Natural Resources
Conservation Service
Ecological site R010XC043OR
SR South 9-12 PZ
Accessed: 11/21/2024
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.
Figure 1. Mapped extent
Areas shown in blue indicate the maximum mapped extent of this ecological site. Other ecological sites likely occur within the highlighted areas. It is also possible for this ecological site to occur outside of highlighted areas if detailed soil survey has not been completed or recently updated.
Associated sites
| R010XC021OR |
SR Clayey 9-12 PZ SR Clayey 9-12" PZ |
|---|---|
| R010XC035OR |
SR Shallow 9-12 PZ SR Shallow 9-12" PZ |
| R010XC038OR |
SR Very Shallow 9-12 PZ SR Very Shallow 9-12" PZ |
| R010XC050OR |
SR Shallow South 9-12 PZ SR Shallow South 9-12" PZ |
Similar sites
| R010XC050OR |
SR Shallow South 9-12 PZ SR Shallow South 9-12" PZ (shallower soil, lower production) |
|---|
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Artemisia tridentata var. wyomingensis |
| Herbaceous |
(1) Pseudoroegneria spicata ssp. spicata |
Physiographic features
This site occurs on canyon sideslopes and south exposures of terraces and tablelands. Slopes range from 12 to 70 percent. Elevations typically range from 2000 to 4500 feet.
Table 2. Representative physiographic features
| Landforms |
(1)
Canyon
(2) Terrace |
|---|---|
| Flooding frequency | None |
| Ponding frequency | None |
| Elevation | 2,000 – 4,500 ft |
| Slope | 12 – 70% |
| Aspect | SE, S, SW |
Climatic features
The annual precipitation ranges from 9 to 12 inches, most of which occurs in the form of rain and snow during the months of November through March. Localized, occasionally severe, convectional storms occur during the summer. The soil temperature regime is typically mesic with a mean annual air temperature of about 52 degrees F. Temperature extremes range from 100 to -20 degrees F. The frost-free period ranges from 120 to 160 days. The optimum period for plant growth is from April through June.
Table 3. Representative climatic features
| Frost-free period (average) | 160 days |
|---|---|
| Freeze-free period (average) | 0 days |
| Precipitation total (average) | 12 in |
Influencing water features
Soil features
The soils of this site are typically moderately deep to deep and moderately well to well-drained. Typically the surface layer is a silt loam or gravelly clay loam about 3 to 10 inches thick. The subsoil is a clay loam, gravelly clay, or clay about 8 to 23 inches thick. Depth to bedrock or lacustrine or alluvial sediments is 20 to 40 inches. Permeability is very slow to moderately rapid. The available water holding capacity is about 4 to 6 inches. The potential for erosion is moderate to severe.
Table 4. Representative soil features
| Surface texture |
(1) Very cobbly silt loam (2) Very gravelly clay loam (3) Gravelly silty clay loam |
|---|---|
| Family particle size |
(1) Clayey |
| Drainage class | Well drained |
| Permeability class | Slow to moderate |
| Soil depth | 20 – 60 in |
| Surface fragment cover <=3" | 35% |
| Surface fragment cover >3" | 20% |
| Available water capacity (0-40in) |
4 – 6 in |
| Calcium carbonate equivalent (0-40in) |
Not specified |
| Electrical conductivity (0-40in) |
Not specified |
| Sodium adsorption ratio (0-40in) |
Not specified |
| Soil reaction (1:1 water) (0-40in) |
6.1 – 8.4 |
| Subsurface fragment volume <=3" (Depth not specified) |
50% |
| Subsurface fragment volume >3" (Depth not specified) |
45% |
Ecological dynamics
Range in Characteristics:
Gravels in the surface layer or a decrease in clay in the subsoil will favor the presence of Thurber needlegrass in the stand. Wyoming big sagebrush is the dominant shrub at the lower end of the precipitation range while basin big sagebrush increases at the higher end of the precipitation range. Production increases on deeper foot slope soils.
