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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
R022AY023NV LOAMY SLOPE 16-20 P.Z.
R022AY024NV MAHOGANY SAVANNA
R022AY030NV GRAVELLY LOAM 14-16 P.Z.
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Artemisia arbuscula
Herbaceous (1) Achnatherum
(2) Bromus marginatusPhysiographic features
This site occurs on convex mountain summits and shoulders. Slopes range from 4 to 30 percent, but slope gradients of 4 to 15 percent are most typical. Elevations are 6000 to over 8000 feet.
Table 2. Representative physiographic features
Landforms (1) Mountain
Flooding frequency None Ponding frequency None Elevation 6000 – 8000 ft Slope 4 – 30 % Ponding depth 0 in Water table depth 0 in 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. The average annual precipitation is 16 to 24 inches, mostly occurring as snow. The linear to convex slope shapes associated with this site cause some of the precipitation to be removed from the site because of wind action, thus reducing the moisture available for plant growth. The mean annual air temperature ranges from 39 to 45 degrees F. The average frost free growing season is 40 to 70 days.
Table 3 Representative climatic features
Frost-free period (average) 70 days Freeze-free period (average) 0 days Precipitation total (average) 20 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 ecological site are typically very shallow or shallow and are well drained. They formed in residuum and colluvium derived from volcanic rocks. Surface layers are modified by a high percentage of coarse rock fragments. Subsoil layers moderately fine or fine textured and are modified by a high percentage of rock fragments. These soils have a mollic epipedon that ranges from 7 to 14 inches thick. The soil characteristic that most influences the vegetative community is the near surface presence of a restrictive layer such as bedrock or an abrupt textural change to a fine textured layer, which limits root penetration and the available waterholding capacity. The soil series associated with this ecological site are Chenhigh and Gerdog. The soil families associated with this ecological site are Chenhigh inclusion and Gerdog inclusion.
Table 4. Representative soil features
Parent material (1) Residuum – volcanic breccia
Surface texture (1) Very gravelly sandy loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Slow to moderate Soil depth 7 – 20 in Surface fragment cover <=3" 20 – 40 % Surface fragment cover >3" 5 – 20 % Available water capacity
(0-40in)1 – 1.6 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)6.1 – 7.3 Subsurface fragment volume <=3"
(Depth not specified)35 – 70 % Subsurface fragment volume >3"
(Depth not specified)5 – 15 % 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:
Prior to 1897, mean fire return intervals for low sagebrush communities have been estimated to be from 35 to over 100 years. Fire most often occurs during wet years with high forage production. Low sagebrush is very susceptible to fire damage. Low sagebrush is usually killed by fire and does not re-sprout. The recovery in burned areas is usually via small, light, wind-dispersed seed for all low sagebrush subspecies. Partially injured low sagebrush may re-grow from living branches, but sprouting does not occur.
Season of burn affects needlegrasses ability to survive a fire. Needlegrasses tend to be more susceptible to fire when burned during mid-summer. The aboveground vegetation of needlegrass species is consumed by fire. When fire severity is high, heat may be transferred below the soil surface further damaging or killing the plant.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 dominated by characterized by an open canopy of soft-woody shrubs and a dense understory of perennial grasses. The plant community is dominated by needlegrasses, mountain brome and low sagebrush. Potential vegetative composition is about 55% grasses, 10% forbs and 35% shrubs. Approximate ground cover (basal and crown) is 25 to 35 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 275 385 495 Shrub/Vine 175 245 315 Forb 50 70 90 Total 500 700 900 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 273–511 Letterman's needlegrass ACLE9 Achnatherum lettermanii 70–105 – western needlegrass ACOCO Achnatherum occidentale ssp. occidentale 70–105 – pine needlegrass ACPI2 Achnatherum pinetorum 70–105 – Thurber's needlegrass ACTH7 Achnatherum thurberianum 35–105 – mountain brome BRMA4 Bromus marginatus 14–35 – Cusick's bluegrass POCU3 Poa cusickii 5–19 – muttongrass POFE Poa fendleriana 5–19 – 2 Secondary Perennial Grasses/Grasslikes 35–105 Indian ricegrass ACHY Achnatherum hymenoides 4–21 – sedge CAREX Carex 4–21 – squirreltail ELEL5 Elymus elymoides 4–21 – needle and thread HECO26 Hesperostipa comata 4–21 – Sandberg bluegrass POSE Poa secunda 4–21 – Forb3 Perennial Forbs 35–105 rockcress ARABI2 Arabis 4–15 – tapertip hawksbeard CRAC2 Crepis acuminata 4–15 – California rayless fleabane ERIN2 Erigeron inornatus 4–15 – buckwheat ERIOG Eriogonum 4–15 – beardtongue PENST Penstemon 4–15 – phlox PHLOX Phlox 4–15 – Shrub/Vine4 Primary Shrubs 140–266 little sagebrush ARAR8 Artemisia arbuscula 140–210 – antelope bitterbrush PUTR2 Purshia tridentata 0–56 – 5 Secondary Shrubs 14–70 curl-leaf mountain mahogany CELE3 Cercocarpus ledifolius 7–21 – rubber rabbitbrush ERNAN5 Ericameria nauseosa ssp. nauseosa var. nauseosa 7–21 – currant RIBES Ribes 7–21 – roundleaf snowberry SYRO Symphoricarpos rotundifolius 7–21 – Interpretations
