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Ecological site R027XY065NV

GRANITIC SLOPE 8-10 P.Z.

Last updated: 6/03/2024
Accessed: 12/30/2024

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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): 027X–Fallon-Lovelock Area

Physiography
Found in the Great Basin Section of the Basin and Range Province of the Intermontane Plateaus this area is characterized by isolated uplifted fault block mountain ranges trending north to south that are separated by broad, hydrologically closed basins. The entire area occurs in the rain-shadow of the Sierra Nevada mountains and is influenced by Pleistocene Lake Lahontan which reached its most recent high stand about 12,000 years ago. There is substantial evidence suggesting the western Great Basin has been the site of pluvial-interpluvial cycles for at least the past two million years.
The mountains and valleys are dissected by the Humboldt, Truckee, Carson, and Walker Rivers and their tributaries, all of which terminate within MLRA 27. Extensive playas can be found throughout this area and are the result of drying of ancient Lake Lahontan. Elevation generally ranges from 3,300 to 5,900 feet (1,005 to 1,800 meters) in valleys, but on some mountain peaks it is more than 7,870 feet (2,400 meters).

Geology
Landforms and soils of this MLRA have been heavily influenced by fluctuating lake level over the last 40,000 years. There is a level line evident on the higher slopes marking the former extent of glacial Lake Lahontan. Almost half of this area has surface deposits of alluvial valley fill influenced by lacustrine sediment. The rest has andesite and basalt rocks of different ages. Mesozoic and Tertiary intrusives are concentrated along the western border of the area, and Lower Volcanic Rocks (17 to 43 million years old) are common on the eastern side of the area. Also, some scattered outcrops of Mesozoic sedimentary and volcanic rocks and tuffaceous sedimentary rocks are in the mountains within the interior of this MLRA.

Climate
The average annual precipitation is 5 to 10 inches (125 to 255 millimeters) in most of the area but is as much as 19 inches (485 millimeters) on high mountain slopes. Most of the rainfall occurs as high-intensity, convective thunderstorms during the growing season. The amount of precipitation is very low from summer to midautumn. The precipitation in winter occurs mainly as snow. The average annual temperature is 43 to 54 degrees F (6 to 12 degrees C). The freeze-free period averages 155 days and ranges from 110 to 195 days, decreasing in length with elevation.

Water
The amount of precipitation is very low, and water for irrigation is obtained principally from diversions on the four large rivers in the area and from water stored in the Lahontan, Rye Patch, and Weber Reservoirs. Pyramid Lake and Walker Lakes are terminal lakes for the Truckee and Walker Rivers, respectively. Much of the annual flow of both rivers is diverted for irrigation, causing lake levels to fall and levels of dissolved salts to increase causing problems for the native Lahontan cutthroat trout.

Soils
The dominant soil orders are Aridisols and Entisols. The soils in the area are predominantly a mesic temperature regime, aridic moisture regime, and have a mixed mineralogy. They are generally well drained, loamy or sandy, commonly skeletal, and shallow to very deep. Accumulation of salts, tufa deposits, and eolian sediments with soluble salts over lacustrine deposits influence most of the soils in the basin landforms of this MLRA. Soils on bedrock-controlled landforms are typically comprised of volcanic or tuffaceous sedimentary colluvium over residuum.

Biological Resources
This area supports extensive areas of salt-desert shrub vegetation. Shadscale and Bailey’s greasewood are widespread, occurring both individually and together. Grasses are generally sparse, although Indian ricegrass is prominent, especially on the sandy soils. Fourwing saltbush, winterfat, spiny hopsage, wolfberry, ephedra, dalea, and bud sagebrush are common shrubs. Basin wildrye, creeping wildrye, alkali sacaton, saltgrass, black greasewood, rubber rabbitbrush, and big saltbush are important plants on saline bottom lands and terraces. A few marsh areas support cattail, bulrushes, sedges, and rushes. Big sagebrush, along with scattered Utah juniper and singleleaf pinyon, is associated with Thurber needlegrass, desert needlegrass, Sandberg bluegrass, and squirreltail on the higher elevation piedmont slopes and mountains.

Ecological site concept

The Granitic Slope 8-10 P.Z. site occurs on mountain slopes and hills on all aspects. Slope gradients of 30 to 50 percent are most typical. Elevations are 4300 to 7600 feet. The soils are shallow and well drained. The soils typically have a coarse to moderately coarse upper surface over weathered granitic parent material.

