Natural Resources
Conservation Service
Ecological site R023XY516OR
STONY LOAM 10-12 PZ
Accessed: 12/22/2024
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
| R023XY211OR |
PUMICE CLAYPAN 10-12 PZ |
|---|---|
| R023XY221OR |
GRAVELLY TERRACE 10-12 PZ |
| R023XY508OR |
PUMICE FLAT 10-12 PZ |
| R023XY514OR |
PUMICE 8-10 PZ |
Similar sites
| R023XY210OR |
PUMICE 10-12 PZ |
|---|
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Purshia tridentata |
| Herbaceous |
(1) Festuca idahoensis |
Physiographic features
This site occurs on nearly level to sloping ridges and buttes. Slopes range from 2 to 30 percent. Elevations range from 4,300 to 5,500 feet.
Table 2. Representative physiographic features
| Landforms |
(1)
Lava plateau
(2) Mountain slope (3) Hill |
|---|---|
| Flooding frequency | None |
| Ponding frequency | None |
| Elevation | 1,311 – 1,676 m |
| Slope | 1 – 25% |
| Aspect | Aspect is not a significant factor |
Climatic features
The annual precipitation ranges from 10 to 12 inches which occurs mainly between the months of November and June, mostly in the form of snow and spring-fall rains. The soil temperature regime is frigid. The average annual air temperature is 44 degrees F with extreme temperatures ranging from -20 to 103 degrees F. The frost free period is 50 to 90 days. The optimum period for plant growth is from April through early 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 of this site generally have a stony loam surface layer and skeletal loam to clay loam subsoils. They are moderately deep to deep and well drained. They are generally formed from volcanic ash and the underlying bedrock. Permeability is moderate and the available water holding capacity (AWC) is 2 to 6.5 inches for the profile. The potential for water or wind erosion is moderate.
Table 4. Representative soil features
| Parent material |
(1)
Volcanic ash
–
basalt
(2) Colluvium – welded tuff (3) Residuum – basalt |
|---|---|
| Surface texture |
(1) Very cobbly sandy loam (2) Gravelly loam |
| Family particle size |
(1) Loamy |
| Drainage class | Well drained |
| Permeability class | Very slow to moderate |
| Soil depth | 36 – 102 cm |
| Surface fragment cover <=3" | 5 – 17% |
| Surface fragment cover >3" | 15 – 25% |
| Available water capacity (0-101.6cm) |
4.83 – 17.27 cm |
| Calcium carbonate equivalent (0-101.6cm) |
0% |
| Electrical conductivity (0-101.6cm) |
0 mmhos/cm |
| Sodium adsorption ratio (0-101.6cm) |
0 |
| Soil reaction (1:1 water) (0-101.6cm) |
6.6 – 7.8 |
| Subsurface fragment volume <=3" (Depth not specified) |
5 – 24% |
| Subsurface fragment volume >3" (Depth not specified) |
5 – 21% |
Ecological dynamics
Range in Characteristics:
The reference native plant community is dominated by Idaho fescue, bitterbrush, and big sagebrush. Bluebunch wheatgrass, western needlegrass, Thurber needlgrass, and Sandberg bluegrass are common. Some juniper may be present, especially on stony areas and on southerly slopes. The vegetative composition of the community is approximately 75 percent grasses, 5 percent forbs, and 25 percent shrubs.
Juniper and bluebunch wheatgrass are more abundant on south aspects and/or stony areas than elsewhere. Some cold north aspects and flat areas have little or no potential for Juniper.
Five states have been identified for this site: a reference state; a state with the presence of annuals; a state that has juniper dominating site resources; a state that is eroded with juniper dominant; and a state with annual dominance.
Reference State: Plant community phase change is driven by fire. Mountain big sagebrush and bitterbrush decline after fire while Idaho fescue, Thurber needlegrass 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 annual weeds. Ecological function has not changed, however the resiliency of the state has been reduced by the presence of invasive weeds. Prescribed grazing maintains state dynamics. Mismanagement of grazing favors sagebrush and Sandberg’s bluegrass and can lead to an increase in cheatgrass. Prescribed grazing can reverse the trend. Reduction in fire frequency facilitates juniper encroachment in both poor and good condition communities. Fire reduces or eliminates juniper and with time sagebrush reestablishes. As juniper dominates the site resources and is out-competing sagebrush and the herbaceous plant community, the site transitions to state 3.
State 3: Juniper dominates site resources. Sagebrush is dead or dying and bitterbrush lacks vigor. Sandberg bluegrass is the dominant species in the interspace and bare ground is significant. The perennial grass component is significantly reduced in both density and productivity. Idaho fescue may be present under the canopy of trees (north slope typically). Spatial and temporal energy capture and nutrient cycling has been truncated. Infiltration may be reduced due to lack of ground cover. Juniper woodland development is complete and soil loss and erosion drive site processes as the site transitions into state 4.
