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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 Unpublished report.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: Antelope bitterbrush/ Big sagebrush 35.200.03.
Sawyer, J.O. and T. Keeler-Wolf. 1995. A Manual of California Vegetation. California Native Plant Society, Sacramento, CA. Bitterbrush Series.
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Artemisia tridentata ssp. vaseyana
(2) Purshia tridentataHerbaceous (1) Achnatherum
(2) PoaPhysiographic features
This site occurs on mountain sideslopes. Slopes range from 4 to 50 percent but 4 to 30 percent is typical. Elevation ranges from 4900 to 7800 feet.
Table 2. Representative physiographic features
Landforms (1) Mountain slope
Elevation 4900 – 7800 ft Slope 4 – 50 % Aspect Aspect is not a significant factor 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 45 degrees F. The average growing season is about 50 to 80 days.
Table 3 Representative climatic features
Frost-free period (average) 80 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
The soils of this site are moderately deep and well drained. Soils formed in volcanic ash and colluvium over residium derived from andesite or tuff. The soil surface is partly covered by 20 percent gravel, 5 percent cobbles and 5 percent stones. There are high amounts of vitric volcanic ash and glass throughout the soil profile which enhances the water holding capacity of these soils. Soil series include: Warnermount.
Table 4. Representative soil features
Parent material (1) Volcanic ash – volcanic breccia
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" 14 – 25 % Surface fragment cover >3" 2 – 10 % Available water capacity
(0-40in)4.3 – 4.4 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)14 – 33 % Subsurface fragment volume >3"
(Depth not specified)2 – 31 % Ecological dynamics
Where management results in abusive grazing use by livestock, woody plant and Sandberg bluegrass increase as Idaho fescue, needlegrasses and other desirable forage plants decrease. Cheatgrass is likely to invade this site. Where this site occurs adjacent to juniper woodland communities these trees readily invade the site.
Fire efects:
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.
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.
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.
Thurber needlegrass is classified as moderately resistant, but depending on season of burn, phenology, and fire severity, this perennial bunchgrass is moderately to severely damaged by fire. Burning has been found to decrease the vegetation and reproductive vigor. Early season burning is more damaging to this needlegrass than late season burning.
Sandberg bluegrass is generally unharmed by fire. It produces little litter, and its small bunch size and sparse litter reduces the amount of heat transferred to perennating buds in the soil. Its rapid maturation in the spring also reduces fire damage, since it is dormant when most fires occur.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 antelope bitterbrush, mountain big sagebrush, bluegrass, and Thurber's and/or western needlegrass. Potential vegetative composition is about 40% grasses, 15% forbs and 45% 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)Shrub/Vine 675 900 1080 Grass/Grasslike 600 800 960 Forb 225 300 360 Total 1500 2000 2400 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 540–920 Sandberg bluegrass POSE Poa secunda 100–200 – bluebunch wheatgrass PSSPS Pseudoroegneria spicata ssp. spicata 100–160 – mountain brome BRMA4 Bromus marginatus 40–160 – Thurber's needlegrass ACTH7 Achnatherum thurberianum 100–134 – Letterman's needlegrass ACLE9 Achnatherum lettermanii 100–133 – western needlegrass ACOCO Achnatherum occidentale ssp. occidentale 100–133 – 2 Secondary Perennial Grasses 60–240 big squirreltail ELMU3 Elymus multisetus 10–40 – slender wheatgrass ELTRT Elymus trachycaulus ssp. trachycaulus 10–40 – Idaho fescue FEID Festuca idahoensis 10–40 – prairie Junegrass KOMA Koeleria macrantha 10–40 – basin wildrye LECI4 Leymus cinereus 10–40 – melicgrass MELIC Melica 10–40 – Forb3 Perennial Forbs 140–840 tapertip hawksbeard CRAC2 Crepis acuminata 10–60 – Lewis flax LILE3 Linum lewisii 10–60 – lupine LUPIN Lupinus 10–60 – beardtongue PENST Penstemon 10–60 – cold-desert phlox PHST11 Phlox stansburyi 10–60 – woolly mule-ears WYMO Wyethia mollis 10–60 – foothill deathcamas ZIPA2 Zigadenus paniculatus 10–60 – common yarrow ACMI2 Achillea millefolium 10–20 – pale agoseris AGGL Agoseris glauca 10–20 – milkvetch ASTRA Astragalus 10–20 – arrowleaf balsamroot BASA3 Balsamorhiza sagittata 10–20 – sagebrush mariposa lily CAMAM9 Calochortus macrocarpus var. macrocarpus 10–20 – castilla CASTI Castilla 10–20 – clarkia CLARK Clarkia 10–20 – 4 Annual Forbs 30–60 pincushion CHAEN Chaenactis 10–20 – grand collomia COGR4 Collomia grandiflora 10–20 – phacelia PHACE Phacelia 10–20 – Shrub/Vine5 Primary Shrubs 500–900 antelope bitterbrush PUTR2 Purshia tridentata 300–500 – mountain big sagebrush ARTRV Artemisia tridentata ssp. vaseyana 200–400 – 6 Secondary Shrubs 140–420 Utah serviceberry AMUT Amelanchier utahensis 20–60 – bitter cherry PREM Prunus emarginata 20–60 – wax currant RICE Ribes cereum 20–60 – Woods' rose ROWO Rosa woodsii 20–60 – roundleaf snowberry SYRO Symphoricarpos rotundifolius 20–60 – spineless horsebrush TECA2 Tetradymia canescens 20–60 – Interpretations
Animal community
Livestock Interpretations:
This site is suited to grazing by cattle and sheep during the late spring, summer and fall. Attentive grazing management is required due to steep slopes and erosive soil surface conditions. Grazing management should be keyed to bluegrass and needlegrass production. Cattle prefer antelope bitterbrush from mid-May through June and again in September and October. Domestic livestock and mule deer may compete for antelope bitterbrush in late summer, fall, and/or winter. 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. Needlegrass and bluegrass are important forage for domestic livestock.
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:
Antelope bitterbrush is important browse for wildlife. Mule deer and elk utilize antelope bitterbrush extensively. It is often critical browse for mule deer in winter. Needlegrass and bluegrass are important forage for several wildlife species.Hydrological functions
Runoff is medium to high. Hydrologic soil group: B.
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
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. Mountain big sagebrush has potential for range restoration and soil stabilization. Letterman’s needlegrass has been used successfully in revegetating mine spoils, and erosion control.
Supporting information
Type locality
Location 1: Modoc County, CA Township/Range/Section T47N R16E S19 Latitude 41° 55′ 38″ Longitude 120° 10′ 38″ General legal description On the Modoc National Forest in the Warner Moutnains 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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