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Ecological site R023XY031NV

CLAYPAN 10-14 P.Z.

Last updated: 4/10/2025
Accessed: 09/15/2026

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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.

MLRA notes

Major Land Resource Area (MLRA): 023X–Malheur High Plateau

Currently there is only a draft of the initial concept for this ecological site. The initial concept for this site places it within the Clay or Claypan ,12” PZ Low and Lahontan sagebrush and bluebunch wheatgrass/ Thurber’s needlegrass Ecological Site Group. To view the General STM and other information available for this ESG please go to https://edit.jornada.nmsu.edu/catalogs/esg/023X/R023XY901NV

The Claypan 10-14” (023XY031NV) ecological is the modal site for this group as it has the most acres mapped. This site occurs on summits and moderate slopes of hills and plateaus on all aspects. Slopes range from 2 to 30 percent, but slope gradients of 2 to 15 percent are typical. Elevations are 5500 to 7000 feet. The soils in this site have thin surface layers and are typically underlain by heavy clay subsoils that exhibit moderate to strong structure. These fine textured subsoils will swell on wetting then shrink and crack upon drying. Swelling of the subsoil with wetting in the early spring results in poor soil aeration, forming a perched water table near the surface. Infiltration of water is restricted once these soils are saturated and the site is subject to loss of water by runoff. The thin surface layer has a low available water capacity due to its limited thickness and reduction in surface layer depth results in decreased productivity of the plant community. These soils normally have a high percentage of gravels and cobbles on the surface which occupy plant growing space yet help to reduce evaporation and conserve soil moisture. Plant growth is initiated with the spring warming of these soils. Pedestalling of some grass plants is common during the winter due to frost heaving. Low sagebrush and Lahontan sagebrush are the dominant shrubs. Bluebunch wheatgrass and Thurber’s needlegrass are dominant grasses. Squawapple (Pheraphyllum ramosissimum) and antelope bitterbrush are also found on this site. Production is about 700 lbs/acre for a normal year.

Associated sites

R023XY020NV	LOAMY 10-12 P.Z.
R023XY021NV	SCABLAND 10-14 P.Z.
R023XY039NV	LOAMY SLOPE 10-14 P.Z.
R023XY041NV	LOAMY 12-14 P.Z.
R023XY044NV	VERY COBBLY CLAYPAN
R023XY059NV	GRAVELLY CLAYPAN 10-12 P.Z.
R023XY060NV	COBBLY CLAYPAN 8-12 P.Z.

Similar sites

R023XY014NV	SHALLOW LOAM 14+ P.Z. FEID dominant grass; higher elevations
R023XY021NV	SCABLAND 10-14 P.Z. POSE dominant grass; less productive site
R023XY079NV	ASHY CLAYPAN (COOL) 10-14 P.Z. FEID dominant grass; high amounts of volcanic ash in soil
R023XY017NV	CLAYPAN 14-16 P.Z. FEID-PSSPS codominant
R023XY044NV	VERY COBBLY CLAYPAN POSE dominant grass; less productive site; extremely cobbly surface
R023XY008NV	MOUNTAIN RIDGE FEID dominant grass; much less productive site
R023XY060NV	COBBLY CLAYPAN 8-12 P.Z. less productive site; many cobbles on surface
R023XY059NV	GRAVELLY CLAYPAN 10-12 P.Z. ACTH7 dominant grass; less production
R023XY078NV	ASHY CLAYPAN 10-14 P.Z. more productive site; high amounts of volcanic ash in soil

Table 1. Dominant plant species

Tree	Not specified
Shrub	(1) Artemisia arbuscula
Herbaceous	(1) Pseudoroegneria spicata ssp. spicata (2) Achnatherum thurberianum

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Physiographic features

This site occurs on summits and moderate slopes of hills, mountains, and plateaus on all aspects. Slopes range from 0 to 50 percent, but slope gradients of 4 to 15 percent are typical. Elevations are 4400 to 7600 feet.

