Natural Resources
Conservation Service
Ecological site R034AY293CO
Sandhills
Last updated: 9/07/2023
Accessed: 12/21/2024
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: 11-13 inches
• RV Frost-Free Days: 75-95 days
Classification 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 Basin
Ecological site concept
• This site does not receive any additional water.
• These soils:
o are not saline or saline-sodic
o are 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 loamy sand to sand in surface mineral layer (4”)
• slopes are 3-45 percent
• does not have a clay content that is greater than 20% in mineral soil surface layer (1-2”)
Associated sites
| R034AY330CO |
Sandy Land |
|---|
Similar sites
| R034AY434CO |
Dry Sandy |
|---|
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Purshia tridentata |
| Herbaceous |
(1) Achnatherum hymenoides |
Physiographic features
This site occurs on rolling sandhills and alluvial fans. Slopes range from 3 to 45 percent. Elevations range from 6000 to 7000 feet. This site occurs on all exposures.
Range Site Description:
Rolling sandhills from aeolian sands from the Brown's Park sandstone form the topography of this landscape. The site is within an elevational range of 5900 to 6300 feet.
Table 2. Representative physiographic features
| Landforms |
(1)
Hill
(2) Breaks (3) Alluvial fan (4) Dune |
|---|---|
| Runoff class | Negligible to medium |
| Flooding frequency | None |
| Ponding frequency | None |
| Elevation | 6,000 – 7,000 ft |
| Slope | 3 – 45% |
| Aspect | Aspect is not a significant factor |
Climatic features
The climate is arid to semi-arid. Winters are cold and summers are warm. The average annual precipitation ranges from 11 to 13 inches.
About half of this precipitation comes in the form of winter snow and spring rains. Spring and fall are peak periods of precipitation. July is usually the driest month. The distribution of precipitation and relatively low spring temperatures favor production of cool season plants.
Plants begin growth in late April. The optimum growth period is from mid-May to late June, unless summer rains occur and are effective in maintaining plant growth. The growing season for native plants is about 110 days. There may be a second growth period in the fall due to a fall precipitation peak.
The average annual air temperature ranges from 42 to 45 degrees Fahrenheit.
The frost free period ranges from 75 to 95 days.
Range Site Description:
The average annual precipitation is 12 to 15 inches with an estimated 50 percent of the moisture falling as snow. The optimum growing season for the native plants is between May 15 to July 15. The average annual temperature is 42 degrees Fahrenheit.
Table 3. Representative climatic features
| Frost-free period (actual range) | 75-95 days |
|---|---|
| Freeze-free period (actual range) | |
| Precipitation total (actual range) | 11-13 in |
| Frost-free period (average) | 95 days |
| Freeze-free period (average) | |
| Precipitation total (average) | 13 in |
Figure 1. Monthly precipitation range
Influencing water features
None
Wetland description
N/A
Soil features
Soils of this site are deep and excessively drained. They formed in eolian sands or residuum. Typically the surface layer is sand or loamy sands 3 to 5 inches thick and is underlain by sands, loamy sands, and sandy loams to a depth greater than 60 inches. The available water holding capacity for these soils is low; runoff is low; hazard for water erosion is slight to high, and hazard for soil blowing is high. This is particularly true on areas where the vegetation has been abused, exposing the soil to wind action. Effective rooting depth is greater than 60 inches. Soils in this site are usually formed from the Browns Park geologic formation.
Soil Series in this site Include:
Maybell Sand 5 to 30 percent slopes
Maybell Sand 3 to 12 percent slopes
Maybell Sand 12 to 45 percent slopes
Yetull Loamy Sand 5 to 25 percent slopes
Table 4. Representative soil features
| Parent material |
(1)
Eolian deposits
–
sandstone
|
|---|---|
| Surface texture |
(1) Sand (2) Loamy sand |
| Family particle size |
(1) Sandy |
| Drainage class | Excessively drained |
| Permeability class | Moderately rapid to rapid |
| Soil depth | 60 in |
| Surface fragment cover <=3" | 5% |
| Available water capacity (0-40in) |
2.6 – 4.3 in |
| Calcium carbonate equivalent (0-40in) |
2% |
| Soil reaction (1:1 water) (0-40in) |
6.6 – 9 |
Ecological dynamics
The plant community is about 40 percent grasses, 10 percent forbs, and 50 percent shrubs, air-dry weight.
