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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.
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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
R023XY221OR GRAVELLY TERRACE 10-12 PZ
Gravelly Terrace 10-12" PZ
R023XY508OR PUMICE FLAT 10-12 PZ
Pumice Flat 10-12" PZ
R023XY514OR Pumice 8-10 PZ
Pumice 8-10" PZ
Similar sites
R023XY508OR PUMICE FLAT 10-12 PZ
Pumice Flat 10-12" PZ
Table 1. Dominant plant species
Tree Not specified
Shrub Not specified
Herbaceous Not specified
Physiographic features
This site occurs on nearly level to gently sloping basin and low ridges. Slopes range from 0 to 20 percent. Elevations range from 4300 to 5000 feet.
Table 2. Representative physiographic features
Landforms (1) Ridge
Elevation 4300 – 5000 ft Slope 0 – 20 % Water table depth 60 in Aspect Aspect is not a significant factor Climatic features
The annual precipitation ranges from 10 to 12 inches. This 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 43 degrees F with extreme temperatures ranging from -30 to 103 degrees F. The frost free period is 50 to 90 days. The optimum period for plant growth is from mid-April through July.
Table 3 Representative climatic features
Frost-free period (average) 90 days Freeze-free period (average) 0 days Precipitation total (average) 10 in BarLineFigure 2. Monthly precipitation range
BarLineFigure 3. Monthly average minimum and maximum temperature
">Influencing water features
Soil features
The soils of this site are very deep pumice sand and are excessively drained. They are generally underlain with mixed sand and gravel and often contain weakly cemented pans. Permeabiliity is moderately rapid and the available water holding capacity (AWC) is 7 to 10 inches for the profile. The potential for water erosion is low and for wind erosion is high.
Table 4. Representative soil features
Surface texture (1) Gravelly sand
Family particle size (1) Sandy
Drainage class Excessively drained Permeability class Moderately rapid Available water capacity
(0-40in)7 – 10 in Ecological dynamics
Range in Characteristics:
Western needlegrass is more abundant where there is more coarse textured and/or gravelly pumice material.
Response to Disturbance:
Burning will temporarily reduce both big sagebrush and bitterbrush while encouraging rabbitbrush. Composition changes from overgrazing, are generally a decline in Idaho fescue and an increase in needlegrass.State and transition model
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More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective textEcosystem states
State 1 submodel, plant communities
State 1
Historic Climax Plant CommunityCommunity 1.1
Historic Climax Plant CommunityThe potential native plant community is dominated by Idaho fescue (about 50 percent). Other prominent species include Thurber needlegrass, western needlegrass, and Ross sedge (about 5 percent each). Bitterbrush dominates the aspect (about 15 percent) and big sagebrush is also common in the stand (10 percent). Vegetative composition is approximately 70 percent grasses, 5 percent forbs, and 25 percent shrubs. Total foliar cover is about 80 percent, of which 30 percent is shrub cover, and 50 percent is grass/forb cover.
Figure 4. 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 513 689 864 Shrub/Vine 189 243 297 Forb 45 68 90 Total 747 1000 1251 Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Perennial, deep-rooted, dominant 360–540 Idaho fescue FEID Festuca idahoensis 360–540 – 2 Perennial, deep-rooted, sub-dominant 135–288 western needlegrass ACOC3 Achnatherum occidentale 90–180 – Thurber's needlegrass ACTH7 Achnatherum thurberianum 18–45 – Ross' sedge CARO5 Carex rossii 18–45 – Indian ricegrass ACHY Achnatherum hymenoides 9–18 – 4 Perennial, shallow-rooted, sub-dominant 9–18 prairie Junegrass KOMA Koeleria macrantha 9–18 – 5 Other perennial grasses, all 9–18 squirreltail ELEL5 Elymus elymoides 0–9 – Sandberg bluegrass POSE Poa secunda 0–9 – Forb7 Perennial, all, dominant 36–72 common yarrow ACMI2 Achillea millefolium 9–18 – buckwheat ERIOG Eriogonum 9–18 – desertparsley LOMAT Lomatium 9–18 – lupine LUPIN Lupinus 9–18 – 9 Other perennial forbs, all 9–18 pussytoes ANTEN Antennaria 0–4 – Douglas' dustymaiden CHDO Chaenactis douglasii 0–4 – common starlily LEMO4 Leucocrinum montanum 0–4 – phacelia PHACE Phacelia 0–4 – phlox PHLOX Phlox 0–4 – Shrub/Vine11 Perennial, evergreen, dominant 180–270 antelope bitterbrush PUTR2 Purshia tridentata 135–180 – mountain big sagebrush ARTRV Artemisia tridentata ssp. vaseyana 45–90 – 15 Other perennial shrubs, all 9–27 yellow rabbitbrush CHVI8 Chrysothamnus viscidiflorus 0–7 – slender buckwheat ERMI4 Eriogonum microthecum 0–7 – rubber rabbitbrush ERNA10 Ericameria nauseosa 0–7 – Interpretations
Animal community
Livestock Grazing:
Water is not usually available on-site. Fall-winter grazing may create a conflict with deer over the use of bitterbrush.
Native Wildlife Associated with the Potential Climax Community:
Deer
Antelope
Rabbits
Deer are important users of bitterbrush for browse.Hydrological functions
The soils of this site have rapid infiltration rates and low runoff potential. The hydrologic soil group is C.
Other information
Adapted species for seedings include crested wheatgrass, Siberian wheatgrass, thickspike wheatgrass, and sheep fescue.
Supporting information
Contributors
Gene Hickman
M. Parks (OSU)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 Contact for lead author Oregon NRCS State Rangeland Management Specialist Date 08/15/2012 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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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 -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
0-5% -
Number of gullies and erosion associated with gullies:
None -
Extent of wind scoured, blowouts and/or depositional areas:
None to some, High 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):
Slightly resistant to erosion: aggregate stability = 1-3 -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Very deep excessively drained pumice sands: Low OM (0-2%) -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Significant ground cover (70-80%) and gentle to moderate slopes (0-20%) effectively limit rainfall 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 > Western needlegrass > Antelope bitterbrush > other grasses = other shrubs > forbsSub-dominant:
Other:
Additional:
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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: 1100, Normal: 900, Unfavorable: 700 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:
Perennial brush species will increase with deterioration of plant community. 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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PrintThe Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.
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