Table 2. Representative physiographic features

Landforms	(1) Mountain (2) Hill (3) Plateau
Elevation	4400 – 7600 ft
Slope	0 – 50 %
Aspect	Aspect is not a significant factor

Climatic features

The climate associated with this site is semiarid and characterized by cool, moist winters and warm, dry summers. Average annual precipitation is 10 to 14 inches. Mean annual air temperature is 45 to 50 degrees F. The average growing season is about 80 to 100 days.

Nevada’s climate is predominantly arid, with large daily ranges of temperature, infrequent severe storms, heavy snowfall in the higher mountains, and great location variations with elevation. Three basic geographical factors largely influence Nevada’s climate: continentality, latitude, and elevation. Continentality is the most important factor. The strong continental effect is expressed in the form of both dryness and large temperature variations. Nevada lies on the eastern, lee side of the Sierra Nevada Range, a massive mountain barrier that markedly influences the climate of the State. The prevailing winds are from the west, and as the warm moist air from the Pacific Ocean ascend the western slopes of the Sierra Range, the air cools, condensation occurs and most of the moisture falls as precipitation. As the air descends the eastern slope, it is warmed by compression, and very little precipitation occurs. The effects of this mountain barrier are felt not only in the West but throughout the state, with the result that the lowlands of Nevada are largely desert or steppes. The temperature regime is also affected by the blocking of the inland-moving maritime air. Nevada sheltered from maritime winds, has a continental climate with well-developed seasons and the terrain responds quickly to changes in solar heating.
Nevada lies within the mid-latitude belt of prevailing westerly winds which occur most of the year. These winds bring frequent changes in weather during the late fall, winter and spring months, when most of the precipitation occurs. To the south of the mid-latitude westerlies, lies a zone of high pressure in subtropical latitudes, with a center over the Pacific Ocean. In the summer, this high-pressure belt shifts northward over the latitudes of Nevada, blocking storms from the ocean. The resulting weather is mostly clear and dry during the summer and early fall, with scattered thundershowers. The eastern portion of the state receives significant summer thunderstorms generated from monsoonal moisture pushed up from the Gulf of California, known as the North American monsoon. The monsoon system peaks in August and by October the monsoon high over the Western U.S. begins to weaken and the precipitation retreats southward towards the tropics (NOAA 2004).

Average annual precipitation is 16 to over 20 inches. Mean annual air temperature is 41 to 44 degrees F. The average growing season is about 50 to 70 days.

Mean annual precipitaion at the Bear Creek, Nevada SNOTEL station (170501020301) is 37.69 inches.

monthly mean precipitation is:
January 3.84; February 3.75; March 4.38; April 4.9;
May 3.99; June 2.82; July .95; August 1.66;
September 1.22; October 2.12;
November 3.67; December 4.38.

Table 3 Representative climatic features

Frost-free period (average)	90 days
Freeze-free period (average)
Precipitation total (average)	10 in

Bar

Line

Figure 1. Monthly precipitation range

Bar

Line

Figure 2. Monthly average minimum and maximum temperature

Figure 3. Annual precipitation pattern

Figure 4 Annual average temperature pattern

Soil features

The soils associated with this site are typically shallow and are typically underlain by heavy clay subsoils that exhibit moderate to strong structure. These fine textured subsoils will swell on wetting then shrink and crack upon drying. Swelling of the subsoil with wetting in the early spring results in poor soil aeration, forming a perched water table near the surface. Infiltration of water is restricted once these soils are saturated and the site is subject to loss of water by runoff. The thin surface layer has a very low available water capacity due to its limited thickness and reduction in surface layer depth results in decreased productivity of the plant community. These soils normally have a high percentage of gravels and cobbles on the surface which occupy plant growing space yet help to reduce evaporation and conserve soil moisture. Plant growth is initiated with the spring warming of these soils. Pedestalling of some grass plants is common during the winter due to frost heaving. The soil moisture regime is aridic bordering on xeric and the temperature regime is mesic. The soils typically have a mollic epipedon and an argillic horizon.
The soil series associated with this site include: Anawalt, Bieber, Devada, Mahala, Ninemile, and Nitpac.

A representative soil series is Devada a clayey, smectitic, mesic, Aridic Lithic Argixeroll. A mollic epipedon occurs from the soil surface to 33 cm and an argillic horizon occurs from 20 to 33 cm. Lithic contact is at 33 cm.

