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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.
Associated sites
R024XY016OR LOAMY 8-10 PZ
Loamy 8-10 PZ (non-aspect, different composition – ARTRW8 and ACTH7 dominant, PSSPS prominent)
R024XY030OR LOAMY SLOPES 6-10 PZ
Loamy Slopes 6-10 PZ (lower production, warmer south slope, different composition – ARTRW8 and ACHY dominant w/GRSP and ACTH7 present)
R024XY303OR SANDY SLOPES 8-11 PZ
Sandy Slopes 8-11 PZ (warmer west slope, shallow sandy loam, different composition – ARTRW8 and HECO26 dominant w/PUTR2 and ACHY present)
R024XY602OR NORTH SLOPES 8-10 PZ
North Slopes 8-10 PZ (cobbly ashy loam, substratum not highly fractured, different composition – ARTRW8 and PSSPS dominant, ACTH7 and POCU3 prominent, PUTR4 absent)
R024XY638OR SOUTH SLOPES 8-10 PZ
South Slopes 8-10 PZ (lower production, warmer south slope, different composition – ARTRW8 and PSSPS dominant w/ACTH7 near co-dominant)
Similar sites
R024XY033OR ARID NORTH SLOPES 6-10 PZ
Arid North Slopes 6-10 PZ (shallow to very shallow soil, different composition – ARTRW8 and PSSPS dominant)
R024XY303OR SANDY SLOPES 8-11 PZ
Sandy Slopes 8-11 PZ (warmer west slope, shallow sandy loam, different composition – ARTRW8 and HECO26 dominant w/PUTR2 and ACHY present)
R024XY602OR NORTH SLOPES 8-10 PZ
North Slopes 8-10 PZ (cobbly ashy loam, substratum not highly fractured, different composition – ARTRW8 and PSSPS dominant, ACTH7 and POCU3 prominent, PUTR4 absent)
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Purshia tridentata
(2) Artemisia tridentata ssp. wyomingensisHerbaceous (1) Pseudoroegneria spicata ssp. spicata
(2) Achnatherum hymenoidesPhysiographic features
This site occurs on north facing aspects of terraces, basin hills and escarpments. Slopes typically range from 15 to 40%. Elevation varies from 3,500 to 5000 feet.
Table 2. Representative physiographic features
Landforms (1) Terrace
(2) Hill
(3) Escarpment
Elevation 3500 – 5000 ft Slope 15 – 40 % Aspect N Climatic features
The annual precipitation ranges from 8 to 10 inches, most of which occurs in the form of rain and snow during the months of December through March. The soil temperature regime is mesic to frigid near mesic with a mean air temperature of 48 degrees F. Temperature extremes range from 110 to -20 degrees F. The frost free period ranges from 80 to 110 days. The optimum growth period for plant growth is from April through June.
Table 3 Representative climatic features
Frost-free period (average) 110 days Freeze-free period (average) 0 days Precipitation total (average) 10 in BarLineFigure 1. Monthly precipitation range
BarLineFigure 2. Monthly average minimum and maximum temperature
">Influencing water features
Soil features
The soils of this site are typically moderately deep over weathered bedrock and well drained. The surface texture is a gravelly ashy loam 3 inches thick over a clay loam to clay subsoil. Permeability is moderately slow. The available water holding capacity (AWC) is about 4 to 6 inches for the profile. The potential for erosion is moderate to severe.
Table 4. Representative soil features
Parent material (1) Volcanic ash – rhyolite
Surface texture (1) Gravelly loam
(2) Ashy
Family particle size (1) Clayey
Drainage class Moderately well drained Permeability class Moderately slow Soil depth 20 – 40 in Available water capacity
(0-40in)4 – 6 in Ecological dynamics
The potential native plant community is dominated by antelope bitterbrush, Wyoming big sagebrush, bluebunch wheatgrass and Indian ricegrass. Sandberg bluegrass, Thurber's needlegrass and needle and thread are common. Spiny hopsage and purple sage are present. Vegetative composition of the community is approximately 65 percent grasses, 10 percent forbs and 25 percent shrubs. The approximate ground cover is 50 to 60 percent (basal and crown).
Range in Characteristics
The depth to a restrictive layer and aspect influences the composition and production of the site. Production will increase with greater soil depth, on steep due north slopes and at the upper end of the precipitation zone. On fractured bedrock, antelope bitterbrush increases. Bluebunch wheatgrass increases on a silty surface. Indian ricegrass and needle and thread increase on coarser surfaces. Spiny hopsage increases at the lower end of the precipitation zone and on droughty slopes.
Response to Disturbance - States
If the condition of the site deteriorates as a result of over grazing, antelope bitterbrush, bluebunch wheatgrass, Indian ricegrass and needle and thread will decrease in the stand. Wyoming and basin big sagebrush, squirreltail and Sandberg bluegrass will increase. Annuals invade. With further deterioration, annuals continue to invade and bare ground increases. Excessive erosion in the bare interspaces reduces the site potential and contributes to downstream sedimentation.
