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Natural Resources
Conservation Service
Ecological site R023XY308OR
NORTH SLOPES 10-12 PZ
Accessed: 08/17/2024
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.
![Location map](/images/maps/R023XY308OR.png)
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
R023XY212OR |
LOAMY 10-12 PZ Loamy 10-12" PZ |
---|---|
R023XY300OR |
SOUTH SLOPES 10-12 PZ South Slopes 8-12" PZ |
R023XY312OR |
SHALLOW NORTH 12-16 PZ Shallow North 12-16" PZ |
Similar sites
R023XY318OR |
LOAMY 12-16 PZ Loamy 12-16" PZ (non-aspect site at higher precipitation) |
---|---|
R023XY310OR |
NORTH SLOPES 12-16 PZ North Slopes 12-16" PZ (higher precipitation) |
Table 1. Dominant plant species
Tree |
Not specified |
---|---|
Shrub |
(1) Artemisia tridentata ssp. tridentata |
Herbaceous |
(1) Festuca idahoensis |
Physiographic features
This site is on north-facing hillslopes and escarpments. Slopes range from 20 to 60 percent. Elevations range from 4500 to 6000 feet.
Table 2. Representative physiographic features
Landforms |
(1)
Escarpment
(2) Hill |
---|---|
Elevation | 1,372 – 1,829 m |
Slope | 20 – 60% |
Aspect | N |
Climatic features
The annual precipitation is 10 to 12 inches most of which occurs in the form of snow during November to March. Spring rains are common. The soil temperature regime is frigid. Extreme air temperatures range from 100 degrees F to -30 degrees F. The frost-free period is about 50 to 90 days. The optimum period for plant growth is from early May to mid-July.
Table 3. Representative climatic features
Frost-free period (average) | 90 days |
---|---|
Freeze-free period (average) | 0 days |
Precipitation total (average) | 305 mm |
Figure 2. Monthly average minimum and maximum temperature
Influencing water features
Soil features
The soils in this site are medium textured throughout, moderately-deep to deep, and well-drained. The soils are formed in colluvium and/or residuum. The surface permeability is moderate and the subsoil has moderately slow permeability. The available water holding capacity (AWC) is 1 to 4 inches for the profile. The soil has a dark colored surface 20 or more inches thick which contains 25 to 60 percent rock fragments. The subsoil contains 20 to 80 percent rock fragments.
Table 4. Representative soil features
Parent material |
(1)
Colluvium
–
basalt
(2) Residuum – welded tuff |
---|---|
Surface texture |
(1) Extremely cobbly loam (2) Very gravelly loam |
Family particle size |
(1) Loamy |
Drainage class | Well drained |
Permeability class | Moderate to moderately slow |
Soil depth | 51 – 152 cm |
Surface fragment cover <=3" | 35 – 60% |
Available water capacity (0-101.6cm) |
1.52 – 10.16 cm |
Soil reaction (1:1 water) (0-101.6cm) |
6.6 – 7.8 |
Subsurface fragment volume >3" (Depth not specified) |
35 – 80% |
Ecological dynamics
Range in Characteristics:
The reference native plant community is dominated by Idaho fescue and Wyoming big sagebrush. Bluebunch wheatgrass is prominent in the understory. Vegetative composition is about 75 percent grasses, 10 percent forbs, and 15 percent shrubs.
Bluebunch wheatgrass increases as aspect becomes more southerly. Gravels in the surface layers favor increases in Thurber's needlgrass.
Four states have been identified for this site: a reference state; a state with the presence of annuals; a state with a shrub/annual co-dominance; and a state with annual dominance.
Reference State: Plant community phase change is driven by infrequent fire. Wyoming and basin big sagebrush decline after fire while Thurber’s needlegrass, Idaho fescue and other grasses increase. Rabbitbrush may temporarily increase after fire. Time facilitates the reintroduction of sagebrush. The introduction of invasive annual grasses and forbs transitions into state 2.
State 2: Compositionally similar to the reference state with a trace of cheatgrass and weedy forbs. Ecological function has not changed, however the resiliency of the state has been reduced by the presence of invasive weeds. Prescribed grazing and infrequent fire (> 50 year return interval) maintain state dynamics. Improper grazing or prolonged drought favors Wyoming and basin big sagebrush, squirreltail and Sandberg’s bluegrass. Prescribed grazing and/or release from drought may reverse the decline in needlegrass and Idaho fescue production. Infrequent fire reduces the shrub community and promotes the bunchgrass component. Mismanaged grazing and/or prolonged drought leads to a biotic threshold and into state 3.
State 3: Wyoming and basin big sagebrush is decadent with little recruitment. The perennial grass component is significantly reduced in both density and productivity. Cheatgrass and/or annual forbs and/or Sandberg’s bluegrass along with sagebrush control site resources and drive ecological dynamics. Bare ground is abundant. Spatial and temporal energy capture and nutrient cycling has been truncated. Infiltration may be reduced due to lack of ground cover. Risk of soil erosion by both wind and water is increased. Catastrophic wildfire will lead to an abiotic threshold and into state 4.
State 4: Cheatgrass and/or annual weed dominated plant community with limited to no shrub or perennial grass component. Soil erosion and redistribution along with changes in dynamic soil properties affect the hydrologic cycle and thus the nutrient cycle. Harsh environmental factors increase state resiliency to change. This state has a reduced likelihood of occurring or persisting due to the frigid soil temperature regime.