Table 4. Representative soil features

Parent material	(1) Residuum – rhyolite
Surface texture	(1) Cobbly loam (2) Very stony loam (3) Cobbly very fine sandy loam
Family particle size	(1) Clayey
Drainage class	Well drained
Permeability class	Slow to very slow
Soil depth	10 – 40 in
Surface fragment cover <=3"	5 – 25 %
Surface fragment cover >3"	1 – 20 %
Available water capacity (0-40in)	1.6 – 2.5 in
Calcium carbonate equivalent (0-40in)	Not specified
Electrical conductivity (0-40in)	0 – 2 mmhos/cm
Sodium adsorption ratio (0-40in)	Not specified
Soil reaction (1:1 water) (0-40in)	6.1 – 8.4
Subsurface fragment volume <=3" (Depth not specified)	5 – 25 %
Subsurface fragment volume >3" (Depth not specified)	0 – 25 %

Ecological dynamics

Where management results in abusive grazing use by livestock and/or feral horses, rabbitbrush, low sagebrush, Hooker balsamroot and bluegrasses increase as bluebunch wheatgrass and Thurber needlegrass decrease. As condition declines further, bluegrasses, low sagebrush and rabbitbrush dominate the site. Cheatgrass and annual mustards readily invade this site.

Fire Ecology:
Prior to 1897, mean fire return intervals for low sagebrush communities have been estimated to be from 35 to over 100 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. 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. Thurber’s needlegrass is classified as moderately resistant, but depending on season of burn, phenology, and fire severity, this perennial bunchgrass is moderately to severely damaged by fire. Early season burning is more damaging to this needlegrass than late season burning. 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

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Standard diagram

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Click on state and transition labels to scroll to the respective text

State 1
Reference State

Community 1.1
Community Phase

The reference plant community is dominated by bluebunch wheatgrass, low sagebrush and Thurber's needlegrass. Potential vegetative composition is about 65% grasses, 10% forbs and 25% shrubs. Approximate ground cover (basal and crown) is about 20 to 35 percent.

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	325	455	585
Shrub/Vine	125	175	225
Forb	50	70	90
Total	500	700	900

Community 1.2
Community Phase

Community 1.3
Community Phase

Pathway a
Community 1.1 to 1.2

Pathway b
Community 1.1 to 1.3

Pathway a
Community 1.2 to 1.1

Pathway a
Community 1.3 to 1.1

Pathway b
Community 1.3 to 1.2

State 2
Current Potential State

Community 2.1
Community Phase

Community 2.2
Community Phase

Community 2.3
Community Phase

Community 2.4
Community Phase (at risk)

