
Prescribed Grazing Key drivers
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Precipitation (monthly scale)
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Wildlife grazing or browsing
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Temperature (monthly scale)
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Livestock grazing or browsing
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Precipitation (annual scale)
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Temperature (annual scale)
Key ecosystem services affected
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Wildlife habitat
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Plant biodiversity
State 2
ErodedThe Eroded State is a result of soil-disturbing activities outside of the normal disturbance regime expected for this site. Examples are high intensity hoof action, anthropogenic activity, rodent activity, or accelerated classic gully or sheet and rill erosion caused by catastrophic drought followed by high precipitation events. It may also occur with continuous season-long high intensity grazing that does not allow for adequate plant recovery.
Characteristics and indicators. There is a shift towards mat-forming and annual forbs, sheet and rill erosion increases, often leading to an increase in the occurrence of classic gullies. Bare ground will increase to levels exceeding 60 percent, and perennial plant cover and composition will decrease.
Resilience management. Site resilience is lower than the Reference State. Once accelerated soil erosion occurs, the site has limited potential to recover after disturbance. Annual weedy forbs and invasive grasses are more likely to invade after ground disturbing activities.
Dominant plant species
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stemless mock goldenweed (Stenotus acaulis), other herbaceous
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spiny phlox (Phlox hoodii), other herbaceous
Dominant resource concerns
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Sheet and rill erosion
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Wind erosion
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Classic gully erosion
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Plant productivity and health
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Plant structure and composition
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Plant pest pressure
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Terrestrial habitat for wildlife and invertebrates
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Feed and forage imbalance
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Inadequate livestock water quantity, quality, and distribution
Community 2.1
Mat Forb/Bare GroundThis plant community is composed of almost entirely mat-forming forbs with bare ground in excess of 50 percent.
The site is not well protected from erosion and Site Stability is Moderate or greater departure from the Reference State. Hydrologic Function is impaired with increased runoff. Biotic integrity is affected by the change in functional/structural group dominance.
It is not often practical or economically feasible to restore this plant community at the present time.
Total annual production ranges from 100 to 300 pounds per acre with a Representative Value (RV) of 200 pounds per acre.Dominant plant species
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stemless mock goldenweed (Stenotus acaulis), other herbaceous
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spiny phlox (Phlox hoodii), other herbaceous
Transition T1A
State 1 to 2Soil-disturbance outside of the normal disturbance regime expected for this site. Examples include high intensity hoof action, anthropogenic activity (e.g. mechanical disturbance), or rodent activity. Catastrophic drought may be a trigger for this transition.
Constraints to recovery.Soil erosion, persistent drought conditions, and herbivory pressure are constraints to recovery to the Reference State.
Context dependence.Warmer and drier climate trends contribute to uncertainty of restoration efforts. Steeper slopes will have more soil erosion and less likelihood of restoration once degraded.
Key drivers
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Precipitation (decadal scale)
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Temperature (decadal scale)
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Climate
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Mechanical soil disturbance
Key ecosystem services affected
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Erosion control
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Nutrient cycling
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Primary production
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Wildlife forage
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Water regulation
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Wildlife habitat
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Storm protection
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Plant biodiversity
Additional community tables
