Natural Resources
Conservation Service
Ecological site R023XY216OR
CLAYPAN 12-16 PZ
Accessed: 12/30/2024
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
| R023XY104OR |
LOAMY BOTTOM Loamy Bottom |
|---|---|
| R023XY218OR |
THIN SURFACE CLAYPAN 10-16 PZ Thin Surface Claypan 10-16" PZ |
| R023XY321OR |
DEEP LOAMY 12-16 PZ Deep Loamy 12-16" PZ |
Similar sites
| R023XY214OR |
CLAYPAN 10-12 PZ Claypan 10-12" PZ (lower precipitation) |
|---|---|
| R023XY218OR |
THIN SURFACE CLAYPAN 10-16 PZ Thin Surface Claypan 10-16" PZ (thin surface soil) |
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Artemisia arbuscula ssp. arbuscula |
| Herbaceous |
(1) Festuca idahoensis |
Physiographic features
This site occurs on various landforms, ranging from nearly level tablelands and alluvial fans to moderately steep escarpments. Slope ranges from 2 to 30 percent (commonly less than 20 percent). Elevations range from 4500 to 6500 feet.
Table 2. Representative physiographic features
| Landforms |
(1)
Alluvial fan
(2) Escarpment |
|---|---|
| Elevation | 4,500 – 6,500 ft |
| Slope | 2 – 30% |
| Water table depth | 60 in |
| Aspect | Aspect is not a significant factor |
Climatic features
The annual precipitation ranges from 12 to 16 inches, most of which occurs in the form of snow during the months of November through March. Occasional spring rains are common. The soil temperatures range from 100 degrees F to -30 degrees F. The frost-free period is from 50 to 100 days. The optimum period for plant growth is from mid-may to mid-July.
Table 3. Representative climatic features
| Frost-free period (average) | 100 days |
|---|---|
| Freeze-free period (average) | 0 days |
| Precipitation total (average) | 16 in |
Influencing water features
Soil features
The soils are very shallow to bedrock or to a strongly developed claypan. The soils are well-drained and have developed in residuum. The permeability is moderate to the bedrock or claypan and slow or very slow in the claypan. The available water holding capacity (AWC) is about 2 to 5 inches for the profile. The surface layer is typically a loam, 5 to 12 inches thick with variable amounts of coarse fragments on the surface. The majority of the soils in this site have a strongly developed claypan subsoil with an abrupt boundary between it and the surface layer. The claypan contains about 40 to 60 percent clay and the surface layer contains about 20 to 27 percent clay. The other soils in this site are very shallow to hard bedrock and typically contain over 60 percent coarse fragments through the profile.
Table 4. Representative soil features
| Parent material |
(1)
Residuum
–
basalt
(2) Colluvium – welded tuff |
|---|---|
| Surface texture |
(1) Very cobbly loam (2) Very stony clay loam |
| Family particle size |
(1) Clayey |
| Drainage class | Well drained |
| Permeability class | Very slow to slow |
| Soil depth | 5 – 15 in |
| Surface fragment cover <=3" | 13 – 25% |
| Surface fragment cover >3" | 10 – 30% |
| Available water capacity (0-40in) |
1.5 – 5.2 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 – 7.8 |
| Subsurface fragment volume <=3" (Depth not specified) |
5 – 25% |
| Subsurface fragment volume >3" (Depth not specified) |
1 – 20% |
Ecological dynamics
Range in Characteristics:
The reference native plant community is dominated by Idaho fescue, bluebunch wheatgrass, and low sagebrush. Vegetative composition is about 60 percent grasses, 10 percent forbs, and 30 percent shrubs.
This site is typically dominated by Idaho fescue. At the lower end of its precipitation range, bluebunch wheatgrass may approach co-dominance. Soils in this site that have a gravelly surface will show an increase in Thurber needlegrass. Idaho fescue production increases with increased soil surface thickness.
