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Ecological site R025XY005OR

SHRUBBY LOAMY BOTTOM

Accessed: 11/21/2024

Home / Esd catalog / MLRA 025X / Ecological site R025XY005OR

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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.

MLRA notes

Major Land Resource Area (MLRA): 025X–Owyhee High Plateau

MLRA 25 lies within the Intermontane Plateaus physiographic province. The southern half is in the Great Basin Section of the Basin and Range Province. This part of the MLRA is characterized by isolated, uplifted fault-block mountain ranges separated by narrow, aggraded desert plains. This geologically older terrain has been dissected by numerous streams draining to the Humboldt River. The northern half of the area lies within the Columbia Plateaus geologic province. This part of the MLRA forms the southern boundary of the extensive Columbia Plateau basalt flows. Deep, narrow canyons drain to the Snake River which incise the broad volcanic plain. The Humboldt River, route of a major western pioneer trail, crosses the southern half of this area. Reaches of the Owyhee River in this area have been designated as National Wild and Scenic Rivers.

Associated sites

R010XY004OR	Meadow Meadow
R025XY007OR	SILTY SWALE 11-13 PZ Silty Swale 11-13 PZ
R025XY012OR	LOAMY 11-13 PZ Loamy 11-13" PZ

R010XY004OR

Meadow

Meadow

R025XY007OR

SILTY SWALE 11-13 PZ

Silty Swale 11-13 PZ

R025XY012OR

LOAMY 11-13 PZ

Loamy 11-13" PZ

Similar sites

R025XY008OR	SILTY SWALE 13-16 PZ Silty Swale 13-16" PZ (available seasonal subsurface flows of shorter duration, lower production)
R010XY005OR	Loamy Bottom Loamy Bottom (higher production, available sub-surface moisture available over a longer period of time)

R025XY008OR

SILTY SWALE 13-16 PZ

Silty Swale 13-16" PZ (available seasonal subsurface flows of shorter duration, lower production)

R010XY005OR

Loamy Bottom

Loamy Bottom (higher production, available sub-surface moisture available over a longer period of time)

Table 1. Dominant plant species

Tree	Not specified
Shrub	(1) Purshia tridentata (2) Artemisia tridentata subsp. tridentata
Herbaceous	(1) Leymus cinereus

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Physiographic features

This site typically occurs on low terraces associated with intermitent and perennial drainage systems and on low terraces in large lake basins. Slopes range from 0 to 8 percent. Elevation varies from 4,000 to 5,500 feet.

Table 2. Representative physiographic features

Landforms	(1) Flood plain (2) Stream terrace
Elevation	1,219 – 1,676 m
Slope	0 – 8%
Aspect	Aspect is not a significant factor

Climatic features

The annual precipitation ranges from 8 to 13 inches, most of which occurs in the form of snow during the months of November through March. Ephemeral subsurface moisture flow augments the precipitation. Localized convection storms occasionally occur during the summer. The soil temperature regime is mesic to frigid with a mean annual air temperature ranging from 44 to 46 degrees F. Temperature extremes range from -30 to 100 degrees F. The frost free period ranges from 30 to 90 days. The optimum growth period for native plants is from April through July.

Table 3. Representative climatic features

Frost-free period (average)	90 days
Freeze-free period (average)	0 days
Precipitation total (average)	330 mm

Bar

Line

Figure 1. Monthly average minimum and maximum temperature

Soil features

The soils of this site are on stream terraces, deep to very deep and moderately well drained. A water table below 30 inches is present in the spring of the year. Typically the surface layer is a silt loam about 26 inches thick. The subsoil is a loam to a sandy clay loam over 40 inches thick. The substratum varies from alluvium to bedrock. Gravel content in the pedon ranges from 0 to 30%. Permeability is moderate. The available water holding capacity is about 10 to 12 inches for the profile. The potential for erosion is moderate.

Table 4. Representative soil features

Surface texture	(1) Silt loam
Family particle size	(1) Loamy
Drainage class	Moderately well drained
Permeability class	Moderate
Soil depth	102 – 178 cm
Available water capacity (0-101.6cm)	25.4 – 30.48 cm
Subsurface fragment volume <=3" (Depth not specified)	0 – 30%

Ecological dynamics

The potential native plant commlunity is dominated by basin wildrye. Antelope bitterbrush and basin big sagebrush are common. Vegetative composition of the community is approximately 80 percent grasses, 5 percent forbs and 15 percent shrubs.

The amount of basin wildrye is dependent on the extent and duration of lateral subsurface water flows. Basin wildrye increases on bottomlands receiving subsurface flows late into the growing season. Antelope bitterbrush increases on coarser soils and at the upper end of the precipitation zone. As a fire susceptible site, the amount of antelope bitterbrush and basin big sagebrush is influenced by fire frequency.