Table 9. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Perennial Mid-Size Cool Season Bunchgrasses 70–140 Montana wheatgrass ELAL7 Elymus albicans 0–140 0–30 bluebunch wheatgrass PSSP6 Pseudoroegneria spicata 18–140 5–30 Indian ricegrass ACHY Achnatherum hymenoides 18–140 5–30 Letterman's needlegrass ACLE9 Achnatherum lettermanii 4–70 1–10 needle and thread HECO26 Hesperostipa comata 0–35 0–10 squirreltail ELEL5 Elymus elymoides 0–35 0–10 slender wheatgrass ELTR7 Elymus trachycaulus 0–18 0–5 Sandberg bluegrass POSE Poa secunda 0–18 0–5 2 Rhizomatous Wheatgrasses 18–35 thickspike wheatgrass ELLAL Elymus lanceolatus ssp. lanceolatus 18–35 5–10 western wheatgrass PASM Pascopyrum smithii 18–35 5–10 3 Miscellaneous Grasses/Grasslikes 7–18 needleleaf sedge CADU6 Carex duriuscula 4–18 1–5 prairie Junegrass KOMA Koeleria macrantha 0–18 0–5 Sandberg bluegrass POSE Poa secunda 4–18 1–5 Grass, perennial 2GP Grass, perennial 0–18 0–5 plains reedgrass CAMO Calamagrostis montanensis 0–4 0–1 Forb4 Perennial Forbs 25–49 buckwheat ERIOG Eriogonum 4–18 1–5 spiny phlox PHHO Phlox hoodii 4–18 1–5 flowery phlox PHMU3 Phlox multiflora 0–11 0–3 flaxleaf plainsmustard SCLI Schoenocrambe linifolia 0–11 0–3 scarlet globemallow SPCO Sphaeralcea coccinea 0–11 0–3 chickensage SPHAE3 Sphaeromeria 0–11 0–3 stemless mock goldenweed STAC Stenotus acaulis 0–11 0–3 thrift mock goldenweed STAR10 Stenotus armerioides 0–11 0–3 hoary tansyaster MACA2 Machaeranthera canescens 0–11 0–3 bluebells MERTE Mertensia 0–11 0–3 locoweed OXYTR Oxytropis 0–11 0–3 beardtongue PENST Penstemon 0–11 0–3 tapertip hawksbeard CRAC2 Crepis acuminata 0–11 0–3 milkvetch ASTRA Astragalus 0–11 0–3 western yarrow ACMIO Achillea millefolium var. occidentalis 0–11 0–3 fleabane ERIGE2 Erigeron 0–11 0–3 onion ALLIU Allium 0–4 0–1 pussytoes ANTEN Antennaria 0–4 0–1 rockcress ARABI2 Arabis 0–4 0–1 sandwort ARENA Arenaria 0–4 0–1 sego lily CANU3 Calochortus nuttallii 0–4 0–1 Indian paintbrush CASTI2 Castilleja 0–4 0–1 Douglas' dustymaiden CHDO Chaenactis douglasii 0–4 0–1 pale bastard toadflax COUMP Comandra umbellata ssp. pallida 0–4 0–1 cryptantha CRYPT Cryptantha 0–4 0–1 larkspur DELPH Delphinium 0–4 0–1 phacelia PHACE Phacelia 0–4 0–1 evening primrose OENOT Oenothera 0–4 0–1 ballhead ipomopsis IPCO5 Ipomopsis congesta 0–4 0–1 flax LINUM Linum 0–4 0–1 desertparsley LOMAT Lomatium 0–4 0–1 Townsend daisy TOWNS Townsendia 0–4 0–1 clover TRIFO Trifolium 0–4 0–1 violet VIOLA Viola 0–4 0–1 deathcamas ZIGAD Zigadenus 0–4 0–1 Forb, perennial 2FP Forb, perennial 0–4 0–1 spearleaf stonecrop SELA Sedum lanceolatum 0–4 0–1 twinpod PHYSA2 Physaria 0–4 0–1 5 Annual Forbs 0–4 rockjasmine ANDRO3 Androsace 0–4 0–1 bushy bird's beak CORA5 Cordylanthus ramosus 0–4 0–1 cryptantha CRYPT Cryptantha 0–4 0–1 flatspine stickseed LAOC3 Lappula occidentalis 0–4 0–1 Forb, annual 2FA Forb, annual 0–4 0–1 Shrub/Vine6 Sagebrush 18–35 Wyoming big sagebrush ARTRW8 Artemisia tridentata ssp. wyomingensis 4–18 1–5 mountain big sagebrush ARTRV Artemisia tridentata ssp. vaseyana 0–18 0–5 little sagebrush ARARL Artemisia arbuscula ssp. longiloba 0–11 0–3 prairie sagewort ARFR4 Artemisia frigida 0–11 0–3 black sagebrush ARNO4 Artemisia nova 0–11 0–3 7 Miscellaneous Shrubs 35–70 alderleaf mountain mahogany CEMO2 Cercocarpus montanus 0–18 0–5 yellow rabbitbrush CHVI8 Chrysothamnus viscidiflorus 4–18 1–5 rubber rabbitbrush ERNA10 Ericameria nauseosa 0–18 0–5 Utah juniper JUOS Juniperus osteosperma 0–18 0–5 needlepod rush JUSC Juncus scirpoides 0–18 0–5 limber pine PIFL2 Pinus flexilis 0–18 0–5 greasewood SAVE4 Sarcobatus vermiculatus 0–11 0–3 spineless horsebrush TECA2 Tetradymia canescens 0–11 0–3 Nuttall's horsebrush TENU2 Tetradymia nuttallii 0–11 0–3 shortspine horsebrush TESP2 Tetradymia spinosa 0–11 0–3 winterfat KRLA2 Krascheninnikovia lanata 4–11 1–3 granite prickly phlox LIPU11 Linanthus pungens 4–11 1–3 plains pricklypear OPPO Opuntia polyacantha 0–4 0–1 bud sagebrush PIDE4 Picrothamnus desertorum 0–4 0–1 shadscale saltbush ATCO Atriplex confertifolia 0–4 0–1 Gardner's saltbush ATGA Atriplex gardneri 0–4 0–1 Shrub (>.5m) 2SHRUB Shrub (>.5m) 0–4 0–1 Table 10. Community 1.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 11. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
The following table lists initial suggested stocking rates for cattle under continuous season-long grazing under normal growing conditions with a harvest efficiency (HE) of 25 percent. These are conservative estimates that should be used only as guidelines in the initial stages of the conservation planning process. Often, the current plant composition does not entirely match any particular plant community described in this ecological site description. A field visit is required to document actual plant composition and production. More precise carrying capacity estimates, considering forage preference and accessibility (slope, distance to water, etc.), should be calculated using this information, particularly when grazers other than cattle are involved. Under more intensive grazing management, improved harvest efficiencies (up to 35 percent) can result in an increased carrying capacity, but recovery time for upland sites is much longer. If distribution problems occur, stocking rates should be reduced or facilitating conservation practices (i.e., cross-fencing, water development) implemented to maintain plant health and vigor.