Associated sites

R027XY047NV	ERODED GRANITIC SLOPE Found on eroded slopes.

R027XY047NV

ERODED GRANITIC SLOPE

Found on eroded slopes.

Similar sites

R027XY088NV	GRANITIC LOAM 10-12 P.Z. ACTH7 dominant grass

R027XY088NV

GRANITIC LOAM 10-12 P.Z.

ACTH7 dominant grass

Table 1. Dominant plant species

Tree	Not specified
Shrub	(1) Artemisia tridentata ssp. wyomingensis
Herbaceous	(1) Achnatherum speciosum

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Physiographic features

The Granitic Slope 8-10 P.Z. site occurs on mountain slopes and hills on all aspects. Slope gradients of 30 to 75 percent are typical on this site. Elevations are 4300 to 7600 feet.

Table 2. Representative physiographic features

Landforms	(1) Mountain slope (2) Hill
Runoff class	Low to very high
Flooding frequency	None
Ponding frequency	None
Elevation	4,300 – 7,600 ft
Slope	30 – 75%
Water table depth	72 in
Aspect	Aspect is not a significant factor

Climatic features

The climate associated with this site is arid, characterized by cool, moist winters and hot, dry summers. Average annual precipitation is 8 to 10 inches. Mean annual temperatures are 49 to 57 degrees F. The average growing season is about 100 to 130 days. No climate station is available.

Table 3. Representative climatic features

Frost-free period (average)	130 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

Soil features

The soils are shallow and well drained. These soils have formed in residuum and colluvium from granitic or metamorphic rock sources. The soils typically have a coarse to moderately coarse upper surface over weathered granitic parent material. Available water capacity is very low. Surface runoff is low to very high. The potential for sheet and rill erosion is high. Soil series associated with the site are Bijorja, Breko, Gabbvally, Petspring, and Wiskiflat.

Table 4. Representative soil features

Parent material	(1) Colluvium – granite (2) Residuum – granite (3) Colluvium – volcanic rock (4) Residuum – volcanic rock
Surface texture	(1) Very bouldery loamy sand (2) Very gravelly coarse sandy loam (3) Very stony loamy coarse sand
Family particle size	(1) Loamy
Drainage class	Well drained
Permeability class	Moderately slow to moderately rapid
Soil depth	3 – 14 in
Surface fragment cover <=3"	23 – 74%
Surface fragment cover >3"	6 – 17%
Available water capacity (0-40in)	0.2 – 3.6 in
Calcium carbonate equivalent (0-40in)	30%
Electrical conductivity (0-40in)	2 mmhos/cm
Sodium adsorption ratio (0-40in)	2
Soil reaction (1:1 water) (0-40in)	6.1 – 9
Subsurface fragment volume <=3" (Depth not specified)	12 – 44%
Subsurface fragment volume >3" (Depth not specified)	5 – 16%

Ecological dynamics

As ecological condition declines, overstory shrubs such as Wyoming big sagebrush, littleleaf horsebrush, and Douglas' rabbitbrush increase as Sandberg's bluegrass and galleta increase in the understory. With further site degradation galleta and bluegrass also decline. After wildfire, Douglas' rabbitbrush, littleleaf horsebrush, wolfberry, spiny hopsage and Nevada ephedra often dominate the aspect. Should excessive soil erosion occur after disturbance and soils become unstable, the potential plant community may be permanently altered to that characterized by the Eroded Granitic Slope (027XY047NV) ecological site. Species likely to invade this site are annuals such as cheatgrass and filaree.

Fire Ecology:
The fire return interval for Wyoming big sagebrush communities ranges from 10 to 70 years. Fire is the principal means of renewal for decadent stands of Wyoming big sagebrush.
Wyoming big sagebrush is killed by fire and establishes after fire from a seedbank; from seed produced by remnant plants that escaped fire; and from plants adjacent to the burn that seed in. Fires in spiny hopsage sites generally occur in late summer when plants are dormant, and sprouting generally does not occur until the following spring. Spiny hopsage is considered to be somewhat fire tolerant and often survives fires that kill sagebrush. Mature spiny hopsage generally sprout after being burned. Spiny hopsage is reported to be least susceptible to fire during summer dormancy. Nevada ephedra generally sprouts after fire damages aboveground vegetation. Underground regenerative structures commonly survive when aboveground vegetation is consumed by fire. However, severe fires may kill shallowly buried regenerative structures. 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. Most perennial grasses have root crowns that can survive wildfire. 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. 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

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Standard diagram

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

Ecosystem states

1. Reference Plant Community

State 1 submodel, plant communities

1.1. Reference Plant Community

State 1
Reference Plant Community

Community 1.1
Reference Plant Community

Figure 3. Granitic slope

The reference plant community is dominated by desert needlegrass and Wyoming big sagebrush. Potential vegetative composition is about 50% grasses, 5% forbs and 45% shrubs. Approximate ground cover (basal and crown) is 20 to 30 percent.