State 4: Juniper dominated state. Soil loss is evident and erosion is active. All ecological processes, hydrologic cycle, nutrient cycle and energy capture have been significantly changed preventing the establishment of perennial plants. An abiotic threshold has been crossed. With catastrophic wildfire, state 5 is achieved.
State 5: Cheatgrass 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.
Response to Disturbance:
Mismanagement of grazing is a significant factor in the decline of Idaho fescue and bluebunch wheatgrass. Heavy fall grazing and heavy deer use may reduce the stand of bitterbrush and increase big sagebrush. Fire will reduce the cover of juniper, bitterbrush, and big sagebrush.
State and transition model
Figure 3. Group 8, STM
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Ecosystem states
State 1 submodel, plant communities
State 1
Reference State
Community 1.1
Reference Plant Community
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 | 504 | 673 | 841 |
| Shrub/Vine | 135 | 179 | 224 |
| Forb | 34 | 45 | 56 |
| Total | 673 | 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 | Perennial, moderately-deep rooted, bunchgrass | 404–448 | ||||
| Idaho fescue | FEID | Festuca idahoensis | 404–448 | – | ||
| 2 | Perennial, moderately-deep rooted, bunchgrass | 90–135 | ||||
| bluebunch wheatgrass | PSSPS | Pseudoroegneria spicata ssp. spicata | 45–90 | – | ||
| Thurber's needlegrass | ACTH7 | Achnatherum thurberianum | 45 | – | ||
| 4 | Perennial, shallow-rooted, bunchgrass | 45 | ||||
| Sandberg bluegrass | POSE | Poa secunda | 45 | – | ||
| 5 | Other perennial grasses | 18–63 | ||||
| western needlegrass | ACOC3 | Achnatherum occidentale | 0–18 | – | ||
| Ross' sedge | CARO5 | Carex rossii | 0–18 | – | ||
| squirreltail | ELEL5 | Elymus elymoides | 0–18 | – | ||
| thickspike wheatgrass | ELLAL | Elymus lanceolatus ssp. lanceolatus | 0–18 | – | ||
| prairie Junegrass | KOMA | Koeleria macrantha | 0–18 | – | ||
|
Forb
|
||||||
| 9 | Other perennial forbs | 9–45 | ||||
| common yarrow | ACMI2 | Achillea millefolium | 0–9 | – | ||
| western pearly everlasting | ANMA | Anaphalis margaritacea | 0–9 | – | ||
| rockcress | ARABI2 | Arabis | 0–9 | – | ||
| basalt milkvetch | ASFI | Astragalus filipes | 0–9 | – | ||
| woollypod milkvetch | ASPU9 | Astragalus purshii | 0–9 | – | ||
| buckwheat | ERIOG | Eriogonum | 0–9 | – | ||
| Lewis flax | LILE3 | Linum lewisii | 0–9 | – | ||
| stoneseed | LITHO3 | Lithospermum | 0–9 | – | ||
| desertparsley | LOMAT | Lomatium | 0–9 | – | ||
| lupine | LUPIN | Lupinus | 0–9 | – | ||
| phlox | PHLOX | Phlox | 0–9 | – | ||
|
Shrub/Vine
|
||||||
| 10 | Deciduous shrub | 90–135 | ||||
| antelope bitterbrush | PUTR2 | Purshia tridentata | 90–135 | – | ||
| 11 | Evergreen shrub | 45–90 | ||||
| mountain big sagebrush | ARTRV | Artemisia tridentata ssp. vaseyana | 45–90 | – | ||
| 15 | Other shrubs | 27–36 | ||||
| yellow rabbitbrush | CHVI8 | Chrysothamnus viscidiflorus | 9–18 | – | ||
| granite prickly phlox | LIPU11 | Linanthus pungens | 0–9 | – | ||
| spineless horsebrush | TECA2 | Tetradymia canescens | 0–9 | – | ||
|
Tree
|
||||||
| 16 | Evergreen tree | 9–45 | ||||
| western juniper | JUOC | Juniperus occidentalis | 9–45 | – | ||
Interpretations
Animal community
Livestock Grazing:
Natural water is not generally available on-site. Excessive fall use by cattle should be avoided when there may be a conflict with wildlife over use of bitterbrush.
Wildlife:
Deer, rabbits, and rodents
Hydrological functions
Watershed:
The soils of this site have high infiltration rates and moderately low runoff potential.
Wood products
Juniper firewood and posts may be produced on some areas. Care should be taken to avoid cutting old-growth juniper.
Other information
Adapted species for seedings include crested wheatgrass, siberian wheatgrass, intermediate wheatgrass, sheep fescue, and big bluegrass.
Supporting information
Contributors
Bob Gillaspy
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 | |
| Approved by | |
| 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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