Natural Resources
Conservation Service
Ecological site DX032X01B176
Very Shallow (VS)
Big Horn Basin Rim
Last updated: 10/04/2019
Accessed: 05/20/2026
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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.
MLRA notes
Major Land Resource Area (MLRA): 032X–Northern Intermountain Desertic Basins
Major land resource area (MLRA):
032X – Northern Intermountain Desertic Basins – This MLRA is comprised of two major Basins, the Big Horn and Wind River. These two basins are distinctly different and are split by LRU’s to allow individual ESD descriptions. These warm basins are surrounded by uplifts and rimmed by mountains, creating a unique set of plant responses and communities. Unique characteristics of the geology and geomorphology single these two basins out.
Further information regarding MLRAs, refer to: United States Department of Agriculture, 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. Available electronically at: http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ref/?cid=nrcs142p2_053624#handbook.LRU notes
Land Resource Unit (LRU):
32X01B (WY): This LRU is the Big Horn Basin within MLRA 32. This LRU is lower in elevation, slightly warmer and receives slightly less overall precipitation than the Wind River Basin (LRU 02). This LRU was originally divided into two LRU's - LRU A which was the core and LRU B which was the rim. With the most current standards, this LRU is divided into two Subsets. This subset is Subset B, referred to as the Rim, is a transitional band between the basin floor and the lower foothills. The subset encircles Subset A which was originally LRU A. As the LRU shifts towards the south and tracks east, changes in geology and relation to the mountain position, creates a minor shift in soil chemistry influencing the variety of ecological sites and plant interactions. The extent of soils currently correlated to this ecological site does not fit within the digitized boundary. Many of the noted soils are provisional and will be reviewed and corrected in mapping update projects. Other map units are correlated as small inclusions within other MLRA’s/LRU’s based on elevation, landform, and biological references.
Moisture Regime: Ustic Aridic – Prior to 2012, many of the soils within this group were correlated as Frigid Ustic Aridic or as Mesic Typic Aridic, with few mapped within this cross over zone. As progressive soil survey mapping continues, these “crossover” or transitional areas are being identified and corrected.
Temperature Regime: Mesic
Dominant Cover: Rangeland, with Saltbush flats the dominant vegetative cover for this LRU/ESD.
Representative Value (RV) Effective Precipitation: 10-14 inches (254 – 355 mm)
RV Frost-Free Days: 105-125 daysClassification relationships
Relationship to Other Established Classification Systems:
National Vegetation Classification System (NVC):
3 Xeromorphic Woodland, Scrub & Herb Vegetation Class
3.B Cool Semi-Desert Scrub & Grassland Subclass
3.B.1 Cool Semi-Desert Scrub & Grassland formation
3.B.1.NE Western North American Cool Semi-Desert Scrub & Grassland Division
M169 Great Basin & Intermountain Tall Sagebrush Shrubland & Steppe Macrogroup
G302 Artemisia Tridentata - Artemisia tripartita - Purshia tridentata Big Sagebrush Steppe Group
Ecoregions (EPA):
Level I: 10 North American Deserts
Level II: 10.1 Cold Deserts
Level III: 10.1.18 Wyoming Basin
Level IV: 10.1.18.g Big Horn Salt Desert Shrub BasinEcological site concept
• Site receives no additional water.
• Slope is < 60%
• Soils are:
o Textures range from loamy sand to clay loam in top 4” (10 cm) of mineral soil surface
o Clay content is ≤ 35% in top 4” (10 cm) of mineral soil surface
o All subsurface horizons have a weighted average of < 35% clay.
o very shallow (< 10 in. (25 cm))
o <3% stone and boulder cover and < 15% cobble and gravel cover
o Generally not skeletal (< 35% rock fragments) but occasionally will have up to 75% gravels and cobbles.Associated sites
R032XY362WY Shallow Loamy (SwLy) 10-14" East Precipitation Zone
Shallow Loamy is commonly located in a complex with very shallow along the scarp face, down slope on the dipslopes of escarpments or hllslopes (ridges) and is associated with inter-bedded sedimentary parent material.
R032XY366WY Shallow Sandy (SwSy) 10-14" East Precipitation Zone
Shallow Sandy is commonly located in a complex with very shallow along the scarp face, down slope on the dipslopes of escarpments or hillslopes (ridges) and is associated with sandstone parent material.
