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Ecological site R022AZ055CA

MOUNTAIN SHOULDERS 20-30 P.Z.

Accessed: 11/23/2024

Home / Esd catalog / MLRA 022A / Ecological site R022AZ055CA

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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): 022A–Sierra Nevada and Tehachapi Mountains

This ESD was developed using older policy requirements which have been improved with the intent of improving ESD products overall. Users should approach these materials with some caution as the content herein, while likely useful for some purposes, was developed within parameters now recognized as needing varying levels of improvement. As always, a site-specific investigation is highly recommended when site-specific management alternatives are to be developed and/or management decisions are to be made.

Each ESD is an interpretation of the ecological relationships between biotic and abiotic aspects of the landscape. Users of this document should be aware of the limitations of this tool to the extent that specific local conditions may not be entirely captured within the ESD. In particular, management decisions should be supported by site-specific inventories, assessments and planning processes based on the best available information including and extending beyond the ESD.

An ESD is not a permanent determination of ecological dynamics. Rather, each ESD is an evolving body of work intrinsically tied to the soil surveys and data associated with soil map unit components of correlated soil-ecological site relationships. As new information becomes available, updates may be made or may be underway at any given time. Minor updates may be made without announcement when such changes do not modify the ecological site concept, the soils correlated or the state-and-transition model.

Associated sites

F022AY126NV	Pinus albicaulis-Pinus flexilis/Poa-Carex
R022AY011NV	MOUNTAIN RIDGE 30+ P.Z.
R022AY024NV	MAHOGANY SAVANNA
R022AY032NV	ALPINE RIDGE

Table 1. Dominant plant species

Tree	Not specified
Shrub	(1) Artemisia tridentata ssp. vaseyana
Herbaceous	(1) Leucopoa kingii (2) Achnatherum occidentale

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Physiographic features

This site occurs on mountain summits and shoulders having a smooth to slightly concave shape. Slopes range from 15 to 50 percent. Elevations are 8000 to 10,500 feet.

Table 2. Representative physiographic features

Landforms	(1) Mountain (2) Mountain slope
Elevation	2,438 – 3,200 m
Slope	15 – 50%

Climatic features

The climate is sub-humid with cold, moist winters, and cool, dry summers. Average annual precipitation is 16 inches to 30 inches. Mean annual air temperature is 36 to 43 degrees F. The average growing season is about
30 to 70 days. Climate data used to support this section were derived from PRISM and is not specifically tied to any dominant climate station.

Table 3. Representative climatic features

Frost-free period (average)	70 days
Freeze-free period (average)	0 days
Precipitation total (average)	762 mm

Bar

Line

Figure 1. Monthly average minimum and maximum temperature

Soil features

The soils associated with this site are very deep, well drained soils that formed in colluvium and residuum from volcanic rocks. The soils are skeletal, have a mollic epipedon, and an argillic horizion. The soils are usually moist in the moisture control section during late fall, winter, and spring, and are dry from July through early October. Soils have high runoff and high permeability. Available water capacity is low. Soil series associated with this site include: Dab

CA729 Toiyabe National Forest Area, California
513;Rubble land-Holdon-Rock outcrop complex, 30 to 100 percent slopes;Dab
791;Dab-Longday-Thiefridge association;Dab;Pachic Argicryolls
792;Dab-Aspocket-Hawkridge association;Dab

NV773 Douglas County Area, Nevada
1000;Dab-Longday-Thiefridge association;Dab;Pachic Argicryolls

Table 4. Representative soil features

Surface texture	(1) Extremely gravelly sandy loam
Family particle size	(1) Loamy
Drainage class	Well drained
Permeability class	Moderate
Soil depth	183 cm
Surface fragment cover <=3"	74%
Surface fragment cover >3"	2%
Available water capacity (0-101.6cm)	8.64 cm
Electrical conductivity (0-101.6cm)	0 mmhos/cm
Sodium adsorption ratio (0-101.6cm)	0
Soil reaction (1:1 water) (0-101.6cm)	6.1 – 7.3

Ecological dynamics

As ecological condition declines, big sagebrush, snowberry and other woody plants increase in prevalence as Letterman's needlegrass, mountain brome and other perennial grasses and forbs decline in the understory.

