Natural Resources
Conservation Service
Ecological site R034AY263WY
Shallow Loamy Calcareous
Foothills and Basins West (SwLyCa)
Accessed: 05/30/2026
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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.
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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.
Associated sites
R034AY204WY Clayey Foothills and Basins West (Cy)
Clayey
R034AY212WY Gravelly Foothills and Basins West (Gr)
Gravelly
R034AY222WY Loamy Foothills and Basins West (Ly)
Loamy
R034AY250WY Sandy Foothills and Basins West (Sy)
Sandy
R034AY262WY Shallow Loamy Foothills and Basins West (SwLy)
Shallow Loamy
Similar sites
R034AY262WY Shallow Loamy Foothills and Basins West (SwLy)
Shallow Loamy (SwLy) 10-14 West has higher production, and has no or incidental amounts of Black Sage.
Table 1. Dominant plant species
Tree Not specified
Shrub Not specified
Herbaceous Not specified
Physiographic features
This site will usually occur in an upland position on rolling to steep slopes (averaging 2 to 15%) on all exposures. Elevations are mostly above 7000 feet.
Table 2. Representative physiographic features
Landforms (1) Alluvial fan
(2) Stream terrace
(3) Ridge
Flooding frequency None Ponding frequency None Elevation 6500 – 7500 ft Slope 0 – 30 % Aspect Aspect is not a significant factor Climatic features
Annual precipitation ranges from 10-14 inches per year. Wide fluctuations may occur in yearly precipitation and result in more dry years than those with more than normal 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. Extreme storms may occur during the winter, but most severely affect ranch operations during late winter and spring.
Daytime winds are generally stronger than nighttime and occasional strong storms may bring brief periods of high winds with gusts to more than 50 mph.
Growth of native cool season plants begins about April 15 and continues to about August 15. Some green up of cool season plants usually occurs in September depending upon fall moisture occurrences.
For detailed information visit the Natural Resources Conservation Service National Water and Climate Center at http://www.wcc.nrcs.usda.gov/cgibin/state.pl?state=wy website. Other climate stations representative of this precipitation zone include ”Border 3 N ” and Kemmerer Wtr Trtmt” in Lincoln County; “Evanston 1 E” in Uinta County; and “Merna” in Sublette County.Table 3 Representative climatic features
Frost-free period (average) 70 days Freeze-free period (average) 100 days Precipitation total (average) 10 in BarLineFigure 2. Monthly precipitation range
BarLineFigure 3. Monthly average minimum and maximum temperature
">Influencing water features
No water features are associated with this site.
Soil features
The soils of this site are moderately deep to deep with root growth restricted by high amounts of lime or coarse fragments at 10 to 20 inches depth. Parent material is residuum. colluvium and alluvium from sedimentary rock.
Table 4. Representative soil features
Surface texture (1) Loam
(2) Clay loam
(3) Sandy loam
Family particle size (1) Loamy
Drainage class Well drained to somewhat excessively drained Permeability class Moderately slow to moderately rapid Soil depth 10 – 20 in Surface fragment cover <=3" 0 – 20 % Surface fragment cover >3" 0 – 15 % Available water capacity
(0-40in)1 – 2.5 in Calcium carbonate equivalent
(0-40in)15 – 25 % Electrical conductivity
(0-40in)0 – 8 mmhos/cm Sodium adsorption ratio
(0-40in)0 – 5 Soil reaction (1:1 water)
(0-40in)6.6 – 8.4 Subsurface fragment volume <=3"
(Depth not specified)0 – 30 % Subsurface fragment volume >3"
(Depth not specified)0 – 20 % Ecological dynamics
As this site deteriorates because of a combination of frequent and severe grazing, species such as unpalatable forbs and green rabbitbrush will increase. Cool-season grasses such as bluebunch wheatgrass and Indian ricegrass will decrease in frequency and production.
These plant communities may not represent every possibility, but they probably are the most prevalent and repeatable plant communities. The plant composition tables shown above have been developed from the best available knowledge at the time of this revision. As more data is collected, some of these plant communities may be revised or removed, and new ones may be added. None of these plant communities should necessarily be thought of as “Desired Plant Communities”. According to the USDA NRCS National Range and Pasture Handbook, Desired Plant Communities (DPC’s) will be determined by the decision-makers and will meet minimum quality criteria established by the NRCS. The main purpose for including any description of a plant community here is to capture the current knowledge and experience at the time of this revision.
