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Draft. A draft ecological site description is either incomplete or has not undergone quality control and quality assurance review.
Classification relationships
Holland, R.F. 1986. Preliminary descriptions of the terrestrial natural communities of California. Unpublished report. State of California, The Resources Agency, Department of Fish and Game, Natural Heritage Division, Sacramento, CA. (Updated September 2003). Element Code: Big Sagebrush 35.110.02.
Sawyer, J.O. and T. Keeler-Wolf. 1995. A Manual of California Vegetation. California Native Plant Society, Sacramento, CA. Big Sagebrush Series.
Associated sites
R021XE202CA Mountain Ridge 30+ P.Z.
R021XE210CA Mahogany Savanna
R021XE216CA Aspen Thicket
R021XE221CA Claypan 30+ P.Z.
R021XE222CA Loamy Slope 30+ P.Z.
R021XE224CA South Slope 30+ P.Z.
Similar sites
R021XE222CA Loamy Slope 30+ P.Z.
More productive site. PSSPS minor component
R021XE223CA Ashy Loamy Slope 16-30 P.Z.
FEID dominant grass.
R021XE224CA South Slope 30+ P.Z.
More productive site. PUTR2 co-dominant shrub, PSSPS dominant grass.
R021XE204CA Eroded Slope 16-30 P.Z.
Less productive site; PUTR2 and ACHNA co-dominant plants.
R021XE228CA Loamy 16-30 P.Z.
FEID dominant grass.
R021XE229CA Ashy Slope 30+ P.Z.
FEID dominant grass.
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Artemisia tridentata ssp. vaseyana
(2) Symphoricarpos rotundifoliusHerbaceous (1) Bromus marginatus
(2) Pseudoroegneria spicata ssp. spicataPhysiographic features
This site occurs on upper backslopes of mountains. Slopes range from 4 to 50 percent but slopes of 15 to 50 percent. Elevations range from 5200 to 9000 feet.
Table 2. Representative physiographic features
Landforms (1) Mountain slope
Elevation 5200 – 9000 ft Slope 4 – 50 % Aspect Aspect is not a significant factor Climatic features
The climate of this site is subhumid, characterized by warm, dry summers and cold, moist winters. The area's precipitation comes mostly from winter Pacific cyclonic storms, with a very slight summer monsoonal season that is erratic but can be locally significant. Most storms have strong winds from the southwest or west, which blow substanial amounts of snow off south and west facing slopes (particularly steep slopes or slopes with short vegetation), and increase snow accumulations on adjacent north and/or east facing slopes, and/or in nearby concave depressions.
Average annual precipitation is 30 to 50 inches with most occurring during the winter months. Approximately half the precipitation falls as snow; half as rain. The mean annual air temperature is 41 to 44 degrees F. The average growing season is 50 to 70 days.Table 3 Representative climatic features
Frost-free period (average) 70 days Freeze-free period (average) 0 days Precipitation total (average) 50 in BarLineFigure 1. Monthly precipitation range
BarLineFigure 2. Monthly average minimum and maximum temperature
">Influencing water features
There are no influencing water features associated with this site.
Soil features
This site occurs on moderately deep, well drained soils that formed in residuum and colluvium derived from andesitic tuff, volcanic ash and volcanic rocks. Soils are usually moist in winter, spring and early summer, dry in late summer and fall. There are high amounts of vitric volcanic ash and glass throughout the soil profile which enhances the water holding capacity of these soils. A mollic epipedon occurs from the mineral soil surface to 25 inches. An argillic horizon occurs from 2 to 25 inches. These soils are usually moist in winter, spring, and early summer and dry in late summer and fall. They have a xeric soil moisture regime and a frigid temperature regime. Soil series associated with this site include Fendersflat.