The production is predominantly made up of antelope bitterbrush. Its aspect is a grass-shrub community dominated by antelope bitterbrush, silver sagebrush, Indian ricegrass, and needleandthread.
The dominant grasses are Indian ricegrass and needleandthread; and the less abundant of the grasses are sand dropseed, prairie Junegrass, and Nevada bluegrass. Smaller amounts of thickspike wheatgrass, western wheatgrass, and galleta. Forbs that make up the plant community include Louisiana sagewort, arrowleaf balsamroot, scarlet globemallow, and western yarrow.
Shrubs that occur on this site are antelope bitterbrush, Wyoming big sagebrush, silver sagebrush, gray horsebrush, and plains pricklypear.
If ecological retrogression is cattle induced, the percentage and production of desirable plants such as Indian ricegrass, needleandthread, prairie Junegrass, Nevada bluegrass, antelope bitterbrush, and winterfat will decrease. If retrogression is sheep induced, the percentage and production of desirable plants such as Indian ricegrass, Nevada bluegrass, prairie Junegrass, arrowleaf balsamroot, Louisiana sage, antelope bitterbrush, black sagebrush, gray horsebrush, silver sagebrush, winterfat, and Wyoming big sagebrush will decrease. Along with the decrease in desirable plants, there will be an increase in plants such as bottlebrush squirreltail, galleta, sand dropseed, foothills deathcamas, hairy goldaster, wooly locoweed, wormwood, rubber rabbitbrush, plains prickly pear, small low rabbitbrush, and annuals such as Russian thistle, cheatgrass, and annual mustards.
Further evidence of retrogression may be "hedging" of shrubs, particularly antelope bitterbrush, blowouts, active dune movement, a large increase in annuals, absence of plant litter and new seedlings, and highly unstable forage production from year to year.
During winters of severe temperatures and snows there will be heavy use in local areas of Wyoming big sagebrush, winterfat, silver sagebrush, gray horsebrush, and rubber rabbitbrush by deer, antelope, livestock, and any elk which occupy the site. Wildlife and livestock will make use of low palatable species to avoid starvation.
Generally there is adequate fuel on this site to carry fire. Should a fire burn across the site, the grasses will be benefited. Shrubs, particularly antelope bitterbrush, will be severely affected and will be several years in recovering. Rabbitbrush and horsebrush species will flourish. Production on the site will decline the first year and, thereafter, grasses and forbs will increase while most shrub species will have a long term increase.
This site will recover slowly from prolonged and/or severe drought. Grasses and forbs will show signs of stress and recovery earlier than shrubs because of their shallow root systems.
Range Site Description:
This site is dominated by antelope bitterbrush. Associated with this shrub are big sagebrush, silver sagebrush, gray horsebrush, low rabbitbrush and rubber rabbitbrush. Prickly pear occurs infrequently. The principal grasses are Indian ricegrass, needle-and-thread, sand dropseed and Sandberg bluegrass. Conspicuous forbs are hairy goldaster, eriogonum, lupine, loco, arrowleaf balsamroot, yarrow, wormwood, death camas, scarlet globemallow, cryptantha, evening-primrose and daisy fleabane.