Response to Disturbance:
If heavy grazing causes site deterioration, Idaho fescue decreases and big sagebrush increases. On severely disturbed areas of this site, green rabbitbrush, prickly gilia, and vetch may be prominent.
State and transition model
![Model diagram](/uploads/med/es/es/12984.jpg)
Figure 3. Group 6, STM
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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
Reference Plant Community
The potential native plant community is dominated by Idaho fescue and Wyoming big sagebrush. Bluebunch wheatgrass is prominent in the understory. Vegetative composition is about 75 percent grasses, 10 percent forbs, and 15 percent shrubs. Approximate ground cover is 50 to 65 percent (basal and crown).
Figure 4. 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 | 588 | 841 | 1093 |
Shrub/Vine | 118 | 168 | 219 |
Forb | 78 | 112 | 146 |
Total | 784 | 1121 | 1458 |
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 | Perennial, deep-rooted, dominant | 448–673 | ||||
Idaho fescue | FEID | Festuca idahoensis | 448–673 | – | ||
2 | Perennial, moderately-deep rooted bunchgrass | 112–168 | ||||
bluebunch wheatgrass | PSSP6 | Pseudoroegneria spicata | 112–168 | – | ||
4 | Perennial, shallow-rooted, bunchgrass | 78–168 | ||||
Cusick's bluegrass | POCU3 | Poa cusickii | 56–112 | – | ||
Sandberg bluegrass | POSE | Poa secunda | 22–56 | – | ||
5 | Other perennial grasses, all | 11–34 | ||||
Thurber's needlegrass | ACTH7 | Achnatherum thurberianum | 0–11 | – | ||
squirreltail | ELEL5 | Elymus elymoides | 0–11 | – | ||
prairie Junegrass | KOMA | Koeleria macrantha | 0–11 | – | ||
Forb
|
||||||
7 | Perennial, all, dominant | 34–67 | ||||
tapertip hawksbeard | CRAC2 | Crepis acuminata | 11–22 | – | ||
phlox | PHLOX | Phlox | 11–22 | – | ||
vetch | VICIA | Vicia | 11–22 | – | ||
9 | Other perennial forbs, all | 11–45 | ||||
naked mariposa lily | CANU2 | Calochortus nudus | 0–11 | – | ||
fleabane | ERIGE2 | Erigeron | 0–11 | – | ||
granite prickly phlox | LIPU11 | Linanthus pungens | 0–11 | – | ||
lupine | LUPIN | Lupinus | 0–11 | – | ||
Shrub/Vine
|
||||||
11 | Evergreen | 78–168 | ||||
basin big sagebrush | ARTRT | Artemisia tridentata ssp. tridentata | 56–112 | – | ||
Wyoming big sagebrush | ARTRW8 | Artemisia tridentata ssp. wyomingensis | 22–56 | – | ||
15 | Other shrubs | 22–56 | ||||
yellow rabbitbrush | CHVI8 | Chrysothamnus viscidiflorus | 0–22 | – | ||
slender buckwheat | ERMI4 | Eriogonum microthecum | 0–22 | – | ||
antelope bitterbrush | PUTR2 | Purshia tridentata | 0–22 | – |
Interpretations
Animal community
Livestock grazing:
This site is suitable for livestock grazing use in spring, summer, and fall. Grazing management should be keyed to Idaho fescue. Deferred grazing is recommended at least once every three years. On slopes greater than 50 percent, cattle use will be reduced.
Native Wildlife Associated with the Climax Community:
Mule deer
Bighorn Sheep
Quail
Burrowing rodents
Rabbits
Mule deer use this site in spring, summer, and fall.
Hydrological functions
The soils of this site have medium infiltration rates and rapid to very rapid runoff potential. The hydrologic soil group is B.
Recreational uses
This site can provide upland game hunting.
Supporting information
Contributors
Bob Gillaspy
M. Parks (OSU)
Range Review Team
RMC, SCS/BLM ESI Team - Hines, OR
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 Frannsen |
---|---|
Contact for lead author | State Rangeland Management Specialist for NRCS - OR |
Date | 08/17/2012 |
Approved by | Bob Gillaspy |
Approval date | |
Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
None, Moderate sheet & rill erosion hazard -
Presence of water flow patterns:
None to some -
Number and height of erosional pedestals or terracettes:
None to very few terracettes -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
2-8% -
Number of gullies and erosion associated with gullies:
None -
Extent of wind scoured, blowouts and/or depositional areas:
None, Slight wind erosion hazard -
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):
Moderately resistant to erosion: aggregate stability = 3-5 -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Deep well drained very gravelly to extremely cobbly loam; weak thin platy to weak fine subangular block structure 7 to 15 inches thick, dry color value 4 - 6: Moderate OM (1-3%) -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Moderate to significant ground cover (50-65%) and moderate to very steep slopes (20-70%) 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:
Idaho fescue > Bluebunch wheatgrass > shrubs > other grasses > forbsSub-dominant:
Other:
Additional:
-
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: 1300, Normal: 1000, Unfavorable: 700 lbs/acre/year at high RSI (RPC) -
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 groups. -
Perennial plant reproductive capability:
All species should be capable of reproducing annually
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