The Historic Climax Plant Community (description follows the plant community diagram) has been determined by study of rangeland relic areas, or areas protected from excessive disturbance. Trends in plant communities going from heavily grazed areas to lightly grazed areas, seasonal use pastures, and historical accounts have also been used.
The following is a State and Transition Model Diagram that illustrates the common plant communities (states) that can occur on the site and the transitions between these communities. The ecological processes will be discussed in more detail in the plant community narratives following the diagram.
State and transition model
Custom diagramStandard diagram
More interactive model formats are also available. View Interactive Models
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 2 submodel, plant communities
State 3 submodel, plant communities
State 1
Bluebunch Wheatgrass/Black Sage Plant Community (HCPC)Community 1.1
Bluebunch Wheatgrass/Black Sage Plant Community (HCPC)The interpretive plant community for this site is the Historic Climax Plant Community. Potential vegetation is about 75% grasses or grass-like plants, 10% forbs, and 15% woody plants. The major grasses include bluebunch wheatgrass, rhizomatous wheatgrass, Indian ricegrass, needleandthread, and bottlebrush squirreltail. Other grasses include Canby, mutton, and Sandberg bluegrass, Letterman needlegrass, needleleaf sedge, plains reedgrass, and prairie junegrass. Black sagebrush is the major woody plant. Other woody plants include Wyoming big, low, and early sagebrush, green rabbitbrush, and winterfat.
A typical plant composition for this state consists of bluebunch wheatgrass 10-25%, rhizomatous wheatgrass 10-25%, needleandthread 5-15%, Indian ricegrass 5-15%, bottlebrush squirreltail 5-10%, other grasses and grass-like plants 10-20%, perennial forbs 5-10%, up to 10% black sagebrush, and 5-15% other woody species. Ground cover, by ocular estimate, varies greatly depending on the amount of exposed parent material, and herbage cover ranges from 15-30%.
The total annual production (air-dry weight) of this state is about 700 lbs./acre, but it can range from about 500 lbs./acre in unfavorable years to about 900 lbs./acre in above average years.
This plant community is extremely stable and well adapted to the Cool Central Desertic Basins and Plateaus climatic conditions. The diversity in plant species allows for high drought tolerance. This is a sustainable plant community (site/soil stability, watershed function, and biologic integrity).
Transitions or pathways leading to other plant communities are as follows:
• Heavy Continuous Season-long Grazing will convert this plant community to the Black Sage/Forb State.
• Wildfire followed by Continuous Season-long Grazing will convert this plant community to the Rhizomatous Wheatgrass/Forb State.Figure 4. Annual production by plant type (representative values) or group (midpoint values)
Figure 5. Plant community growth curve (percent production by month). WY0301 , 34AC, Upland Sites. All Upland Sites.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec J F M A M J J A S O N D 5 40 50 5 State 2
Black Sage/Forb Plant CommunityCommunity 2.1
Black Sage/Forb Plant CommunityThis plant community is the result of frequent and severe grazing. Black and Wyoming big sagebrush dominate this plant community with annual production often exceeding 55%. Forbs dominate the understory.
The total annual production (air-dry weight) of this state is about 300 pounds per acre, but it can range from about 100 lbs./acre in unfavorable years to about 500 lbs./acre in above average years.
Soil erosion is accelerated because of increased bare ground. The biotic community has been compromised, but is relatively stable. The watershed is functioning, but is at risk of further degradation. Water flow patterns and pedestals are obvious. Infiltration is reduced and runoff is increased.
Transitions or pathways leading to other plant communities are as follows:
• Prescribed Grazing will return this state to near Historic Climax Plant Community (Bluebunch Wheatgrass/Black Sage State).
Figure 6. Plant community growth curve (percent production by month). WY0301 , 34AC, Upland Sites. All Upland Sites.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec J F M A M J J A S O N D 5 40 50 5 State 3
Rhizomatous Wheatgrass/Forb Plant CommunityCommunity 3.1
Rhizomatous Wheatgrass/Forb Plant CommunityThis plant community is a result of wildfire followed by improper grazing. Dominant grasses include rhizomatous wheatgrass, bottlebrush squirreltail, and Sandberg bluegrass. A variety of forbs flourish and thistles invade.
The total annual production (air-dry weight) of this state is about 150 pounds per acre, but it can range from about 50 lbs./acre in unfavorable years to about 350 lbs./acre in above average years.