If the condition of the site deteriorates as a result of overgrazing, basin wildrye and antelope bitterbrush decrease. Basin big sagebrush, green rabbitbrush and creeping wildrye increase. Bluegrasses and annuals invade. With further deterioration annuals and shrubs increase and useable forage production decreases. Streambanks become unstable from loss of vegetation and channels degrade, becoming deeper and wider in the process. Subsurface flows are affected. Peak discharges increase, the water table drops and storage of water for late season use is reduced. Erosion from concentrated flows reduces the site potential and contributes to downstream sedimentation.

State and transition model

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

Figure 2. Annual production by plant type (representative values) or group (midpoint values)

Table 5. Annual production by plant type

Plant type	Low (kg/hectare)	Representative value (kg/hectare)	High (kg/hectare)
Grass/Grasslike	1793	3138	4483
Shrub/Vine	336	588	841
Forb	112	196	280
Total	2241	3922	5604

Additional community tables

Table 6. Community 1.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production (kg/hectare)	Foliar cover (%)
Grass/Grasslike
1	Dominant, perennial, deep rooted grasses			2550–2942
	basin wildrye	LECI4	Leymus cinereus	2550–2942	–
2	Sub-dominant, perennial, deep rooted grasses			157–785
	sedge	CAREX	Carex	78–392	–
	beardless wildrye	LETR5	Leymus triticoides	78–392	–
3	Sub-dominant, perennial, shallow rooted grasses			39–78
	bluegrass	POA	Poa	39–78	–
4	All other perennial grasses			78–303
	bluebunch wheatgrass	PSSPS	Pseudoroegneria spicata ssp. spicata	39–78	–
	squirreltail	ELEL5	Elymus elymoides	8–45	–
	Idaho fescue	FEID	Festuca idahoensis	8–45	–
	rush	JUNCU	Juncus	8–45	–
	prairie Junegrass	KOMA	Koeleria macrantha	8–45	–
	Cusick's bluegrass	POCU3	Poa cusickii	8–45	–
Forb
5	Dominant perennial forbs			67–202
	milkvetch	ASTRA	Astragalus	22–78	–
	lupine	LUPIN	Lupinus	22–78	–
	common yarrow	ACMI2	Achillea millefolium	22–45	–
6	All other perennial forbs			40–150
	ragwort	SENEC	Senecio	11–39	–
	tapertip hawksbeard	CRAC2	Crepis acuminata	11–39	–
	fleabane	ERIGE2	Erigeron	2–9	–
	stoneseed	LITHO3	Lithospermum	2–9	–
	desertparsley	LOMAT	Lomatium	2–9	–
	phlox	PHLOX	Phlox	2–9	–
	buttercup	RANUN	Ranunculus	2–9	–
	dock	RUMEX	Rumex	2–9	–
	deathcamas	ZIGAD	Zigadenus	2–9	–
	white sagebrush	ARLU	Artemisia ludoviciana	2–9	–
Shrub/Vine
7	Dominant, perennial shrubs			196–392
	basin big sagebrush	ARTRT	Artemisia tridentata ssp. tridentata	196–392	–
	antelope bitterbrush	PUTR2	Purshia tridentata	196–392	–
8	All other perennial shrubs			78–241
	willow	SALIX	Salix	22–78	–
	greasewood	SAVE4	Sarcobatus vermiculatus	11–39	–
	wax currant	RICE	Ribes cereum	11–39	–
	rose	ROSA5	Rosa	11–39	–
	yellow rabbitbrush	CHVI8	Chrysothamnus viscidiflorus	11–22	–
	rubber rabbitbrush	ERNA10	Ericameria nauseosa	11–22	–

Interpretations

Animal community

This site offers food and cover for mule deer, antelope, rodents and a variety of birds. It is an important wintering area for mule deer and antelope.

Hydrological functions

The soils are in hydrologic group B. The soils of this site have moderately low runoff potential.

Other products

This site is suited to use by cattle, sheep and horses in late spring, summer and fall under a planned grazing system. Limitations in the spring are saturated, wet soils and unstable banks. Use should be postponed until the soils are firm enough to prevent trampling damage and soil compaction yet, while soil moisture is adequate to allow the completion of the plant growth cycle. Improvement and/or maintenance of bank protecting vegetation should be considered during all seasons, particularly in the fall and winter for spring high flow periods.

Other information

The soils in this site have excellent water holding capacity providing late season water for plant growth and slow water release to streams. When incised channels are present, rehabilitation will markedly improve production and restore good hydrologic characteristics. On altered sites, the reintroduction of desirable plants may be needed to fully restore the site potential.

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:

Download reference sheet