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Ecological site R024XY031OR

DROUGHTY SHALLOW SLOPES
6-10 PZ

Accessed: 04/16/2026

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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.

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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

R024XY015OR	DESERT LOAM 6-10 PZ Desert Loam 6-10 PZ
R024XY016OR	LOAMY 8-10 PZ Loamy 8-10 PZ
R024XY017OR	SHALLOW LOAM 8-10 PZ Shallow Loam 8-10 PZ
R024XY020OR	SHRUBBY LOAM 8-10 PZ Shrubby Loam 8-10 PZ
R024XY030OR	LOAMY SLOPES 6-10 PZ Shallow Loamy Slopes 6-10 PZ
R024XY032OR	ARID SOUTH SLOPES 6-10 PZ South Slopes 6-10PZ
R024XY033OR	ARID NORTH SLOPES 6-10 PZ North Slopes 6-10 PZ

Similar sites

R024XY032OR	ARID SOUTH SLOPES 6-10 PZ Shallow Loamy Slopes 6-10 PZ (deeper, lower soluble salts, higher production)
R024XY030OR	LOAMY SLOPES 6-10 PZ South Slopes 6-10 PZ (lower soluble salts)

R024XY032OR

ARID SOUTH SLOPES 6-10 PZ

Shallow Loamy Slopes 6-10 PZ (deeper, lower soluble salts, higher production)

R024XY030OR

LOAMY SLOPES 6-10 PZ

South Slopes 6-10 PZ (lower soluble salts)

Table 1. Dominant plant species

Tree	Not specified
Shrub	(1) Atriplex confertifolia (2) Picrothamnus desertorum
Herbaceous	(1) Achnatherum hymenoides (2) Elymus elymoides

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Physiographic features

This site occurs on south facing sideslopes of basin hills and low mountains. Slopes range from 30-70%. Elevation varies from 4400-5500 feet.

Table 2. Representative physiographic features

Landforms	(1) Hill (2) Mountain
Elevation	4400 – 5500 ft
Slope	30 – 70 %
Aspect	S

Climatic features

The annual precipitation ranges from 6 to 10 inches, most of which occurs during the months of December through March. The mean annual air temperature is 48 degrees F. Temperature extremes range from 100 to -31 degrees F. The period of optimum plant growth is from the first of April through early June.

Table 3 Representative climatic features

Frost-free period (average)	0 days
Freeze-free period (average)	0 days
Precipitation total (average)	10 in

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Figure 2. Monthly precipitation range

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Figure 3. Monthly average minimum and maximum temperature

Soil features

The soils of this site are very shallow over a strongly cemented duripan or bedrock. Typically the surface is a very cobbly clay loam over a cobbly clay loam subsoil. They are sodium affected. Peremeability is moderate to moderately slow. The available water holding capacity (AWC) is about .5 to 3 inches for the profile. The potential for erosion is high. See Appendix II for soils on which this site occurs.

Representative Soil for this Site-
Skedaddle very cobbly clay loam, 30-70% slopes
Skedaddle (shallow): Loamy-skeletal, mixed, natric, mesic, Lithic Xeric Torriorthents

Table 4. Representative soil features

Surface texture	(1) Clay loam
Family particle size	(1) Clayey
Permeability class	Moderate to moderately slow

Ecological dynamics

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. Indian ricegrass will increase on coarser soils and warmer slopes. Squirreltail will increase on older surfaces with heavy erosion pavement.

Response to Disturbance-
If the condition of the site deteriorates as a result of overgrazing, Indidan ricegrass will decrease in the stand. WIth further deterioration, bud sagebrush will decrease followed by shadscale and squirreltail. Bare ground will increase, erosion accelerates and site productivity decreases. The invasion of annuals and reestablishmentof perennials is limited to eroded surfaces and in areas of dense cobbles and heavy erosion pavement.

State and transition model

Custom diagram

Standard diagram

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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 text

Ecosystem states

1. Historic Climax Plant Community

State 1 submodel, plant communities

1.1. Historic Climax Plant Community

State 1
Historic Climax Plant Community

Community 1.1
Historic Climax Plant Community

The potential native plant community is dominated by shadscale. Bud sagebrush, spiny hopsage and Indian ricegrass are prominent in the stand. The vegetation composition of the community is approximately 70% grass, 25% shrubs and 5% forbs. the approximate ground cover is 20-40% (basal and Crown).

