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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 Unpublished report.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: Low Sagebrush Dwarf Scrub 35.120.00.
Sawyer, J.O. and T. Keeler-Wolf. 1995. A Manual of California Vegetation. California Native Plant Society, Sacramento, CA. Low Sagebrush Series.
Associated sites
F021XE230CA Pinus ponderosa/Symphoricarpos rotundifolius/Achnatherum
F021XE237CA Juniperus occidentalis var. occidentalis/Artemisia tridentata ssp. vaseyana/Achnatherum thurberianum
R021XE201CA Ashy Slope 16-30 P.Z.
R021XE204CA Eroded Slope 16-30 P.Z.
R021XE205CA South Slope 16-30 P.Z.
Similar sites
R021XE221CA Claypan 30+ P.Z.
More productive site. FEID dominant grass.
R021XE227CA Cobbly Claypan 30+ P.Z.
Less productive site. POSE dominant grass.
R021XE209CA Ashy Claypan 16-30 P.Z.
More productive site. FEID dominant grass.
R021XE212CA Scabland 30+ P.Z.
Less productive site. ERMIA2 and POSE co-dominant plants.
R021XE202CA Mountain Ridge 30+ P.Z.
Higher elevations. FEID dominant grass.
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Artemisia arbuscula ssp. arbuscula
Herbaceous (1) Pseudoroegneria spicata ssp. spicata
(2) PoaPhysiographic features
This site occurs on mountain slopes. Slopes range from 4 to 50 percent. Elevations range from 4900 to 7000 feet.
Table 2. Representative physiographic features
Landforms (1) Mountain slope
Elevation 4900 – 7000 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 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
This site occurs on very shallow and shallow, well drained soils that formed in volcanic ash and colluvium over residuum dervied from andesite tuff or tuff-breccia. These soils are usually moist in winter, spring, and early summer, dry later in summer and fall. These soils have high amounts of vitric volcanic ash and glass throughout the soil profile which enhances the water holding capacity of these soils. Mollic epipedon 7 to 14 in thickness. Soil series associated with this site include Welltomas.
Table 4. Representative soil features
Parent material (1) Colluvium – pyroclastic rock
Surface texture (1) Very gravelly loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderate Soil depth 7 – 14 in Surface fragment cover <=3" 40 – 45 % Surface fragment cover >3" 5 – 10 % Available water capacity
(0-40in)1.1 – 1.2 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)40 – 45 % Subsurface fragment volume >3"
(Depth not specified)5 – 10 % Ecological dynamics
Where management results in abusive grazing use by livestock, rabbitbrush, low sagebrush, and bluegrasses increase as bluebunch wheatgrass decrease. As condition declines further, bluegrasses, low sagebrush and rabbitbrush dominate the site. Cheatgrass and annual mustards readily invade this site.
Fire effects:
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.
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.
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.
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
Figure 3. Claypan 16-30" P.Z.
Figure 4. Claypan 16-30" P.Z.
The reference plant community is dominated by bluebunch wheatgrass, low sagebrush and bluegrass. Potential vegetative composition is about 45% grasses, 20% forbs and 35% shrubs.
Figure 5. 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 225 315 405 Shrub/Vine 175 245 315 Forb 100 140 180 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 175–350 bluebunch wheatgrass PSSPS Pseudoroegneria spicata ssp. spicata 140–245 – Sandberg bluegrass POSE Poa secunda 35–105 – 2 Secondary Perennial Grasses/Grasslikes 16–84 needlegrass ACHNA Achnatherum 4–21 – sedge CAREX Carex 4–21 – squirreltail ELEL5 Elymus elymoides 4–21 – Idaho fescue FEID Festuca idahoensis 4–21 – Forb3 Perennial Forbs 48–252 common yarrow ACMI2 Achillea millefolium 4–21 – onion ALLIU Allium 4–21 – rockcress ARABI Arabidopsis 4–21 – loosehead sandwort ARCOS2 Arenaria congesta var. subcongesta 4–21 – woollypod milkvetch ASPU9 Astragalus purshii 4–21 – Indian paintbrush CASTI2 Castilleja 4–21 – hawksbeard CREPI Crepis 4–21 – desertparsley LOMAT Lomatium 4–21 – lupine LUPIN Lupinus 4–21 – Gairdner's yampah PEGAG Perideridia gairdneri ssp. gairdneri 4–21 – spreading phlox PHDID2 Phlox diffusa ssp. diffusa 4–21 – spiny phlox PHHO Phlox hoodii 4–21 – 4 Annual Forbs 14–35 Shrub/Vine5 Primary Shrubs 140–245 little sagebrush ARAR8 Artemisia arbuscula 140–245 – 6 Secondary Shrubs 35–105 yellow rabbitbrush CHVI8 Chrysothamnus viscidiflorus 7–21 – sulphur-flower buckwheat ERUM Eriogonum umbellatum 7–21 – antelope bitterbrush PUTR2 Purshia tridentata 7–21 – roundleaf snowberry SYRO Symphoricarpos rotundifolius 7–21 – Interpretations
Animal community
Livestock Interpretations:
This site is suited to grazing by cattle and sheep during the late spring, summer and fall. Grazing should be keyed to bluebunch wheatgrass and Sandberg's bluegrass production. Domestic sheep and to a much lesser degree cattle consume low sagebrush, particularly during the spring, fall and winter. Sandberg's bluegrass is a widespread and drought resistant forage grass. It is one of the earliest grasses in the spring and is sought by domestic livestock. Bluebunch wheatgrass is an 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:
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. Low sagebrush is an important food source for sage grouse throughout the year, especially between October and April. Mule deer utilize and sometimes prefer low sagebrush, particularly in winter and early spring. Bluebunch wheatgrass is an important forage for several wildlife species.Hydrological functions
Runoff is medium to high. Hydrologic soil Group: D.
Supporting information
Type locality
Location 1: Modoc County, CA Township/Range/Section T42N R15E S3 Latitude 41° 31′ 3″ Longitude 120° 13′ 40″ General legal description Deep Creek Canyon, on the Modoc National Forest in the Warner Mountains, Modoc County, CA. 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) 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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