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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: 12-15 inches
• RV Frost-Free Days: 75-95 daysClassification relationships
Relationship to Other Established Classification Systems
National Vegetation Classification System (NVC):
3 Semi-Desert
3.B.1 Cool Semi-Desert Scrub & Grassland
D040 Western North American Cool Semi-Desert Scrub &
Grassland
M169 Great Basin & Intermountain Tall Sagebrush Shrubland &
Steppe Group
A3184 Wyoming big sagebrush Dry Steppe and Shrubland Alliance
CEGL001043 Artemisia tridentata ssp. wyomingensis/Elymus
elymoides Shrubland Association
Ecoregions (EPA):
Level I: 10 North American Deserts
Level II: 10.1 Cold Deserts
Level III: 10.1.4 Wyoming BasinEcological site concept
• Site does not receive any additional water.
• Soils are:
o may be slightly saline or saline-sodic.
o are deep, very deep
o are not skeletal within 20” of soil surface, minimal rock fragments at
the soil surface
o are not strongly or violently effervescent in surface mineral 10”.
o surface textures usually range from loamy fine sand to fine sandy loam in surface
mineral 4”.
• Slope is less than 30%.
• Clay content is less than 35% and greater than 18% in mineral soil surface 1-2”.Associated sites
R034AY330CO Sandy Land
Site has coarser textured soils
Similar sites
R034AY424CO Loamy 7-10 PZ
Site has lower precipitation, lower production
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Artemisia tridentata ssp. wyomingensis
(2) Chrysothamnus viscidiflorusHerbaceous (1) Pascopyrum smithii
(2) Hesperostipa comataPhysiographic features
The landscape characteristics of this site is nearly level to moderately steep. Degree of slope ranges from 0 to 30 percent with the direction of slope not affecting the site.
Elevation ranges from 5500 to 7000 feet above sea level.Table 2. Representative physiographic features
Landforms (1) Ridge
(2) Hillslope
Runoff class Low to high Flooding frequency None to rare Ponding frequency None Elevation 5500 – 7000 ft Slope 0 – 30 % Aspect Aspect is not a significant factor Climatic features
Annual precipitation ranges between 12 to 15 inches, with about 50 percent coming as snow.
The optimum growing season for native plants is April 15 to July 1. The average temperature of the growing season averages around 55 to 60 degrees Fahrenheit. Winters average around 20 to 25 degrees Fahrenheit. Moisture comes fairly uniform over the months except for November through February which are slightly below that of the others.Table 3 Representative climatic features
Frost-free period (characteristic range) 60-70 days Freeze-free period (characteristic range) 90-90 days Precipitation total (characteristic range) 10-20 in Frost-free period (actual range) 50-80 days Freeze-free period (actual range) 80-100 days Precipitation total (actual range) 10-20 in Frost-free period (average) 60 days Freeze-free period (average) 90 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) MAYBELL [USC00055446], Maybell, CO
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(2) CRAIG MOFFAT CO AP [USW00024046], Craig, CO
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(3) BROWNS PARK STORE [USC00051018], Maybell, CO
">Influencing water features
None
Wetland description
None
Soil features
Generally deep medium to moderately coarse textured soils. Dark grayish brown soils with weak to moderate subsoil development. These soils have good water-holding capacity and take water moderately well making them favorable for good plant growth.
Soils in this site include: Hanley gravelly loamy fine sand and Piceance fine sandy loam.Table 4. Representative soil features
Parent material (1) Alluvium – sandstone and shale
(2) Loess
Surface texture (1) Gravelly loamy fine sand
(2) Fine sandy loam
Drainage class Well drained Permeability class Moderately slow to moderately rapid Soil depth 20 – 60 in Surface fragment cover <=3" 0 – 10 % Surface fragment cover >3" 0 – 5 % Available water capacity
(0-40in)3 – 8 in Soil reaction (1:1 water)
(0-40in)7.4 – 8.4 Subsurface fragment volume <=3"
(0-40in)0 – 30 % Subsurface fragment volume >3"
(0-40in)0 – 10 % Ecological dynamics
An open stand of Wyoming big sagebrush with an abundance of grasses including western wheatgrass, bluebunch wheatgrass, needleandthread, squirreltail, bluegrasses and Indian ricegrass. Shrubs, other than big sagebrush are gray horsebrush, low rabbitbrush, tall rabbitbrush, and serviceberry. Principal forbs are American vetch, buckwheats, bluebells, balsamroot, globemal1ow, lupine, yarrow, and feabane.
This site is treeless.State and transition model
Custom diagramStandard diagramMore 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 Grass/ShrubThis site supports a plant community of approximately 50 to 70 percent grass/grass like, 10 to 20 percent forbs, and 20 to 30 percent shrubs. Optimum ground cover is 30 percent.
Invaders on this site include pinyon pine and Utah juniper. Cheatgrass and other introduced annuals that are not a part of the potential plant community invade when the cover deteriorates.