R032XY358WY Shallow Clayey (SwCy) 10-14" East Precipitation Zone
Shallow Clayey is commonly located in a complex with very shallow along the scarp face, down slope on the dipslopes of escarpments or hillslopes (ridges) and is associated with non-marine shale parent material.
Similar sites
R032XY176WY Very Shallow (VS) 5-9” Big Horn Basin Precipitation Zone
Very Shallow Big Horn Basin Core will be lower in production.
R032XY276WY Very Shallow (VS) 5-9” Wind River Basin Precipitation Zone
Very Shallow Wind River Basin Core will be lower in production.
Table 1. Dominant plant species
Tree Not specified
Shrub Not specified
Herbaceous (1) Pseudoroegneria spicata
(2) Hesperostipa comataLegacy ID
R032XB176WY
Physiographic features
This site occurs on steep slopes and ridge tops, but may occur on all slopes.
Table 2. Representative physiographic features
Landforms (1) Intermontane basin > Hill
(2) Intermontane basin > Ridge
(3) Intermontane basin > Escarpment
Runoff class Negligible to high Elevation 5400 – 7500 ft Slope 0 – 60 % Aspect Aspect is not a significant factor Climatic features
Annual Precipitation and modeled relative effective annual precipitation ranges from 10 to 14 inches (254 – 355 mm). The normal precipitation pattern shows peaks in May and June and a secondary peak in September. This amounts to about 50% of the mean annual precipitation. Much of the moisture that falls in the latter part of the summer is lost by evaporation and much of the moisture that falls during the winter is lost by sublimation. Average snowfall is about 20 inches annually. 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, due to the high elevation and dry air, which permits rapid incoming and outgoing radiation. Cold air outbreaks from Canada in winter move rapidly from northwest to southeast and account for extreme minimum temperatures. Chinook winds may occur in winter and bring rapid rises in temperature. Extreme storms may occur during the winter, but most severely affect ranch operations during late winter and spring. High winds are generally blocked form the basin by high mountains but can occur in conjunction with an occasional thunderstorm. Growth of native cool-season plants begins about April 1st and continues to about July 1st. Cool weather and moisture in September may produce some green up of cool season plants that will continue to late October. For detailed information visit the Natural Resources Conservation Service National Water and Climate Center at http://www.wcc.nrcs.usda.gov/. "Clark 3NE", "Cody", "Cody 12SE", "Heart Mtn", “Powell Fld Stn", "Shell 1NE", and "Thermopolis 9NE" are the representative weather stations. The following graphs and charts are a collective sample representing the averaged normals and 30-year annual rainfall data for the selected weather stations from 1981 to 2010.Table 3 Representative climatic features
Frost-free period (characteristic range) 90-90 days Freeze-free period (characteristic range) 110-120 days Precipitation total (characteristic range) 10-10 in Frost-free period (actual range) 80-110 days Freeze-free period (actual range) 110-130 days Precipitation total (actual range) 10-10 in Frost-free period (average) 90 days Freeze-free period (average) 120 days Precipitation total (average) 10 in Characteristic rangeActual rangeBarLineFigure 2. Monthly precipitation range
Characteristic rangeActual rangeBarLineFigure 3. Monthly minimum temperature range
Characteristic rangeActual rangeBarLineFigure 4. Monthly maximum temperature range
BarLineFigure 5. Monthly average minimum and maximum temperature
Figure 6. Annual precipitation pattern
Figure 7 Annual average temperature pattern
Climate stations used
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(1) THERMOPOLIS 9NE [USC00488884], Thermopolis, WY
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(2) SHELL 1NE [USC00488124], Shell, WY
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(3) CODY 12SE [USC00481850], Meeteetse, WY
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(4) CODY [USC00481840], Cody, WY
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(5) HEART MTN [USC00484411], Powell, WY
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(6) POWELL FLD STN [USC00487388], Powell, WY
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(7) CLARK 3NE [USC00481775], Powell, WY
">Influencing water features
The characteristics of these upland soils have no influence from ground water (water table below 60 inches (150 cm)) and have minimal influence from surface water/overland flow. There may be isolated features that are affected by snow pack that persists longer than surrounding areas due to position on the landform (shaded/protected pockets); but overflow is not a suitable fit. No streams are classified within this ecological site.
Soil features
The soils of this site are very shallow (less than 10” to bedrock) well-drained soils formed in residuum. These soils have rapid to slow permeability and can be of any texture. This site usually occurs on steep slopes, but may be on any slope. The bedrock will include all kinds except soft clay shales, igneous and some volcanic. The soil characteristic having the most influence on the plant community is the very shallow depth to bedrock, which drastically limits the available moisture.
