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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
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 shallow
o are skeletal within 20” of the soil surface; and have minimal rock fragments at the soil surface
o are strongly or violently effervescent in the surface mineral layer (within top 10”)
o have surface textures that usually range from loam and stony loam in surface mineral layer (4”)
• have slopes less than 25 percent
• does not have a clay content that is greater than 35% in mineral soil surface layer (1-2”)Associated sites
R034AY298CO Rolling Loam
R034AY293CO Sandhills
Similar sites
R034AY420CO Cold Desert Breaks
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Purshia tridentata
(2) CercocarpusHerbaceous (1) Pseudoroegneria spicata
(2) Hesperostipa comataPhysiographic features
This site occupies stony ridges and canyon slopes with some rock outcroppings lying adjacent to larger Rolling Loam and Sandy Foothill range sites.
Degree of slope ranges from 3 to 25 percent. Direction of slope varies from west to south. Elevation ranges from 5500 to7000 feet above sea level.Table 2. Representative physiographic features
Landforms (1) Hill
(2) Plateau
(3) Ridge
Runoff class High to very high Flooding frequency None Ponding frequency None Elevation 5500 – 7000 ft Slope 3 – 25 % Aspect W, S, SW Climatic features
Annual precipitation averages from 12 to 15 inches. About half of the annual precipitation is in the form of snow. Optimum growing season for native plants is mid-April to July. Winters are typically cold. Range forage plants are favored by spring moisture from accumulated snow. July and August are usually the driest months of the growing period.
Table 3 Representative climatic features
Frost-free period (characteristic range) 50 days Freeze-free period (characteristic range) 80-100 days Precipitation total (characteristic range) 10-20 in Frost-free period (actual range) 50 days Freeze-free period (actual range) 80-100 days Precipitation total (actual range) 10-20 in Frost-free period (average) 50 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) BROWNS PARK STORE [USC00051018], Maybell, CO
">Influencing water features
None
Wetland description
None
Soil features
Soils in this site are shallow, brown to dark gray brown, medium textured loam or stony loam underlaid by sandstone or shale. The soils have moderate permeability, but due to the steep slopes, the effective moisture is reduced. This is generally a droughty and unproductive site.
Soils in this site include: Crestman, Duffymont, and Tolman.Table 4. Representative soil features
Parent material (1) Slope alluvium
(2) Residuum
Surface texture (1) Very stony loam
(2) Loam
Family particle size (1) Loamy
Drainage class Well drained to excessively drained Permeability class Moderate to rapid Depth to restrictive layer 4 – 20 in Soil depth 4 – 20 in Surface fragment cover <=3" 0 – 30 % Surface fragment cover >3" 0 – 40 % Available water capacity
(0-20in)0.7 – 2.7 in Calcium carbonate equivalent
(0-20in)5 – 15 % Soil reaction (1:1 water)
(0-20in)6.6 – 8.4 Subsurface fragment volume <=3"
(0-20in)0 – 30 % Subsurface fragment volume >3"
(0-20in)0 – 40 % Ecological dynamics
The aspect of this site is a rather sparse stand of shrubs and grass. Bluebunch wheatgrass, needleandthread, Indian ricegrass, prairie Junegrass, western wheatgrass and bottlebrush squirreltail are the principal grass species. Shrubs of this site include antelope bitterbrush, mountain mahogany, Wyoming big sagebrush and black sagebrush. Important forbs are arrowleaf balsamroot, buckwheat, lupine, loco, and stemless goldenweed. Additional plants include native bluegrass, low rabbitbrush, gray horsebrush, serviceberry and snakeweed.
The site is treeless. Optimum ground cover is 20 percent. Invaders on this site are mainly introduced species.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 textT1A - Heavy Continuous Season-long Grazing T1B - Continuous Season-long Grazing; Wildfire R2A - Prescribed Grazing R3A - Prescribed Grazing State 1 submodel, plant communities
State 1
ReferenceThe interpretive plant community for this site is the Reference Plant Community. Potential vegetation is about 75 percent grasses or grass-like plants, 10 percent forbs, and 15 percent 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 sagebrush, green rabbitbrush, and winterfat.
A typical plant composition for this state consists of bluebunch wheatgrass 10 to 25 percent, rhizomatous wheatgrass 10 to 25 percent, needleandthread 5 to 15 percent, Indian ricegrass 5 to 15 percent, bottlebrush squirreltail 5 to 10 percent, other grasses and grass-like plants 10 to 20 percent, perennial forbs 5 to 10 percent, up to 10 percent black sagebrush, and 5 to 15 percent other woody species. Ground cover, by ocular estimate, varies greatly depending on the amount of exposed parent material, and herbage cover ranges from 15 to 30 percent.
The total annual production (air-dry weight) of this state is about 700 pounds per acre (lbs./ac), 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.Community 1.1
Reference Community PhaseOptimum ground cover is 20 percent. Invaders on this site are mainly introduced species.
The plant community is made up of approximately 35 to 60 percent grasses, 5 to 15 percent forbs, and 35 to 50 percent.
Total Annual Production:
Favorable years 800 lbs/ac air dry
Unfavorable years 400 lbs/ac air dry
Median years 500 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 210 240 445 Shrub/Vine 170 210 275 Forb 20 50 80 Total 400 500 800 State 2
Black Sagebrush/ForbState 3
Rhizomatous Wheatgrass/ForbTransition T1A
State 1 to 2Heavy Continuous Season-long Grazing
Transition T1B
State 1 to 3Continuous Season-long Grazing; Wildfire
Restoration pathway R2A
State 2 to 1Prescribed Grazing
Restoration pathway R3A
State 3 to 1Prescribed Grazing
Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 175–300 western wheatgrass PASM Pascopyrum smithii 50–75 – Sandberg bluegrass POSE Poa secunda 25–50 – bluebunch wheatgrass PSSP6 Pseudoroegneria spicata 25–40 – needle and thread HECOC8 Hesperostipa comata ssp. comata 25–40 – prairie Junegrass KOMA Koeleria macrantha 0–25 – squirreltail ELEL5 Elymus elymoides 0–25 – Indian ricegrass ACHY Achnatherum hymenoides 0–20 – Forb2 25–75 arrowleaf balsamroot BASA3 Balsamorhiza sagittata 5–25 – lupine LUPIN Lupinus 5–25 – locoweed OXYTR Oxytropis 5–25 – stemless mock goldenweed STAC Stenotus acaulis 5–25 – buckwheat ERIOG Eriogonum 0–10 – Shrub/Vine3 175–250 black sagebrush ARNO4 Artemisia nova 25–75 – Wyoming big sagebrush ARTRW8 Artemisia tridentata ssp. wyomingensis 25–75 – yellow rabbitbrush CHVI8 Chrysothamnus viscidiflorus 25–50 – antelope bitterbrush PUTR2 Purshia tridentata 25–50 – spineless horsebrush TECA2 Tetradymia canescens 15–25 – alderleaf mountain mahogany CEMO2 Cercocarpus montanus 15–25 – Utah serviceberry AMUT Amelanchier utahensis 15–25 – broom snakeweed GUSA2 Gutierrezia sarothrae 0–10 – Interpretations
Animal community
WILDLIFE INTERPRETATIONS:
This site offers a medium rating for antelope, deer, and jackrabbits. It offers a low rating for bison, elk, cottontail, and upland game birds.
GRAZING INTERPRETATIONS:
Thir site offers a medium value for sheep. It offers a low value for cattle and horses.Hydrological functions
This site offers a low 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 Open sagebrush areas near 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
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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