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Ecological site R011XY005OR

Swale 8-11 PZ

Accessed: 11/21/2024

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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

R011XY012OR	Silty 8-11 PZ Silty 8-11 PZ
R011XY013OR	Clayey 8-11 PZ Clayey 8-11 PZ
R011XY016OR	Sandy 8-11 PZ Sandy 8-11 PZ
R011XY020OR	South Slopes 8-11 PZ South Slopes 8-11 PZ
R011XY032OR	Silty North Slopes 8-11 PZ Silty North Slopes 8-11 PZ
R011XY034OR	Sandy North Slopes 8-11 PZ Sandy North Slopes 8-11 PZ

Similar sites

R011XY012OR	Silty 8-11 PZ Silty 8-11 PZ (subsurface flows absent, lower production, different composition - beardless wheatgrass dominant)
R010XY005OR	Loamy Bottom Loamy Bottom (longer subsurface flow duration, higher Production)

R011XY012OR

Silty 8-11 PZ

Silty 8-11 PZ (subsurface flows absent, lower production, different composition - beardless wheatgrass dominant)

R010XY005OR

Loamy Bottom

Loamy Bottom (longer subsurface flow duration, higher Production)

Table 1. Dominant plant species

Tree	Not specified
Shrub	(1) Artemisia tridentata ssp. tridentata
Herbaceous	(1) Leymus cinereus (2) Pseudoroegneria spicata ssp. inermis

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Physiographic features

This site occurs on low elevation terrace swales in the Malheur, Owyhee and adjacent Snake River drainage. Slopes typically range from 0 to 8%. Elevations vary from 2,100 to 3,200 feet.

Table 2. Representative physiographic features

Landforms	(1) Swale
Flooding duration	Brief (2 to 7 days) to very brief (4 to 48 hours)
Flooding frequency	Frequent to occasional
Ponding duration	Brief (2 to 7 days) to very brief (4 to 48 hours)
Ponding frequency	Occasional to rare
Elevation	2,100 – 3,200 ft
Slope	8%
Aspect	Aspect is not a significant factor

Climatic features

The annual precipitation ranges from 8 to 11 inches, most of which occurs in the form of rain during the months of December through April. An ephemeral supply of subsurface moisture augments the precipitation. The soil temperature regime is mesic with a mean air temperature of 53 degrees F. Temperature extremes range from 110 to -10 degrees F. The frost free period ranges from 150 to 190 days. The optimum growth period for plant growth is late March through June.

Table 3. Representative climatic features

Frost-free period (average)	190 days
Freeze-free period (average)	0 days
Precipitation total (average)	11 in

Soil features

The soils of this site are typically deep to very deep and well drained. Typically the surface layer is a silt loam to a very fine sandy loam 8 to 16 inches thick. The subsoil is a silt loam to silty clay loam over 40 inches thick. Depth to lacustrine and alluvial sediments or bedrock ranges from 40 to greater than 60 inches. Permeability is moderate. The available water holding capacity (AWC) is about 6 to 8 inches for the profile. The erosion potential is moderate to severe.

Table 4. Representative soil features

Parent material	(1) Loess – rhyolite
Surface texture	(1) Silt loam (2) Very fine sandy loam
Family particle size	(1) Loamy
Drainage class	Moderately well drained to well drained
Permeability class	Moderate to moderately rapid
Soil depth	40 – 60 in
Available water capacity (0-40in)	6 – 8 in

Ecological dynamics

The potential native plant community is dominated by basin wildrye, beardless wheatgrass and needle and thread. Basin big sagebrush, Thurber’s needlegrass and bluebunch wheatgrass are common. Sandberg bluegrass, a variety of forbs and other shrubs are present. Vegetative composition of the community is approximately 85 percent grasses, 10 percent forbs and 5 percent shrubs. The approximate ground cover is 80 to 90 percent (basal and crown).

Range in Characteristics:
Basin wildrye increases with the extent and duration of subsurface moisture. Beardless wheatgrass increases on silty surfaces and as the extent and duration of subsurface moisture decreases. Needle and thread increases on sandy surfaces and in lower precipitation areas. As a site highly susceptible to fire, the amount of basin big sagebrush significantly decreases with increasing fire frequency. Production increases at the upper end of the precipitation zone.

Response to Disturbance:
When the condition of the site deteriorates as a result of over grazing basin wildrye, beardless wheatgrass and needle and thread rapidly decrease. Basin big sagebrush cheatgrass, other annuals, biennial weeds and bulbous bluegrass invade. With fire and continued disturbance big sagebrush is severely impacted. Rabbitbrush increases slightly and annuals and noxious biennial forbs strongly invade. Bare ground increases and excessive erosion contributes to downstream sedimentation. The excessive erosion is most pronounced in drainage areas where deep incised gulley’s form.