The state is unstable and is not protected from excessive erosion. The biotic integrity of this plant community is not intact. This state is at risk depending on how far a shift has occurred toward cheatgrass and/or bare ground. The watershed is not functioning.
Transitions or pathways leading to other plant communities are as follows:
• Prescribed Grazing will return this state to near Historic Climax Plant Community (Bluebunch Wheatgrass/Black Sage State).
Figure 7. Plant community growth curve (percent production by month). WY0301 , 34AC, Upland Sites. All Upland Sites.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec J F M A M J J A S O N D 5 40 50 5 Additional community tables
Table 5. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 70–175 bluebunch wheatgrass PSSP6 Pseudoroegneria spicata 70–175 – 2 70–175 western wheatgrass PASM Pascopyrum smithii 70–175 – 3 35–105 needle and thread HECO26 Hesperostipa comata 35–105 – 4 35–105 Indian ricegrass ACHY Achnatherum hymenoides 35–105 – 5 35–70 squirreltail ELEL5 Elymus elymoides 35–70 – 6 70–140 Grass, perennial 2GP Grass, perennial 0–35 – Letterman's needlegrass ACLE9 Achnatherum lettermanii 0–35 – needleleaf sedge CADU6 Carex duriuscula 0–35 – plains reedgrass CAMO Calamagrostis montanensis 0–35 – prairie Junegrass KOMA Koeleria macrantha 0–35 – muttongrass POFE Poa fendleriana 0–35 – Sandberg bluegrass POSE Poa secunda 0–35 – Forb7 35–70 Forb, perennial 2FP Forb, perennial 0–35 – yarrow ACHIL Achillea 0–35 – rosy pussytoes ANRO2 Antennaria rosea 0–35 – milkvetch ASTRA Astragalus 0–35 – Indian paintbrush CASTI2 Castilleja 0–35 – mouse-ear chickweed CERAS Cerastium 0–35 – tapertip hawksbeard CRAC2 Crepis acuminata 0–35 – fleabane ERIGE2 Erigeron 0–35 – buckwheat ERIOG Eriogonum 0–35 – aster EUCEP2 Eucephalus 0–35 – flax LINUM Linum 0–35 – granite prickly phlox LIPU11 Linanthus pungens 0–35 – stoneseed LITHO3 Lithospermum 0–35 – bluebells MERTE Mertensia 0–35 – nailwort PARON Paronychia 0–35 – beardtongue PENST Penstemon 0–35 – phacelia PHACE Phacelia 0–35 – spiny phlox PHHO Phlox hoodii 0–35 – stonecrop SEDUM Sedum 0–35 – stemless mock goldenweed STAC Stenotus acaulis 0–35 – princesplume STANL Stanleya 0–35 – clover TRIFO Trifolium 0–35 – Shrub/Vine8 35–70 black sagebrush ARNO4 Artemisia nova 35–70 – 9 35–105 little sagebrush ARAR8 Artemisia arbuscula 0–35 – little sagebrush ARARL Artemisia arbuscula ssp. longiloba 0–35 – big sagebrush ARTR2 Artemisia tridentata 0–35 – yellow rabbitbrush CHVI8 Chrysothamnus viscidiflorus 0–35 – winterfat KRLA2 Krascheninnikovia lanata 0–35 – Table 6. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 7. Community 3.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
Animal Community – Wildlife Interpretations
Bluebunch Wheatgrass/Black Sage Plant Community (HCPC): Suitable thermal and escape cover for most wildlife is limited due to the low height and density of woody plants. However, black sagebrush provides important winter forage for mule deer and antelope. Open and bare ridges are suitable locations for sage grouse leks. Year-round habitat is provided for sage grouse and many other sagebrush obligate species such as the sage sparrow, Brewer’s sparrow, sage thrasher, pygmy rabbit, sagebrush vole, horned lizard, and pronghorn antelope.
Black Sage/Forb Plant Community: This plant community may be beneficial for the same wildlife that would use the Historic Climax Plant Community. However, the plant community composition is less diverse, and thus, less apt to meet the seasonal needs of these animals.
Rhizomatous Wheatgrass/Forb Plant Community: This plant community may be beneficial for the same wildlife that would use the Historic Climax Plant Community. However, the plant community composition is less diverse, and thus, less apt to meet the seasonal needs of these animals.
