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Conservation Service

Ecological site R010XY114OR

Cool Swale 9-12 PZ

Accessed: 12/21/2024

Home / Esd catalog / MLRA 010X / Ecological site R010XY114OR

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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.

Table 1. Dominant plant species

Tree	Not specified
Shrub	(1) Artemisia tridentata ssp. tridentata
Herbaceous	(1) Leymus cinereus (2) Hesperostipa comata

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Physiographic features

This site occurs adjacent to and on the floodplains of ephemeral streams. It is at the upper end of drainages occupying broad to narrow swale areas. Slopes range from 2 to 12 percent. Elevations range from 2700 to 4000 feet.

Table 2. Representative physiographic features

Landforms	(1) Flood plain (2) Stream (3) Swale
Elevation	2,700 – 4,000 ft
Slope	2 – 12%
Water table depth	60 in
Aspect	Aspect is not a significant factor

Climatic features

The annual precipitation ranges from 9 to 12 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 near frigid to frigid with a mean annual air temperature of 47 degrees F. Temperature extremes range from 100 to -20 degrees F. The frost-free period ranges from 60 to 100 days. The optimum growth period for native plants is from April through June.

Table 3. Representative climatic features

Frost-free period (average)	100 days
Freeze-free period (average)	0 days
Precipitation total (average)	12 in

Soil features

The soils of this site are recent, deep to very deep and well-drained. Typically the surface layer is a silt loam about 10 inches thick. The subsoil is a silt loam to silty clay loam over 40 inches thick. The substratum varies from alluvium to bedrock. Permeability is moderate. The available water holding capacity (AWC) is about 8 to 10 inches for the profile. Seasonal subsurface flows from adjacent slopes augment the availabe water. The potential for erosion is moderate.

Table 4. Representative soil features

Surface texture	(1) Silt loam
Family particle size	(1) Clayey
Drainage class	Well drained
Permeability class	Moderate
Soil depth	50 in
Available water capacity (0-40in)	8 – 10 in

Ecological dynamics

Range in Characteristics:

The amount of basin wildrye depends on the extent and duration of lateral subsurface water flows. Basin wildrye decreases and needle-grasses increase on the upper ends of watersheds where drainage area is limited. Production follows a similar pattern increasing on swales with large drainage areas. As a site susceptible to fire, the amount of basin big sagebrush is influenced by fire frequency.

Response to Disturbance:

If the condition of the site deteriorates as a result of overgrazing basin wildrye, western needlegrass and Idaho fescue decrease. Needle-and-thread, western wheatgrass, basin big sagebrush, and green rabbitbrush increase. With further deterioration, needle-and-thread and western wheatgrass decrease. Sagebrush and green rabbitbrush continue to increase and annuals invade. 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. Plants well adapted to a drier climatic regime increase or invade and production drops.

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 potential native plant community is dominated by basin wildrye and needlegrasses. Basin big sagebrush, Idaho fescue, and western wheatgrass are common in the stand. Threadleaf sedge, bluebunch wheatgrass, Sandberg bluegrass, and a variety of forbs are present. Vegetative composition of the community is approximately 85 percent grasses, 5 percent forbs, and 10 percent shrubs. Approximate ground cover is 70-80 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	468	906	1344
Shrub/Vine	60	108	156
Forb	48	84	120
Total	576	1098	1620

Figure 3. Plant community growth curve (percent production by month). OR4451, B10 SR Fan and Swale, 9-16 pz . SR Fan and Swale, 9-16 pz RPC Growth Curve.