States: ARTRT/POSE-BRTE (degraded without fire); POSE-POBU/biennial forbs and BRTE/biennial forbs (following fire on degraded range)

State and transition model

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Standard diagram

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Ecosystem states

2. Reference plant community

State 1 submodel, plant communities

1.1. Reference plant community

State 1
Reference plant community

Community 1.1
Reference plant community

The reference plant community is dominated by basin wildrye, beardless wheatgrass and needle and thread. Basin big sagebrush, Thurber’s needlegrass and bluebunch wheatgrass are common. Sandberg bluegrass, a variety of forbs and other shrubs are present. Vegetative composition of the community is approximately 85 percent grasses, 10 percent forbs and 5 percent shrubs. The approximate ground cover is 80 to 90 percent (basal and crown).

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	850	1275	1700
Forb	100	150	200
Shrub/Vine	50	75	100
Total	1000	1500	2000

Additional community tables

Table 6. Community 1.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production (lb/acre)	Foliar cover (%)
Grass/Grasslike
1	Domininat, deep rooted, perennial bunchgrasses			750–1050
	basin wildrye	LECI4	Leymus cinereus	450–600	–
	beardless wheatgrass	PSSPI	Pseudoroegneria spicata ssp. inermis	300–450	–
2	Sub-dominant, deep rooted, perennial bunchgrass			225–375
	needle and thread	HECO26	Hesperostipa comata	225–375	–
3	Other perennial grasses			30–150
	Thurber's needlegrass	ACTH7	Achnatherum thurberianum	45–120	–
	bluebunch wheatgrass	PSSPS	Pseudoroegneria spicata ssp. spicata	30–75	–
	three-angle spikerush	ELTR5	Eleocharis tricostata	0–45	–
	Indian ricegrass	ACHY	Achnatherum hymenoides	0–45	–
	Sandberg bluegrass	POSE	Poa secunda	15–30	–
	foxtail wheatgrass	PSSA2	×Pseudelymus saxicola	0–30	–
	squirreltail	ELEL5	Elymus elymoides	10–30	–
Forb
4	Dominant, perennial forbs			45–90
	arrowleaf balsamroot	BASA3	Balsamorhiza sagittata	15–30	–
	buckwheat	ERIOG	Eriogonum	15–30	–
	desertparsley	LOMAT	Lomatium	15–30	–
5	Other perennial forbs			45–150
	common yarrow	ACMI2	Achillea millefolium	5–15	–
	hawksbeard	CREPI	Crepis	5–15	–
	fleabane	ERIGE2	Erigeron	5–15	–
	milkvetch	ASTRA	Astragalus	5–15	–
	western stoneseed	LIRU4	Lithospermum ruderale	5–15	–
	lupine	LUPIN	Lupinus	0–15	–
	phlox	PHLOX	Phlox	5–15	–
	plains pricklypear	OPPO	Opuntia polyacantha	0–10	–
	bastard toadflax	COMAN	Comandra	0–8	–
	beardtongue	PENST	Penstemon	0–5	–
	scarlet globemallow	SPCO	Sphaeralcea coccinea	0–5	–
	woodland-star	LITHO2	Lithophragma	2–5	–
	common woolly sunflower	ERLA6	Eriophyllum lanatum	0–5	–
	haplopappus	HAPLO11	Haplopappus	0–5	–
	povertyweed	IVAX	Iva axillaris	0–5	–
	onion	ALLIU	Allium	2–5	–
	pussytoes	ANTEN	Antennaria	0–5	–
	white sagebrush	ARLU	Artemisia ludoviciana	0–5	–
	mariposa lily	CALOC	Calochortus	0–3	–
Shrub/Vine
6	Dominant, evergreen shrub			30–75
	basin big sagebrush	ARTRT	Artemisia tridentata ssp. tridentata	30–75	–
7	Other shrubs			30–75
	fourwing saltbush	ATCA2	Atriplex canescens	0–45	–
	spiny hopsage	GRSP	Grayia spinosa	10–45	–
	broom snakeweed	GUSA2	Gutierrezia sarothrae	0–30	–
	rubber rabbitbrush	ERNA10	Ericameria nauseosa	0–30	–
	littleleaf horsebrush	TEGL	Tetradymia glabrata	5–20	–

Interpretations

Animal community

Livestock Grazing:
This site is suitable for livestock grazing use in the late fall, winter and early spring under a planned grazing system. Use should be postponed until the soils are firm enough to prevent trampling damage and soil compaction. Grazing management should be keyed for basin wildrye, beardless wheatgrass and needle and thread. Deferred grazing or rest is recommended at least once every three years.

Native Wildlife Associated with the Potential Climax Community:
This site is commonly used by pronghorn antelope, mule deer, rabbits, rodents, upland birds and various predators. It provides excellent winter cover for sage grouse and other upland bird species. Antelope and mule deer make excellent use of the site for winter and early spring forage.

Hydrological functions

The soils of this site are typically in an upland topographic position. They have moderate runoff potential and medium infiltration rates when the hydrologic cover is high. Hydrologic cover is high when the basin wildrye, beardless wheatgrass and needle and thread deep rooted bunchgrass component is greater than 70 percent of potential. The soils are in hydrologic group B.

Other information

The soils of this site have excellent water holding capacities, accumulating off-site subsurface flows and providing late season water for plant growth. When incised channels are present, rehabilitation will markedly improve production and restore good hydrologic characteristics. On altered sites the reintroduction of desirable deep rooted plants may be needed to fully restore the site productivity.

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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