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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
For further information regarding MLRAs, refer to:
http://soils.usda.gov/survey/geography/mlra/index.htmlLRU notes
Land Resource Unit (LRU) 34A-10:
• Moisture Regime: aridic ustic
• Temperature Regime: frigid
• Dominant Cover: rangeland
• Representative Value (RV) Effective Precipitation: 14-18 inches
• RV Frost-Free Days: 98-114 daysClassification relationships
Relationship to Other Established Classification Systems
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 does not receive any additional water.
• These soils:
o are not saline or saline-sodic
o are moderately deep, or deep
o are skeletal within 20” of the soil surface; and have minimal rock fragments at the soil surface
o are not strongly or violently effervescent in the surface mineral layer (within top 10”)
o have surface textures that usually range from sandy loam to clay loam in surface mineral layer (4”)
• have slopes greater than 30 percent
• does not have a clay content that is greater than 35% in mineral soil surface layer (1-2”)Associated sites
R034AY300CO Loamy Breaks
Similar sites
R034AY331CO Sandy Slopes
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Cercocarpus
(2) Purshia tridentataHerbaceous (1) Pseudoroegneria spicata
(2) Achnatherum hymenoidesPhysiographic features
This site occurs on moderate to very steep stony slopes. Direction of slope in the upper foothill zone is north and east, and in the lower oakbrush zone is south and west.
Elevation ranges from 6000 to 8000 feet.Table 2. Representative physiographic features
Landforms (1) Hillslope
Runoff class Medium to very high Elevation 6000 – 8000 ft Slope 15 – 90 % Aspect Aspect is not a significant factor Climatic features
Annual precipitation varies from 14 to 18 inches. More than one half of the effective moisture is snow. Optimum growing season for the native vegetation is May 15 to June 30. Winters are typically cold, averaging below freezing.
June, July, and August are generally the drier months. April and May are usually windy.Table 3 Representative climatic features
Frost-free period (characteristic range) 70-80 days Freeze-free period (characteristic range) 100-110 days Precipitation total (characteristic range) 20-20 in Frost-free period (actual range) 70-80 days Freeze-free period (actual range) 90-120 days Precipitation total (actual range) 10-20 in Frost-free period (average) 80 days Freeze-free period (average) 110 days Precipitation total (average) 20 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) CRAIG MOFFAT CO AP [USW00024046], Craig, CO
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(2) HAYDEN [USC00053867], Hayden, CO
">Influencing water features
N/A
Wetland description
N/A
Soil features
Soils in this range site are moderately deep to deep stone filled sandy loam to light clay loam. Permeability is moderate and moisture holding capacity is reduced due to stoniness. These soils are droughty because of steepness of slopes. Stones in the profile enhanced plant growth by increasing water available in a given volume of soil.
Table 4. Representative soil features
Parent material (1) Colluvium
Surface texture (1) Stony sandy loam
Family particle size (1) Loamy
Permeability class Moderate Soil depth 30 – 78 in Surface fragment cover >3" 0 – 50 % Available water capacity
(Depth not specified)0.7 – 3 in Soil reaction (1:1 water)
(Depth not specified)6.6 – 8.4 Subsurface fragment volume >3"
(Depth not specified)0 – 50 % Ecological dynamics
This is a browse-grass plant community. Approximately one half of the annual production is made up of grass species. Bluebunch wheatgrass, Indian ricegrass, western wheatgrass, prairie Junegrass, and bottlebrush squirreltail are the most abundant grasses. The main browse plants are mountain mahogany, antelope bitterbrush, serviceberry, and big sagebrush. Principal forb species include Indian paintbrush, arrowleaf balsamroot, low larkspur, buckwheat, and longleaf phlox.
State and transition model
More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective textEcosystem states
State 1 submodel, plant communities
State 1
ReferenceCommunity 1.1
Mixed Shrubs/Perennial BunchgrassesThis site may have scattered pinyon pine and Utah juniper. Optimum ground cover is 25 percent.
Invaders on this site are cheatgrass, cactus, thistle species, plus numerous other annual species which move in as the plant community deteriorates.
Total annual production.
Favorable years 1200 Pounds per Acre air dry
Median years 900 Pounds per Acre air dry
Unfavorable years 500 Pounds per Acre air dry
Growth curve number???
Mar Apr May Jun Jul Aug Sep Oct
8 32 32 18 0 0 4 6Figure 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 125 405 560 Shrub/Vine 290 385 500 Forb 85 115 140 Total 500 905 1200 State 2
DegradedThis State is result of soil-disturbing activities such as hoof-action, anthropogenic activity, and rodent activity. It can also occur after brush management followed by improper grazing techniques that usually include high-intensity grazing without appropriate recovery periods.