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	0	5	10	25	25	20	5	5	5	0	0

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	Perennial, deep-rooted, dominant			120–360
	basin wildrye	LECI4	Leymus cinereus	120–360	–
2	Perennial, deep-rooted, sub-dominant			288–840
	western needlegrass	ACOC3	Achnatherum occidentale	60–180	–
	Idaho fescue	FEID	Festuca idahoensis	60–180	–
	needle and thread	HECO26	Hesperostipa comata	60–180	–
	western wheatgrass	PASM	Pascopyrum smithii	60–180	–
	Thurber's needlegrass	ACTH7	Achnatherum thurberianum	24–60	–
	threadleaf sedge	CAFI	Carex filifolia	24–60	–
4	Perennial, shallow-rooted, sub-dominant			36–96
	bluebunch wheatgrass	PSSP6	Pseudoroegneria spicata	24–60	–
	bluebunch wheatgrass	PSSP6	Pseudoroegneria spicata	24–60	–
	prairie Junegrass	KOMA	Koeleria macrantha	12–36	–
	prairie Junegrass	KOMA	Koeleria macrantha	12–36	–
5	Other perennial grasses, all			24–48
	squirreltail	ELEL5	Elymus elymoides	0–24	–
	Sandberg bluegrass	POSE	Poa secunda	0–24	–
Forb
7	Perennial,all, dominant			36–72
	fleabane	ERIGE2	Erigeron	12–24	–
	buckwheat	ERIOG	Eriogonum	12–24	–
	lupine	LUPIN	Lupinus	12–24	–
	fleabane	ERIGE2	Erigeron	12–24	–
	buckwheat	ERIOG	Eriogonum	12–24	–
	lupine	LUPIN	Lupinus	12–24	–
9	Other perennial forbs, all			12–48
	common yarrow	ACMI2	Achillea millefolium	0–4	–
	white sagebrush	ARLU	Artemisia ludoviciana	0–4	–
	milkvetch	ASTRA	Astragalus	0–4	–
	tapertip hawksbeard	CRAC2	Crepis acuminata	0–4	–
	stoneseed	LITHO3	Lithospermum	0–4	–
	desertparsley	LOMAT	Lomatium	0–4	–
	locoweed	OXYTR	Oxytropis	0–4	–
	phlox	PHLOX	Phlox	0–4	–
	sagebrush buttercup	RAGL	Ranunculus glaberrimus	0–4	–
	globemallow	SPHAE	Sphaeralcea	0–4	–
	deathcamas	ZIGAD	Zigadenus	0–4	–
	common yarrow	ACMI2	Achillea millefolium	0–4	–
	white sagebrush	ARLU	Artemisia ludoviciana	0–4	–
	milkvetch	ASTRA	Astragalus	0–4	–
	tapertip hawksbeard	CRAC2	Crepis acuminata	0–4	–
	stoneseed	LITHO3	Lithospermum	0–4	–
	desertparsley	LOMAT	Lomatium	0–4	–
	locoweed	OXYTR	Oxytropis	0–4	–
	phlox	PHLOX	Phlox	0–4	–
	sagebrush buttercup	RAGL	Ranunculus glaberrimus	0–4	–
	globemallow	SPHAE	Sphaeralcea	0–4	–
	deathcamas	ZIGAD	Zigadenus	0–4	–
Shrub/Vine
11	Perennial, evergreen, dominant			24–60
	basin big sagebrush	ARTRT	Artemisia tridentata ssp. tridentata	24–60	–
12	Perennial, evergreen, sub-dominant			24–48
	basin big sagebrush	ARTRT	Artemisia tridentata ssp. tridentata	12–24	–
	yellow rabbitbrush	CHVI8	Chrysothamnus viscidiflorus	12–24	–
15	Other perennial shrubs, all			12–48
	rubber rabbitbrush	ERNA10	Ericameria nauseosa	0–12	–
	antelope bitterbrush	PUTR2	Purshia tridentata	0–12	–
	horsebrush	TETRA3	Tetradymia	0–12	–

Interpretations

Animal community

Livestock Grazing:

This site is suited to use by cattle, sheep, and horses in 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 enough to allow the completion of the plant growth cycle. Improvement and/or maintenance of herbaceous bank protection should be considered during all seasons, particularly going into the winter for spring high flow periods.

Native Wildlife Associated with the Potential Climax Community:

Deer
Antelope
Hawks
Songbirds
Rodents

This site will offer 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. This site is potentially subject to three high flow periods: low elevation snowmelt, high elevation snowmelt, and summer cloudburst flow.

Other information

The soils of this site have excellent water holding capacities providing late season water for plant growth and slow water releases to streams. When incised channels are present, rehabilitation will markedly improve production and restore good hydrologic characteristics. On alterd sites the reintroduction of desirable deep rooted palnts 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