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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 Unpublished report.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.
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Artemisia tridentata ssp. vaseyana
Herbaceous (1) Festuca idahoensis
(2) Pseudoroegneria spicata ssp. spicataPhysiographic features
This site occurs on steep north facing mountain slopes. Slopes range from 30 to 50 percent. Elevations range from 5800 to 7500 feet.
Table 2. Representative physiographic features
Landforms (1) Mountain slope
Elevation 5800 – 7500 ft Slope 30 – 50 % Aspect N Climatic features
The climate of this site is temperate, 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. Average annual precipitation ranges from 16 to 30 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 about 50 to 70 days.
Table 3 Representative climatic features
Frost-free period (average) 70 days Freeze-free period (average) 0 days Precipitation total (average) 30 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 residuun 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. Mollic epipedon from soil surface to 25 inches. Argillic horizon from 2 to 25 inches. Soil series include Fendersflat. Soil Family: Vitrandic Argixerolls.
Table 4. Representative soil features
Parent material (1) Volcanic ash – tuff
Surface texture (1) Very gravelly sandy loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderate Soil depth 14 – 20 in Surface fragment cover <=3" 35 – 40 % Surface fragment cover >3" 5 – 11 % Available water capacity
(0-40in)2.4 – 2.5 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)35 – 40 % Subsurface fragment volume >3"
(Depth not specified)5 – 11 % Ecological dynamics
Where management results in abusive grazing use by livestock, mountain big sagebrush will increase at the expense of Idaho fescue and bluebunch wheatgrass. Moderate to heavy sheep use of this site will decrease abundance of Idaho fescue, needlegrass and bluegrasses. Heavy, early season, cattle or horse use will decrease bluebunch wheatgrass composition in the community. Cheatgrass and thistle are plant species most likely to invade this site.
Fire effects:
Presettlement fire return intervals in mountain big sagebrush communities varied from 15-25 years. 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.
Idaho fescue grows in a dense, fine-leaved tuft. Fires tend to burn within the accumulated fine leaves at the base of the plant and may produce temperatures sufficient to kill some of the root crown. Mature Idaho fescue plants are commonly reported to be severely damaged by fire in all seasons.
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 CommunityThe reference plant community is characterized by an overstory of soft-woody shrubs 0.5-1 m tall and an understory of perennial grasses. The representative plant community is dominated by bluebunch wheatgrass, Idaho fescue and mountain big sagebrush. Potential vegetative composition is about 60% grasses, 15% forbs and 25% shrubs.
Figure 3. 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 480 600 840 Shrub/Vine 200 250 350 Forb 120 150 210 Total 800 1000 1400 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 450–700 Idaho fescue FEID Festuca idahoensis 250–350 – bluebunch wheatgrass PSSPS Pseudoroegneria spicata ssp. spicata 150–250 – Sandberg bluegrass POSE Poa secunda 50–100 – 2 Secondary Perennial Grasses/Grasslike 25–100 Thurber's needlegrass ACTH7 Achnatherum thurberianum 5–20 – mountain brome BRMA4 Bromus marginatus 5–20 – sedge CAREX Carex 5–20 – squirreltail ELEL5 Elymus elymoides 5–20 – basin wildrye LECI4 Leymus cinereus 5–20 – Forb3 Perennial Forbs 30–120 arrowleaf balsamroot BASA3 Balsamorhiza sagittata 5–20 – sagebrush mariposa lily CAMAM9 Calochortus macrocarpus var. macrocarpus 5–20 – castilla CASTI Castilla 5–20 – tapertip hawksbeard CRAC2 Crepis acuminata 5–20 – lupine LUPIN Lupinus 5–20 – cold-desert phlox PHST11 Phlox stansburyi 5–20 – 4 Annual Forbs 10–40 grand collomia COGR4 Collomia grandiflora 5–20 – phacelia PHACE Phacelia 5–20 – Shrub/Vine5 Primary Shrubs 150–200 mountain big sagebrush ARTRV Artemisia tridentata ssp. vaseyana 150–200 – 6 Secondary Shrubs 40–120 parsnipflower buckwheat ERHEH3 Eriogonum heracleoides var. heracleoides 10–30 – antelope bitterbrush PUTR2 Purshia tridentata 10–30 – roundleaf snowberry SYRO Symphoricarpos rotundifolius 10–30 – Interpretations
Animal community
Livestock Interpretations:
This site is suited to cattle and sheep grazing during the spring, early summer and fall. Attentive grazing management is required on steep slopes due to erosive soil surface conditions. Grazing should be keyed to Idaho fescue and bluebunch wheatgrass 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.
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:
Mountain big sagebrush is highly preferred winter forage for mule deer. Big sagebrush is also used by wildlife for both food and cover. Idaho fescue provides important forage for several wildlife species. Bluebunch wheatgrass is also a crucial source of forage.Hydrological functions
Runoff is medium. Hydrologic soil group: D.
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 Latitude 41° 28′ 1″ Longitude 120° 12′ 4″ General legal description On the Modoc National Forest in the Warner Mountains Other references
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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