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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 Unpublished report.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
Physiographic features
This site occurs on mountain sideslopes. Slopes range from 4 to 50 percent, but slope gradients from 15 to 50 percent are most typical. Elevations range from 7500 to 8200 feet.
Table 2. Representative physiographic features
Landforms (1) Mountain slope
Elevation 7500 – 8200 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. 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.
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
The soils associated with this site are moderately deep, well drained soils that formed in residuum and colluvium derived from andesitic tuff, volcanic ash, and volcanic rocks. These soils have high amounts of vitric volcanic ash and glass throughout the soil profile which enhances the waterholding capacity. The soil profile is modified with 35 to 60 percent rock fragments, mainly gravels and cobbles. A mollic epipedon occurs from the soil surface to 25 inches. An argillic horizon occurs from 2 to 25 inches.
Table 4. Representative soil features
Parent material (1) Residuum – andesite
Surface texture (1) Ashy loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderate Soil depth 20 – 40 in Surface fragment cover <=3" 15 – 20 % Surface fragment cover >3" 0 – 5 % Available water capacity
(0-40in)3 – 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)15 – 30 % Subsurface fragment volume >3"
(Depth not specified)5 – 45 % Ecological dynamics
Where management results in abusive grazing use by livestock, woody plants, bottlebrush squirreltail, and Sandberg bluegrass increase as Idaho fescue, and other desirable forage grasses decrease. Thistle and cheatgrass are species likely to invade this site. Where this site occurs adjacent to juniper woodland communities these trees readily invade the 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.
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 dominated by mountain big sagebrush and Idaho fescue. Sedge and Sandberg bluegrass are other important species associated with this site. Potential vegetative composition is about 55% grasses, 20% 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 330 495 660 Shrub/Vine 150 225 312 Forb 120 180 240 Total 600 900 1212 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/Grasslike 270–540 Idaho fescue FEID Festuca idahoensis 180–270 – Sandberg bluegrass POSE Poa secunda 45–135 – sedge CAREX Carex 45–135 – 2 Secondary Perennial Grasses 30–108 needlegrass ACHNA Achnatherum 5–18 – mountain brome BRMA4 Bromus marginatus 5–18 – squirreltail ELEL5 Elymus elymoides 5–18 – slender wheatgrass ELTRT Elymus trachycaulus ssp. trachycaulus 5–18 – melicgrass MELIC Melica 5–18 – bluebunch wheatgrass PSSPS Pseudoroegneria spicata ssp. spicata 5–18 – Forb3 Perennial Forbs 50–90 common yarrow ACMI2 Achillea millefolium 5–9 – milkvetch ASTRA Astragalus 5–9 – sagebrush mariposa lily CAMAM9 Calochortus macrocarpus var. macrocarpus 5–9 – castilla CASTI Castilla 5–9 – tapertip hawksbeard CRAC2 Crepis acuminata 5–9 – prickly hawkweed HIHO Hieracium horridum 5–9 – lupine LUPIN Lupinus 5–9 – Brown's peony PABR Paeonia brownii 5–9 – beardtongue PENST Penstemon 5–9 – woolly mule-ears WYMO Wyethia mollis 5–9 – 4 Annual Forbs 18–72 Shrub/Vine5 Primary Shrubs 153–270 mountain big sagebrush ARTRV Artemisia tridentata ssp. vaseyana 135–225 – roundleaf snowberry SYRO Symphoricarpos rotundifolius 18–45 – 6 Secondary Shrubs 36–108 Utah serviceberry AMUT Amelanchier utahensis 9–27 – yellow rabbitbrush CHVI8 Chrysothamnus viscidiflorus 9–27 – currant RIBES Ribes 9–27 – Interpretations
Animal community
Livestock Interpretations:
This site is suited to grazing by cattle and sheep during spring, summer and fall. Attentice grazing management is required due to steep slopes and erosive soil surface conditions. Grazing management should be keyed to Idaho fescue and Sandberg's bluegrass production. Livestock water is usually adequate as this site normally occurs at higher elevations where flowing streams and springs are common.
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:
Wildlife rely on mountain big sage for both food and cover. Mountain big sagebrush is highly preferred winter forage for mule deer. Idaho fescue provides important forage for several wildlife species as does Sandberg's bluegrass.Hydrological functions
Runoff is low to high.
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 T39N R16E S27 Latitude 41° 13′ 16″ Longitude 120° 8′ 25″ General legal description On the Modoc National Forest in the Warner Mountains, Modoc County, CA. 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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PrintThe Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.
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