Four states have been identified for this site: a reference state; a state with the presence of annuals; a state that has juniper and low sagebrush co-dominant on the site, and a state with annual dominance.
Reference State: Stable plant community affected infrequently by fire. Plant communities are dominated by low sagebrush with some communities exhibiting a small percentage of old growth juniper. Infrequent fire (> 80 to 100 year intervals) maintaines site dynamics. Fire reduces shrub cover in a mosaic, patchy pattern. 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/or medusahead and other annual weeds. Ecological function has not changed, however the resiliency of the state has been reduced by the presence of invasive weeds. Infrequent fire (> 80 to 100 years) reduces shrub cover, removes young juniper and promotes grass production while time since fire allows shrub recovery. Mismanagement of grazing facilitates an increase in Sandberg’s bluegrass, weedy species, young juniper and low sagebrush. Moderately deep-rooted bunchgrasses will decline in production and density. Prescribed grazing can reverse the trend. Loss of moderately deep-rooted perennial bunchgrasses with or without an increase in young Juniper brings the site to State 3.
State 3: Dominated by low sagebrush and possibly young juniper with minimal perennial, moderately deep-rooted bunchgrasses. Cheatgrass and/or medusahead along with other weedy forbs have increased in density and cover. Sandberg’s bluegrass cover and vigor is declining. Water flow paths are evident. Sagebrush, and possibly juniper, control site resources. Catastrophic wildfire leading to annual dominated plant community will take the site to State 4.
State 4: Cheatgrass and/or medusahead dominated. Few old growth juniper may be present. Rabbitbrush increased with few to no low sagebrush. Wind and water erosion drive site processes.
Response to Disturbance:
If heavy grazing causes site deterioration, Idaho fescue will decline in vigor and density, and bluebunch wheatgrass will follow suit. Less desirable shrubs and forbs will increase. In the absence of fire, western juniper will increase on this site.
State and transition model
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State 1 submodel, plant communities
State 2 submodel, plant communities
State 3 submodel, plant communities
State 4 submodel, plant communities
State 1
Reference State
Community 1.1
Reference Plant Community
The potential native plant community is dominated by Idaho fescue, bluebunch wheatgrass, and low sagebrush. Vegetative composition is about 60 percent grasses, 10 percent forbs, and 30 percent shrubs. Approximate ground cover is 20-30 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 | 300 | 420 | 540 |
| Shrub/Vine | 130 | 185 | 240 |
| Forb | 50 | 70 | 90 |
| Tree | 20 | 25 | 30 |
| Total | 500 | 700 | 900 |
Community 1.2
Perennail Grass and Forb Community
Patchy reduction in shrub density due to fire. The potential native plant community is dominated by Idaho fescue, bluebunch wheatgrass, and low sagebrush. Vegetative composition is about 70 percent grasses, 20 percent forbs, and 10 percent shrubs. Approximate ground cover is 20-30 percent (basal and crown).
Figure 3. Annual production by plant type (representative values) or group (midpoint values)
Table 6. Annual production by plant type
| Plant type | Low (lb/acre) |
Representative value (lb/acre) |
High (lb/acre) |
|---|---|---|---|
| Grass/Grasslike | 350 | 490 | 630 |
| Forb | 100 | 140 | 180 |
| Shrub/Vine | 30 | 45 | 60 |
| Tree | 20 | 25 | 30 |
| Total | 500 | 700 | 900 |
Pathway 1.1A
Community 1.1 to 1.2
Infrequent fire (> 80 to 100 year intervals) maintained site dynamics. Fire reduced shrub cover in a mosaic, patchy pattern.
Conservation practices
| Prescribed Burning |
|---|
Pathway 1.2A
Community 1.2 to 1.1
Time since fire allows low sagebrush to increase.
