Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.
Ecological site concept
This site occurs on lower sideslopes of mountains. Elevations are 3800 to 5000 feet. Slopes range from 8 to 75 percent. The soils that characterize this site are well drained and shallow and very shallow. They are formed in granitic alluvium. Surface textures are extremely gravelly loams.
Please refer to group concept R030XB056NV to view the provisional STM.
This site occurs on lower sideslopes of mountains. Elevations are 3800 to 5000 feet. Slopes range from 8 to 75 percent.
Table 2. Representative physiographic features
Landforms
(1) Mountain slope
Elevation
3,800–5,000 ft
Slope
8–75%
Aspect
Aspect is not a significant factor
Climatic features
The climate on this site is arid characterized by warm, moist winters (30 to 60 degrees F) and hot, dry summers (70 to 100 degrees F). The average annual precipitation ranges from 4 to 8 inches with most falling as rain from November to March. Approximately 25% of the annual precipitation occurs from July to September as a result of summer convection storms. Mean annual air temperature is 57 to 66 degrees F.
The average frost-free period is 200 to 300 days.
Table 3. Representative climatic features
Frost-free period (average)
300 days
Freeze-free period (average)
Precipitation total (average)
8 in
Influencing water features
Soil features
The soils that characterize this site are well drained and shallow and very shallow. They are formed in granitic alluvium. Surface textures are extremely gravelly loams. Subsurface textures are extremely gravelly loams and extremely gravelly clay loams. Available water capacity is very low and permeability is moderately slow. Wind erosion hazard is negligible due to surface rock fragments. Effective rooting depth is 10 to 16 inches to bedrock.
Please refer to group concept R030XB056NV to view the provisional STM.
The historic site potential is characterized by low, often intricately branched shrubs, 0.5 to 1 meter tall, with an open or continuous canopy. This site is dominated by blackbrush. Perennial grasses and forbs are common. Annuals are seasonally present. Pockets of cryptogamic crust have developed between the surface rock fragments. This site is stable in this condition.
Blackbrush is a long-lived dominant on older, undisturbed geomorphic surfaces. Succession occurs at a very slow rate. Increasing in cover and density, this shrub becomes more dominant over time. Following a fire, blackbrush decreases or is removed from the community. California buckwheat and white burrobush will increase. Non-native annual grasses and forbs, such as red brome, schismus and red-stem filaree are post-fire invaders on this site. Current knowledge indicates that the return of blackbrush may take many years.
Management for this site would be to protect it from excessive disturbance and maintain existing plant cover. Close roads and trails no longer being used and revegetate using native species indigenous to this site. Water developments would increase the species diversity of this site.
Species indigenous to this site are recommended for any revegetation efforts.
Blackbrush has medium erosion control potential, low establishment requirements and low long and short-term revegetation potential. Spiny hopsage is rated as having moderate potential for erosion control. Creosotebush may also be used to rehabilitate disturbed sites. Once established, creosotebush may improve sites for annual forbs and grasses. Nevada ephedra forms dense, spreading colonies, which make it valuable for soil stabilization. Desert needlegrass may be used for revegetation in areas of light disturbance, but it is susceptible to excessive trampling.
Transplanting seedlings is more effective than direct seeding. Planting in late fall or early spring allows for acclimation to summer conditions. Transplants that are dormant during the hot, dry season are best maintained that way rather than attempting to force them to break dormancy and undergo new vegetative growth out of season. Supplemental irrigation is recommended for the first growing season, especially if winter rainfall has been sparse. Summer annuals and non-native plants should be removed from around the transplanted shrubs to reduce competition for water. Protection from rodents is also recommended.
Desert communities are usually unaffected by fire because of low fuel loads, although a year of exceptionally heavy winter rains can generate fuels by producing a heavy stand of annual forbs and grasses. When fires do occur, the effect on the ecosystem may be extreme due to the harsh environment and the slow rate of recovery. Blackbrush, white bursage and creosotebush possess limited sprouting ability, thus, can be killed by high intensity fires. Blackbrush and creosotebush are very slow to reinvade burned areas. White bursage can rapidly re-establish from seed. Nevada ephedra, spiny hopsage and desert needlegrass are reported to resprout from the root crown after a fire damages aboveground vegetation.
State and transition model
More interactive model formats are also available.
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The representative natural plant community is Blackbush Scrub or Black Bush Series. This community is dominated by blackbrush and desert needlegrass. Potential vegetative composition is about 15% grasses, 10% forbs, and 75% shrubs.
The following table lists the major plant species and percentages by weight, air dry, of the total plant community that each contributes in an average production year. Fluctuations in species composition and relative production may change from year to year dependent upon abnormal precipitation or other climatic factors.
Forest overstory. Allow no more than 5% of each species of this group, and no more than 20% in aggregate
Forest understory. Allow no more than 2% of each species of the grasses group, and no more than 8% in aggregate
Allow no more than 2% of each species of the forbs group, and no more than 10% in aggregate
Figure 1. Annual production by plant type (representative values) or group (midpoint values)
Table 4. Annual production by plant type
Plant type
Low (lb/acre)
Representative value (lb/acre)
High (lb/acre)
Shrub/Vine
56
150
225
Grass/Grasslike
11
30
45
Forb
8
20
30
Total
75
200
300
Table 5. Ground cover
Tree foliar cover
0%
Shrub/vine/liana foliar cover
4-11%
Grass/grasslike foliar cover
1-2%
Forb foliar cover
0-1%
Non-vascular plants
0%
Biological crusts
0%
Litter
0%
Surface fragments >0.25" and <=3"
0%
Surface fragments >3"
0%
Bedrock
0%
Water
0%
Bare ground
0%
Figure 2. Plant community growth curve (percent production by month). CA3018, Blackbrush. Growth starts in late winter. Flowering and seed set occur by June. Seeds remain on the shrubs for several months. Dormancy occurs during the hot summer months..