Transition T1A
State 1 to 2The driver for transition T1A from State 1 (Reference State) to State 2 (Degraded) is low to high intensity, long duration, and high frequency herbivory events.
Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Grasses 315–495 Indian ricegrass ACHY Achnatherum hymenoides 45–90 – prairie Junegrass KOMA Koeleria macrantha 45–90 – western wheatgrass PASM Pascopyrum smithii 45–90 – bluebunch wheatgrass PSSP6 Pseudoroegneria spicata 45–90 – muttongrass POFE Poa fendleriana 25–45 – squirreltail ELEL5 Elymus elymoides 25–45 – needle and thread HECOC8 Hesperostipa comata ssp. comata 25–45 – Forb2 Forbs 90–135 arrowleaf balsamroot BASA3 Balsamorhiza sagittata 10–25 – Indian paintbrush CASTI2 Castilleja 10–25 – yellow larkspur DELU Delphinium luteum 10–25 – buckwheat ERIOG Eriogonum 10–25 – Fremont's beardtongue PEFR Penstemon fremontii 10–25 – longleaf phlox PHLO2 Phlox longifolia 10–25 – scarlet globemallow SPCO Sphaeralcea coccinea 10–25 – Shrub/Vine3 Shrubs 315–450 alderleaf mountain mahogany CEMO2 Cercocarpus montanus 45–135 – antelope bitterbrush PUTR2 Purshia tridentata 45–135 – yellow rabbitbrush CHVI8 Chrysothamnus viscidiflorus 70–90 – big sagebrush ARTR2 Artemisia tridentata 65–90 – snowberry SYMPH Symphoricarpos 36–45 – Interpretations
Animal community
INTERPRETATIONS FOR GRAZING ANIMALS:
This site provides a low value rating for cattle and sheep. It is not applicable for horses.
INTERPRETATIONS FOR WILDLIFE:
This site provides a medium value rating for deer, elk, cottontail, jackrabbit, and upland game birds. It is not applicable for antelope and waterfowl.Hydrological functions
This site provides a low value rating for watershed.
Recreational uses
RECREATION AND NATURAL BEAUTY:
This site provides a medium value.Wood products
This site supports an occasional pinyon or Utah juniper which could be used for fence posts.
Other information
RARE, THREATENED OR ENDANGERED PLANTS AND ANIMALS
(To be added when known)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. 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.
Type locality
Location 1: Moffat County, CO Township/Range/Section T6N R100W S29 General legal description Sec 29, T6N, R100W, Moffat County, Colorado – south side of Yampa Bench Road at the foot of the Castle Park Dugway. Other references
Belnap, J. and S. L. Phillips. 2001. Soil biota in an ungrazed grassland: Response to annual grass (Bromus tectorum) invasion. Ecological Applications: 11: 1261-1275.
Caudle, D., H. Sanchez, J. DiBenedetto, C. Talbot, and M. Karl. 2013. Draft Interagency Ecological Site Handbook for Rangelands. US Dept. of Agriculture. Washington D.C
Cleland, D.T.; Freeouf, J.A.; Keys, J.E., Jr.; Nowacki, G.J.; Carpenter, C; McNab, W.H. 2007. Ecological Subregions: Sections and Subsections of the Conterminous United States.[1:3,500,000], Sloan, A.M., cartog. Gen. Tech. Report WO-76. Washington, DC: U.S. Department of Agriculture, Forest Service.
Musgrave, G.W. 1955. How much of the rain enters the soil? In Water: U.S. Department of Agriculture Yearbook. Washington, D.C. P. 151-159.
National Engineering Handbook. US Department of Agriculture, Natural Resources Conservation Service. Available: http://www.info.usda.gov/CED/Default.cfm#National%20Engineering%20Handbook. Accessed February 25, 2008.
Passey, H. B., W. K. Hugie, E. W. Williams, and D. E. Ball. 1982. Relationships between soil, plant community, and climate on rangelands of the Intermountain west. USDA, Soil Conservation Service, Tech. Bull. No. 1669.
Soil Survey Staff, Natural Resources Conservation Service, United States Department of Agriculture. Web Soil Survey. Available online at http://websoilsurvey.nrcs.usda.gov/. Accessed [8/10/2015].
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.
Western Regional Climate Center. Retrieved from http://www.wrcc.dri.edu/summary/Climsmco.html on May 17, 2018.Contributors
Suzanne Mayne Kinney
Approval
Kirt Walstad, 4/10/2025
Acknowledgments
Field offices in Colorado where the site occurs: Craig, Eagle, Glenwood Springs, Meeker, and Steamboat Springs.
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 04/10/2025 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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