Natural Resources
Conservation Service
Ecological site R023XY314OR
GRAVELLY NORTH SLOPES 12-16 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
| R023XY302OR |
SOUTH SLOPES 12-16 PZ South Slopes 12-16" PZ |
|---|---|
| R023XY310OR |
NORTH SLOPES 12-16 PZ North Slopes 12-16" PZ |
| R023XY312OR |
SHALLOW NORTH 12-16 PZ Shallow North 12-16" PZ |
| R023XY318OR |
LOAMY 12-16 PZ Loamy 12-16" PZ |
| R023XY321OR |
DEEP LOAMY 12-16 PZ Deep Loamy 12-16" PZ |
Similar sites
| R023XY310OR |
NORTH SLOPES 12-16 PZ North Slopes 12-16" Pz (less stones) |
|---|
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Artemisia tripartita |
| Herbaceous |
(1) Festuca idahoensis |
Physiographic features
This site occurs on north exposures of mountain side slopes. Slopes range from 20-50%. Elevation ranges from 5200 to 6400 feet.
Table 2. Representative physiographic features
| Landforms |
(1)
Mountain slope
|
|---|---|
| Flooding frequency | None |
| Ponding frequency | None |
| Elevation | 5,200 – 6,400 ft |
| Slope | 20 – 50% |
| Aspect | N |
Climatic features
The annual precipitation is 12 to 16 inches but typically occurs in the lower end of the precipitation range. Most of the preciptation occurs as snow during the months of October through April. The soil temperature regime is frigid. Extreme air temperatures can range from 100 degrees F. to -30 degrees F. The frost-free period is 50 to 90 days. The optimum period for plant growth is from late April to July.
Table 3. Representative climatic features
| Frost-free period (average) | 90 days |
|---|---|
| Freeze-free period (average) | 0 days |
| Precipitation total (average) | 16 in |
Influencing water features
Soil features
The soils are moderatley deep to bedrock, medium textured and well drained formed in colluvium. The soil is dark colored throughout the profile. Rock fragments range from 15 to 35 percent in the surface and 35 to 50 percent in the subsoil or substratum. Permeabilty is moderate. The available water holding capacity (AWC) is about 1.5 to 3 inches for the profile.
Table 4. Representative soil features
| Parent material |
(1)
Residuum
–
basalt
(2) Colluvium – andesite |
|---|---|
| Surface texture |
(1) Very stony loam |
| Drainage class | Well drained |
| Permeability class | Moderate |
| Soil depth | 20 – 40 in |
| Surface fragment cover <=3" | 2 – 15% |
| Surface fragment cover >3" | 2 – 25% |
| Available water capacity (0-40in) |
1.7 – 2.5 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) |
6.6 – 7.3 |
| Subsurface fragment volume <=3" (Depth not specified) |
2 – 15% |
| Subsurface fragment volume >3" (Depth not specified) |
2 – 25% |
Ecological dynamics
Range in Characteristics:
The reference native plant community is dominated by Idaho fescue and three-tip sagebrush. Cusick bluegrass and bluebunch wheatgrass occur in significant amounts. Numerous forbs are present. Mountain snowberry, shrubby buckwheat, and mountain big sagebrush are common. Vegetative composition is about 65 percent grasses, 10 percent forbs, and 25 percent shrubs.
Variabilty in plant composition results from changes in precipitation and aspect. Bluebunch wheatgrass increases in proportion at lower precipitation range and on westerly slopes.
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 juniper dominant; and a state with annual dominance.
Reference State: Plant community phase change is driven by fire. Mountain big sagebrush declines after fire while Idaho fescue and other grasses increase. May see a temporary increase in rabbitbrush 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 other 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. Cheatgrass increases. 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. Juniper can out-compete sagebrush and the herbaceous plant community which brings the site to state 3.
State 3: Juniper dominates site resources. Sagebrush is dead or dying and bitterbrush lacks vigor. Sandberg’s 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 goes 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:
If mismanaged grazing causes site deterioration, Idaho fescue and Cusick bluegrass decline. The shrub component and Sandberg bluegrass become more dominant, and western juniper can invade. If the site is burned, three-tip sagebrush, rabbitbrush, and gray horsebrush increase in density.
State and transition model
Figure 2. Group 8, STM
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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 three-tip sagebrush. Cusick bluegrass and bluebunch wheatgrass occur in significant amounts. Numerous forbs are present. Mountain snowberry, shrubby buckwheat, and mountian big sagebrush are common. Vegetative composition is about 65 percent grass, 10 percent forbs, and 25 percent shrubs.
