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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
R007XY012OR Sandy 8-10 PZ
Sandy 8-10" PZ
R007XY014OR Loamy 8-10 PZ
Loamy 8-10" PZ
R007XY015OR Shallow Loam 8-10 PZ
Shallow Loam 8-10" PZ
Similar sites
R007XY015OR Shallow Loam 8-10 PZ
Shallow Loam 8-10" PZ (lower production)
R007XY013OR Sandy Loam 8-10 PZ
Sandy Loam 8-10" PZ (coarser surface texture)
Table 1. Dominant plant species
Tree Not specified
Shrub Not specified
Herbaceous Not specified
Physiographic features
This site occurs on nearly level to gently rolling terraces and uplands.
Table 2. Representative physiographic features
Landforms (1) Terrace
Flooding frequency None Elevation 500 – 1100 ft Slope 0 – 20 % Water table depth 60 in Aspect Aspect is not a significant factor Climatic features
The annual precipitation ranges from 8 to 10 inches which occurs mostly as rain during the months of November through April. The temperature regime is mesic with temperature extremes ranging from 115 degrees F to -10 F. The frost-free period is 180 to 215 days, and the optimum period for plant growth is mid-March to mid-June.
Table 3 Representative climatic features
Frost-free period (average) 220 days Freeze-free period (average) Precipitation total (average) 10 in ">Influencing water features
Soil features
The soils of this site are moderately deep to very deep, well drained silt loams formed in loess over calcareous lacustrine sediments, alluvium, or basalt. Permeability is moderate and the available water capacity is 5 to 12 inchesw for the profile. There is a slight hazard for both wind and water erosion.
Table 4. Representative soil features
Surface texture (1) Silt loam
Drainage class Well drained Permeability class Moderate Soil depth 40 – 60 in Available water capacity
(0-40in)5 – 12 in Ecological dynamics
If heavy grazing causes site deterioration, bluebunch wheatgrass decreases in the stand; sandberg bluegrass, broom snakeweed, rabbitbrush, and big sagebrush increase. With further deterioration, cheatgrass, mustards, tasrweed, and diffuse knapweed invade the site. Frequent burning commonly results in an increase in rabbitbrush and cheatgrass.
There is little variation in this site. The uniform, moderately deep to very deep silt loam favors dominance by bluebunch wheatgrass. Needleandthread will increase in areas of soil textural changes to very fine sandy loams.State and transition model
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Click on state and transition labels to scroll to the respective textEcosystem states
State 1 submodel, plant communities
State 1
ReferenceCommunity 1.1
Bluebunch Wheatgrass, Sandberg Bluegrass, and Basin Big SagebrushThere is little variation in the characteristics of this site. The uniform, moderately deep to cvery deep silt loam favors dominance of bluebunch wheatgrass. Needle and thread will increase in some areas of soil textural changes to very fine sandy loams.
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 432 555 672 Forb 36 50 84 Shrub/Vine 24 40 54 Total 492 645 810 Figure 3. Plant community growth curve (percent production by month). OR2271 , B7 LOAMY, GOOD CONDITION. RPC growth curve B7 LOAMY, GOOD CONDITION.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec J F M A M J J A S O N D 0 15 25 20 15 10 0 0 5 10 0 0 Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Dominant deep rooted perennial grasses 360–480 bluebunch wheatgrass PSSP6 Pseudoroegneria spicata 360–480 – 2 Sub-dominant deep rooted perennial grasses 6–30 needle and thread HECO26 Hesperostipa comata 6–30 – 3 Dominant shallow rooted perennial grasses 60–150 Sandberg bluegrass POSE Poa secunda 60–150 – 5 Other perennial grasses 6–12 Indian ricegrass ACHY Achnatherum hymenoides 0–6 – squirreltail ELEL5 Elymus elymoides 0–6 – Forb7 Dominant perennial forbs 12–36 common yarrow ACMI2 Achillea millefolium 6–18 – phlox PHLOX Phlox 6–18 – 8 Sub-dominant perennial forbs 18–36 pussytoes ANTEN Antennaria 6–12 – milkvetch ASTRA Astragalus 6–12 – desertparsley LOMAT Lomatium 6–12 – 9 Other perennial forbs 6–12 onion ALLIU Allium 0–6 – balsamroot BALSA Balsamorhiza 0–6 – naked mariposa lily CANU2 Calochortus nudus 0–6 – fleabane ERIGE2 Erigeron 0–6 – lupine LUPIN Lupinus 0–6 – Shrub/Vine11 Dominant evergreen shrubs 12–30 basin big sagebrush ARTRT Artemisia tridentata ssp. tridentata 12–30 – 12 Sub-dominant evergreen shrubs 6–12 rubber rabbitbrush ERNA10 Ericameria nauseosa 6–12 – 15 Other shrubs 6–12 Wyoming big sagebrush ARTRW8 Artemisia tridentata ssp. wyomingensis 0–6 – green rabbitbrush ERTE18 Ericameria teretifolia 0–6 – broom snakeweed GUSA2 Gutierrezia sarothrae 0–6 – spineless horsebrush TECA2 Tetradymia canescens 0–6 – Interpretations
Animal community
This site provides nesting cover for long-billed curlew, and food and cover fro mule deer, pronghorn antelope, song birds, small mammals and their associated predators.
The scarcity of water is the limiting factor in the use of this site by wildlife. When located near dependable water sources, and irrigated croplands, this site is used extensively by ring-necked pheasants.
Livestock Grazing:
This site is well suited to fall, winter, and spring grazing by livestock in a grazing system that provides for spring deferment in two out of three years.Hydrological functions
The soils of this site have moderate intake rates and low runoff potential. The hydrologic soil groups are B and C.
Other information
Caution must be exercised in seeding because the soils are droughty and subject to wind erosion.
Supporting information
Contributors
Alan Bahn
E Ersch (OSU)
J P ReppApproval
Kirt Walstad, 2/06/2025
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 07/26/2012 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
None, slight 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):
2-10% -
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 to strongly resistant to erosion; aggregate stability = 5-6 -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Moderately deep to very deep, well drained silt loams; Low OM (2-3%) -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Moderate ground cover (30-50%) and slopes (0-20%) should limit rainfall impact and overland flow; slightly increased flow possible on steeper slopes (up to 20%) -
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:
Needle and thread > Bluebunch wheatgrass > basin big sagebrush > sandberg bluegrass > dominant forbs >= other grasses = other forbs = other shrubsSub-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):
In areas with adequate plant cover -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
Favorable: 800, Normal: 600, Unfavorable: 500 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:
Rabbitbrush, sage brush and broom snakeweed may increase and reduce cover of herbaceous plants. Cheatgrass and annual forbs invade sites that have lost shallow 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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