Animal Community – Grazing Interpretations
The following table lists suggested stocking rates for cattle under continuous season-long grazing under normal growing conditions. 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 (as described in this ecological site description). Because of this, a field visit is recommended, in all cases, to document plant composition and production. More precise carrying capacity estimates should eventually be calculated using this information along with animal preference data, particularly when grazers other than cattle are involved. Under more intensive grazing management, improved harvest efficiencies can result in an increased carrying capacity.
Plant Community Production (lb./ac)and Carrying Capacity* (AUM/ac)
Bluebunch Wheatgrass/Black Sage (HCPC) 500-900 lb./ac and 0.17 AUM/ac
Black Sage/Forb 100-500 lb./ac and 0.09 AUM/ac
Rhizomatous Wheatgrass/Forb 50-300 lb./ac and 0.04 AUM/ac
* - Continuous, season-long grazing by cattle under average growing conditions.
Grazing by domestic livestock is one of the major income-producing industries in the area. Rangeland in this area may provide yearlong forage for cattle, sheep, or horses. During the dormant period, the forage for livestock use needs to be supplemented with protein because the quality does not meet minimum livestock requirements.
Hydrological functions
Water is the principal factor limiting forage production on this site. This site is dominated by soils in hydrologic group D. Infiltration is low when soils are wet due to shallow depth to bedrock and/or impervious subsurface layer. Runoff potential for this site varies from high to moderate depending on soil depth, bedrock type (impervious vs. permeable) and ground cover (refer to Part 630, NRCS National Engineering Handbook for detailed hydrology information).
Rills and gullies should not typically be present. Water flow patterns should be barely distinguishable if at all present. 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. Cryptogrammic crusts are present, but only cover 1-2% of the soil surface.
Recreational uses
This site provides hunting opportunities for upland game species.
Wood products
No appreciable wood products are present on the site.
Other products
None noted.
Supporting information
Inventory data references
Information presented here has been derived from NRCS clipping data and other inventory data. Field observations from range trained personnel were also used. Those involved in developing this site include: Bill Christensen, Range Management Specialist, NRCS; Karen Clause, Range Management Specialist, NRCS; and Everet Bainter, Range Management Specialist, NRCS. Other sources used as references include USDA NRCS Water and Climate Center, USDA NRCS National Range and Pasture Handbook, and USDA NRCS Soil Surveys from various counties.
Contributors
Karen Clause
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) K. Clause, E. Bainter Contact for lead author karen.clause@wy.usda.gov or 307-367-2257 Date 03/16/2007 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
Rare to nonexistent. Where present, short and widely spaced. -
Presence of water flow patterns:
Barely observable. -
Number and height of erosional pedestals or terracettes:
Rare to nonexistent. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Bare ground can range from 20-50%. -
Number of gullies and erosion associated with gullies:
Active gullies should not be present. -
Extent of wind scoured, blowouts and/or depositional areas:
Rare to nonexistent. -
Amount of litter movement (describe size and distance expected to travel):
Herbaceous litter expected to move only in small amounts (to leeward side of shrubs) due to wind. Large woody debris from sagebrush will show no movement. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Soil Stability Index ratings range from 1 (interspaces) to 5 (under plant canopy), but average values should be 3.0 or greater. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Soil data is limited for this site. Soil OM usually varies from .5 to 1.5%. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Plant community consists of 65-80% grasses, 10% forbs, and 10-25% shrubs. Evenly distributed plant canopy (30-60%) and litter plus slow to moderate infiltration rates result in minimal runoff. Basal cover is typically less than 5% for this site and does very little to effect runoff on this site. Surface rock fragments of 10-20% provide stability to the site, but reduce infiltration. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
None. -
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:
Mid-size, cool season bunchgrasses>> cool season rhizomatous grasses=perennial shrubs>>perennial forbs>short, cool season bunchgrasses -
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Minimal decadence, typically associated with shrub component. -
Average percent litter cover (%) and depth ( in):
Litter ranges from 10-25% of total canopy measurement with total litter (including beneath the plant canopy) from 20-50% expected. Herbaceous litter depth typically ranges from 3-10mm. Woody litter can be up to a couple inches (4-6 cm). -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
English: 500-900 lb/ac (700 lb/ac average); Metric 560-1008 kg/ha (784 kg/ha average). -
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:
Bare ground greater than 75% is the most common indicator of a threshold being crossed. Rabbitbrush, Sandberg bluegrass, buckwheat, and phlox are common increasers. Annual weeds such as kochia, mustard, lambsquarter, and Russian thistle are common invasive species in disturbed sites. -
Perennial plant reproductive capability:
All species are capable of reproducing, except in drought years.
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