Major Soil Series correlated to this site include: RentsacTable 4. Representative soil features
Parent material (1) Residuum – interbedded sedimentary rock
Surface texture (1) Channery loam
(2) Fine sandy loam
(3) Sandy loam
(4) Silt loam
Family particle size (1) Loamy
Drainage class Well drained to excessively drained Permeability class Slow to moderately rapid Depth to restrictive layer 0 – 10 in Soil depth 1 – 10 in Surface fragment cover <=3" 0 – 20 % Surface fragment cover >3" 0 – 20 % Available water capacity
(0-40in)0.3 – 1.7 in Calcium carbonate equivalent
(0-40in)0 – 5 % Electrical conductivity
(0-40in)0 – 4 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 – 15 % Subsurface fragment volume >3"
(Depth not specified)0 – 25 % Ecological dynamics
**Disclaimer** This PROVISIONAL ecological site was developed for an extended MLRA concept where the foothills (10-14" precipitation Frigid climatic zone) was included in this site. This has created an exaggerated or elevated production value for this site description.
Potential vegetation on this site is dominated by a variety of mid cool-season perennial grasses. Other significant vegetation includes winterfat and a variety of forbs and shrubs. The expected potential composition for this site is about 70% grasses, 10% forbs and 20% woody plants. The composition and production will vary naturally due to historical use, fluctuating precipitation and fire frequency.
As this site deteriorates, species such as short warm-season grasses, juniper, and shrubs will increase. Plains pricklypear and weedy annuals will invade. Cool season grasses such as bluebunch wheatgrass will decrease in frequency and production.
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.
Following are the narratives for each of the described plant communities. 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.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/ NeedleandthreeadCommunity 1.1
Bluebunch Wheatgrass/ NeedleandthreeadThe interpretive plant community for this site is the Historic Climax Plant Community. This state evolved with grazing by large herbivores and droughty soils due to the limited water holding capacity. Fire, although rare due to the sparseness of the vegetation is a component of this plant community. This plant community can be found on areas that are properly managed with grazing and on areas receiving occasional short periods of rest. Potential vegetation is about 70% grasses or grass-like plants, 10% forbs, and 20% woody plants. Cool season mid-grasses dominate the state.
The major grasses include bluebunch and/or Griffith’s wheatgrasses, prairie junegrass, Indian ricegrass, and needleandthread. Other grasses and grasslikes occurring on the site include rhizomatous wheatgrasses, bottlebrush squirreltail, Sandberg bluegrass, Fendler threeawn, blue grama, and threadleaf sedge. Shrubs most commonly found are black and Wyoming big sagebrush, green and rubber rabbitbrush, winterfat, and juniper. Curl-leaf mountainmahogany is also a major shrub along the western slopes of the Bighorn mountains but does not occur in the Wind River Basin or along the slopes of the Owl Creek and Absaroka mountain ranges. Antelope bitterbrush and limber pine are very common on sites in the upper precipitation range of this zone. A variety of forbs can be present and plant diversity is high (see Plant Composition Table).
The total annual production (air-dry weight) of this state is about 350 pounds per acre, but it can range from about 250 lbs./acre in unfavorable years to about 500 lbs./acre in above average years.
The state is stable and well adapted to the Northern Intermountain Desertic Basins climate. The diversity in plant species allows for high drought resistance. 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:
• Moderate Continuous Season-Long Grazing will convert this plant community to the Perennial Grass/Mixed Shrub Plant Community. Prolonged drought will exacerbate this transition.Figure 8. Annual production by plant type (representative values) or group (midpoint values)
Figure 9. Plant community growth curve (percent production by month). WY0701 , 10-14E 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 25 40 10 5 10 5 State 2
Perennial Grass/Mixed ShrubCommunity 2.1
Perennial Grass/Mixed ShrubHistorically, this plant community evolved under grazing and a rare fire event. Currently, it is found under moderate, season-long grazing by livestock and is exacerbated by prolonged drought conditions. A fire regime for this site is basically non-existent. This plant community is still dominated by cool-season grasses, while short warm-season grasses and miscellaneous forbs account for the balance of the understory. A variety of shrubs makes up the overstory.