Response to Disturbance:
If the condition of the site deteriorates as a result of overgrazing, bluebunch wheatgrass and Thurber needlegrass decrease while sagebrush, rabbitbrush, and Sandberg bluegrass increase. Bluebunch wheatgrass is the preferred species during spring and summer. With further deterioration, annuals invade. Under deteriorated conditions, annual grasses and shrubs dominate the site.
State and transition model
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Ecosystem states
State 1 submodel, plant communities
State 1
Reference Plant Community
Community 1.1
Reference Plant Community
The potential native plant community is dominated by Wyoming big sagebrush and bluebunch wheatgrass. Basin big sagebrush, Thurber needlegrass, and Sandberg bluegrass are common in the stand. Vegetative composition of the community is approximately 85 percent grasses, 5 percent forbs, and 10 percent shrubs. Approximate ground cover is 50 to 70 percent (basal and crown).
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 | 510 | 680 | 850 |
| Shrub/Vine | 60 | 80 | 100 |
| Forb | 30 | 40 | 50 |
| Total | 600 | 800 | 1000 |
Figure 3. Plant community growth curve (percent production by month). OR4501, B10 SR Souths & Shallows 9-12 pz. SR Souths & Shallows 9-12 pz RPC Growth Curve.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| J | F | M | A | M | J | J | A | S | O | N | D |
| 0 | 0 | 5 | 10 | 40 | 30 | 5 | 5 | 5 | 0 | 0 | 0 |
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 | Perennial, deep-rooted, dominant | 480–640 | ||||
| bluebunch wheatgrass | PSSPS | Pseudoroegneria spicata ssp. spicata | 480–640 | – | ||
| 2 | Perennial, deep-rooted, sub-dominant | 40–160 | ||||
| Thurber's needlegrass | ACTH7 | Achnatherum thurberianum | 40–160 | – | ||
| 4 | Perennial, shallow-rooted, sub-dominant | 24–64 | ||||
| Sandberg bluegrass | POSE | Poa secunda | 24–64 | – | ||
| 5 | Other perennial grasses | 16–40 | ||||
| squirreltail | ELEL5 | Elymus elymoides | 0–16 | – | ||
| Idaho fescue | FEID | Festuca idahoensis | 0–16 | – | ||
| basin wildrye | LECI4 | Leymus cinereus | 0–16 | – | ||
|
Forb
|
||||||
| 6 | Perennial, all, dominant | 16–40 | ||||
| arrowleaf balsamroot | BASA3 | Balsamorhiza sagittata | 16–40 | – | ||
| 7 | Perennial forb | 8–16 | ||||
| desertparsley | LOMAT | Lomatium | 8–16 | – | ||
| 8 | Perennial forb | 8–16 | ||||
| lupine | LUPIN | Lupinus | 8–16 | – | ||
| 9 | Other perennial forbs, all | 8–40 | ||||
| common yarrow | ACMI2 | Achillea millefolium | 0–8 | – | ||
| onion | ALLIU | Allium | 0–8 | – | ||
| pussytoes | ANTEN | Antennaria | 0–8 | – | ||
| milkvetch | ASTRA | Astragalus | 0–8 | – | ||
| tapertip hawksbeard | CRAC2 | Crepis acuminata | 0–8 | – | ||
| fleabane | ERIGE2 | Erigeron | 0–8 | – | ||
| buckwheat | ERIOG | Eriogonum | 0–8 | – | ||
| stoneseed | LITHO3 | Lithospermum | 0–8 | – | ||
| tansyaster | MACHA | Machaeranthera | 0–8 | – | ||
| phacelia | PHACE | Phacelia | 0–8 | – | ||
| phlox | PHLOX | Phlox | 0–8 | – | ||
| primrose | PRIMU | Primula | 0–8 | – | ||
|
Shrub/Vine
|
||||||
| 11 | Perennial, evergreen, dominant | 16–40 | ||||
| Wyoming big sagebrush | ARTRW8 | Artemisia tridentata ssp. wyomingensis | 16–40 | – | ||
| 12 | Perennial, evergreen, sub-dominant | 24–56 | ||||
| basin big sagebrush | ARTRT | Artemisia tridentata ssp. tridentata | 8–24 | – | ||
| rubber rabbitbrush | ERNA10 | Ericameria nauseosa | 8–16 | – | ||
| antelope bitterbrush | PUTR2 | Purshia tridentata | 8–16 | – | ||
| 14 | Perennial, deciduous, sub-dominant | 0–32 | ||||
| wild crab apple | PERA4 | Peraphyllum ramosissimum | 0–16 | – | ||
