Natural Resources
Conservation Service
Ecological site R010XC021OR
SR Clayey 9-12 PZ
Accessed: 12/06/2024
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
R010XC020OR |
SR Loamy 9-12 PZ SR Loamy 9-12 PZ |
---|---|
R010XC035OR |
SR Shallow 9-12 PZ SR Shallow 9-12 PZ |
R010XC043OR |
SR South 9-12 PZ SR South 9-12 PZ |
R010XC063OR |
SR Droughty North 9-12 PZ SR Droughty North 9-12 PZ |
R010XC064OR |
SR North 9-12 PZ SR North 9-12 PZ |
Similar sites
R010XC035OR |
SR Shallow 9-12 PZ SR Shallow 9-12 PZ (shallower depth, lower production) |
---|---|
R010XC020OR |
SR Loamy 9-12 PZ SR Loamy 9-12 PZ (coarser surface texture, clayey subsoil at greater depth, different composition - Thurber’s needlegrass sub-dominant) |
Table 1. Dominant plant species
Tree |
Not specified |
---|---|
Shrub |
(1) Artemisia tridentata ssp. wyomingensis |
Herbaceous |
(1) Pseudoroegneria spicata ssp. spicata |
Physiographic features
This site occurs on mid elevation terrace, tablelands and rolling uplands. Slopes typically range from 2 to 12%. Elevations vary from 2,000 to 3,500 feet.
Table 2. Representative physiographic features
Landforms |
(1)
Terrace
(2) Hill |
---|---|
Elevation | 610 – 1,067 m |
Slope | 2 – 12% |
Aspect | Aspect is not a significant factor |
Climatic features
The annual precipitation ranges from 9 to 12 inches, most of which occurs in the form of snow and rain during the months of November through April. Localized convection storms occasionally occur during the summer. The soil temperature regime is mesic with a mean air temperature of 52 degrees F. Temperature extremes range from 100 to -10 degrees F. The frost free period ranges from 110 to 140 days. The optimum growth period for plant growth is April through June.
Table 3. Representative climatic features
Frost-free period (average) | 140 days |
---|---|
Freeze-free period (average) | 169 days |
Precipitation total (average) | 305 mm |
Figure 2. Monthly precipitation range
Figure 3. Monthly average minimum and maximum temperature
Influencing water features
Soil features
The soils of this site are typically moderately deep to deep and well drained. Typically the surface layer is a silty clay loam 6 to 10 inches thick. The subsoil is a silt clay loam to clay 10 to 25 inches thick. Depth to an indurated pan, lacustrine or alluvial sediments, or bedrock is 20 to greater than 40 inches. Permeability is moderate to very slow. The available water holding capacity (AWC) is about 4 to 6 inches for the profile. The erosion potential is moderate to severe.
Table 4. Representative soil features
Parent material |
(1)
Eolian deposits
–
rhyolite
|
---|---|
Surface texture |
(1) Sandy clay loam |
Family particle size |
(1) Clayey |
Drainage class | Well drained |
Permeability class | Moderate to very slow |
Soil depth | 51 – 152 cm |
Available water capacity (0-101.6cm) |
10.16 – 15.24 cm |
Ecological dynamics
The reference plant community is dominated by Wyoming big sagebrush and bluebunch wheatgrass. Basin big sagebrush and Thurber needlegrass are present. Sandberg bluegrass is the dominant shallow rooted perennial grass. A variety of forbs are common. Vegetative composition of the community is approximately 80 percent grasses, 10 percent forbs and 10 percent shrubs. The approximate ground cover is 70 to 80 percent (basal and crown).
Range in Characteristics:
Bluebunch wheatgrass increases on clayey surfaces. Thurber’s needlegrass increases on loamy surfaces and on droughtier sites. Wyoming big sagebrush is clearly dominant at lower precipitations while basin big sagebrush increases at higher precipitations. Crab apple is associated with sediments including those interlaid with diatomaceous earth. Production increases at the upper end of the precipitation zone.