The dominant grasses include bluebunch wheatgrass, needleandthread, and rhizomatous wheatgrasses. Grasses and grasslikes of secondary importance include Sandberg bluegrass, blue grama, Fendler threeawn, and threadleaf sedge. Forbs commonly found in this plant community include tufted evening primrose, stemless mock goldenweed, Hood’s phlox, sulfur flower buckwheat, and scarlet globemallow. Shrubs most commonly found are black and Wyoming big sagebrush, green and rubber rabbitbrush, and juniper. Curl-leaf mountainmahogany is also a major shrub along the western slopes of the Bighorn mountains but does not occur in the Wind River Basin or along the slopes of the Owl Creek and Absaroka mountain ranges. Antelope bitterbrush and limber pine are very common on sites in the upper precipitation range of this zone. These shrubs account for 20% to 30% of the total production.
When compared to the Historical Climax Plant Community, shrubs such as sagebrush and juniper have increased. Indian ricegrass and bluebunch and/or Griffiths wheatgrasses have decreased. Indian ricegrass may occur in only trace amounts under the sagebrush canopy or within patches of pricklypear. Blue grama and threadleaf sedge have increased. Plains pricklypear cactus will also have invaded, but occurs only in small patches. In addition, the amount of winterfat may or may not have changed depending on the season of use.
The total annual production (air-dry weight) of this state is about 300 pounds per acre, but it can range from about 225 lbs./acre in unfavorable years to about 450 lbs./acre in above average years.
This plant community is resistant to change. The herbaceous species present are well adapted to grazing; however, species composition can be altered through long-term overgrazing. The herbaceous component is mostly intact and plant vigor and replacement capabilities are sufficient. Water flow patterns and litter movement may be occurring but only on steeper slopes. Incidence of pedestalling is minimal. Soils are mostly stable and the surface shows minimum soil loss. The watershed is functioning and the biotic community is intact.
Transitional pathways leading to other plant communities are as follows:
• Prescribed grazing or possibly long-term prescribed grazing, will convert this plant community to the HCPC. The probability of this occurring is high especially if rotational grazing along with short deferred grazing is implemented as part the prescribed method of use. In addition, the removal of fire suppression will allow a somewhat natural fire regime to reoccur to more easily transition between this plant community and the HCPC. A prescribed fire treatment can be useful to hasten this transition, if desired. The wide gaps between plants, however, may create a problem in carrying a fire.
• Frequent and severe grazing over the long-term will convert this plant community to the Mixed Shrub/Bare Ground Plant Community.Figure 10. Plant community growth curve (percent production by month). WY0701 , 10-14E 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 25 40 10 5 10 5 State 3
Mixed Shrub/ Bare GroundCommunity 3.1
Mixed Shrub/ Bare GroundThis state currently is found under heavy, season-long grazing by livestock and the absence of fire. Shrubs are significant components of this plant community and account for greater than 30% of the total production. Cool-season grasses have been reduced. Bare ground, warm season grasses, and annual plants dominate the understory.
The dominant grasses/grasslikes are threadleaf sedge and blue grama. Black and Wyoming big sagebrush, green rabbitbrush, and juniper are the common shrubs found on this site. Typically these sites are dominated by either black sagebrush or juniper. Concurrently, curl-leaf mountainmahogany can also dominate sites along the western slopes of the Bighorn mountains especially where fire suppression has persisted. Antelope bitterbrush, if not removed by over browsing, may still be present in the upper precipitation range of this zone, but these plants usually exhibit a gnarled hedged appearance as a result of heavy use. Limber pine may have increased on sites in the upper precipitation range of this zone, but will not exceed 10% of the total annual production.
Weedy annual species such as cheatgrass and Russian thistle may occupy the site if a seed source is available. Cactus and sageworts often invade. Noxious weeds such as Russian knapweed may invade the site if a seed source is available. The interspaces between plants have expanded significantly, leaving the amount of bare ground more prevalent. As compared with the HCPC, there is a reduction in the annual production, but the increase in juniper and sagebrush off sets some of the decline in the herbaceous production.
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 250 lbs./acre in above average years.
This plant community is resistant to change. These areas are actually more resistant to fire as less fine fuels are available and the bare ground between the shrubs is increased. Continued frequent and severe grazing or the removal of grazing does not seem to affect the composition or structure of the plant community. Plant diversity is poor. The plant vigor is diminished and replacement capabilities are limited due to the reduced number of cool-season grasses. Plant litter is noticeably less when compared to the HCPC.
