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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 Unpublished report.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.
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Artemisia arbuscula ssp. arbuscula
Herbaceous (1) Poa secunda
Physiographic features
This site occurs on mountain slopes. Slopes range from 2 to 15 percent. Elevations range from 6400 to 8200 feet.
Table 2. Representative physiographic features
Landforms (1) Mountain slope
Elevation 6400 – 8200 ft Slope 2 – 15 % 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 is 30 to 50 inches with most occurring during the winter months. Approximately half the precipitation falls as snow; half as rain. The mean annual air temperature is 38 to 44 degrees F. The average growing season is about 30 to 60 days.
Table 3 Representative climatic features
Frost-free period (average) 60 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
Soils of this site are very shallow to shallow and well drained. The soils are formed in volcanic ash and colluvium over residium derived from glassy tuff or tuff-breccia. There are high amounts of vitric volcanic ash and glass throughout the soil profile which enhances water holding capacity. Soils series include Fingerridge.
Table 4. Representative soil features
Parent material (1) Colluvium – tuff
Surface texture (1) Extremely gravelly loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderate Soil depth 7 – 14 in Surface fragment cover <=3" 20 – 65 % Surface fragment cover >3" 0 – 75 % Available water capacity
(0-40in)1.8 – 1.9 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)20 – 65 % Subsurface fragment volume >3"
(Depth not specified)5 – 75 % Ecological dynamics
Low sagebrush, Douglas' rabbitbrush and Sandberg’s bluegrass increase while Thurber’s needlegrass, bluebunch wheatgrass, and other desirable forage grasses decrease with excessive use by livestock.
Fire effects:
Prior to 1897 mean fire return intervals for low sagebrush have been estimated to be from 90 to 138 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.
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.
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 dominated by low sagebrush and Sandberg bluegrass. Potential vegetative composition is about 35% grasses, 20% forbs and 45% shrubs.
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)Shrub/Vine 135 180 225 Grass/Grasslike 105 140 175 Forb 60 80 100 Total 300 400 500 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 80–140 Sandberg bluegrass POSE Poa secunda 80–140 – 2 Secondary Perennial Grasses 8–32 Thurber's needlegrass ACTH7 Achnatherum thurberianum 2–8 – squirreltail ELEL5 Elymus elymoides 2–8 – Idaho fescue FEID Festuca idahoensis 2–8 – bluebunch wheatgrass PSSPS Pseudoroegneria spicata ssp. spicata 2–8 – Forb3 Perennial Forbs 26–52 common yarrow ACMI2 Achillea millefolium 2–4 – onion ALLIU Allium 2–4 – loosehead sandwort ARCOS2 Arenaria congesta var. subcongesta 2–4 – milkvetch ASTRA Astragalus 2–4 – hawksbeard CREPI Crepis 2–4 – buckwheat ERIOG Eriogonum 2–4 – desertparsley LOMAT Lomatium 2–4 – lupine LUPIN Lupinus 2–4 – cryptantha owl's-clover ORCUC2 Orthocarpus cuspidatus ssp. cryptanthus 2–4 – common twinpod PHDID Physaria didymocarpa var. didymocarpa 2–4 – spreading phlox PHDID2 Phlox diffusa ssp. diffusa 2–4 – spiny phlox PHHO Phlox hoodii 2–4 – spearleaf stonecrop SELA Sedum lanceolatum 2–4 – 4 Annual Forbs 4–20 Shrub/Vine5 Primary Shrubs 140–180 little sagebrush ARAR8 Artemisia arbuscula 140–180 – 6 Secondary Shrubs 16–72 yellow rabbitbrush CHVI8 Chrysothamnus viscidiflorus 4–12 – sulphur-flower buckwheat ERUM Eriogonum umbellatum 4–12 – antelope bitterbrush PUTR2 Purshia tridentata 4–12 – roundleaf snowberry SYRO Symphoricarpos rotundifolius 4–12 – spineless horsebrush TECA2 Tetradymia canescens 4–12 – 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 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.
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.
Hydrological functions
Runoff is medium to high. Hydrologic soil group: D.
Supporting information
Type locality
Location 1: Modoc County, CA Township/Range/Section T44N R15E S3 Latitude 41° 37′ 9″ Longitude 120° 15′ 7″ General legal description On the Modoc National Forest in the Warner Mountains 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.
Modoc Elk Working Group. 2000. The Greater Modoc Area A Strategic Plan for Elk Management. Modoc County, CA
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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