Response to Disturbance:
When the condition of the site deteriorates as a result of over grazing bluebunch wheatgrass rapidly decreases. Wyoming big sagebrush and Sandberg bluegrass increase. Cheatgrass, medusahead, other annuals, biennial weeds and bulbous bluegrass are strong invaders. With fire and continued disturbance sagebrush is severely impacted, rabbitbrush increases slightly and annuals and noxious biennial forbs continue to invade. Bare ground increases and excessive erosion contributes to downstream sedimentation. The excessive erosion is most pronounced in drainage areas where deep incised gulley’s form.
States: ARTRW/POSE-BRTE; POSE-POBU/biennial forbs or BRTE-TACA8/biennial forbs (following fire on degraded range)
Treatment Response:
The repair pathways located between State 1 and States 2 and 3 indicates potential for rehabilitation. It will require mechanical or chemical treatment of sagebrush and annual grasses along with seeding of native or adapted introduced species in either of these two plant communities. If annual grasses are present in either of them it will require long term treatment. Since the risk of a seeding failure is high, it would be advisable to implement assisted succession by planting an aggressive perennial such as crested wheatgrass and then following up years later with a reintroduction of native species. Every effort should be made to prevent establishment of annual grasses on this site.
Reference Plant Community
State 1 – Reference State
Three plant community phases occur in the Reference State. They are phase 1.1, the perennial grass and forb phase, phase 1.2, the sagebrush grass phase and phase 1.3, the sagebrush dominant phase.
Phase 1.1. The perennial grass and forb phase. This plant community is strongly dominated by bluebunch wheatgrass with Thurber’s needlegrass, basin wildrye and Sandberg bluegrass being common. Lesser amounts of other perennial grasses and a small amount of forbs are also present. Energy capture, nutrient cycling and water use are controlled by the perennial grasses.
Phase 1.2. The Reference Plant Community Phase (RPCP) is the sagebrush grass phase. The sagebrush grass phase results with prescribed grazing and a normal fire frequency of 40-60 years (1.1A). Wyoming big sagebrush and basin big sagebrush are both common. The composition of sagebrush within the plant community will increase as the length of time between fires gets longer. Grasses compose 85 % of the community, forbs 5% and shrubs 10%. A period of improper grazing can accelerate the increase in sagebrush even if the bunchgrass plant community is maintained. Under prescribed grazing and fire the plant community pathway (1.2A) moves back toward Phase 1.1, the perennial grass and forb phase. With the continued absence of fire and improper grazing management or drought (1.2B), the plant community will move towards phase 1.3, sagebrush dominant phase. The ecological processes in this phase are still controlled by the perennial grasses.
Phase 1.3. The sagebrush dominant phase is dominated by Wyoming or basin big sagebrush, and lesser amounts of bluebunch wheatgrass, Thurber’s needlegrass, basin wildrye and Idaho fescue. Sandberg bluegrass has increased in the stand as well as cheatgrass. Big sagebrush controls the ecological processes in this plant community. This phase is a result of the absence of fire with improper grazing or drought and can occur through community pathways 1.1B or 1.2B. This phase is the “at risk” plant community within State 1. As the site deteriorates the potential for cheatgrass invasion increases. With prescribed grazing and fire this phase can be returned to Phase 1.1 by community pathway 1.3A. Since this phase is “at risk” it can transition to State 2 (IRT1A) with the continued lack of fire and improper grazing or drought. With fire, improper grazing and drought this plant community can transition to State 3 (IRT1B).
State 2. This State is dominated by big sagebrush which controls all of the ecological processes. Initially, Phase 2.1, the sagebrush dominant phase is occupied by Wyoming and basin big sagebrush, with minor amounts of bluebunch wheatgrass and Thurber’s needlegrass. Sandberg bluegrass has increased along with cheatgrass. If fire continues to be suppressed and severe improper grazing continues, the sagebrush will become decadent and the cheatgrass will replace the bunchgrass understory. The potential for soil erosion increases as this transition in the plant community occurs. The risk of an irreversible transition (IRT2A) over an abiotic threshold to the Erosional State, State 4, increases with fire, improper grazing or drought.
State 3. This state is dominated by annual grasses with few other shallow-rooted grasses in the understory but may have some rabbitbrush (3.1) in the overstory. This state is recognized as the annual grass phase and is a result of fire, improper grazing and drought. Continued improper grazing and fire will transition this state to the eroded state 4. The ecological processes in this state are controlled by the annual grasses.