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 text
Ecosystem states
State 1 submodel, plant communities
State 1
Reference State
Community 1.1
Antelope bitterbrush/Indian ricegrass/Needle and thread
This site supports a plant community of approximately 30 to 50 percent grass/grass-like, 5 to 10 percent forbs, and 45 to 60 percent shrubs. Of this production, 25 percent will likely be unpalatable or out of reach of grazing animals. Basal area is approximately 25 percent. Range Site Description: Percent ground cover is generally about 25 percent. Plants not a part of the potential community that are most likely to invade when the cover deteriorates are cheatgrass and other introduced annuals. Total Annual Production: Favorable years 1200 lbs/ac air dry Unfavorable years 600 lbs/ac air dry Median years 850 lbs/ac air dry
Figure 2. 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 | 230 | 340 | 560 |
| Shrub/Vine | 330 | 445 | 550 |
| Forb | 40 | 65 | 90 |
| Total | 600 | 850 | 1200 |
State 2
Degraded State
This 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 2
The 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 (lb/acre) | Foliar cover (%) | |
|---|---|---|---|---|---|---|
|
Grass/Grasslike
|
||||||
| 1 | 255–425 | |||||
| Indian ricegrass | ACHY | Achnatherum hymenoides | 85–125 | – | ||
| needle and thread | HECOC8 | Hesperostipa comata ssp. comata | 85–125 | – | ||
| prairie Junegrass | KOMA | Koeleria macrantha | 35–85 | – | ||
| sand dropseed | SPCR | Sporobolus cryptandrus | 35–85 | – | ||
| Sandberg bluegrass | POSE | Poa secunda | 35–85 | – | ||
| squirreltail | ELEL5 | Elymus elymoides | 15–35 | – | ||
| thickspike wheatgrass | ELLAL | Elymus lanceolatus ssp. lanceolatus | 10–25 | – | ||
| threadleaf sedge | CAFI | Carex filifolia | 10–25 | – | ||
| western wheatgrass | PASM | Pascopyrum smithii | 10–25 | – | ||
| James' galleta | PLJA | Pleuraphis jamesii | 10–25 | – | ||
| bluebunch wheatgrass | PSSP6 | Pseudoroegneria spicata | 10–25 | – | ||
| sixweeks fescue | VUOC | Vulpia octoflora | 10–15 | – | ||
| Grass, perennial | 2GP | Grass, perennial | 0–10 | – | ||
|
Forb
|
||||||
| 2 | 45–85 | |||||
| sand lupine | LUAM | Lupinus ammophilus | 10–15 | – | ||
| locoweed | OXYTR | Oxytropis | 10–15 | – | ||
| longleaf phlox | PHLO2 | Phlox longifolia | 10–15 | – | ||
| scarlet globemallow | SPCO | Sphaeralcea coccinea | 10–15 | – | ||
| deathcamas | ZIGAD | Zigadenus | 10–15 | – | ||
| white sagebrush | ARLU | Artemisia ludoviciana | 10–15 | – | ||
| arrowleaf balsamroot | BASA3 | Balsamorhiza sagittata | 10–15 | – | ||
| bastard toadflax | COMAN | Comandra | 10–15 | – | ||
| common yarrow | ACMI2 | Achillea millefolium | 10–15 | – | ||
| sulphur-flower buckwheat | ERUM | Eriogonum umbellatum | 10–15 | – | ||
| hairy false goldenaster | HEVI4 | Heterotheca villosa | 0–10 | – | ||
| tarragon | ARDR4 | Artemisia dracunculus | 0–10 | – | ||
| prairie fleabane | ERST3 | Erigeron strigosus | 0–10 | – | ||
| spotted evening primrose | OECA3 | Oenothera canescens | 0–10 | – | ||
| Forb, perennial | 2FP | Forb, perennial | 0–10 | – | ||
|
Shrub/Vine
|
||||||
| 3 | 380–510 | |||||
| antelope bitterbrush | PUTR2 | Purshia tridentata | 250–350 | – | ||
| silver sagebrush | ARCA13 | Artemisia cana | 45–85 | – | ||
| Wyoming big sagebrush | ARTRW8 | Artemisia tridentata ssp. wyomingensis | 45–85 | – | ||
| plains pricklypear | OPPO | Opuntia polyacantha | 20–45 | – | ||
| spineless horsebrush | TECA2 | Tetradymia canescens | 20–35 | – | ||
| rubber rabbitbrush | ERNA10 | Ericameria nauseosa | 20–35 | – | ||
| winterfat | KRLA2 | Krascheninnikovia lanata | 10–20 | – | ||
| granite prickly phlox | LIPU11 | Linanthus pungens | 10–20 | – | ||
| yellow rabbitbrush | CHVIV4 | Chrysothamnus viscidiflorus ssp. viscidiflorus var. viscidiflorus | 10–20 | – | ||
| black sagebrush | ARNO4 | Artemisia nova | 10–20 | – | ||
Interpretations
Animal community
WILDLIFE INERPRTATIONS:
This range site provides habitats which support a resident animal community that is characterized by antelope, sagegrouse, Nuttal and desert cottontail, white-tailed jackrabbit, sage thrasher, western bluebird, western meadowlark, Brewers sparrow, mourning dove, red-tailed hawk, marsh hawk, golden eagle, seasonal use by muledeer, and occasonally elk during winter.
