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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: 12-16 inches
• RV Frost-Free Days: 93-110 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 may be slightly saline or saline-sodic
o are moderately deep, deep, or very deep
o are not 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 clay loam to clay in surface mineral layer (4”)
• have slopes greater than 30 percent
• have a clay content that is greater than 35% in mineral soil surface layer (1-2”)Associated sites
R034AY303CO Loamy Slopes
Similar slopes; loamy soil textures
Similar sites
DX034A02X104 Clayey Pinedale Plateau (Cy PP)
Similar soils; lower slopes; in adjoining LRU in WY.
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Atriplex confertifolia
Herbaceous (1) Leymus salinus
(2) Poa fendlerianaPhysiographic features
Topography is moderately steep to very steep and hilly with slopes ranging from 15 to 65 percent. At lower elevations and low precipitation zones, the site is on north and east facing slopes. At higher elevations and precipitation zones, the site occurs on south and west exposures. The site occurs at elevations ranging from 5500 to 7000 feet about sea level.
Table 2. Representative physiographic features
Landforms (1) Intermontane basin > Hill
Elevation 5500 – 7000 ft Slope 15 – 65 % Aspect W, S, SW Climatic features
The average annual precipitation ranges from 12 to 16 inches with more than 50 percent of the moisture falling between April 1 and September 30. The growing season starts April 1 and ends in late September
July, August, and September are the months with the highest amount of precipitation.Table 3 Representative climatic features
Frost-free period (characteristic range) 60-80 days Freeze-free period (characteristic range) 90-110 days Precipitation total (characteristic range) 10-20 in Frost-free period (actual range) 60-90 days Freeze-free period (actual range) 90-110 days Precipitation total (actual range) 10-20 in Frost-free period (average) 70 days Freeze-free period (average) 100 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) MAYBELL [USC00055446], Maybell, CO
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(2) CRAIG 4 SW [USC00051932], Hamilton, CO
">Influencing water features
None
Wetland description
N/A
Soil features
Weakly developed, moderately deep, brown clay textured soils, underlain by clay shale of Wasatch or Mesa Verde age. The A1 horizon varies from two to four inches thick, and contains about 45 percent clay. The B2t layer is also clay, and is lighter colored. Permeability is better than normal for soils of clay texture. Water holding capacity is high.
Table 4. Representative soil features
Parent material (1) Alluvium
Surface texture (1) Clay
(2) Clay loam
Drainage class Moderately well drained to well drained Permeability class Moderately rapid to very slow Soil depth 20 – 80 in Surface fragment cover <=3" 0 – 15 % Surface fragment cover >3" 0 – 30 % Available water capacity
(0-40in)6 – 8 in Electrical conductivity
(0-20in)0 – 8 mmhos/cm Sodium adsorption ratio
(0-20in)0 – 5 Soil reaction (1:1 water)
(0-20in)6.6 – 8.4 Ecological dynamics
This is a grassland site with small amounts of shrubs and forbs. Dominant grasses include Salina wildrye, muttongrass, western wheatgrass, Junegrass, and squirreltail. Forbs include onion, Hoods phlox(spiny phlox), stonecrop, hollyleaf clover, fleabane, and aster. Native shrubs on the site include shadscale, big sagebrush, snowberry, serviceberry, tall rabbitbrush, low rabbitbrush, and greasewood.
Plants not native to the site that are most likely to invade are cheatgrass and other introduced plants.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
ReferenceThe interpretive plant community for this site is the Reference Plant Community. This state evolved with grazing by large herbivores and is suited for grazing by domestic livestock. Potential vegetation is estimated at 65 percent grasses or grass-like plants, 15 percent forbs and 20 percent woody plants. The major grasses include western wheatgrass, mutton bluegrass, and Saline wildrye. Other grasses and grass-like plants may include bottlebrush squirreltail, prairie junegrass, and Sandberg bluegrass. Shadscale is the major woody plant. Other woody plants that may occur include yellow rabbitbrush, and serviceberry.
A typical plant composition for this state consists of western wheatgrass 25 to 35 percent, mutton bluegrass 5 to 15 percent, Saline wildrye 5 to 15 percent, bottlebrush squirreltail 1 to 10 percent, other grasses and grass-like plants 10 to 20 percent, perennial forbs 5 to 15 percent, shadscale 10 to 20 percent, and 5 to 10 percent other woody species.
The state is stable and well adapted to the Cool Central Desertic Basins & Plateaus climatic conditions. The diversity in plant species allow 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:
• Nonuse will convert this plant community to the Shadscale/Squirreltail State.
• Heavy Continuous Season-long Grazing will convert this plant community to the Shadscale/Bare ground State.Community 1.1
Perennial Grass - ShrubsPlant Composition details below.
Figure 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 180 360 405 Shrub/Vine 190 240 325 Forb 30 50 70 Total 400 650 800 Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 295–425 western wheatgrass PASM Pascopyrum smithii 130–195 – muttongrass POFE Poa fendleriana 33–65 – saline wildrye LESA4 Leymus salinus 33–65 – squirreltail ELELC2 Elymus elymoides ssp. californicus 0–33 – prairie Junegrass KOMA Koeleria macrantha 0–33 – Forb2 35–65 Forb, perennial 2FP Forb, perennial 0–20 – onion ALLIU Allium 0–20 – aster ASTER Aster 0–20 – streamside fleabane ERGLP Erigeron glabellus var. pubescens 0–20 – stonecrop HYLOT Hylotelephium 0–20 – spiny phlox PHHO Phlox hoodii 0–20 – hollyleaf clover TRGY Trifolium gymnocarpon 0–20 – Shrub/Vine3 195–295 shadscale saltbush ATCO Atriplex confertifolia 33–98 – Subshrub, deciduous, broadleaf 2SSDB Subshrub, deciduous, broadleaf 0–33 – Utah serviceberry AMUT Amelanchier utahensis 0–33 – big sagebrush ARTR2 Artemisia tridentata 0–33 – Interpretations
Animal community
GRAZING INTERPRETATIONS:
This site has a medium value for grazing by sheep and cattle and low value for horses.
WILDLIFE INTERPRETATIONS:
This site offers a grazing value for antelop and elk and medium value for deer, cottontail, and jackrabbits. It has no value for bison. It offers high value for upland game birds.Hydrological functions
The site is of medium value for watershed.
Recreational uses
It offers medium value for recreation and natural beauty.
Wood products
No known value.
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.
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
Approval
Kirt Walstad, 4/10/2025
Acknowledgments
The site occurs in the Craig, Glenwood Springs, and Meeker Field Offices.
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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