Stocking rates are expressed in Animal Unit Months (AUMs) which is defined as the amount of forage consumed by a 1,000 pound cow with a less than 4 month old calf at her side.
Plant Community - Production (lb./ac Low-RV-High) - AUMS/ac - ac/AUM
1.1 Bunchgrass/Mixed Shrub 200-350-500 0.05 20
1.2 Rhizomatous wheatgrass/Mat Forb 200-350-500 0.03 33
2.1 Mat Forb/Bare Ground 100-200-300 0.02 50
* Continuous, season-long grazing by cattle under average growing conditions.
Calculation for stocking rates are as follows: Using Representative (RV) values for production, take forage palatable to grazing cattle and multiply by 0.25 Harvest Efficiency (HE) and divide by 912.5 pounds per AUM air-dry weight (ADW) to arrive at the initial suggested stocking rate in AUMs per acre.
Grazing by domestic livestock is one of the major income-producing industries in the area. Rangeland in this area may provide year-long forage for cattle, sheep, or horses. During the dormant period, the forage for livestock must be supplemented with protein because the quality does not meet minimum livestock requirements.
Distance to water, shrub density, and slope can affect grazing capacity within a management unit. Accessibility adjustments should be made for the planning area as necessary. For example, 30 percent of a management unit may have 25 percent slopes and distances of greater than one mile from water, resulting in a 50 percent reduction in grazing access; therefore, the adjustment is calculated for 30 percent of the unit (i.e. 50 percent reduction on 30 percent of the management unit). Fencing, slope length, management, access, terrain, kind and class of livestock, and breeds are all factors that can increase or decrease the percent of grazing access within a management unit. Adjustments should be made that incorporate these factors when calculating the carrying capacity of a management unit.
Wildlife:
Reference State:
1.1 Bunchgrass/Mixed Shrub: This community phase provides winter, transitional and summer habitat for mule deer, pronghorn and elk. Although this community makes up a small portion on the overall landscape, the site occurs within areas highly used by big game species, thus providing a diverse suite of herbaceous and shrub species important for micro-nutrient requirements for ungulates throughout the year. The area provides additional foraging resources for shrub steppe generalists, such as Vesper Sparrows and Horned Larks, but does not provide sufficient nesting cover or escape from predators.
1.2 Rhizomatous Wheatgrass/Mat Forb: This community is variable in its value to wildlife. Value is low for species dependent on a greater mixture of shrubs and mid-size cool season bunchgrasses. The area provides some foraging opportunities for shrub steppe generalists, but lacks structure to provide adequate cover and mat-forming forbs often occupy the space and nutrients needed for more desirable forbs.
Eroded State:
2.1 Mat Forb/Bareground: This community phase is highly variable in its value to wildlife. It typically is less diverse, has lower forage value and has limited to no structure that wildlife need for cover. This state is vulnerable to repeated disturbance which can result in a complete loss of value for wildlife. In addition, sites in this state are more susceptible to invasion of non-native species, further degrading the value for wildlife.Hydrological functions
Water is the principal factor limiting forage production on this site. This site is dominated by soils in hydrologic group B and C. Infiltration ranges from moderately slow to moderately rapid. Runoff potential for this site varies from moderate to high depending on soil hydrologic group and ground cover. In many cases, areas with greater than 75 percent ground cover have the greatest potential for high infiltration and lower runoff. Areas where ground cover is less than 50 percent have the greatest potential to have reduced infiltration and higher runoff (refer to Part 630, NRCS National Engineering Handbook for detailed hydrology information).
