Natural Resources
Conservation Service
Ecological site R030XA068NV
CALCAREOUS HILL 5-7 P.Z.
Last updated: 2/18/2025
Accessed: 03/16/2025
General information
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 the summits and sideslopes of hills on all aspects. Slopes range from 2 to 75 percent, but slope gradients of 15 to 50 percent are typical. Elevations are 2300 to 4500 feet. The soils associated with this site are very shallow to moderately deep and well to somewhat excessively drained. These soils have formed in colluvium from volcanic parent material.
Please refer to group concept R030XA045CA to view the provisional STM.
Similar sites
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|---|---|
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| R030XA002NV |
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Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Atriplex confertifolia |
| Herbaceous |
Not specified |
Physiographic features
This site occurs on the summits and sideslopes of hills on all aspects. Slopes range from 2 to 75 percent, but slope gradients of 15 to 50 percent are typical. Elevations are 2300 to 4500 feet.
Table 2. Representative physiographic features
| Landforms |
(1)
Hill
|
|---|---|
| Elevation | 701 – 1,372 m |
| Slope | 2 – 75% |
| Aspect | Aspect is not a significant factor |
Climatic features
The climate is hot and arid, with mild winters and very hot summers. Precipitation is greatest in the winter with a lesser secondary peak in summer, typical of the Mojave Desert. Average annual precipitation is 5 to 7 inches. Mean annual air temperature is 56 to 64 degrees F. The average growing season is about 150 to 230 days.
Table 3. Representative climatic features
| Frost-free period (average) | 230 days |
|---|---|
| Freeze-free period (average) | |
| Precipitation total (average) | 178 mm |
Influencing water features
There are no influencing water features associated with this site.
Soil features
The soils associated with this site are very shallow to moderately deep and well to somewhat excessively drained. These soils have formed in colluvium from volcanic parent material. High amounts of rock fragments occur at the soil surface which occupy plant growing space yet help to reduce evaporation and conserve soil moisture. Runoff is very high, available water capacity is veru low and water intake rates are slow to moderately rapid. The soil series associated with this site include: Bullfor and Upspring.
Table 4. Representative soil features
| Surface texture |
(1) Very gravelly sandy loam (2) Very gravelly fine sandy loam (3) Very cobbly clay loam |
|---|---|
| Family particle size |
(1) Loamy |
| Drainage class | Well drained to somewhat excessively drained |
| Permeability class | Slow to moderately rapid |
| Soil depth | 10 – 102 cm |
| Surface fragment cover <=3" | 8 – 60% |
| Surface fragment cover >3" | 3 – 11% |
| Available water capacity (0-101.6cm) |
1.52 – 6.1 cm |
| Calcium carbonate equivalent (0-101.6cm) |
0% |
| Electrical conductivity (0-101.6cm) |
0 – 2 mmhos/cm |
| Sodium adsorption ratio (0-101.6cm) |
0 – 5 |
| Soil reaction (1:1 water) (0-101.6cm) |
7.9 – 9 |
| Subsurface fragment volume <=3" (Depth not specified) |
8 – 52% |
| Subsurface fragment volume >3" (Depth not specified) |
3 – 26% |
Ecological dynamics
Please refer to group concept R030XA045CA to view the provisional STM.
As ecological condition declines, creosotebush, white burrubrush, and wolfberry increase. Following mechanical disturbance or wildfire, introduced annual grasses and forbs readily invade or increase on this site.