State 4. This is the eroded state and is recognized by the soil erosion that is occurring or has occurred on the site in the past. Since this state has occurred through widespread erosion as a result of severe improper grazing in combination with fire all of the other states can transition to this State. The increase in bare ground facilitates the increase in wind and/or water erosion. Abiotic factors control site resources and ecological functions. Rehabilitation of this state may not be practical or possible due to extreme soil loss.
State and transition model
Figure 4. SR CLAYEY 9-12 PZ - R010XC021OR
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Ecosystem states
State 1 submodel, plant communities
State 1
Reference State
Community 1.1
Reference Plant Community
The reference plant community is dominated by Wyoming big sagebrush and bluebunch wheatgrass. Basin big sagebrush and Thurber needlegrass are present. Sandberg bluegrass is the dominant shallow rooted perennial grass. A variety of forbs are common. Vegetative composition of the community is approximately 80 percent grasses, 10 percent forbs and 10 percent shrubs. The approximate ground cover is 70 to 80 percent (basal and crown).
Figure 5. 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 | 572 | 953 | 1429 |
Shrub/Vine | 67 | 112 | 168 |
Forb | 34 | 56 | 84 |
Total | 673 | 1121 | 1681 |
Figure 6. Plant community growth curve (percent production by month). OR4461, B10 SR Lmy Clayey & No. 9-12pz. SR Lmy Clayey & No. 9-12pz 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 | 15 | 35 | 25 | 10 | 0 | 10 | 0 | 0 | 0 |
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 | Dominant, perennial, deep-rooted bunchgrass | 560–785 | ||||
bluebunch wheatgrass | PSSPS | Pseudoroegneria spicata ssp. spicata | 560–785 | – | ||
2 | Sub-dominant, perennial, deep rooted bunchgrass | 34–90 | ||||
Thurber's needlegrass | ACTH7 | Achnatherum thurberianum | 34–90 | – | ||
3 | Sub-dominant, perennial, shallow-rooted grass | 22–56 | ||||
Sandberg bluegrass | POSE | Poa secunda | 22–56 | – | ||
4 | Other perennial grasses | 22–135 | ||||
basin wildrye | LECI4 | Leymus cinereus | 34–90 | – | ||
Idaho fescue | FEID | Festuca idahoensis | 22–56 | – | ||
Cusick's bluegrass | POCU3 | Poa cusickii | 0–22 | – | ||
squirreltail | ELEL5 | Elymus elymoides | 11–22 | – | ||
Forb
|
||||||
7 | Dominant, perennial forb | 22–56 | ||||
arrowleaf balsamroot | BASA3 | Balsamorhiza sagittata | 11–34 | – | ||
desertparsley | LOMAT | Lomatium | 11–22 | – | ||
9 | Other perennial forbs | 11–56 | ||||
agoseris | AGOSE | Agoseris | 0–11 | – | ||
onion | ALLIU | Allium | 0–11 | – | ||
pussytoes | ANTEN | Antennaria | 0–11 | – | ||
milkweed | ASCLE | Asclepias | 0–11 | – | ||
milkvetch | ASTRA | Astragalus | 0–11 | – | ||
mariposa lily | CALOC | Calochortus | 0–11 | – | ||
Indian paintbrush | CASTI2 | Castilleja | 0–11 | – | ||
bastard toadflax | COMAN | Comandra | 0–11 | – | ||
tapertip hawksbeard | CRAC2 | Crepis acuminata | 0–11 | – | ||
hawksbeard | CREPI | Crepis | 0–11 | – | ||
fleabane | ERIGE2 | Erigeron | 0–11 | – | ||
buckwheat | ERIOG | Eriogonum | 0–11 | – | ||
common woolly sunflower | ERLA6 | Eriophyllum lanatum | 0–11 | – | ||
haplopappus | HAPLO11 | Haplopappus | 0–11 | – | ||
woodland-star | LITHO2 | Lithophragma | 0–11 | – | ||
stoneseed | LITHO3 | Lithospermum | 0–11 | – | ||
lupine | LUPIN | Lupinus | 0–11 | – | ||
hoary tansyaster | MACA2 | Machaeranthera canescens | 0–11 | – | ||
beardtongue | PENST | Penstemon | 0–11 | – | ||
phlox | PHLOX | Phlox | 0–11 | – | ||
deathcamas | ZIGAD | Zigadenus | 0–11 | – | ||
Shrub/Vine
|
||||||
11 | Dominant, evergreen shrub | 34–90 | ||||
basin big sagebrush | ARTRT | Artemisia tridentata ssp. tridentata | 22–56 | – | ||
13 | Other shrubs | 11–22 | ||||
threetip sagebrush | ARTR4 | Artemisia tripartita | 0–11 | – | ||
yellow rabbitbrush | CHVI8 | Chrysothamnus viscidiflorus | 0–11 | – | ||
rubber rabbitbrush | ERNA10 | Ericameria nauseosa | 0–11 | – | ||