States: ARTRW8(T)-GRSP/ELEL5-POSE-bare ground with erosion pavement; Annuals-bare ground with erosion pavementState and transition model
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
Reference StateCommunity 1.1
Reference Plant CommunityThe reference native plant community is dominated by antelope bitterbrush, Wyoming big sagebrush, bluebunch wheatgrass and Indian ricegrass. Sandberg bluegrass, Thurber's needlegrass and needle and thread are common. Spiny hopsage and purple sage are present. Vegetative composition of the community is approximately 65 percent grasses, 10 percent forbs and 25 percent shrubs. The approximate ground cover is 50 to 60 percent (basal and crown).
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 390 520 650 Shrub/Vine 150 200 250 Forb 60 80 100 Total 600 800 1000 Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Dominant, moderate rooted bunchgrass 200–320 bluebunch wheatgrass PSSPS Pseudoroegneria spicata ssp. spicata 200–320 – 2 Sub-dominant, moderate rooted bunchgrass 120–240 Indian ricegrass ACHY Achnatherum hymenoides 120–240 – 3 Common, moderate and shallow rooted bunchgrasses 40–160 needle and thread HECO26 Hesperostipa comata 16–80 – Sandberg bluegrass POSE Poa secunda 16–40 – Thurber's needlegrass ACTH7 Achnatherum thurberianum 8–40 – 4 Other perennial grasses 13–56 Thurber's needlegrass ACTH7 Achnatherum thurberianum 8–40 – squirreltail ELEL5 Elymus elymoides 5–16 – Forb5 Common, perennial forbs 50–80 arrowleaf balsamroot BASA3 Balsamorhiza sagittata 8–24 – tapertip hawksbeard CRAC2 Crepis acuminata 8–16 – fleabane ERIGE2 Erigeron 8–16 – buckwheat ERIOG Eriogonum 8–16 – granite prickly phlox LIPU11 Linanthus pungens 8–16 – phlox PHLOX Phlox 8–16 – 6 Other forbs 15–50 milkvetch ASTRA Astragalus 5–15 – lupine LUPIN Lupinus 5–15 – mariposa lily CALOC Calochortus 0–5 – Indian paintbrush CASTI2 Castilleja 0–5 – pussytoes ANTEN Antennaria 2–5 – rockcress ARABI2 Arabis 0–5 – Shrub/Vine7 Dominant, deciduous, sprouting shrub 40–120 antelope bitterbrush PUTR2 Purshia tridentata 40–120 – 8 Co-dominant, evergreen, non-sprouting shrubs 60–120 Wyoming big sagebrush ARTRW8 Artemisia tridentata ssp. wyomingensis 40–80 – basin big sagebrush ARTRT Artemisia tridentata ssp. tridentata 15–40 – 9 Other shrubs 15–40 spiny hopsage GRSP Grayia spinosa 10–25 – slender buckwheat ERMI4 Eriogonum microthecum 0–16 – rubber rabbitbrush ERNA10 Ericameria nauseosa 0–15 – yellow rabbitbrush CHVI8 Chrysothamnus viscidiflorus 5–15 – purple sage SADO4 Salvia dorrii 0–15 – littleleaf horsebrush TEGL Tetradymia glabrata 0–15 – Interpretations
Animal community
Livestock Grazing
This site is suitabity for livestock grazing use in the late spring and fall under a planned grazing system. Use should be postponed until the soils are firm enough to prevent trampling damage and soil compaction. Care should be taken to avoid plant crown damage and soil movement when the soils are wet. Grazing management should be keyed to antelope bitterbrush, bluebunch wheatgrass and Indian ricegrass. The bunchgrasses can be severely damaged if heavily grazed during periods of flowering and grass seed formation before root reserves have accumulated and soil moisture is low. Antelope bitterbrush can be severely damaged with heavy use of current and prior year’s growth. Deferred grazing or rest is recommended at least once every three years.
Wildlife
This site offers food and cover for mule deer, antelope and a variety of birds, rodents and associated predators. It is an important spring, fall and winter use area for mule deer and antelope.
Hydrological functions
Watershed-
The soils of this site have a moderate to high runoff potential. Hydrologic cover is good when the antelope bitterbrush, bluebunch wheatgrass and Indian ricegrass component is greater than 70 percent of potential. The soils are in hydrologic group C.Other information
This site has limited potential for range seeding due to steepness and a usual stony surface. Extended drought can inhibit germination and establishment of available species.
Supporting information
Contributors
Bob Gillaspy
C.D. Tackman And M.B. Hale
C.D. Tackman, M.B. Hale Data Entry AVB 5/09
C.Tackman,R.Williams, A Bahn Up-dateRangeland 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
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Number and extent of rills:
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Presence of water flow patterns:
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Number and height of erosional pedestals or terracettes:
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Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
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Number of gullies and erosion associated with gullies:
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Extent of wind scoured, blowouts and/or depositional areas:
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Amount of litter movement (describe size and distance expected to travel):
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Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
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Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
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Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
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Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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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:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
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Average percent litter cover (%) and depth ( in):
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Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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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:
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Perennial plant reproductive capability:
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