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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 Unpublished report.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.
Associated sites
F021XE230CA Pinus ponderosa/Symphoricarpos rotundifolius/Achnatherum
F021XE237CA Juniperus occidentalis var. occidentalis/Artemisia tridentata ssp. vaseyana/Achnatherum thurberianum
R021XE205CA South Slope 16-30 P.Z.
R021XE210CA Mahogany Savanna
R021XE223CA Ashy Loamy Slope 16-30 P.Z.
Similar sites
R021XE206CA Mountain Shoulders 30+ P.Z.
More productive site; BRMA4 dominant grass; PUTR2 minor component.
R021XE201CA Ashy Slope 16-30 P.Z.
More productive site. FEID dominant grass.
R021XE222CA Loamy Slope 30+ P.Z.
More productive site; PUTR2 minor component.
R021XE224CA South Slope 30+ P.Z.
More productive site at higher elevations. ACHNA co-dominant grass.
R021XE205CA South Slope 16-30 P.Z.
Deeper soils, more productive site.
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Artemisia tridentata ssp. vaseyana
(2) Purshia tridentataHerbaceous (1) Pseudoroegneria spicata ssp. spicata
(2) AchnatherumPhysiographic features
This site occurs on steep eroded backslopes of mountains. Slopes range from 4 to 75 percent, but slope gradients of 30 to 75 are most typical. Elevations range from 5000 to 6700 feet.
Table 2. Representative physiographic features
Landforms (1) Mountain slope
Elevation 5000 – 6700 ft Slope 4 – 75 % Aspect Aspect is not a significant factor Climatic features
The climate of this site is subhumid, characterized by cool, moist winters and warm, dry summers. 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 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 43 to 45 degrees F. The average growing season is about 60 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 very shallow to weathered bedrock. They are well drained soils that formed in volcanic ash and residuum and colluvium from andesite, andesitic tuff or tuff-breccia. These soils are moist in winter and spring, and dry in summer and fall. The effective moisture is low because of the very shallow, droughty soil and steep slopes. The moisture regime is aridic bordering on xeric. These soils are high in vitric volcanic ash and glass throughout the soil profile which enhances the water holding capacity of these soils. Soil series associated with this site include Hartner.
Table 4. Representative soil features
Parent material (1) Residuum – andesite
Surface texture (1) Ashy sandy loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderate to moderately rapid Soil depth 4 – 10 in Surface fragment cover <=3" 23 – 47 % Surface fragment cover >3" 2 – 4 % Available water capacity
(0-40in)0.5 – 0.6 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)5 – 35 % Subsurface fragment volume >3"
(Depth not specified)0 – 5 % Ecological dynamics
Fire Ecology:
Presettlement fire return intervals in mountain big sagebrush communities varied from 15 to 25 years, however, on this sparse site fire return intervals are probably greater than 100 years. 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. Western juniper commonly increases on this site when fire return intervals exceed 50 years.
Fire effects:
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.
Antelope bitterbrush is very susceptible to fire kill. It is considered a weak sprouter and is often killed by summer or fall fire. Anterlope bitterbrush in some areas may sprout after light-severity spring fires. Season of burning and environmental conditions impact antelope bitterbrushs ability to survive fire and resprout. High fuel consumptions increase antelope bitterbrush mortality and therefore favors seedling establishment.
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.
Thurber needlegrass is moderately to severely damaged by fire depending on season of burn, phenology, and fire severity. Thurber needlegrass is the least fire-resistant needlegrass, due to its densely tufted stems. Early season burning is more damaging to this needlegrass than late season burning.
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 an open canopy of soft-woody shrubs, 0.5 to 1 meter tall, and a sparse understory of deep-rooted perennial grasses and forbs. The plant community is dominated by mountain big sagebrush, antelope bitterbrush, bluebunch wheatgrass and species of needlegrass. Potential vegetative composition is about 40% grasses, 20% forbs, 35% shrubs and up to 5% trees. Approximate ground cover (basal and canopy) is variable, depending on microclimatic conditions, and ranges from 2 to 20 percent.