Total Annual Production:
Favorable years 1000 lbs/ac air dry
Unfavorable years 500 lbs/ac air dry
Median years 800 lbs/ac air dryFigure 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 270 480 585 Shrub/Vine 155 200 250 Forb 75 120 165 Total 500 800 1000 Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 400–560 western wheatgrass PASM Pascopyrum smithii 120–200 – Grass, perennial 2GP Grass, perennial 80–120 – needle and thread HECOC8 Hesperostipa comata ssp. comata 80–120 – Grass-like (not a true grass) 2GL Grass-like (not a true grass) 0–80 – Sandberg bluegrass POSE Poa secunda 40–80 – bluebunch wheatgrass PSSP6 Pseudoroegneria spicata 24–40 – Indian ricegrass ACHY Achnatherum hymenoides 25–40 – squirreltail ELEL5 Elymus elymoides 25–40 – prairie Junegrass KOMA Koeleria macrantha 25–40 – Forb2 80–160 Forb, perennial 2FP Forb, perennial 0–80 – yarrow ACHIL Achillea 10–25 – onion ALLIU Allium 10–25 – arrowleaf balsamroot BASA3 Balsamorhiza sagittata 10–25 – daisy CHRYS2 Chrysanthemum 10–25 – buckwheat ERIOG Eriogonum 10–25 – prairie fleabane ERST3 Erigeron strigosus 10–25 – lupine LUPIN Lupinus 10–25 – bluebells MERTE Mertensia 10–25 – locoweed OXYTR Oxytropis 10–25 – phlox PHLOX Phlox 10–25 – scarlet globemallow SPCO Sphaeralcea coccinea 10–25 – American vetch VIAM Vicia americana 10–25 – deathcamas ZIGAD Zigadenus 10–25 – Shrub/Vine3 160–240 Wyoming big sagebrush ARTRW8 Artemisia tridentata ssp. wyomingensis 80–120 – yellow rabbitbrush CHVI8 Chrysothamnus viscidiflorus 25–40 – spineless horsebrush TECA2 Tetradymia canescens 25–40 – Utah serviceberry AMUT Amelanchier utahensis 25–40 – plains pricklypear OPPO Opuntia polyacantha 0–15 – Interpretations
Animal community
WILDLIFE INTERPRETATIONS:
This site offers a high value rating for antelope, deer, cottontail, jackrabbit, and upland game birds. It offers a medium value rating for elk.
GRAZING INTERPRETATIONS:
This site offers a high value for cattle sheep and horses.Hydrological functions
This site offers a medium value for watershed.
Recreational uses
Medium value.
Wood products
None.
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 General legal description The open sagebrush areas southwest of the Great Divide, Moffat County, Colorado. 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
Jim Kellogg
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) J. Murray, C. Holcomb, L. Santana, F. Cummings, S. Jaouen Contact for lead author Date 01/18/2005 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
None to slight on gentle slopes. Rills can be more defined on steeper slopes, especially following intense storms. -
Presence of water flow patterns:
Flow paths should be short and mostly disconnected with debris dams obvious. -
Number and height of erosional pedestals or terracettes:
Pedestals may occur on steeper slopes near or in flow paths. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Expect 20-25% bareground. Extended drought can cause bare ground to increase. -
Number of gullies and erosion associated with gullies:
Gullies tend to be infrequent. Possible due to natural disturbance or off-site influence. -
Extent of wind scoured, blowouts and/or depositional areas:
Wind scouring/deposits are possible due to natural disturbance. Incidences would be infrequent. -
Amount of litter movement (describe size and distance expected to travel):
Litter movement associated with flow paths. Movement expected to be short and minimal. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Stability class rating anticipated to be 3-5 in the interspaces at soil surface. Surface soil aggregates should be fairly stable. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Average SOM is 1-3%. Soils are deep and well-drained. The A-horizon is 0-6 inches in depth or more with a brown to dark brown color. Structure ranges from fine to moderately coarse granular. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Diverse grass, forb, shrub canopy and root structure reduces raindrop impact and slows overland flow providing increased time for infiltration to occur. Extended drought reduces cool season bunchgrasses causing decreased infiltration and increased runoff following intense storms. -
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:
cool season bunchgrass >Sub-dominant:
cool season rhizomatous grass > (non sprouting) shrubs, = forbs = sprouting shrubsOther:
Additional:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Typically minimal. Expect slight shrub and grass mortality/ decadence during and following drought or lack of disturbance. -
Average percent litter cover (%) and depth ( in):
Litter cover declines during and following extended drought. -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
500 lbs./ac. low precip years; 800 lbs./ac. average precip years; 1000 lbs./ac. above average precip. years. After extended drought or the first growing season following wildfire, production may be significantly reduced by 200 - 300 lbs./ac. or more. -
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:
Cheatgrass, pinyon/juniper and noxious weeds. Big sagebrush is a native increaser on this site. -
Perennial plant reproductive capability:
The only limitations are weather-related, wildfire, natural disease, inter-species competition, wildlife, and insects that may temporarily reduce reproductive capability.
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