Pathway a
Community 2.1 to 2.2

Pathway b
Community 2.1 to 2.3

Pathway c
Community 2.1 to 2.4

Pathway a
Community 2.2 to 2.1

Pathway b
Community 2.2 to 2.4

Pathway a
Community 2.3 to 2.1

Pathway b
Community 2.3 to 2.2

Pathway a
Community 2.4 to 2.1

Pathway b
Community 2.4 to 2.2

State 3
Shrub State

Community 3.1
Community Phase

Community 3.2
Community Phase

Pathway a
Community 3.1 to 3.2

Pathway a
Community 3.2 to 3.1

State 4
Tree State

Community 4.1
Community Phase

Community 4.2
Community Phase

Pathway a
Community 4.1 to 4.2

State 5
Annual State

Community 5.1
Community Phase

State 6
Eroded State

Not verified

Community 6.1
Community Phase

Transition A
State 1 to 2

Transition A
State 2 to 3

Transition B
State 2 to 4

Transition C
State 2 to 5

Transition A
State 3 to 4

Transition B
State 3 to 5

Transition C
State 3 to 6

Restoration pathway A
State 4 to 2

Transition A
State 4 to 5

Transition B
State 4 to 6

Transition A
State 5 to 6

Additional community tables

Table 6. Community 1.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)
Grass/Grasslike
1	Primary Perennial Grasses			350–665
	bluebunch wheatgrass	PSSPS	Pseudoroegneria spicata ssp. spicata	210–350	–
	Thurber's needlegrass	ACTH7	Achnatherum thurberianum	105–245	–
	Sandberg bluegrass	POSE	Poa secunda	17–35	–
2	Secondary Perennial Grasses			14–35
	Indian ricegrass	ACHY	Achnatherum hymenoides	4–14	–
	Webber needlegrass	ACWE3	Achnatherum webberi	4–14	–
	squirreltail	ELEL5	Elymus elymoides	4–14	–
	Idaho fescue	FEID	Festuca idahoensis	4–14	–
Forb
3	Perennial			35–105
	aster	ASTER	Aster	4–21	–
	Hooker's balsamroot	BAHO	Balsamorhiza hookeri	4–21	–
	tapertip hawksbeard	CRAC2	Crepis acuminata	4–21	–
	fleabane	ERIGE2	Erigeron	4–21	–
	buckwheat	ERIOG	Eriogonum	4–21	–
	phlox	PHLOX	Phlox	4–21	–
Shrub/Vine
4	Primary Shrubs			70–140
	little sagebrush	ARAR8	Artemisia arbuscula	70–140	–
5	Secondary Shrubs			35–70
	yellow rabbitbrush	CHVI8	Chrysothamnus viscidiflorus	7–21	–
	wild crab apple	PERA4	Peraphyllum ramosissimum	7–21	–
	antelope bitterbrush	PUTR2	Purshia tridentata	7–21	–

Table 7. Community 1.2 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Table 8. Community 1.3 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Table 9. Community 2.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Table 10. Community 2.2 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Table 11. Community 2.3 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Table 12. Community 2.4 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Table 13. Community 3.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Table 14. Community 3.2 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Table 15. Community 4.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Table 16. Community 4.2 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Table 17. Community 5.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Table 18. Community 6.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Interpretations

Animal community

Livestock Interpretations:
This site is suited for livestock grazing. Grazing management should be keyed to perennial grass production. Bluebunch wheatgrass is considered one of the most important forage grass species on western rangelands for livestock. Although bluebunch wheatgrass can be a crucial source of forage, it is not necessarily the most highly preferred species. Thurber’s needlegrass species begin growth early in the year and remain green throughout a relatively long growing season. This pattern of development enables animals to use Thurber’s needlegrass when many other grasses are unavailable. Cattle prefer Thurber’s needlegrass in early spring before fruits have developed as it becomes less palatable when mature. Thurber’s needlegrasses are grazed in the fall only if the fruits are softened by rain. Sandberg and Canby's bluegrasses are widespread forage grasses. They are one of the earliest grasses in the spring and are sought by domestic livestock and several wildlife species. Sandberg and Canby's bluegrasses are palatable species, but their production is closely tied to weather conditions. They produces little forage in drought years, making them a less dependable food source than other perennial bunchgrasses. Domestic sheep and to a much lesser degree cattle consume low sagebrush, particularly during the spring, fall and winter.

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. Mule deer utilize and sometimes prefer low sagebrush, particularly in winter and early spring. Sagebrush-grassland communities provide critical sage-grouse breeding and nesting habitats. Meadows surrounded by sagebrush may be used as feeding and strutting grounds. Sagebrush is a crucial component of their diet year-round, and sage-grouse select sagebrush almost exclusively for cover. Bluebunch wheatgrass is considered one of the most important forage grass species on western rangelands for wildlife. Bluebunch wheatgrass does not generally provide sufficient cover for ungulates, however, mule deer are frequently found in bluebunch-dominated grasslands. Thurber needlegrass is valuable forage for wildlife. Sandberg and Canby's bluegrasses are desirable for pronghorn antelope and mule deer in the spring and preferable in the spring, summer, and fall for elk and desirable as part of their winter range.

Hydrological functions

Runoff is medium to high. Permeability is slow to very slow. Hydrologic soil group is D. Rills and pedestals are none to rare. Occurrence of pedestals is usually limited to areas of water flow patterns. Frost heaving of shallow rooted plants should not be considered a "normal" condition. Water flow patterns are rare but can be expected in areas recently subjected to summer convection storms or rapid snowmelt, usually on steeper slopes. Gullies are none. Perennial herbaceous plants (especially deep-rooted bunchgrasses [bluebunch wheatgrass & Thurber's needlegrass]) slow runoff and increase infiltration. Shrub canopy and associated litter break raindrop impact and provide opportunity for snow catch and accumulation on site.