Conservation practices
| Prescribed Grazing |
|---|
State 2
Low Sagebrush - Bunchgrass with Annuals
Compositionally similar to the reference state with a trace of cheatgrass and/or medusahead and other annual weeds. Ecological function has not changed, however the resiliency of the state has been reduced by the presence of invasive weeds. Infrequent fire (> 80 to 100 years) reduces shrub cover, removes young juniper and promotes grass production while time since fire allows shrub recovery.
Community 2.1
Sagebrush Steppe with Annuals
Compositionally similar to the reference community with a trace of cheatgrass and/or medusahead and other annual weeds.
Community 2.2
Perennial Grass and Forb with Annuals
Patchy reduction in shrub density due to fire. The potential native plant community is dominated by Idaho fescue, bluebunch wheatgrass, and low sagebrush. Vegetative composition is about 70 percent grasses, 20 percent forbs, and 10 percent shrubs. Approximate ground cover is 20-30 percent (basal and crown). Annual grasses and forbs are present.
Community 2.3
Low Sagebrush - Sandberg Bluegrass
Plant community is dominated by low sagebrush and Sandberg bluegrass. Idaho fescue and bluebunch wheatgrass have decreased in production and cover.
Pathway 2.1A
Community 2.1 to 2.2
Fire (> 80 to 100 years) reduces shrub cover, removes young juniper, and promotes grass production.
Conservation practices
| Prescribed Burning |
|---|
Pathway 2.1B
Community 2.1 to 2.3
Improper grazing facilitates an increase in Sandberg’s bluegrass, weedy species, young juniper and low sagebrush. Moderately deep-rooted bunchgrasses decline in production and density.
Pathway 2.2A
Community 2.2 to 2.1
Time since fire allows shrub recovery.
Conservation practices
| Prescribed Grazing |
|---|
Pathway 2.2B
Community 2.2 to 2.3
Improper grazing facilitates an increase in Sandberg’s bluegrass, weedy species, young juniper and low sagebrush. Moderately deep-rooted bunchgrasses decline in production and density.
Pathway 2.3A
Community 2.3 to 2.1
Prescribed grazing allows medium-rooted perennial bunchgrasses to become dominant.
Conservation practices
| Prescribed Grazing |
|---|
State 3
Low Sagebrush with Annuals
Low sagebrush and possibly young juniper dominated, with minimal perennial, moderately deep-rooted grasses. Cheatgrass and/or medusahead along with other weedy forbs are increased in density and cover. Sandberg’s bluegrass cover and vigor is declining. Water flow paths are evident. Low sagebrush, and possibly juniper, control site resources.
Community 3.1
Low Sagebrush and Annuals
Site is dominated by low sagebrush and annual grasses. Juniper density and cover has increased. Soil erosion is evident. Bare ground has increased.
State 4
Annual Grass
Cheatgrass and/or medusahead dominated. Few old growth juniper may be present. Rabbitbrush increased with few to no low sagebrush. Wind and water erosion drive site processes.
Community 4.1
Annual Grasses
Site is dominated by annual grasses and forbs. Rabbitbrush has increased. Soil erosion is evident.
Transition T1A
State 1 to 2
Introduction of Annuals
Transition T2A
State 2 to 3
Low sagebrush dominates with a possible co-dominate of young juniper. Moderately deep-rooted perennial bunchgrasses are rare. Cheatgrass and/or medusahead and other weedy annuals are abundant. Bare ground is significant and water flow paths evident. Sandberg’s bluegrass is pedestalled and reduced in vigor and/or cover. This site has crossed a biotic threshold.
Transition T2B
State 2 to 4
Catastrophic wildfire leading to annual dominated plant community.
Restoration pathway R3A
State 3 to 2
Requires mechanical or chemical treatment of sagebrush or mechanical treatment of juniper along with treatment of cheatgrass and/or medusahead. Desired grasses and forbs may need to be seeded. Low success rate.
Conservation practices
| Brush Management | |
|---|---|
| Prescribed Grazing | |
| Range Planting |
Transition T3A
State 3 to 4
Catastrophic wildfire leading to annual dominated plant community.