Soil erosion is accelerated because of increased bare ground. Water flow patterns and pedestalling are obvious. Infiltration is reduced and runoff is increased. Rill channels may be noticeable in the interspaces and gullies may be establishing where rills have concentrated down slope.
Transitional pathways leading to other plant communities are as follows:
• Brush management (fire) and prescribed grazing will return this state to near Historic Climax Plant Community. Seeding native perennials is usually necessary to hasten establishment of these species.Figure 11. Plant community growth curve (percent production by month). WY0701 , 10-14E 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 25 40 10 5 10 5 Additional community tables
Table 5. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 105–158 Montana wheatgrass ELAL7 Elymus albicans 105–158 – bluebunch wheatgrass PSSP6 Pseudoroegneria spicata 105–158 – 2 4–35 needle and thread HECO26 Hesperostipa comata 4–35 – 3 4–35 prairie Junegrass KOMA Koeleria macrantha 4–35 – 4 4–35 Indian ricegrass ACHY Achnatherum hymenoides 4–35 – 5 18–70 Grass, perennial 2GP Grass, perennial 0–18 – Indian ricegrass ACHY Achnatherum hymenoides 0–18 – Fendler threeawn ARPUL Aristida purpurea var. longiseta 0–18 – blue grama BOGR2 Bouteloua gracilis 0–18 – threadleaf sedge CAFI Carex filifolia 0–18 – squirreltail ELEL5 Elymus elymoides 0–18 – western wheatgrass PASM Pascopyrum smithii 0–18 – Sandberg bluegrass POSE Poa secunda 0–18 – Forb6 4–35 Forb, perennial 2FP Forb, perennial 0–18 – small-leaf pussytoes ANPA4 Antennaria parvifolia 0–18 – Franklin's sandwort ARFR Arenaria franklinii 0–18 – prairie sagewort ARFR4 Artemisia frigida 0–18 – cutleaf daisy ERCO4 Erigeron compositus 0–18 – fleabane ERIGE2 Erigeron 0–18 – sulphur-flower buckwheat ERUM Eriogonum umbellatum 0–18 – tufted evening primrose OECA10 Oenothera caespitosa 0–18 – woolly groundsel PACA15 Packera cana 0–18 – nailwort PARON Paronychia 0–18 – phlox PHLOX Phlox 0–18 – scarlet globemallow SPCO Sphaeralcea coccinea 0–18 – stemless four-nerve daisy TEACA2 Tetraneuris acaulis var. acaulis 0–18 – prairie thermopsis THRH Thermopsis rhombifolia 0–18 – Shrub/Vine7 0–35 black sagebrush ARNO4 Artemisia nova 0–35 – 8 0–35 curl-leaf mountain mahogany CELE3 Cercocarpus ledifolius 0–35 – 9 18–35 Shrub (>.5m) 2SHRUB Shrub (>.5m) 0–18 – Wyoming big sagebrush ARTRW8 Artemisia tridentata ssp. wyomingensis 0–18 – shadscale saltbush ATCO Atriplex confertifolia 0–18 – yellow rabbitbrush CHVI8 Chrysothamnus viscidiflorus 0–18 – rubber rabbitbrush ERNA10 Ericameria nauseosa 0–18 – Utah juniper JUOS Juniperus osteosperma 0–18 – winterfat KRASC Krascheninnikovia 0–18 – limber pine PIFL2 Pinus flexilis 0–18 – antelope bitterbrush PUTR2 Purshia tridentata 0–18 – skunkbush sumac RHTR Rhus trilobata 0–18 – 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
Historic Climax Plant Community: The predominance of grasses in this plant community favors grazers and mixed-feeders, such as bison, elk, and antelope. Suitable thermal and escape cover for deer may be limited due to the low quantities of woody plants. However, topographical variations could provide some escape cover. When found adjacent to sagebrush dominated states, this plant community may provide brood rearing/foraging areas for sage grouse, as well as lek sites. Other birds that would frequent this plant community include western meadowlarks, horned larks, and golden eagles. Many grassland obligate small mammals would occur here.
Perennial Grass/Mixed Shrub: The combination of a shrub overstory and an understory of grasses and forbs provide a very diverse plant community for wildlife. This diversity provides important winter ranges for mule deer and antelope as they may use this state for winter foraging. Cottontail and jack rabbits will use this area for both forage and cover year-round. It may provide winter, nesting, brood-rearing, and foraging habitat for upland game birds including sage grouse. Brewer’s sparrows’ nest in big sagebrush plants and hosts of other nesting birds utilize juniper stands as well.