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
J
F
M
A
M
J
J
A
S
O
N
D
0
10
30
35
20
5
0
0
0
0
0
0
Figure 3. Plant community growth curve (percent production by month). CA3087, Desert needlegrass. Growth begins in mid-winter and continues through summer, setting seed in late summer..
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
J
F
M
A
M
J
J
A
S
O
N
D
0
5
15
25
20
15
15
5
0
0
0
0
Additional community tables
Interpretations
Animal community
This site provides habitat for small mammals such as antelope ground squirrels, Panamint kangaroo rats, long-tailed pocket mice, and deer mice. Black-tailed jackrabbits, coyotes and feral burros are also common.
This site provides habitat for lizards such as side-blotched lizard, western whiptail, desert night lizard and desert spiny lizard. The depth to bedrock is a restrictive feature for burrowing reptiles such as the desert tortoise.
Birds common to this site include black-throated and sage sparrows, greater roadrunners, Empidonax species, ruby-crowned kinglets, and blue-gray gnatcatchers.
LIVESTOCK GRAZING:
This site has limited use for livestock grazing due to low productivity and lack of stockwater. Blackbrush is fair winter browse for sheep and cattle. It is better utilized by sheep and goats than cattle. Spiny hopsage is considered good to fair forage for sheep and goats, and fair to poor for cattle. Nevada ephedra is rated good to fair forage for goats and fair to poor for cattle and sheep. California buckwheat is considered fair to poor browse for cattle and sheep, and fair for goats. White bursage is fair browse for cattle and horses, and fair to good browse for sheep. White bursage is one of the major forage species of feral burros, especially in winter. Creosotebush is unpalatable to livestock. Domestic sheep use creosotebush primarily for shade. During favorable years, annual forbs and grasses provide additional forage on this site.
General guide to initial stocking rate. Before making specific recommendations, an on-site evaluation must be made.
Pounds/acre
air dry AUM/AC AC/AUM
Normal Years 200
Hydrological functions
Runoff is high. Hydrologic group D - soils having very slow infiltration rates when thoroughly wetted and consisting chiefly of clay soils with a high swelling potential, soils with a permanent high water table, soils with a claypan or clay layer at or near the surface, and shallow soils over nearly impervious material. Hydrologic conditions: good - >70% ground cover (includes litter, grass and brush overstory); fair - 30 to 70% ground cover; poor <30% ground cover.
Soil Series: Newera
Hydrologic Group: D
Hydrologic Conditions and Runoff Curves:
Good 84; Fair 86; Poor 88
Recreational uses
This site is highly valued for open space and those interested in desert ecology. Flowering wildflowers and shrubs may also attract visitors during the spring.
Other information
Military Operations - Management for this site would be to protect it from excessive disturbance and maintain existing plant cover. Land clearing or other disturbances that destroy the vegetation, the cryptogamic crust and the soil structure can result in soil compaction, reduced infiltration rates, accelerated erosion, soil blowing and barren areas. Rest or protect sites from further disturbance.
Supporting information
Inventory data references
Sampling technique
___ NV-ECS-1
___ SCS-Range 417
_2_ Other
Type locality
Location 1: San Bernardino County, CA
UTM zone
N
UTM northing
3931490
UTM easting
542930
General legal description
Non-sectionalized area of T17N R4E
Approximately 2 miles north of Drinkwater Lake
East of Leach Lake Quadrangle
UTM 11S 0542930e 3931490n (Datum=NAS-C)
San Bernardino Co., CA
Other references
Brown, T.K. and K. A. Nagy with R.D. Nieuhaus, Inc. 1995. Final Report, Herpetological Surveys and Physiological Studies on the Western Portion of Fort Irwin NTC.
Brydolf, B. with R.D. Nieuhaus, Inc. 1996. Final Report, 1994 Avian Survey at the National Training Center, Fort Irwin, CA.
Recht, M.A. with R.D. Nieuhaus, Inc. 1995. Final Report, 1994 Small Mammal Surveys of Selected Sites at the National Training Center Fort Irwin, California.
Contributors
P. Novak-Echenique
Approval
Sarah Quistberg, 2/26/2025
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
02/26/2025
Approved by
Sarah Quistberg
Approval date
Composition (Indicators 10 and 12) based on
Annual Production
Indicators
Number and extent of rills:
Presence of water flow patterns:
Number and height of erosional pedestals or terracettes:
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are
not bare ground):
Number of gullies and erosion associated with gullies:
Extent of wind scoured, blowouts and/or depositional areas:
Amount of litter movement (describe size and distance expected to travel):
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range
of values):
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Effect of community phase composition (relative proportion of different functional groups) and spatial
distribution on infiltration and runoff:
Presence and thickness of compaction layer (usually none; describe soil profile features which may be
mistaken for compaction on this site):
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:
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or
decadence):
Average percent litter cover (%) and depth ( in):
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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:
The Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.
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