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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 Unpublished report.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: Silver Sagebrush Scrub 35.150.00.
Associated sites
R021XE208CA Semi-Wet Meadow 16+ P.Z.
R021XE222CA Loamy Slope 30+ P.Z.
Similar sites
R021XE203CA Moist Mountain Basin
More productive site; dominated by perennial grasses and sedges on a wetter site.
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Artemisia cana ssp. bolanderi
Herbaceous (1) Achnatherum
(2) Poa secundaPhysiographic features
This site occurs on ground moraines on mountains and plateaus. Slopes range from 0 to 15 percent but 2 to 8 percent are typical. Elevations range from 6700 to 8000 feet.
Table 2. Representative physiographic features
Landforms (1) Ground moraine
Flooding duration Very brief (4 to 48 hours) Flooding frequency None to rare Ponding frequency None Elevation 6700 – 8000 ft Slope 0 – 15 % Water table depth 42 – 84 in 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 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
Endosaturation is present with an apparent seasonal high water table between 3.5 and 5 feet (common deep free water duration and depth class) from January through May.
Soil features
Soils of this site are very deep, well drained soils that formed in glacial till and glacial debris, volcanic ash, and alluvium derived from andesite and andesitic tuff. There are high amounts of vitric volcanic ash and glass throughout the soil profile which enhances the water holding capacities of these soils. Soils are moist in winter and spring, dry in late summer and fall. Soils are completely dry for at least 45 consecutive days between July and October. Endosaturation is present with an apparent seasonal high water table between 3.5 to 5 feet from January through May. A mollic epipedon is present from the soil surface to 26 inches. An argillic horizon is present from 10 to 44 inches. Soils series associated with this site include Boulderfan.
Table 4. Representative soil features
Parent material (1) Alluvium – andesite
Surface texture (1) Ashy loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderate Soil depth 72 – 84 in Surface fragment cover <=3" 10 – 20 % Surface fragment cover >3" Not specified Available water capacity
(0-40in)6.7 – 6.8 in Calcium carbonate equivalent
(0-40in)Not specified Electrical conductivity
(0-40in)0 – 2 mmhos/cm Sodium adsorption ratio
(0-40in)Not specified Soil reaction (1:1 water)
(0-40in)5.6 – 7.3 Subsurface fragment volume <=3"
(Depth not specified)10 – 23 % Subsurface fragment volume >3"
(Depth not specified)1 – 48 % Ecological dynamics
As ecological condition declines, Nevada bluegrass and Lemmons and western needlegrass composition are reduced as silver sagebrush and rabbitbrush increase.
Fire Ecology:
Silver sagebrush communities experience stand-replacement fires. Fire frequencies are uncertain: fire histories for silver sagebrush communities are sparse to altogether lacking. Since plant productivity and community structure vary across the species wide geographical distribution, historic fire intervals were probably similarly varied.
Fire Effects:
Fire typically top-kills silver sagebrush, but it has a strong sprouting response. Perennating buds on rhizomes and roots are protected by soil, enabling silver sagebrush to survive even severe surface fires.
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.
Needlegrass is moderately to severely damaged by fire depending on season of burn, phenology, and fire severity. Early season burning is damaging to 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 characterized as an overstory of soft-woody shrubs up to one meter tall with an understory of perennial grasses and grass-like plants. The plant community is dominated by silver sagebrush, species of needlegrass, and Nevada bluegrass. Potential vegetative composition is about 55% grasses, 10% forbs and 35% shrubs. Approximate cover (basal and crown) is about 40 to 50 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 440 660 770 Shrub/Vine 280 420 490 Forb 80 120 140 Total 800 1200 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 305–620 Lemmon's needlegrass ACLE8 Achnatherum lemmonii 120–210 – western needlegrass ACOC3 Achnatherum occidentale 120–210 – Sandberg bluegrass POSE Poa secunda 65–200 – 2 Secondary Perennial Grasses/Grasslikes 36–216 mountain brome BRMA4 Bromus marginatus 6–36 – sedge CAREX Carex 6–36 – big squirreltail ELMU3 Elymus multisetus 6–36 – slender wheatgrass ELTR7 Elymus trachycaulus 6–36 – purple oniongrass MESP Melica spectabilis 6–36 – mat muhly MURI Muhlenbergia richardsonis 6–36 – Forb3 Perennial Forbs 54–108 mat muhly MURI Muhlenbergia richardsonis 6–36 – common yarrow ACMI2 Achillea millefolium 6–12 – pale agoseris AGGL Agoseris glauca 6–12 – grand collomia COGR4 Collomia grandiflora 6–12 – tailcup lupine LUCAC3 Lupinus caudatus ssp. caudatus 6–12 – cryptantha owl's-clover ORCUC2 Orthocarpus cuspidatus ssp. cryptanthus 6–12 – beardtongue PENST Penstemon 6–12 – phlox PHLOX Phlox 6–12 – clover TRIFO Trifolium 6–12 – woolly mule-ears WYMO Wyethia mollis 6–12 – 4 Annual Forbs 12–60 sedge CAREX Carex 6–36 – Shrub/Vine5 Primary Shrubs 204–420 silver sagebrush ARCAB3 Artemisia cana ssp. bolanderi 180–360 – roundleaf snowberry SYRO Symphoricarpos rotundifolius 24–60 – 6 Secondary Shrubs 24–48 little sagebrush ARAR8 Artemisia arbuscula 12–24 – rubber rabbitbrush ERNA10 Ericameria nauseosa 12–24 – Interpretations