| antelope bitterbrush | PUTR2 | Purshia tridentata | 0–16 | – | ||
| 15 | Other perennial shrubs, all | 8–24 | ||||
| threetip sagebrush | ARTR4 | Artemisia tripartita | 0–8 | – | ||
| hackberry | CELTI | Celtis | 0–8 | – | ||
| yellow rabbitbrush | CHVI8 | Chrysothamnus viscidiflorus | 0–8 | – | ||
| broom snakeweed | GUSA2 | Gutierrezia sarothrae | 0–8 | – | ||
| horsebrush | TETRA3 | Tetradymia | 0–8 | – | ||
Interpretations
Animal community
Livestock Grazing:
Warm temperatures and early maturing forage attract livestock to south-facing slopes in early spring. Without a grazing system that will give periodic deferment, there will be a decline in plant vigor and reproduction. Failure to manage livestock on these sites will lead to the rapid loss of any productive value.
Native Wildlife Associated with the Potential Climax Community:
Mule deer
Hawks
Rodents
Songbirds
The southerly aspect of this site offers warm temperatures and early spring growth that attracts several grazing and browsing forms of wildlife and gallinaceous birds in winter and spring.
Hydrological functions
The soils are in hydrologic group C. The soils of this site have moderate runoff potential and medium infiltration rates when the hydrologic cover is good. Hydrologic cover is good when the bluebunch wheatgrass deep rooted bunchgrass component is >70 percent of potential. Under lower seral conditions runoff potential is high. This occurs when deep rooted perennial bunchgrass cover is low and bare ground increases.
Supporting information
Contributors
A. Bahn, H. Futter, G. Kuehl, K. Danks, H. Barrett
Bob Gillaspy
M. Parks (OSU)
T.Bloomer, E.Petersen, B.Gillaspy, A.Bahn
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) | Jeff Repp and Bruce Franssen |
|---|---|
| Contact for lead author | State Rangeland Management Specialist |
| Date | 04/15/2005 |
| Approved by | Bob Gillaspy |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
None. -
Presence of water flow patterns:
None to few (on steeper slopes) -
Number and height of erosional pedestals or terracettes:
None. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
5-20% -
Number of gullies and erosion associated with gullies:
None. -
Extent of wind scoured, blowouts and/or depositional areas:
None. -
Amount of litter movement (describe size and distance expected to travel):
Fine - limited movement -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Moderate to significant resistant to erosion: aggregate stability = 3-6 -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Moderate medium granular structure to weak medium platy structure, dry color value 3 - 6, 3 - 12 inches thick; Moderate OM (2-4%) -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Moderate ground cover (50-70%) and moderate to steep slopes (12-70%) moderately limit rainfall impact and overland flow. -
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:
Deep rooted perennial bunchgrassesSub-dominant:
Evergreen shrubs >= perennial forbsOther:
Shallow rooted perennial bunchgrassesAdditional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Normal decadence and mortality expected. -
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
Favorable: 1000, Normal: 800, Unfavorable: 600 lbs/acre/year -
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:
Western Juniper readily invades the site. Cheatgrass and Medusahead invade sites that have lost deep rooted perennial grass functional group. -
Perennial plant reproductive capability:
All species should be capable of reproducing annually.
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