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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 Unpublished report.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-Antelope Bitterbrush 35.110.07.
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) Purshia tridentata
(2) Artemisia tridentata ssp. vaseyanaHerbaceous (1) Pseudoroegneria spicata ssp. spicata
(2) AchnatherumPhysiographic features
This site occurs on south facing slopes of mountains. Slopes range from 30 to 50 percent. Elevations range from 5500 to 7700 feet.
Table 2. Representative physiographic features
Landforms (1) Mountain slope
Elevation 5500 – 7700 ft Slope 30 – 50 % Aspect S 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 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 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) 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 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.
Table 4. Representative soil features
Parent material (1) Volcanic ash – pyroclastic rock
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" 5 – 25 % Surface fragment cover >3" 2 – 28 % Available water capacity
(0-40in)3.9 – 4 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 – 25 % Subsurface fragment volume >3"
(Depth not specified)2 – 40 % Ecological dynamics
Where management results in abusive use by livestock, needlegrass, bluebunch wheatgrass, and other palatable grasses decrease in the understory. With contiued site degradation, mountain big sagebrush and snowberry increase in density and often dominate the site.
Fire effects:
Presettlement fire return intervals for antelope bitterbrush range from 15-25 years. Season of burning and environmental conditions impact antelope bitterbrush ability to survive fire and sprout. It is considered a weak sprouter and is often killed by summer or fall fire. Antelope bitterbrush in some areas may sprout after light-severity spring fire. High fuel consumptions increase antelope bitterbrush mortality and therefore favors seedling establishment.
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.
Little specific information is available on adaptations of Letterman's needlegrass to fire. It is morphologically similar to Columbia needlegrass, which is only slightly to moderately damaged by fire. Season of burn affects the plant's ability to survive a fire. Post fire regeneration is through seeding and tillering.
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 dominated by bluebunch wheatgrass, antelope bitterbrush and mountain big sagebrush. Potential vegetative composition is about 50% grasses, 20% forbs and 30% 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 475 650 900 Shrub/Vine 285 390 540 Forb 190 260 360 Total 950 1300 1800 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 455–845 bluebunch wheatgrass PSSPS Pseudoroegneria spicata ssp. spicata 260–390 – mountain brome BRMA4 Bromus marginatus 65–130 – Sandberg bluegrass POSE Poa secunda 65–130 – Letterman's needlegrass ACLE9 Achnatherum lettermanii 33–98 – western needlegrass ACOCO Achnatherum occidentale ssp. occidentale 32–97 – 2 Secondary Perennial Grasses 14–78 big squirreltail ELMU3 Elymus multisetus 7–39 – slender wheatgrass ELTRT Elymus trachycaulus ssp. trachycaulus 7–39 – Forb3 Perennial Forbs 91–169 common yarrow ACMI2 Achillea millefolium 7–13 – rockcress ARABI Arabidopsis 7–13 – milkvetch ASTRA Astragalus 7–13 – sagebrush mariposa lily CAMAM9 Calochortus macrocarpus var. macrocarpus 7–13 – castilla CASTI Castilla 7–13 – tapertip hawksbeard CRAC2 Crepis acuminata 7–13 – ballhead waterleaf HYCA4 Hydrophyllum capitatum 7–13 – Lewis flax LILE3 Linum lewisii 7–13 – desertparsley LOMAT Lomatium 7–13 – lupine LUPIN Lupinus 7–13 – beardtongue PENST Penstemon 7–13 – woolly mule-ears WYMO Wyethia mollis 7–13 – foothill deathcamas ZIPA2 Zigadenus paniculatus 7–13 – 4 Annual Forbs 7–13 grand collomia COGR4 Collomia grandiflora 7–13 – Shrub/Vine5 Primary Shrubs 260–520 mountain big sagebrush ARTRV Artemisia tridentata ssp. vaseyana 195–325 – antelope bitterbrush PUTR2 Purshia tridentata 65–195 – 6 Secondary Shrubs 39–78 American black elderberry SANIC4 Sambucus nigra ssp. canadensis 13–26 – roundleaf snowberry SYRO Symphoricarpos rotundifolius 13–26 – Interpretations
Animal community
Livestock Interpretations:
This site is suited to cattle and sheep use during the spring, early summer and fall. Due to its southerly exposure, this site loses its snow cover earlier in the spring and plant growth is initiated before that of most adjacent sites. Thus, livestock may concentrate on this site during early spring grazing periods. Grazing should be keyed to bluebunch wheatgrass and needlegrass 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.
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. Bluebunch wheatgrass provides important forage for many types of domestic livestock and several wildlife species.Hydrological functions
Runoff is medium. Hydrologic group: C.
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. Antelope bitterbrush is extensively used in land reclamation. Antelope bitterbrush enhances succession by retaining soil and depositing organic material, and, in some habitats and with some ecotypes, by fixing nitrogen. Letterman’s needlegrass has been used successfully in revegetating mine spoils, and erosion control.
Supporting information
Type locality
Location 1: Modoc County, CA Latitude 41° 56′ 7″ Longitude 120° 9′ 49″ 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.
Modoc Elk Working Group. 2000. The Greater Modoc Area A Strategic Plan for Elk Management. Modoc County, CA
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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