Table 4. Representative soil features
Parent material (1) Residuum – andesite
Surface texture (1) Gravelly loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderate Soil depth 20 – 40 in Surface fragment cover <=3" 0 – 5 % Surface fragment cover >3" 20 – 28 % Available water capacity
(0-40in)3.9 – 5.2 in Calcium carbonate equivalent
(0-40in)Not specified Electrical conductivity
(0-40in)Not specified Sodium adsorption ratio
(0-40in)Not specified Soil reaction (1:1 water)
(0-40in)6.1 – 7.3 Subsurface fragment volume <=3"
(Depth not specified)20 – 40 % Subsurface fragment volume >3"
(Depth not specified)2 – 40 % Ecological dynamics
Fire Ecology:
Prior to settlement in the mid to late 1800's, the primary disturbance in the sagebrush steppe was fire. Presettlement fire return intervals in mountain big sagebrush communities varied from 15 to 25 years. At this interval, the bunchgrass dominated community will be maintained. Following a fire, mountain big sagebrush will often reestablish within 10 to 15 years. Within 15 to 25 years, the brush community may return to preburn density and cover. When sagebrush canopy cover reaches about 15%, the perennial grasses and forbs start to decline.
Fire plays a major role in recycling organic matter in these communities. Without fire, nutrients are tied up in dead woody vegetation. Fire return intervals of 25 to 50 years will maintain a shrub-dominated site. Perennial grasses generally produce small to moderate amounts of seed per plant during wet years, and little or no seed during dry years. Most of the seed does not survive for more than one year, thus seedbanks are small or absent. The initial response from grasses is largely from existing plants that survived the fire. Existing plants provide seed, which if the amount and timing of precipitation is adequate, can result in many new grass plants. Perennial grasses increase less rapidly than forbs, but quicker than sagebrush and most other shrubs than reestablish from seed.
Mountain big sagebrush communities are considered low risk for cheatgrass displacement due to lower winter temperatures and more moisture availability for perennial grasses to reestablish after fire. Although, fire on this site in fair to poor condition can result in cheatgrass-Douglas' rabbitbrush dominant communities.
Fire Effects:
First order effects are the immediate actions of fire and include plant mortality, consumption of organic material, creation of smoke and changes to the physical-chemical environment. Second order effects include the following:
1. Change in microclimate
2. Increase in range of soil temperatures
3. Change in soil nutrients and microbial activity
4. Regeneration of vegetation
5. Successsion and new vegetation patterns
6. Change in plant growth rates and competitive interactions
7. Altered wildlife habitat and activity of invertebrates and vertebrates
8. Changed water storage capacity and pattern of runoff.
Mountain big sagebrush is highly susceptible to injury from fire. Plants are readily killed in all seasons, even light severity fires. Mountain big sagebrush plants top-killed by fire will not resprout.
Burning bluebunch wheatgrass may remove most of the aboveground biomass but does not usually result in plant mortality. Bluebunch wheatgrass is generally favored by burning. Burning stimulates flowering and seed production. However, season of burning affects mortality.
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 textEcosystem states
State 1 submodel, plant communities
State 1
Reference StateCommunity 1.1
Reference Plant Community
Figure 3. Mountain Shoulder
The reference plant community is dominated by mountain brome and mountain big sagebrush. Bluebunch wheatgrass is an important grass species associated with this site. Potential vegetative composition is about 45% grasses, 20% forbs and 35% shrubs. Approximate canopy cover is 35 to 40%. Basal cover is 5 to 10 percent.