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)
Shrub/Vine	188	276	364
Grass/Grasslike	80	140	200
Forb	4	18	32
Total	272	434	596

Additional community tables

Table 6. Community 1.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)
Grass/Grasslike
1	Perennial, Deep-rooted, Dominant			60–120
	Indian ricegrass	ACHY	Achnatherum hymenoides	40–80	–
	squirreltail	ELEL5	Elymus elymoides	20–60	–
5	Perennial, Others (PPGG), ALL			20–60
	desert needlegrass	ACSP12	Achnatherum speciosum	5–15	–
	Thurber's needlegrass	ACTH7	Achnatherum thurberianum	5–15	–
	Webber needlegrass	ACWE3	Achnatherum webberi	5–15	–
	Sandberg bluegrass	POSE	Poa secunda	5–15	–
Forb
9	Perennial, Other (PPFF), ALL			4–32
	milkvetch	ASTRA	Astragalus	0–4	–
	Indian paintbrush	CASTI2	Castilleja	0–4	–
	skeletonweed	CHAET	Chaetadelpha	0–4	–
	Douglas' dustymaiden	CHDO	Chaenactis douglasii	0–4	–
	tapertip hawksbeard	CRAC2	Crepis acuminata	0–4	–
	buckwheat	ERIOG	Eriogonum	0–4	–
	pricklyphlox	LEPTO2	Leptodactylon	0–4	–
	phlox	PHLOX	Phlox	0–4	–
	scarlet globemallow	SPCO	Sphaeralcea coccinea	0–4	–
Shrub/Vine
11	Perennial, Evergreen, Dominant			160–280
	shadscale saltbush	ATCO	Atriplex confertifolia	120–200	–
	bud sagebrush	PIDE4	Picrothamnus desertorum	40–80	–
12	Perennial, Evergreen, Sub-Dominant			20–60
	spiny hopsage	GRSP	Grayia spinosa	20–60	–
15	Perennial, Other(SSSS), ALL			8–24
	yellow rabbitbrush	CHVI8	Chrysothamnus viscidiflorus	2–5	–
	rubber rabbitbrush	ERNA10	Ericameria nauseosa	2–5	–
	winterfat	KRLA2	Krascheninnikovia lanata	2–5	–
	littleleaf horsebrush	TEGL	Tetradymia glabrata	2–5	–
	shortspine horsebrush	TESP2	Tetradymia spinosa	2–5	–

Interpretations

Animal community

Wildlife-
This site is commonly used by mule deer, California bighorn sheep, rodents, upland birds and various predators. This site is important wintering area for many species of wildlife.

Livestock grazing-
This site has limited suitability to use by cattle, sheep and horses in the late spring and fall under a planned grazing system. The key species are Indian ricegrass and bud sagebrush. Indian ricegrass can be severely damaged if heavily grazed duringperiods of flowering and grass seed formation before root reserves have accumulated and soil moisture is low. Bud sagebrush and shadscale can be severely dmamaged if heavily grazed in the late winter and early spring during periods of "bark slippage". Care should be taken to avoid plant crown damage and soil compaction when soils are wet. The shallow soils on the steep slopes of this site are very susceptible to movement and compaction from hoof action.

Hydrological functions

watershed-
The soils of this site have high runoff potential because of low intake rates, very shallow depths and steep slopes. The hydrologic cover condition is fair when the ecological condition is high.

Other information

This site has virtually no potential for range seedig because it is steep, droughty and stony. In areas where dense cobbles and heavy erosion pavement exists, the potential for natural seeding reestablishment is low.

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)
Contact for lead author
Date
Approved by
Approval date
Composition (Indicators 10 and 12) based on	Annual Production

Indicators

Number and extent of rills:
Presence of water flow patterns:
Number and height of erosional pedestals or terracettes:
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Number of gullies and erosion associated with gullies:
Extent of wind scoured, blowouts and/or depositional areas:
Amount of litter movement (describe size and distance expected to travel):
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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:
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Average percent litter cover (%) and depth ( in):
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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 plant reproductive capability:

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