Rills and gullies may occur on steeper slopes, but gullies are rare and spaced appropriately for slope characteristics. Water flow patterns may be present but should be barely distinguishable. Pedestals are only slightly present in association with bunchgrasses. Litter typically falls in place, and signs of movement are not common. Chemical and physical crusts are rare to non-existent. Cryptogamic crusts are present, but only cover one to two percent of the soil surface.Recreational uses
This site provides hunting opportunities for upland game species. The wide variety of plants that bloom in the spring have an aesthetic value that appeals to recreationists.
Supporting information
Inventory data references
Information presented here has been derived from historic and recent clipping data and other inventory data. Field observations from range trained personnel were also used. Inventory Data Resources include: 4 National Resource Inventory (NRI) points (2011-2017) 4 Bureau of Land Management Assessment, Inventory, and Monitoring (BLM-AIM) points (2011-2018) - 3 points are duplicate of NRI 3 Tier I NRCS Ecological Site Inventory (NRCS-ESI) points (2004-2006) 1 BLM-ESI point (2017)
References
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. 2021 (Date accessed). USDA PLANTS Database. http://plants.usda.gov.
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1980. USNVC [United States National Vegetation Classification]. 2019. United States National Vegetation Classification Database, V2.03. Federal Geographic Data Committee, Vegetation Subcommittee, Washington DC.. USNVC: http://usnvc.org/.
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Aikens, E.O., M.J. Kauffman, J.A. Merkle, Dwinnell, G.A. Fralick, and K.L. Monteith. 2017. The greenscape shapes surfing of resource waves in a large migratory herbivor.. Ecology Letters 20:741–750.
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Bestelmeyer, B., J.R. Brown, K.M. Havstad, B. Alexander, G. Chavez, and J.E. Herrick. 2003. Development and Use of State and Transition Models for Rangelands. Jornal of Range Management 56:114–126.
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Bestelmeyer, B., J.R. Brown, J.E. Herrick, D.A. Trujillo, and K.M. Havstad. 2004. Land Management in the American Southwest: a state-and-transition approach to ecosystem
complexity. Environmental Management 34:38–51. -
Bestelmeyer, B. and J. Brown. 2005. State-and-Transition Models 101: A Fresh look at vegetation change.
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Bestelmeyer, B.T., K. Moseley, P.L. Shaver, H. Sanchez, D.D. Briske, and M.E. Fernandez-Gimenez. 2010. Practical guidance for developing state-and-transition models. Rangelands 32:23–30.
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Bowker, K.A. 2000. Jonah Field: A Shallow Sweetspot in the Basin-Centered Gas Accumulation of the Northern Green River Basin, Wyoming..
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Briske, D.D., B.T. Bestelmeyer, T.K. Stringham, and P.L. Shaver. 2008. Recommendations for Development of Resilience-Based State-and-Transition Models. Rangeland Ecology & Management 61:359–367.
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Chambers, J.C., J.L. Beck, T.J. Christiansen, K.J. Clause, J.B. Dinkins, K.E. Doherty, K.A. Griffin, D.W. Havlina, K.F. Henke, L.L. Kurth, J.D. Maestas, M. Manning, K.E. Mayer, B.A. Mealor, C. McCarthy, M.A. Perea, and D.A. Pyke. 2016. Using resilience and resistance concepts to manage threats to sagebrush ecosystems, Gunnison sage-grouse, and Greater sage-grouse in their eastern range: A strategic multi-scale approach.. Gen. Tech. Rep. RMRS-GTR-356.. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fort Collins, CO. 1–143.
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Miller, J.F., R.H. Frederick, and R.J. Tracey. 1973. “Precipitation-Frequency Atlas of the United States” NOAA Atlas 2, Volume 2 (Wyoming). National Weather Service, Silver Spring, Maryland.
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Schoeneberger, P.J. and D.A. Wysocki. 2017. Geomorphic Description
System, Version 5.0.. -
Stringham, T.K., W.C. Kreuger, and P.L. Shaver. 2003. State and Transition Modeling: an ecological process approach. Journal of Range Management 56:106–113.
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U. S. Environmental Protection Agency. 2010. Level III and IV ecoregions of the continental United States. U.S. EPA, National Health and Environmental Effects Research Laboratory, Corvallis, Oregon, U.S..
Other references
Site concept, plant community data, and interpretations are based on ecological site descriptions (ESDs) from MLRA 34A-Foothills and Basins West (10-14W).
This ESD replaces R034AY276WY Very Shallow MLRA 34A-Foothills and Basins West (VS 10-14W), but only within geographic extent of the Pinedale Plateau LRU.
Further data collection and ecological site refinement are ongoing until the ESD has reached "Approved" status.Contributors
Bryan Christensen
Karen J. ClauseApproval
Kirt Walstad, 2/19/2025
Acknowledgments
Sublette County Conservation District Wyoming Game and Fish Department
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 02/18/2025 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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