Mixed Shrub/Bare Ground: This plant community can provide winter foraging for mule deer and antelope, as sagebrush can approach 15% protein and 40-60% digestibility during that time.
Due to the sparseness of the vegetation, this community does not provide escape and thermal cover for large ungulates or for nesting habitat for sage grouse. An exception is if large shrubs such as juniper or sometimes mountainmahogany dominate a site. In these cases, sufficient thermal and escape cover will meet the needs of many wildlife species.
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. If distribution problems occur, stocking rates must be reduced to maintain plant health and vigor.
Plant Community Production Carrying Capacity*
(lb./ac) (AUM/ac)
Historic Climax Plant Community 250-500 .15
Perennial Grass/Mixed Shrub 225-450 .12
Mixed Shrub/Bare Ground 50-250 .03
* - 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 highly variable and is dominated by soils in hydrologic group B and C, with localized areas in hydrologic group D. Infiltration ranges from slow to very rapid. Runoff potential for this site varies from moderate to high depending on soil hydrologic group, slope and ground cover. In many cases, areas with greater than 75% ground cover have the greatest potential for high infiltration and lower runoff. An example of an exception would be where short-grasses form a strong sod and dominate the site. Areas where ground cover is less than 50% 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 be present, but should be small. Water flow patterns should be barely distinguishable. Pedestals are only slightly present in association with bunchgrasses such as bluebunch wheatgrass. 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 1-2% of the soil surface.Recreational uses
This site provides hunting opportunities for upland game species. The wide varieties of plants which bloom from spring until fall have an esthetic value that appeals to visitors.
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 inventory data. Field observations from range trained personnel were also used. Those involved in developing this site include: Chris Krassin, Range Management Specialist, NRCS and Everet Bainter, Range Management Specialist. Other sources used as references include USDA NRCS Water and Climate Center, USDA NRCS National Range and Pasture Handbook, USDI and USDA Interpreting Indicators of Rangeland Health Version 3, and USDA NRCS Soil Surveys from various counties.
Approval
Scott Woodall, 10/04/2019
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) Ray Gullion, E. Bainter Contact for lead author ray.gullion@wy.usda.gov or 307-347-2456 Date 05/02/2008 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
Some rills to be expected on this site. Depending on slope, rills range from .5-2 inches (1-5 cm) wide and are found every 3-6 feet (1-2 m). -
Presence of water flow patterns:
Some observable. -
Number and height of erosional pedestals or terracettes:
Slight pedestalling evident. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Bare ground can range from 30-60%. -
Number of gullies and erosion associated with gullies:
Active gullies, where present, should be rare. -
Extent of wind scoured, blowouts and/or depositional areas:
Minimal to nonexistent. -
Amount of litter movement (describe size and distance expected to travel):
Herbaceous litter expected to move in moderate amounts. Large woody debris will show only slight movement down slope. -
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 6 (under plant canopy), but average values should be 2.5 or greater. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Currently no soil series are correlated to this ecological site. Soil OM of less than 1% is expected. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Plant community consists of 60-80% grasses, 15% forbs, and 5-25% shrubs. Sparse plant canopy (20-60%) and litter, steep slopes, plus slow to moderate infiltration rates result in slight to moderate runoff. Basal cover is typically less than 5% and does very little to effect runoff on this site. Bedrock outcropping provides stability to the site, but reduces infiltration. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
No compaction layer exists, but shallow depth to and exposed bedrock may be mistaken for a compaction layer. -
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:
mid-size, cool season bunchgrassesSub-dominant:
perennial shrubs/trees perennial forbsOther:
cool season rhizomatous grasses short, cool season bunchgrassesAdditional:
-
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 5-20% of total canopy measurement with total litter (including beneath the plant canopy) from 15-50% expected. Herbaceous litter depth is typically shallow, ranging from 2-8 mm. Woody litter can be up to several inches (>8 cm). -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
English: 250-500 lb/ac (375 lb/ac average); Metric: 280 - 560 kg/ha (420 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% and the presence of cheatgrass are the most common indicators of a threshold being crossed. Short warm season grasses, juniper, shrubs, Sandberg bluegrass, and phlox are common increasers. Annual weeds such as cheatgrass, mustards, kochia, 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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PrintThe Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.
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