Restoration pathway R4A
State 4 to 2
Requires mechanical and/or chemical treatment of annual grasses along with seeding of perennial grass and shrubs. Chemical treatment of rabbitbrush may be needed. High probability of failure.
Conservation practices
| Brush Management | |
|---|---|
| Range Planting | |
| Integrated Pest Management (IPM) |
Additional community tables
Table 7. 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 | 350–595 | ||||
| Idaho fescue | FEID | Festuca idahoensis | 280–420 | – | ||
| bluebunch wheatgrass | PSSP6 | Pseudoroegneria spicata | 70–175 | – | ||
| 2 | Perennial, deep-rooted, sub-dominant | 21–105 | ||||
| Thurber's needlegrass | ACTH7 | Achnatherum thurberianum | 14–70 | – | ||
| squirreltail | ELEL5 | Elymus elymoides | 7–35 | – | ||
| 4 | Perennial, shallow-rooted, sub-dominant | 14–70 | ||||
| Sandberg bluegrass | POSE | Poa secunda | 14–70 | – | ||
| 5 | Other perennial grasses, all | 7–35 | ||||
| prairie Junegrass | KOMA | Koeleria macrantha | 0–7 | – | ||
| Cusick's bluegrass | POCU3 | Poa cusickii | 0–7 | – | ||
|
Forb
|
||||||
| 7 | Perennial, all, dominant | 7–21 | ||||
| phlox | PHLOX | Phlox | 7–21 | – | ||
| 8 | Perennial, all, sub-dominant | 7–14 | ||||
| desertparsley | LOMAT | Lomatium | 7–14 | – | ||
| 9 | Other perennial forbs, all | 14–70 | ||||
| agoseris | AGOSE | Agoseris | 0–14 | – | ||
| pussytoes | ANTEN | Antennaria | 0–14 | – | ||
| milkvetch | ASTRA | Astragalus | 0–14 | – | ||
| balsamroot | BALSA | Balsamorhiza | 0–14 | – | ||
| tapertip hawksbeard | CRAC2 | Crepis acuminata | 0–14 | – | ||
| larkspur | DELPH | Delphinium | 0–14 | – | ||
| fleabane | ERIGE2 | Erigeron | 0–14 | – | ||
| buckwheat | ERIOG | Eriogonum | 0–14 | – | ||
| aster | EUCEP2 | Eucephalus | 0–14 | – | ||
| lupine | LUPIN | Lupinus | 0–14 | – | ||
| beardtongue | PENST | Penstemon | 0–14 | – | ||
| largehead clover | TRMA3 | Trifolium macrocephalum | 0–14 | – | ||
|
Shrub/Vine
|
||||||
| 11 | Perennial, evergreen, dominant | 70–105 | ||||
| little sagebrush | ARAR8 | Artemisia arbuscula | 70–105 | – | ||
| 12 | Perennial, evergreen, sub-dominant | 7–14 | ||||
| yellow rabbitbrush | CHVI8 | Chrysothamnus viscidiflorus | 0–7 | – | ||
|
Tree
|
||||||
| 16 | Perennial, evergreen, dominant | 14–35 | ||||
| western juniper | JUOC | Juniperus occidentalis | 14–35 | – | ||
Table 8. Community 1.2 plant community composition
| Group | Common name | Symbol | Scientific name | Annual production (lb/acre) | Foliar cover (%) | |
|---|---|---|---|---|---|---|
|
Grass/Grasslike
|
||||||
| 1 | Perennial, deep-rooted, dominant | 330–510 | ||||
| Idaho fescue | FEID | Festuca idahoensis | 240–360 | – | ||
| bluebunch wheatgrass | PSSP6 | Pseudoroegneria spicata | 90–150 | – | ||
| 2 | Perennial, deep-rooted, sub-dominant | 32–130 | ||||
| Thurber's needlegrass | ACTH7 | Achnatherum thurberianum | 20–70 | – | ||
| squirreltail | ELEL5 | Elymus elymoides | 12–60 | – | ||
| 4 | Perennial, shallow-rooted, sub-dominant | 12–60 | ||||
| Sandberg bluegrass | POSE | Poa secunda | 12–60 | – | ||
| 5 | Other perennial grasses, all | 6–30 | ||||
| prairie Junegrass | KOMA | Koeleria macrantha | 0–15 | – | ||
| bluegrass | POA | Poa | 0–15 | – | ||
|
Forb
|
||||||
| 7 | Perennial, all, dominant | 12–36 | ||||