Animal community
Livestock Interpretations:
This site is suited to livestock production. Grazing management should be keyed to needlegrass production. Domestic sheep and to a much lesser degree cattle consume low sagebrush, particularly during the spring, fall and winter. Letterman’s needlegrass begins growth early in the year and remains green throughout the relatively long growing season, thus, making it valuable forage for 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:
Low sagebrush is considered a valuable browse plant during the spring, fall and winter months. In some areas it is of little value in winter due to heavy snow. Mule deer utilize and sometimes prefer low sagebrush, particularly in winter and early spring. Letterman's needlegrass provides valuable forage for many species of wildlife. Lettermans needlegrass is consumed by mule deer. Letterman's needlegrass provides some cover for small birds and mammals.Hydrological functions
Runoff is very high and permeability is slow to moderate.
Other information
Low sagebrush can be successfully transplanted or seeded in restoration.
Letterman's needlegrass has been used successfully in revegetating mine spoils. This species also has good potential for erosion control.Supporting information
Type locality
Location 1: Mono County, CA Latitude 38° 41′ 43″ Longitude 119° 37′ 39″ General legal description Toiyabe National Forest, approximately 0.8 miles from High Peak. Other references
USDA NRCS Plants Database (Online; http://plants.usda.gov/).
Fire Effects Information System (Online; http://www.fs.fed.us/database/feis/plants).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) Patti Novak-Echenique Contact for lead author State Rangeland Management Specialist Date 07/18/2013 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
Rills are none to rare. A few rills can be expected on steeper slopes in areas subjected to summer convection storms or rapid spring snowmelt. -
Presence of water flow patterns:
Waterflow patterns are none to rare but can be expected in areas recently subjected to summer convection storms or rapid snowmelt, usually on steeper slopes. -
Number and height of erosional pedestals or terracettes:
Pedestals are none to rare. Occurrence is usually limited to areas of waterflow patterns. Frost heaving of shallow rooted plants should not be considered a "normal" condition. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Bare Ground 10-20% depending on the amount of surface cover of rock fragments. -
Number of gullies and erosion associated with gullies:
None -
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 large rainfall 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 soil 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):
Surface structure is typically fine subangular blocky. Soil surface colors are grayish browns and soils are typified by a mollic epipedon. Organic matter of the surface 2 to 4 inches is typically 1.25 to 3 percent dropping off quickly below. Organic matter content can be more or less depending on micro-topography. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Perennial herbaceous plants (especially deep-rooted bunchgrasses [needlegrasses] slow runoff and increase infiltration. Shrub canopy and associated litter break raindrop impact. Snow catch and accumulation is limited on the wind-swept summits and sideslopes. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
Compacted layers are none. Subsoil argillic horizons are not to be interpreted as compacted. -
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 bunchgrassesSub-dominant:
low shrubs (low sagebrush)>deep-rooted, cool season, perennial forbs> associated shrubs > shallow-rooted, cool season, perennial bunchgrasses>fibrous, shallow-rooted, cool season, perennial and annual 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 individual shrubs common and standing dead shrub canopy material may be as much as 25% of total woody canopy; some of the mature bunchgrasses (<10%) have dead centers. -
Average percent litter cover (%) and depth ( in):
Reference Plant Community: Under shrubs and between plant interspaces (20-35%) and litter depth is < 1/4 inch. -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
For normal or average growing season (through June) ± 700 lbs/ac; Favorable years ±900 lbs/ac and unfavorable years ± 500 lbs/ac. -
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:
Potential invaders include cheatgrass, medusahead, and annual mustards. -
Perennial plant reproductive capability:
All functional groups should reproduce in average (or normal) and above average growing season years. Reduced growth and reproduction occur during extended or extreme drought periods.
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