Figure 3. 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 | 390 | 585 | 780 |
| Shrub/Vine | 150 | 225 | 300 |
| Forb | 60 | 90 | 120 |
| Total | 600 | 900 | 1200 |
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, moderately-deep rooted, bunchgrass | 450–540 | ||||
| Idaho fescue | FEID | Festuca idahoensis | 450–540 | – | ||
| 2 | Perennial, moderately-deep rooted, bunchgrass | 9–45 | ||||
| bluebunch wheatgrass | PSSPS | Pseudoroegneria spicata ssp. spicata | 9–45 | – | ||
| 5 | Perennial, shallow-rooted, bunchgrass | 90–225 | ||||
| Cusick's bluegrass | POCU3 | Poa cusickii | 45–135 | – | ||
| Sandberg bluegrass | POSE | Poa secunda | 45–90 | – | ||
| 6 | Other Perennial Grasses | 9–45 | ||||
| western needlegrass | ACOC3 | Achnatherum occidentale | 0–9 | – | ||
| California brome | BRCA5 | Bromus carinatus | 0–9 | – | ||
| squirreltail | ELEL5 | Elymus elymoides | 0–9 | – | ||
| basin wildrye | LECI4 | Leymus cinereus | 0–9 | – | ||
|
Forb
|
||||||
| 7 | Perennial Forbs | 45–135 | ||||
| tapertip hawksbeard | CRAC2 | Crepis acuminata | 9–27 | – | ||
| avens | GEUM | Geum | 9–27 | – | ||
| western stoneseed | LIRU4 | Lithospermum ruderale | 9–27 | – | ||
| lupine | LUPIN | Lupinus | 9–27 | – | ||
| spreading phlox | PHDI3 | Phlox diffusa | 9–27 | – | ||
| 9 | Other Perennial Forbs | 9–27 | ||||
| common yarrow | ACMI2 | Achillea millefolium | 0–9 | – | ||
| arrowleaf balsamroot | BASA3 | Balsamorhiza sagittata | 0–9 | – | ||
| mariposa lily | CALOC | Calochortus | 0–9 | – | ||
| Indian paintbrush | CASTI2 | Castilleja | 0–9 | – | ||
| granite prickly phlox | LIPU11 | Linanthus pungens | 0–9 | – | ||
|
Shrub/Vine
|
||||||
| 12 | Deciduous Shrubs | 90–135 | ||||
| threetip sagebrush | ARTR4 | Artemisia tripartita | 90–135 | – | ||
| 13 | Evergreen Shrubs | 18–45 | ||||
| mountain big sagebrush | ARTRV | Artemisia tridentata ssp. vaseyana | 18–45 | – | ||
| 15 | Other Shrubs | 9–45 | ||||
| yellow rabbitbrush | CHVI8 | Chrysothamnus viscidiflorus | 0–9 | – | ||
| buckwheat | ERIOG | Eriogonum | 0–9 | – | ||
| antelope bitterbrush | PUTR2 | Purshia tridentata | 0–9 | – | ||
| mountain snowberry | SYOR2 | Symphoricarpos oreophilus | 0–9 | – | ||
| spineless horsebrush | TECA2 | Tetradymia canescens | 0–9 | – | ||
Interpretations
Animal community
Livestock Grazing:
This site is best suited fro mid-summer and fall grazing. Without periodic deferment spring grazing will decrease forage plant vigor.
Wildlife:
This site is used by mule deer for food in spring, summer and fall.
Native Wildlife Associated With The Potential Climax Community:
Mule deer.
Hydrological functions
The soils of this site have medium infiltration rates and medium to rapid runoff potential. The hydrologic soil group is B.
Wood products
This site is susceptible to invasion by western juniper. In this event, the site site will produce fence posts and firewood.
Other information
Reseeding of this site with a range drill si not feasible due to slope steepness and stoniness of the soil.
Supporting information
Contributors
Bob Gillaspy
Justin Gredvig
SCS/BLM ESI Team, Hines, OR 1994
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 in Oregon |
| 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 -
Number and height of erosional pedestals or terracettes:
None to some pedestals -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
10-35% -
Number of gullies and erosion associated with gullies:
None -
Extent of wind scoured, blowouts and/or depositional areas:
None, Moderate 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):
Moderately deep well drained very stony loam soils with 2-25% surface fragments; weak fine granular structure, dry color value 4, 12 inches thick; moderate OM (2-3%) -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Low ground cover (25-35%) and gentle to moderately steep slopes (20-50%) slightly 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 > other grasses > shrubs > 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: 1200, Normal: 900, Unfavorable: 600 lbs/acre/year at high RSI (HCPC) -
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 will invade with lack of fire. Cheatgrass invades 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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