Animal community
Livestock Interpretations:
This site is suitable for cattle and sheep during late spring, summer and fall. Grazing should be keyed to perennial grass and palatable shrub production. Livestock may browse silver sagebrush when upland vegetation has already dried. Domestic sheep generally browse silver sagebrush more heavily than cattle, especially during the fall when forbs and grasses have dried. Lemmons and western needlegrasses are desirable forage for all classes of 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:
Silver sagebrush provides valuable habitat and forage for wildlife. Silver sagebrush is browsed by deer, elk and sage grouse. When plentiful silver sagebrush is important in the diet of sage grouse. Lemmons and western needlegrasses are important forage species to many browsing and grazing wildlife species.
Hydrological functions
Runoff is low to medium and permeability is moderate. Endosaturation is present with an apparent season high water table between 3.5 and 5 feet from January through May. Hydrologic soil group: B.
Recreational uses
This site offers recreational opportunities such as hunting, hiking and photography.
Other products
Tribes of the Great Basin used silver sagebrush branches as a fuelbed for roasting pinyon pine cones. The branches were also used in ceremonial rites.
Other information
Silver sagebrush has potential as a soil stabilizer and for use in rangeland, wildlife and riparian restoration projects.
Supporting information
Type locality
Location 1: Modoc County, CA Township/Range/Section T38N R16E S3 Latitude 41° 11′ 11″ Longitude 120° 8′ 10″ General legal description On the Modoc National Forest just south of the Patterson Guard Station Road and about a mile north of Camp One Spring. Modoc Co., California. 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) 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:
None -
Presence of water flow patterns:
Slope gradients are typically less than 8% and water flow patterns are rare. Rare flooding occurs for brief periods during spring runoff. -
Number and height of erosional pedestals or terracettes:
Pedestals are rare. Frost heaving and shrink-swell soil activity that affects shallow rooted plants are not indicators of soil erosion. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Bare ground ~55%; surface rock fragments up to 10%; shrub canopy 15 to 30% -
Number of gullies and erosion associated with gullies:
Gullies are none to rare. -
Extent of wind scoured, blowouts and/or depositional areas:
None -
Amount of litter movement (describe size and distance expected to travel):
Fine litter (foliage from grasses and annual & perennial forbs) expected to move distance of slope length during intense summer convection storms or rapid snowmelt events. Persistent litter (large woody material) will remain in place except during catastrophic events. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Soil stability values should be 3 to 6 on most surface textures found on this site (to be field tested). -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Soil structure is typically weak very fine and fine subangular blocky structure. Soil surface colors are dark and soils are typified by a mollic epipedon. Organic carbon of the surface 2 to 4 inches is typically 1 to 3 percent, dropping off quickly below. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Deep rooted perennial grass plants (needlegrass and wheatgrass) and increase infiltration. Shrub canopy and associated litter break raindrop impact and provide opportunity for snow catch and accumulaton on site. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
Compacted layers are not typical. Argillic subsoil horizons are not to be interpretated as compacted soil layers. -
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:
Deep-rooted, cool-season perennial bunchgrasses > tall shrubs >> shallow-rooted cool-season perennial grasses and grass-like plantsSub-dominant:
deep-rooted, cool-season perennial forbs > fibrous, shallow-rooted cool-season annual and perennial forbsOther:
Additional:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Dead branches within indvidual shrubs is somewhat common and standing dead shrub canopy material may be as much as 15% of total woody canopy. Some of the mature bunchgrasses (<10%) have dead centers. -
Average percent litter cover (%) and depth ( in):
Between plant interspaces ~35% and depth is <1/2 inch. -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
For normal or average growing season ~1200 lbs. -
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:
Cheatgrass, annual mustards, tall whitetop, Russian thislte and foxtail barley are invaders on this site. Rubber rabbitbrush and silver sagebrush are increasers on this site. -
Perennial plant reproductive capability:
All functional groups should reproduce in average and above average growing season years.
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