Natural Resources
Conservation Service
Ecological site R034AY298CO
Rolling Loam
Last updated: 9/07/2023
Accessed: 11/23/2024
General information
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.html
LRU 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 days
Classification 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 Basin
Ecological 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 |
| Herbaceous |
(1) Pascopyrum smithii |
Physiographic 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 | 1,676 – 2,134 m |
| 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) | 57-67 days |
|---|---|
| Freeze-free period (characteristic range) | 88-92 days |
| Precipitation total (characteristic range) | 305-381 mm |
| Frost-free period (actual range) | 54-75 days |
| Freeze-free period (actual range) | 75-95 days |
| Precipitation total (actual range) | 279-406 mm |
| Frost-free period (average) | 62 days |
| Freeze-free period (average) | 90 days |
| Precipitation total (average) | 330 mm |
Figure 1. Monthly precipitation range
Figure 2. Monthly minimum temperature range
Figure 3. Monthly maximum temperature range
Figure 4. Monthly average minimum and maximum temperature
Figure 5. Annual precipitation pattern
Figure 6. Annual average temperature pattern
Climate stations used
-
(1) MAYBELL [USC00055446], Maybell, CO
-
(2) CRAIG MOFFAT CO AP [USW00024046], Craig, CO
-
(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 | 51 – 152 cm |
| Surface fragment cover <=3" | 0 – 10% |
| Surface fragment cover >3" | 0 – 5% |
| Available water capacity (0-101.6cm) |
7.62 – 20.32 cm |
| Soil reaction (1:1 water) (0-101.6cm) |
7.4 – 8.4 |
| Subsurface fragment volume <=3" (0-101.6cm) |
0 – 30% |
| Subsurface fragment volume >3" (0-101.6cm) |
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
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Ecosystem states
State 1 submodel, plant communities
State 1
Reference State
Community 1.1
Mixed Grass/Shrub
This 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 dry
Figure 7. Annual production by plant type (representative values) or group (midpoint values)
Table 5. Annual production by plant type
| Plant type | Low (kg/hectare) |
Representative value (kg/hectare) |
High (kg/hectare) |
|---|---|---|---|
| Grass/Grasslike | 303 | 538 | 656 |
| Shrub/Vine | 174 | 224 | 280 |
| Forb | 84 | 135 | 185 |
| Total | 561 | 897 | 1121 |
Additional community tables
Table 6. Community 1.1 plant community composition
| Group | Common name | Symbol | Scientific name | Annual production (kg/hectare) | Foliar cover (%) | |
|---|---|---|---|---|---|---|
|
Grass/Grasslike
|
||||||
| 1 | 448–628 | |||||
| western wheatgrass | PASM | Pascopyrum smithii | 135–224 | – | ||
| Grass, perennial | 2GP | Grass, perennial | 90–135 | – | ||
| needle and thread | HECOC8 | Hesperostipa comata ssp. comata | 90–135 | – | ||
| Grass-like (not a true grass) | 2GL | Grass-like (not a true grass) | 0–90 | – | ||
| Sandberg bluegrass | POSE | Poa secunda | 45–90 | – | ||
| bluebunch wheatgrass | PSSP6 | Pseudoroegneria spicata | 27–45 | – | ||
| Indian ricegrass | ACHY | Achnatherum hymenoides | 28–45 | – | ||
| squirreltail | ELEL5 | Elymus elymoides | 28–45 | – | ||
| prairie Junegrass | KOMA | Koeleria macrantha | 28–45 | – | ||
|
Forb
|
||||||
| 2 | 90–179 | |||||
| Forb, perennial | 2FP | Forb, perennial | 0–90 | – | ||
| yarrow | ACHIL | Achillea | 11–28 | – | ||
| onion | ALLIU | Allium | 11–28 | – | ||
| arrowleaf balsamroot | BASA3 | Balsamorhiza sagittata | 11–28 | – | ||
| daisy | CHRYS2 | Chrysanthemum | 11–28 | – | ||
| buckwheat | ERIOG | Eriogonum | 11–28 | – | ||
| prairie fleabane | ERST3 | Erigeron strigosus | 11–28 | – | ||
| lupine | LUPIN | Lupinus | 11–28 | – | ||
| bluebells | MERTE | Mertensia | 11–28 | – | ||
| locoweed | OXYTR | Oxytropis | 11–28 | – | ||
| phlox | PHLOX | Phlox | 11–28 | – | ||
| scarlet globemallow | SPCO | Sphaeralcea coccinea | 11–28 | – | ||
| American vetch | VIAM | Vicia americana | 11–28 | – | ||
| deathcamas | ZIGAD | Zigadenus | 11–28 | – | ||
|
Shrub/Vine
|
||||||
| 3 | 179–269 | |||||
| Wyoming big sagebrush | ARTRW8 | Artemisia tridentata ssp. wyomingensis | 90–135 | – | ||
| yellow rabbitbrush | CHVI8 | Chrysothamnus viscidiflorus | 28–45 | – | ||
| spineless horsebrush | TECA2 | Tetradymia canescens | 28–45 | – | ||
| Utah serviceberry | AMUT | Amelanchier utahensis | 28–45 | – | ||
| plains pricklypear | OPPO | Opuntia polyacantha | 0–17 | – | ||
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, 9/07/2023
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 | Kirt Walstad |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
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:
-
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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