wild crab apple | PERA4 | Peraphyllum ramosissimum | 0–11 | – | ||
antelope bitterbrush | PUTR2 | Purshia tridentata | 0–11 | – | ||
littleleaf horsebrush | TEGL | Tetradymia glabrata | 0–11 | – |
Interpretations
Animal community
Livestock Grazing:
This site is suitable for livestock grazing use in the spring, and fall under a planned grazing system. Use should be postponed until the soils are firm enough to prevent trampling damage and soil compaction. Grazing management should be keyed for bluebunch wheatgrass. Deferred grazing or rest is recommended at least once every three years.
Native Wildlife Associated with the Potential Climax Community:
This site is commonly used by pronghorn antelope, mule deer, rabbits, rodents, upland birds and various predators. It is a preferred site for sage grouse nesting, rearing and wintering. Antelope and mule deer make excellent use of the site for winter and spring forage.
Mule deer
Hawks
Rodents
This site offers food and cover for mule deer, rodents, and a variety of birds.
Hydrological functions
The soils of this site are typically in an upland topographic position. They have moderate runoff potential and medium infiltration rates when the hydrologic cover is high. Hydrologic cover is high when bluebunch wheatgrass and other deep rooted bunchgrass component is greater than 70 percent of potential. The soils are in hydrologic groups C and D.
Supporting information
Other references
Stringham, Tamzen, 2007. Final Report for USDA Ecological Site Description. Oregon State University, Corvallis, Oregon.
USDI Bureau of Land Management, US Geological Survey; USDA Natural Resources Conservation Service, Agricultural Research Service; Interpreting Indicators of Rangeland Health. Technical Reference 1734-6; Version 4-2005.
Contributors
BLM/SCS Team - Burns - A. Bahn, H. Futter, K. Danks, G. Kuehl, H. Barrett
M. Parks (OSU)
T.Bloomer, E.Petersen, 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) | James A. Cornwell, State Rangeland Management Specialist, NRCS, Idaho (Retired); Lee Brooks, Assistant State Conservationist, NRCS, Idaho (Retired). |
---|---|
Contact for lead author | State Rangeland Management Specialist for NRCS – Oregon |
Date | 09/10/2009 |
Approved by | Bob Gillaspy |
Approval date | |
Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
None. Moderate sheet and rill erosion hazard. -
Presence of water flow patterns:
None. -
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):
30-40%. -
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, typically < two feet. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Moderately resistant to erosion. Aggregate stability 3-5. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Structure ranges from weak to strong very thin platy and platy structure. SOM is 0.5 to 2.0 percent. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Significant ground cover and gentle slopes (2-20%) 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. Deeper soils on this site have a duripan or cemented hardpan between 20-30 inches. -
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, cool-season bunchgrasses >>Sub-dominant:
Shallow-rooted, perennial, cool-season bunchgrasses >Other:
Tall shrubs > ForbsAdditional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Big sagebrush will become decadent in the absence of normal fire frequency and ungulate grazing. Grass and forb mortality will occur as tall shrubs increase. Normal decadence would be expected in the bluebunch wheatgrass. This would be evidenced by the dead centers in the plants. -
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
Favorable: 1400; Normal: 1000; Unfavorable: 600 lbs/ac/yr -
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, medusahead, dalmation toadflax, Russian, diffuse and spotted knapweed -
Perennial plant reproductive capability:
All species should be capable of reproducing annually.
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