GRAZING INTERPRETATIONS:
This site is very productive in palatable species. In order to maintain this high productivity, care must be taken to avoid overgrazing. Herding of sheep and movement of cattle during early spring growth is necessary to avoid depletion of stored carbohydrates and photosynthetic material by continual spring grazing. A system of deferred grazing, which varies the season of grazing in pastures during successive years, is needed to maintain a healthy well-balanced plant community. Rest during different seasons of the year benefits different plants. Fall and winter rest (October-March) benefits shrubs such as antelope bitterbrush, winterfat, silver sagebrush, Wyoming big sagebrush, and black sagebrush. Spring rest (March-May) benefits cool season plants such as Indian ricegrass, needleandthread, prairie junegrass, Nevada bluegrass, arrowleaf balsamroot, and Louisiana sage. Deferment during late winter and early spring reduces competition between wildlife and livestock for palatable shrubs and forbs.
Vegetation palatability by animal class is based on the attractiveness of the plant to animals as forage. Grazing preference changes from time to time and place to place depending on the animal class, plant palatability and nutrient value, stage of growth, and season of use.
GUIDE TO INITIAL STOCKING RATES:
Stocking rates given below are based on continuous use for the entire growing season and are intended only as an initial guide. Forage needs are calculated on the basis of 900 lbs of air-dry forage per animal unit month (AUM). To maintain proper use and allow for forage that disappears through trampling, small herbivore use, weathering, etc., 35 percent of the palatable forage produced is considered available for grazing by large herbivores.
CONDITION CLASS - (PERCENT CLIMAX VEGETATION)
excellent - (76-100) - 3.7 AC/AUM - .27 AUM/AC
good - (51-75) - 6.0 AC/AUM - .17 AUM/AC
fair - (26-50) - 13.0 AC/AUM - .08 AUM/AC
poor - (0-25) - 20.0+ AC/AUM - .05 AUM/AC
Adjustments to the initial stocking rates should be made as needed to obtain proper use. With specialized grazing systems, large livestock breeds, uncontrolled big game herbivores, inaccessability, dormant season use, etc., stocking rate adjustments will be required.
Hydrological functions
Soils in this site are grouped into "A" hydrologic group, as outlined in the Soils of Colorado Loss Factors and Erodibilitv Hydrologic Groupinqs handbook. Field investigations are needed to determine hydrologic cover conditions and hydrologic curve numbers. Refer to Peak Flows in Colorado handbook, and SCS National Enqineerinq Handbook, Section 4, for hydrologic curve numbers in determining runoff quantities.
Recreational uses
There is limited potential for this site with regard to natural beauty. There is, however, a very high potential for this site in hunting big game species, as well as coyotes and rabbits. There is also a high potential for wildlife observation and picture taking.
Wood products
None.
Other products
None noted.
Other information
Deathcamas is poisonous to sheep and may affect cattle and horses. One half pound will poison sheep. Spring and summer are the seasons of most common poisoning.
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 Kinney
Approval
Kirt Walstad, 9/07/2023
Acknowledgments
Field offices in Colorado where the site occurs: Craig
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 | 09/12/2023 |
| Approved by | Kirt Walstad |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
-
Presence of water flow patterns:
-
Number and height of erosional pedestals or terracettes:
-
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
-
Number of gullies and erosion associated with gullies:
-
Extent of wind scoured, blowouts and/or depositional areas:
-
Amount of litter movement (describe size and distance expected to travel):
-
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
-
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
-
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
-
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
-
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:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
-
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
-
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:
-
Perennial plant reproductive capability:
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