Fire Ecology:
The fire return interval for mountain big sagebrush communities ranges from 15 to 40 years. Mountain big sagebrush is highly susceptible to injury from fire. Plants are readily killed in all seasons, even by light severity fires. Mountain big sagebrush plants are top-killed by fire and will not resprout. Regeneration of mountain big sagebrush is from on-site or off-site seed. Depending on circumstances of the environment and seed source, mountain big sagebrush seeds may sprout profusely the spring after burning, or very sparsely.

Mountain brome is top-killed by fire. Mountain brome appears to recover from fire within a few years.

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. 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 characterized by an open canopy of soft-woody shrubs and a dense understory of perennial grasses. The plant community is dominated by western needlegrass, mountain brome and mountain big sagebrush. Potential vegetative composition is about 30% shrubs, 50% grasses and grass-like plants, and 10% forbs. Approximate ground cover(basal and crown) is 20 to 35 percent.

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	314	471	628
Shrub/Vine	90	135	179
Forb	45	67	90
Total	449	673	897

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	Primary Perennial Grasses			343–565
	spike fescue	LEKI2	Leucopoa kingii	235–303	–
	western needlegrass	ACOCO	Achnatherum occidentale ssp. occidentale	67–101	–
	mountain brome	BRMA4	Bromus marginatus	13–54	–
	purple oniongrass	MESP	Melica spectabilis	13–54	–
	bluegrass	POA	Poa	13–54	–
2	Secondary Perennial Grasses/Grasslikes			34–67
	Letterman's needlegrass	ACLE9	Achnatherum lettermanii	3–20	–
	sedge	CAREX	Carex	3–20	–
	big squirreltail	ELMU3	Elymus multisetus	3–20	–
Forb
3	Perennial Forbs			40–101
	tapertip hawksbeard	CRAC2	Crepis acuminata	13–34	–
	lupine	LUPIN	Lupinus	13–34	–
	phlox	PHLOX	Phlox	3–13	–
	buckwheat	ERIOG	Eriogonum	3–13	–
	rockcress	ARABI2	Arabis	3–13	–
Shrub/Vine
4	Primary Shrubs			101–135
	mountain big sagebrush	ARTRV	Artemisia tridentata ssp. vaseyana	101–135	–
5	Secondary Shrubs			13–54
	slender buckwheat	ERMI4	Eriogonum microthecum	3–13	–
	antelope bitterbrush	PUTR2	Purshia tridentata	3–13	–
	mountain snowberry	SYOR2	Symphoricarpos oreophilus	3–13	–

Interpretations

Animal community

Livestock Interpretations:
Mountain big sagebrush is eaten by domestic sheep and cattle, but has long been considered to be of low palatability to domestic livestock, a competitor with more desirable species, and a physical impediment to grazing.

Mountain brome is palatable to all classes of livestock throughout the growing season. Plants become fibrous at maturity but livestock readily graze the ripe seed heads. Domestic sheep have shown rapid weight gain on ranges with an abundance of ripe Mountain brome seed heads.

Wildlife Interpretations:
Mountain big sagebrush is highly preferred and nutritious winter forage for mule deer.

Mountain brome provides high-quality forage and is sometimes planted as a pasture grass. Various small animals including rodents and geese graze Mountain brome foliage, and the seeds furnish food for many bird and rodent species.

Other information

Mountain big sagebrush is easily propagated from seed under greenhouse, nursery, and common garden conditions and has been successfully seeded directly into field sites. Mountain big sagebrush has also been successfully planted in field sites using nursery-grown bareroot and containerized stock.

Mountain brome is useful for revegetating disturbed sites due to rapid establishment and good soil stabilizing capability. It has proved effective for stabilizing watersheds.

Supporting information

Type locality

Location 1: Mono County, CA
Township/Range/Section	T8N R22E S33
Latitude	38° 29′ 19″
Longitude	119° 34′ 3″
General legal description	Toiyabe National Forest in Corral Valley, about two miles south of Rodriguez Flat

Contributors

ALM/GKB

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