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Draft. A draft ecological site description is either incomplete or has not undergone quality control and quality assurance review.
Associated sites
R022AY011NV MOUNTAIN RIDGE 30+ P.Z.
R022AY012NV BARREN SLOPE 20+ P.Z.
R022AY021NV SOUTH SLOPE 30+ P.Z.
R022AY024NV MAHOGANY SAVANNA
R022AY031NV LOAMY SLOPE 30+ P.Z.
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Artemisia tridentata ssp. vaseyana
Herbaceous (1) Achnatherum occidentale ssp. occidentale
(2) Bromus marginatusPhysiographic features
This site occurs on mountain summits and shoulders having a smooth to slightly concave shape. Slopes range from 2 to over 15 percent, but slope gradients of 2 to 8 percent are most typical. Elevations are 8500 to over 9000 feet.
Table 2. Representative physiographic features
Landforms (1) Mountain slope
(2) Mountain
Flooding frequency None Ponding frequency None Elevation 8500 – 9000 ft Slope 2 – 15 % Aspect Aspect is not a significant factor Climatic features
The climate on this site is subhumid-continental, characterized by cold, moist winters, and cool dry summers. Average annual precipitation is 20 inches to over 40 inches. Mean annual air temperature is 35 to 42 degrees F. The average growing season is about 30 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
The soils that support this site are typically moderately deep to deep and are well to somewhat excessively drained. They formed in residuum and colluvium derived from volcanic or granitic rocks and from mixed glacial till. Surface layers are coarse to moderately coarse textured with greater than 35 percent rock fragments. Subsoil layers range from moderately coarse to moderately fine textured and are modified by 35 to over 80 percent rock fragments. These soils have a mollic epipedon that is more than 16 inches thick. The soil series associated with this site are Dunderberg, Hawkinspeak, and Waterpeak.
Table 4. Representative soil features
Parent material (1) Residuum – granite
Surface texture (1) Very gravelly sandy loam
(2) Very stony sandy loam
(3) Gravelly loamy coarse sand
Family particle size (1) Loamy
Drainage class Well drained to somewhat excessively drained Permeability class Moderately rapid to moderate Soil depth 33 – 60 in Surface fragment cover <=3" 20 – 55 % Surface fragment cover >3" 8 – 9 % Available water capacity
(0-40in)2.9 – 3.8 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)13 – 41 % Subsurface fragment volume >3"
(Depth not specified)3 – 25 % Ecological dynamics
As ecological condition declines, big sagebrush, snowberry and other woody plants increase in prevalence as Letterman's needlegrass, mountain brome and other perennial grasses and forbs decline in the understory.
Fire Ecology:
Presettlement fire return intervals in mountain big sagebrush communities varied from 15 to 25 years. Plants are readily killed in all seasons, even light severity fires. Mountain big sagebrush is highly susceptible to injury from fire. It is often top-killed by fire and will not resprout.
Perennial needlegrasses tend to be among the least fire resistant bunchgrass due to the densely tufted stems. Western needlegrass is only slightly to moderately damaged by fire, because it has relatively few culms per clump which may help to minimize the amount of subsurface heat transfer and subsequent damage.
Mountain brome is likely to be top-killed by fire, although the coarse stems and broad leaves may be more fire-resistant than fine-leaved bunchgrasses. Mountain brome is most susceptible to fire damage when it is actively growing in spring and early summer. Purple oniongrass has a high fire tolerance due to the rhizomatous growth.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 Community
The reference plant community is characterized by an open canopy of soft-woody shrubs and a dense understory of perennial grasses. The plant community is dominated by western needlegrass, mountain brome and mountain big sagebrush. Potential vegetative composition is about 70% grasses, 10% forbs, and 20% shrubs. Approximate ground cover(basal and crown) is 35 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 455 595 735 Shrub/Vine 130 170 210 Forb 65 85 105 Total 650 850 1050 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 544–900 western needlegrass ACOCO Achnatherum occidentale ssp. occidentale 255–382 – mountain brome BRMA4 Bromus marginatus 255–382 – purple oniongrass MESP Melica spectabilis 17–68 – bluegrass POA Poa 17–68 – 2 Secondary Perennnial Grasses/Grasslikes 43–85 tapertip hawksbeard CRAC2 Crepis acuminata 22–50 – lupine LUPIN Lupinus 22–50 – Letterman's needlegrass ACLE9 Achnatherum lettermanii 4–26 – sedge CAREX Carex 4–26 – big squirreltail ELMU3 Elymus multisetus 4–26 – spike fescue LEKI2 Leucopoa kingii 4–26 – Forb3 Primary Perennial Forbs 34–86 mountain big sagebrush ARTRV Artemisia tridentata ssp. vaseyana 90–155 – tapertip hawksbeard CRAC2 Crepis acuminata 17–43 – lupine LUPIN Lupinus 17–43 – 4 Secondary Perennial Forbs 17–85 sedge CAREX Carex 20–30 – rockcress ARABI2 Arabis 4–17 – buckwheat ERIOG Eriogonum 4–17 – phlox PHLOX Phlox 4–17 – Shrub/Vine5 Primary Shrubs 128–170 mountain big sagebrush ARTRV Artemisia tridentata ssp. vaseyana 128–170 – 6 Secondary Shrubs 17–68 slender buckwheat ERMI4 Eriogonum microthecum 9–17 – antelope bitterbrush PUTR2 Purshia tridentata 9–17 – roundleaf snowberry SYRO Symphoricarpos rotundifolius 9–17 – Interpretations
Animal community
Livestock Interpretations:
This site is suited to livestock grazing. Grazing management should be keyed to western needlegrass and mountain brome production. Mountain 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. Mountain brome is one of the most important forage grasses in the quaking aspen zone. Mountain brome is ranked as excellent forage for both cattle and horses and good for domestic sheep. Domestic will graze mountain brome only when it is fairly succulent. Western needlegrass begins growth early in the year and remains green throughout the relatively long growing season, thus, making it valuable forage for livestock. Palatability for purple oniongrass is high for grazers and medium for browsers.
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:
Mountain big sagebrush is highly preferred and nutritious winter forage for mule deer. Mountain brome seedheads and seeds provide food for many birds and small mammals. Pronghorn antelope will consume mountain brome primarily in the spring. The palatability of mountain brome is excellent for deer, particularly during the late spring and early summer. Western needlegrass is an important forage species for several wildlife species. Purple oniongrass is an important forage species for many wildlife species.
Hydrological functions
Runoff is low to very high.
Other products
Native people used mountain 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 is easily propagated from seed under greenhouse, nursery, and common garden conditions and has been successfully seeded directly into field sites.
Mountain brome is useful for revegetating disturbed sites due to rapid establishment and good soil stabilizing capability. It has proved effective for stabilizing watersheds.Supporting information
Type locality
Location 1: Alpine County, CA Latitude 38° 44′ 12″ Longitude 119° 52′ 35″ General legal description Toiyabe National Forest. Other references
Fire Effect Information System (Online; http://www.fs.fed.us/database/feis/plants/).
USDA-NRCS Plants Database (Online; http://plants.usda.gov/).
Contributors
ALC/GKB
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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