Fire Ecology:
Shadscale 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. The mean fire return interval for shadscale communities range from 35 to 100 years. Increased presence of non-native annual grasses, such as cheatgrass, can alter fire regimes by increasing fire frequency under wet to near-normal summer moisture conditions. Fires in creosotebush scrub were an infrequent event in pre-settlement desert habitats, because fine fuels from winter annual plants were probably sparse, only occurring in large amounts during exceptionally wet winters. Fire kills many creosotebush. Creosotebush is poorly adapted to fire because of its limited sprouting ability. Creosotebush survives some fires that burn patchily or are of low severity. Spiny menodora often survives fire because its foliage does not readily burn. Fires in the Mojave desert are infrequent and of low severity because production of annual and perennial herbs seldom provides a fuel load capable of sustaining fire. Fire generally kills white bursage. However, most white bursage plants burned because their canopies contained numerous small branches in proximity to herbaceous fuels. Fire typically destroys aboveground parts of Anderson wolfberry, but the degree of damage to the plant depends on fire severity. Nevada ephedra is top-killed by fire. Underground regenerative structures commonly survive when aboveground vegetation is consumed by fire. Nevada ephedra generally sprouts after fire damages aboveground vegetation and may increase in plant cover. Desert needlegrass has persistent dead leaf bases, which make it susceptible to burning. Fire removes the accumulation; a rapid, cool fire will not burn deep into the root crown and surviving tufts will resprout. Indian ricegrass can be killed by fire, depending on severity and season of burn. Indian ricegrass reestablishes on burned sites through seed dispersed from adjacent unburned areas.
State and transition model
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Ecosystem states
State 1 submodel, plant communities
State 1
Reference Plant Community
Community 1.1
Reference Plant Community
The reference plant community is dominated by shadscale, creosotebush, and spiny menodora. White bursage, Anderson's wolfberry, and Ephedra ssp., are other important plants associated with this site. Potential vegetative composition is about 10% grasses, 10% annual and perennial forbs, and 80% shrubs. Approximate ground cover (basal and crown) is 3 to 8 percent.
Figure 1. Annual production by plant type (representative values) or group (midpoint values)
Table 5. Annual production by plant type
| Plant type | Low (kg/hectare) |
Representative value (kg/hectare) |
High (kg/hectare) |
|---|---|---|---|
| Shrub/Vine | 45 | 135 | 224 |
| Forb | 6 | 17 | 28 |
| Grass/Grasslike | 6 | 17 | 28 |
| Total | 57 | 169 | 280 |
Additional community tables
Table 6. Community 1.1 plant community composition
| Group | Common name | Symbol | Scientific name | Annual production (kg/hectare) | Foliar cover (%) | |
|---|---|---|---|---|---|---|
|
Grass/Grasslike
|
||||||
| 1 | Primary Perennial Grasses | 7–18 | ||||
| Indian ricegrass | ACHY | Achnatherum hymenoides | 3–9 | – | ||
| desert needlegrass | ACSP12 | Achnatherum speciosum | 3–9 | – | ||
| 2 | Secondary Perennial Grasses | 1–13 | ||||
| low woollygrass | DAPU7 | Dasyochloa pulchella | 1–6 | – | ||
| squirreltail | ELEL5 | Elymus elymoides | 1–6 | – | ||
| James' galleta | PLJA | Pleuraphis jamesii | 1–6 | – | ||
|
Forb
|
||||||
| 3 | Perennial Forbs | 1–13 | ||||
| 4 | Annual forbs | 1–17 | ||||
|
Shrub/Vine
|
||||||
| 5 | Primary shrubs | 64–145 | ||||
| shadscale saltbush | ATCO | Atriplex confertifolia | 17–43 | – | ||
| creosote bush | LATR2 | Larrea tridentata | 17–34 | – | ||
| spiny menodora | MESP2 | Menodora spinescens | 9–26 | – | ||
| water jacket | LYAN | Lycium andersonii | 9–17 | – | ||
| burrobush | AMDU2 | Ambrosia dumosa | 9–17 | – | ||
| Nevada jointfir | EPNE | Ephedra nevadensis | 3–9 | – | ||
| 6 | Secondary shrubs | 9–26 | ||||
| fourwing saltbush | ATCA2 | Atriplex canescens | 2–9 | – | ||
| burrobrush | HYSA | Hymenoclea salsola | 2–9 | – | ||
| winterfat | KRLA2 | Krascheninnikovia lanata | 2–9 | – | ||
| desert pepperweed | LEFR2 | Lepidium fremontii | 2–9 | – | ||
| Nevada dalea | PSPO | Psorothamnus polydenius | 2–9 | – | ||
Interpretations
Animal community
Livestock Interpretations:
