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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 Unpublished report.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: Rabbitbrush Scrub 35.300.00.
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Chrysothamnus viscidiflorus
Herbaceous (1) Lupinus caudatus ssp. caudatus
(2) AchnatherumPhysiographic features
This site occurs in concave positions off the lee-ward side of mountain summits. Slopes range from 8 to 30 percent. Elevations range from 7500 to 9700 feet.
Table 2. Representative physiographic features
Landforms (1) Mountain
Elevation 7500 – 9700 ft Slope 8 – 30 % Aspect NE, E 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.
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
Snow lakes are created by melting snow.
Soil features
The soils associated with this site are moderately deep to weathered bedrock. They are well drained and are formed in residuum and colluvium from volcanic rocks. These soils have high amounts of vitric volcanic ash and glass throughout the profile. The profile is modified with 35 to 60 percent rock fragments, mainly gravels. Soil family: Vitrandic cryorthents.
Table 4. Representative soil features
Parent material (1) Residuum – pyroclastic rock
Surface texture (1) Ashy sandy loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderately rapid Soil depth 20 – 39 in Surface fragment cover <=3" 28 – 47 % Surface fragment cover >3" 0 – 4 % Available water capacity
(0-40in)2.1 – 2.2 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)5.6 – 6.5 Subsurface fragment volume <=3"
(Depth not specified)28 – 47 % Subsurface fragment volume >3"
(Depth not specified)0 – 4 % Ecological dynamics
As ecological condition deteriorates, lupine will increase and can eventually dominate this site. Needlegrass composition declines as bottlebrush squirreltail increases in density. On lower condition sites, rabbitbrush often invades the plant community.
Fire effects:
Tailcup lupine is favored or relatively unaffected by fire in sagebrush or pinyon-juniper habitats. It also germinated from buried seed after fire. The top-killed plants may make a ready recovery and rapid increase in vigor, but an increase in plant numbers must await seed production, usually in the second growing season after burning.
Little specific information is available on adaptations of Letterman's needlegrass to fire. It is morphologically similar to Columbia needlegrass, which is only slightly to moderately damaged by fire. Season of burn affects the plant's ability to survive a fire. Needlegrass tends to be more susceptible to fire when burned during mid-summer. Post-fire regeneration is through seeding and tillering.
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 yellow rabbitbrush, tailcup lupine and western and pine needlegrass. Potential vegetative composition is about 40% grasses, 40% forbs and 20% shrubs. Approximate ground cover (basal and crown) ranges from 50 to 60 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 80 120 200 Forb 80 120 200 Shrub/Vine 40 60 100 Total 200 300 500 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 60–120 sedge CAREX Carex 15–45 – western needlegrass ACOCO Achnatherum occidentale ssp. occidentale 23–38 – pine needlegrass ACPI2 Achnatherum pinetorum 22–37 – 2 Secondary Perennial Grasses/Grasslikes 10–45 squirreltail ELEL5 Elymus elymoides 2–9 – spikerush ELEOC Eleocharis 2–9 – Colorado fescue FEBRC Festuca brachyphylla ssp. coloradensis 2–9 – Cusick's bluegrass POCUE2 Poa cusickii ssp. epilis 2–9 – spike trisetum TRSP2 Trisetum spicatum 2–9 – Forb3 Primary Perennial Forbs 45–90 tailcup lupine LUCAC3 Lupinus caudatus ssp. caudatus 45–90 – 4 Secondary Perennial Forbs 24–72 alpine pussytoes ANAL4 Antennaria alpina 2–6 – prickly sandwort ARAC2 Arenaria aculeata 2–6 – aster ASTER Aster 2–6 – Mt. Hood pussypaws CIUMU Cistanthe umbellata var. umbellata 2–6 – owl's-claws HYHO Hymenoxys hoopesii 2–6 – Gray's licorice-root LIGR Ligusticum grayi 2–6 – alpine mountainsorrel OXDI3 Oxyria digyna 2–6 – beardtongue PENST Penstemon 2–6 – cold-desert phlox PHST11 Phlox stansburyi 2–6 – creeping sibbaldia SIPR Sibbaldia procumbens 2–6 – Shasta clover TRPR4 Trifolium productum 2–6 – California valerian VACA2 Valeriana californica 2–6 – 5 Annual Forbs 6–30 Shrub/Vine6 Primary Shrubs 30–75 yellow rabbitbrush CHVIV2 Chrysothamnus viscidiflorus ssp. viscidiflorus 30–75 – 7 Secondary Shrubs 12–36 little sagebrush ARAR8 Artemisia arbuscula 3–9 – mountain big sagebrush ARTRV Artemisia tridentata ssp. vaseyana 3–9 – sulphur-flower buckwheat ERUM Eriogonum umbellatum 3–9 – Interpretations
Animal community
Livestock Interpretations:
This site is moderately suitable for livestock grazing in the late spring and fall. Restrictions to grazing include short growing season, due to long periods of snow cover, and relatively low forage production. Grazing should be keyed to western and pine needlegrasses. Western and pine needlegrasses provide desirable forage for domestic sheep and cattle.
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:
This site provides wildlife habitat during periods without snow cover. Needlegrass and sedge species provide valuable forage to many classes of wildlife.
Hydrological functions
Runoff is low to high. Permeability is moderately rapid. Hydrologic soil group: D.
Supporting information
Type locality
Location 1: Modoc County, CA Latitude 41° 56′ 58″ Longitude 120° 8′ 28″ 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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