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)Grass/Grasslike 292 405 540 Shrub/Vine 228 315 420 Forb 130 180 240 Total 650 900 1200 Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Primary Perennial Grasses 243–450 mountain brome BRMA4 Bromus marginatus 90–180 – bluebunch wheatgrass PSSPS Pseudoroegneria spicata ssp. spicata 90–135 – Sandberg bluegrass POSE Poa secunda 18–45 – Lemmon's needlegrass ACLE8 Achnatherum lemmonii 22–45 – Letterman's needlegrass ACLE9 Achnatherum lettermanii 23–45 – 2 Secondary Perennial Grasses/Grasslikes 25–135 sedge CAREX Carex 5–27 – big squirreltail ELMU3 Elymus multisetus 5–27 – slender wheatgrass ELTRT Elymus trachycaulus ssp. trachycaulus 5–27 – basin wildrye LECI4 Leymus cinereus 5–27 – melicgrass MELIC Melica 5–27 – Forb3 Perennial Forbs 65–351 slender wheatgrass ELTRT Elymus trachycaulus ssp. trachycaulus 5–27 – melicgrass MELIC Melica 5–27 – common yarrow ACMI2 Achillea millefolium 5–27 – pale agoseris AGGL Agoseris glauca 5–27 – milkvetch ASTRA Astragalus 5–27 – sagebrush mariposa lily CAMAM9 Calochortus macrocarpus var. macrocarpus 5–27 – castilla CASTI Castilla 5–27 – tapertip hawksbeard CRAC2 Crepis acuminata 5–27 – larkspur DELPH Delphinium 5–27 – ballhead waterleaf HYCAC Hydrophyllum capitatum var. capitatum 5–27 – Lewis flax LILE3 Linum lewisii 5–27 – lupine LUPIN Lupinus 5–27 – Brown's peony PABR Paeonia brownii 5–27 – cold-desert phlox PHST11 Phlox stansburyi 5–27 – woolly mule-ears WYMO Wyethia mollis 5–27 – 4 Annual Forbs 18–72 sedge CAREX Carex 5–27 – Shrub/Vine5 Primary Shrubs 180–297 mountain big sagebrush ARTRV Artemisia tridentata ssp. vaseyana 135–225 – roundleaf snowberry SYRO Symphoricarpos rotundifolius 45–72 – 6 Secondary Shrubs 72–216 Utah serviceberry AMUT Amelanchier utahensis 9–27 – big sagebrush ARTRS2 Artemisia tridentata ssp. spiciformis 9–27 – curl-leaf mountain mahogany CELE3 Cercocarpus ledifolius 9–27 – yellow rabbitbrush CHVI8 Chrysothamnus viscidiflorus 9–27 – bitter cherry PREM Prunus emarginata 9–27 – spineless horsebrush TECA2 Tetradymia canescens 9–27 – Interpretations
Animal community
Livestock Interpretations:
This site is suited to grazing by cattle and sheep during the late spring, summer and fall. Grazing management should be keyed to perennial grass and palatable shrub production. 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 and bluebunch wheatgrass are important forage species for domestic livestock. Should management result in abusive use by livestock, mountain brome and bluebunch wheatgrass will decrease as mountain big sagebrush and other unpalatable shrubs increase in the overstory.
Stocking rates vary over time depending upon season of use, climate variations, site, and previous and current management goals. A safe starting stocking rate is an estimated stocking rate that is fine tuned by the client by adaptive management through the year and from year to year.
Wildlife Interpretations:
Big sagebrush is highly preferred and nutritious winter forage for mule deer. Sage grouse are also highly dependent on big sagebrush for both food and cover. Mountain brome and bluebunch wheatgrass are important forage for several wildlife species.Hydrological functions
Runoff is high to very high. Perennial herbaceous plants (especially deep-rooted bunchgrasses) slow runoff and increase infiltration.
Recreational uses
This site is suitable for hiking, birdwatching and hunting.
Other products
Native peoples used big sagebrush leaves and branches for medicinal teas, and the leaves as a fumigant. Bark was woven into mats, bags and clothing.
Other information
Mountain big sagebrush has potential for range restoration and soil stabilization.
Supporting information
Type locality
Location 1: Modoc County, CA Township/Range/Section T47N R16E S8 Latitude 41° 57′ 52″ Longitude 120° 10′ 10″ General legal description Mount Bidwell, on the Modoc National Forest in the Warner Mountains, Modoc County, CA. Other references
Modoc Elk Working Group. 2000. The Greater Modoc Area - Strategic Plan for Elk Management. Modoc County, CA
Fire Effects Information System [Online]. http://www.fs.fed.us/feis
Miles, S.R. and C.B. Goudey. 1997. Ecological Subregions of California Section and Subsection Descriptions. United States Department of Agriculture Forest Service, Pacific Southwest Region R5-EM-TP-005. Subsection M261Gf-Warner Mountains.Contributors
P.NOVAK-ECHENIQUE
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
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Number and extent of rills:
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Presence of water flow patterns:
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Number and height of erosional pedestals or terracettes:
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Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
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Number of gullies and erosion associated with gullies:
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Extent of wind scoured, blowouts and/or depositional areas:
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Amount of litter movement (describe size and distance expected to travel):
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Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
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Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
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Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
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Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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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:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
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Average percent litter cover (%) and depth ( in):
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Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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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:
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Perennial plant reproductive capability:
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