This site has limited value for livestock grazing, due to the low forage production, steep slopes and stony surfaces. Desert needlegrass produces considerable basal foliage and is good forage while young. Young desert needlegrass is palatable to all classes of livestock. Mature herbage is moderately grazed by horses and cattle but rarely grazed by sheep. Indian ricegrass is highly palatable to all classes of livestock in both green and cured condition. It supplies a source of green feed before most other native grasses have produced much new growth. Shadscale provides good browse for domestic sheep and goats. Shadscale leaves and seeds are an important component of domestic sheep and cattle winter diets. Shadscale tends to be browse tolerant. Heavy grazing during the winter and/or spring reduces shadscale. Die-off can also occur during extended periods of high precipitation. Shadscale is tolerant of early spring light-intensity browsing. Creosotebush is unpalatable to livestock. Consumption of creosotebush may be fatal to sheep. Cattle will graze the stems of spiny menodora in the spring before the stems become woody and spiny. Spiny menodora has lower palatability than the other shrubs but is consumed during early spring before spines mature. White bursage is of intermediate forage value. It is fair to good forage for horses and fair to poor for cattle and sheep. However, because there is often little other forage where white bursage grows, it is often highly valuable to browsing animals and is sensitive to browsing. Anderson wolfberry is sometimes used as forage by livestock and feral burros. Nevada ephedra is important winter range browse for domestic cattle, sheep and goats. Nevada ephedra is usually grazed heavily and seems to be perfectly safe for grazing livestock since it induces neither toxicity in ewes or cows, nor congenital deformities in lambs.
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:
Shadscale is a valuable browse species providing a source of palatable, nutritious forage for a wide variety of wildlife. The fruits and leaves are a food source for deer, desert bighorn sheep and pronghorn antelope. Creosotebush is unpalatable to most browsing wildlife. Elk will graze the stems of spiny menodora in the spring before the stems become woody and spiny. White bursage is an important browse species for wildlife. Mule deer, bighorn sheep, and pronghorn browse Nevada ephedra, especially in spring and late summer when new growth is available. Mountain quail eat Ephedra seeds. Desert bighorn sheep and feral horses and burros will graze desert needlegrass. Indian ricegrass is eaten by pronghorn in "moderate" amounts whenever available. In Nevada it is consumed by desert bighorns. A number of heteromyid rodents inhabiting desert rangelands show preference for seed of Indian ricegrass. Indian ricegrass is an important component of jackrabbit diets in spring and summer. In Nevada, Indian ricegrass may even dominate jackrabbit diets during the spring through early summer months. Indian ricegrass seed provides food for many species of birds. Doves, for example, eat large amounts of shattered Indian ricegrass seed lying on the ground.
Hydrological functions
Runoff is very high. Permeability is slow to moderately rapid.
Other products
Indian ricegrass was traditionally eaten by some Native Americans. The Paiutes used seed as a reserve food source. Seeds of shadscale were used by Native Americans for bread and mush. Creosotebush has been highly valued for its medicinal properties by Native Americans. It has been used to treat at least 14 illnesses. Twigs and leaves may be boiled as tea, steamed, pounded into a powder, pressed into a poultice, or heated into an infusion. White bursage is a host for sandfood, a parasitic plant. Sandfood was a valuable food supply for Native Americans. Native Americans used the fleshy berries of Anderson wolfberry either fresh or boiled and then dried them for later use. Some Native American tribes steeped the twigs of Nevada ephedra and drank the tea as a general beverage.
Other information
Desert needlegrass may be used for groundcover in areas of light disturbance, but it is susceptible to excessive trampling. Once established, creosotebush may improve sites for annuals that grow under its canopy by trapping fine soil, organic matter, and symbiont propagules. It may also increase water infiltration and storage. White bursage may be used to revegetate disturbed sites in southwestern deserts. Anderson wolfberry is also used as an ornamental valued chiefly for its showy red berries.
Supporting information
Other references
Fire Effects Information System (Online; http://www.fs.fed.us/database/feis/plants/).
USDA-NRCS Plants Database (Online; http://www.plants.usda.gov).
Contributors
HA
Approval
Kendra Moseley, 2/18/2025
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 | 03/16/2025 |
| Approved by | Kendra Moseley |
| 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:
-
Perennial plant reproductive capability:
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