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 20 100 160 Shrub/Vine 18 88 140 Forb 10 50 80 Tree 2 12 20 Total 50 250 400 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 34–130 bluebunch wheatgrass PSSPS Pseudoroegneria spicata ssp. spicata 25–75 – Sandberg bluegrass POSE Poa secunda 3–25 – Lemmon's needlegrass ACLE8 Achnatherum lemmonii 2–10 – Letterman's needlegrass ACLE9 Achnatherum lettermanii 2–10 – Thurber's needlegrass ACTH7 Achnatherum thurberianum 2–10 – 2 Secondary Perennial Grasses 2–20 Indian ricegrass ACHY Achnatherum hymenoides 1–10 – squirreltail ELELE Elymus elymoides ssp. elymoides 1–10 – sagebrush mariposa lily CAMAM9 Calochortus macrocarpus var. macrocarpus 1–5 – Indian paintbrush CASTI2 Castilleja 1–5 – hawksbeard CREPI Crepis 1–5 – common woolly sunflower ERLA6 Eriophyllum lanatum 1–5 – naked buckwheat ERNU3 Eriogonum nudum 1–5 – desertparsley LOMAT Lomatium 1–5 – lupine LUPIN Lupinus 1–5 – goosefoot violet VIPU4 Viola purpurea 1–5 – woolly mule-ears WYMO Wyethia mollis 1–5 – Forb3 Perennial Forbs 9–45 sagebrush mariposa lily CAMAM9 Calochortus macrocarpus var. macrocarpus 1–5 – Indian paintbrush CASTI2 Castilleja 1–5 – hawksbeard CREPI Crepis 1–5 – common woolly sunflower ERLA6 Eriophyllum lanatum 1–5 – naked buckwheat ERNU3 Eriogonum nudum 1–5 – desertparsley LOMAT Lomatium 1–5 – lupine LUPIN Lupinus 1–5 – goosefoot violet VIPU4 Viola purpurea 1–5 – woolly mule-ears WYMO Wyethia mollis 1–5 – 4 Annual Forbs 4–20 diamond clarkia CLRH Clarkia rhomboidea 1–5 – buckwheat ERIOG Eriogonum 1–5 – monkeyflower MIMUL Mimulus 1–5 – phacelia PHACE Phacelia 1–5 – Shrub/Vine5 Primary Shrubs 43–115 mountain big sagebrush ARTRV Artemisia tridentata ssp. vaseyana 25–65 – antelope bitterbrush PUTR2 Purshia tridentata 13–38 – rubber rabbitbrush ERNA10 Ericameria nauseosa 5–12 – 6 Secondary Shrubs 6–30 littleleaf brickellbush BRMI Brickellia microphylla 1–5 – curl-leaf mountain mahogany CELE3 Cercocarpus ledifolius 1–5 – yellow rabbitbrush CHVIV2 Chrysothamnus viscidiflorus ssp. viscidiflorus 1–5 – sulphur-flower buckwheat ERUM Eriogonum umbellatum 1–5 – pale monardella MOGL Monardella glauca 1–5 – purple sage SADO4 Salvia dorrii 1–5 – Tree7 Evergreen 2–13 western juniper JUOC Juniperus occidentalis 2–13 – Interpretations
Animal community
Grazing Interpretations:
This site is poorly suited for livestock grazing due to steep slopes and low forage production. Grazing management should be keyed to perennial grass production. Where management results in abusive livestock use, perennial grasses will decrease and rubber rabbitbrush will increase. Thistles, medusahead, and cheatgrass are species likely to invade this site.
Wildlife Interpretations:
This site is only marginally suitable for use by large mammals, however it does provide habitat for small mammals and birds.Hydrological functions
The soil is in Hydrologic Group D. Runoff is high to very high and permeability is moderate to moderately rapid.
Recreational uses
The steepness of slopes limits extensive recreation use on this site. Recreational uses include 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. 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 Township/Range/Section T42N R16E S30 Latitude 41° 28′ 19″ Longitude 120° 11′ 29″ General legal description Granger Creek Canyon, on the Modoc National Forest in the Warner Mountains, Modoc Co. CA. Other references
Modoc Elk Working Group. 2000. The Greater Modoc Area - A 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) P. Novak-Echenique Contact for lead author State Rangeland Management Specialist Date 02/08/2007 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:
Thistles, medusahead, and cheatgrass are species likely to invade this site. -
Perennial plant reproductive capability:
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