| phlox | PHLOX | Phlox | 12–36 | – | ||
| 8 | Perennial, all, sub-dominant | 12–24 | ||||
| desertparsley | LOMAT | Lomatium | 12–24 | – | ||
| 9 | Other perennial forbs, all | 24–120 | ||||
| agoseris | AGOSE | Agoseris | 0–10 | – | ||
| pussytoes | ANTEN | Antennaria | 0–10 | – | ||
| milkvetch | ASTRA | Astragalus | 0–10 | – | ||
| balsamroot | BALSA | Balsamorhiza | 0–10 | – | ||
| tapertip hawksbeard | CRAC2 | Crepis acuminata | 0–10 | – | ||
| larkspur | DELPH | Delphinium | 0–10 | – | ||
| fleabane | ERIGE2 | Erigeron | 0–10 | – | ||
| buckwheat | ERIOG | Eriogonum | 0–10 | – | ||
| aster | EUCEP2 | Eucephalus | 0–10 | – | ||
| lupine | LUPIN | Lupinus | 0–10 | – | ||
| beardtongue | PENST | Penstemon | 0–10 | – | ||
| largehead clover | TRMA3 | Trifolium macrocephalum | 0–10 | – | ||
|
Shrub/Vine
|
||||||
| 11 | Perennial, evergreen, dominant | 15–25 | ||||
| little sagebrush | ARAR8 | Artemisia arbuscula | 15–25 | – | ||
| 12 | Perennial, evergreen, sub-dominant | 20–30 | ||||
| yellow rabbitbrush | CHVI8 | Chrysothamnus viscidiflorus | 20–30 | – | ||
|
Tree
|
||||||
| 16 | Perennial, evergreen, dominant | 14–35 | ||||
| western juniper | JUOC | Juniperus occidentalis | 14–35 | – | ||
Interpretations
Animal community
Livestock Grazing:
This site is suitable for cattle, horses, and sheep use in late spring, summer, and fall under a planned grazing system. Deferred grazing should be delayed until the soil is dry so that damage to plant roots and crowns is avoided.
Native Wildlife Associated with the Potential Climax Community:
Mule deer
Pronghorn antelope
Sage grouse
Quail
During spring, mule deer will feed in the area if adequate escape cover is nearby. Antelope will use this site year round.
Hydrological functions
The soils of this site have slow infiltration rates and slow to rapid runoff potential. The hydrologic soil group is D.
Wood products
Where juniper has encroached on this site, it has the potential for producing fence posts, firewood, and other specialty products.
Supporting information
Contributors
Bob Gillaspy
Cici Brooks
M. Parks (OSU)
MAS
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 for NRCS - OR |
| Date | 08/16/2012 |
| 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 few - pedestals -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
5-15% -
Number of gullies and erosion associated with gullies:
None -
Extent of wind scoured, blowouts and/or depositional areas:
None, moderate wine 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):
Very shallow, well drained very stony or cobbly clay loams, silty clay loams, or very stony loams (5-12" thick), with up to 60% coarse fragments on the surface: Moderate OM (1-3%) -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Slight ground cover (20-30%) and gentle to moderate slopes (2-30%) 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 - claypan at 5-12" -
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 > other grasses > shrubs > forbs > treesSub-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: 900, Normal: 700, Unfavorable: 500 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:
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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