Recreational uses

Aesthetic value is derived from the diverse floral and faunal composition and the colorful flowering of wild flowers and shrubs during the spring and early summer. This site offers rewarding opportunities to photographers and for nature study. This site is used for hiking and has potential for upland and big game hunting.

Other information

Low sagebrush can be successfully transplanted or seeded in restoration.

Supporting information

Type locality

Location 1: Humboldt County, NV
Township/Range/Section	T45N R24E S5
UTM zone	N
UTM northing	309349
UTM easting	4635602
Latitude	41° 50′ 57″
Longitude	119° 17′ 47″
General legal description	S 1/2, About 2 miles south of Gooch Spring on County Road 8A, on hillside along north side of road, USF&WS Sheldon Antelope Range, Humboldt County, Nevada. This site also occurs in Washoe County, Nevada.

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

BH/SW

Approval

Kendra Moseley, 4/10/2025

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)	GK BRACKLEY
Contact for lead author	State Rangeland Management Specialist
Date	06/20/2006
Approved by
Approval date
Composition (Indicators 10 and 12) based on	Annual Production

Indicators

Number and extent of rills:
Rills are rare. A few rills can be expected on steeper slopes in areas subjected to summer convection storms or rapid spring snowmelt.
Presence of water flow patterns:
Water flow patterns are rare but can be expected in areas recently subjected to summer convection storms or rapid snowmelt, usually on steeper slopes.
Number and height of erosional pedestals or terracettes:
Pedestals are rare. Occurrence is usually limited to areas of water flow patterns. Frost heaving of shallow rooted plants should not be considered a "normal" condition.
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Bare Ground up to 30% depending on amount of surface rock fragments
Number of gullies and erosion associated with gullies:
None
Extent of wind scoured, blowouts and/or depositional areas:
None
Amount of litter movement (describe size and distance expected to travel):
Fine litter (foliage from grasses and annual & perennial forbs) expected to move distance of slope length during intense summer convection storms or rapid snowmelt events. Persistent litter (large woody material) will remain in place except during large rainfall events.
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Soil stability values should be 3 to 6 on most soil textures found on this site. (To be field tested.)
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Surface structure is typically thin to thick platy, subangular blocky or massive. Soil surface colors are dark and soils are typified by a mollic epipedon. Organic matter of the surface 2 to 4 inches is typically 1.25 to 3 percent dropping off quickly below. Organic matter content can be more or less depending on micro-topography.
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Perennial herbaceous plants (especially deep-rooted bunchgrasses [bluebunch wheatgrass & Thurber's needlegrass]) slow runoff and increase infiltration. Shrub canopy and associated litter break raindrop impact and provide opportunity for snow catch and accumulation on site.
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
Compacted layers are none. Platy or massive sub-surface horizons or subsoil argillic horizons are not to be interpreted as compacted.
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:
Deep-rooted, cool season, perennial bunchgrasses

Sub-dominant:
low shrubs (low sagebrush)>deep-rooted, cool season, perennial forbs> shallow-rooted, cool season, perennial bunchgrasses>associated shrubs>fibrous, shallow-rooted, cool season, perennial and annual forbs

Other:

Additional:
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Dead branches within individual shrubs common and standing dead shrub canopy material may be as much as 25% of total woody canopy; some of the mature bunchgrasses (<10%) have dead centers.
Average percent litter cover (%) and depth ( in):
Under canopy and between plant interspaces up to 35% and litter depth is ± 1/4 inch.
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
For normal or average growing season (through mid-June) ± 700 lbs/ac; Favorable years ±900 lbs/ac, unfavorable years ±500 lbs/ac
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:
Potential invaders include cheatgrass, annual mustards, medusahead and western juniper.
Perennial plant reproductive capability:
All functional groups should reproduce in average (or normal) and above average growing season years

Download reference sheet

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