Figure 4. 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	200	300	400
Shrub/Vine	180	270	360
Forb	20	30	40
Total	400	600	800

Additional community tables

Table 6. Community 1.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production (lb/acre)	Foliar cover (%)
Grass/Grasslike
1	Primary Perennial Grasses			264–378
	desert needlegrass	ACSP12	Achnatherum speciosum	240–300	–
	Indian ricegrass	ACHY	Achnatherum hymenoides	12–48	–
	Sandberg bluegrass	POSE	Poa secunda	12–30	–
2	Secondary Perennial Grasses			12–48
	squirreltail	ELEL5	Elymus elymoides	3–18	–
	needle and thread	HECO26	Hesperostipa comata	3–18	–
	James' galleta	PLJA	Pleuraphis jamesii	3–18	–
	sand dropseed	SPCR	Sporobolus cryptandrus	3–18	–
Forb
3	Perennial			12–48
	James' galleta	PLJA	Pleuraphis jamesii	3–18	–
	buckwheat	ERIOG	Eriogonum	3–12	–
	phlox	PHLOX	Phlox	3–12	–
	globemallow	SPHAE	Sphaeralcea	3–12	–
Shrub/Vine
4	Primary Shrubs			174–278
	spiny hopsage	GRSP	Grayia spinosa	12–48	–
	Nevada jointfir	EPNE	Ephedra nevadensis	12–30	–
	Forb, perennial	2FP	Forb, perennial	3–12	–
	buckwheat	ERIOG	Eriogonum	3–12	–
	phlox	PHLOX	Phlox	3–12	–
	globemallow	SPHAE	Sphaeralcea	3–12	–
5	Secondary Shrubs			12–60
	yellow rabbitbrush	CHVI8	Chrysothamnus viscidiflorus	3–18	–
	water jacket	LYAN	Lycium andersonii	3–18	–
	desert peach	PRAN2	Prunus andersonii	3–18	–
	desert bitterbrush	PUGL2	Purshia glandulosa	3–18	–
	Stansbury cliffrose	PUST	Purshia stansburiana	3–18	–
	desert snowberry	SYLO	Symphoricarpos longiflorus	3–18	–
Tree
6	Evergreen			6–36
	spiny hopsage	GRSP	Grayia spinosa	12–48	–
	winterfat	KRLA2	Krascheninnikovia lanata	6–18	–
	Utah juniper	JUOS	Juniperus osteosperma	3–18	–
	singleleaf pinyon	PIMO	Pinus monophylla	3–18	–

Interpretations

Animal community

Livestock Interpretations:
This site is suited for livestock grazing. Grazing management should be keyed to desert needlegrass, indian ricegrass, and bluegrass production. 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. Bluegrass is a widespread forage grass. It is one of the earliest grasses in the spring and is sought by domestic livestock and several wildlife species. Sandberg bluegrass is a palatable species, but its production is closely tied to weather conditions. It produces little forage in drought years, making it a less dependable food source than other perennial bunchgrasses. Livestock browse Wyoming big sagebrush, but may use it only lightly when palatable herbaceous species are available. Spiny hopsage provides a palatable and nutritious food source for livestock, particularly during late winter through spring. Domestic sheep browse the succulent new growth of spiny hopsage in late winter and early spring.
Nevada ephedra is important winter range browse for domestic cattle, sheep and goats.

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:
Wyoming big sagebrush is preferred browse for wild ungulates, and Wyoming big sagebrush communities are important winter ranges for big game. Pronghorn usually browse Wyoming big sagebrush heavily. Wyoming big sagebrush communities are critical habitat for the birds.
Spiny hopsage provides a palatable and nutritious food source for big game animals. Spiny hopsage is used as forage to at least some extent by domestic goats, deer, pronghorn, and rabbits. Mule deer, bighorn sheep, and pronghorn browse Nevada ephedra, especially in spring and late summer when new growth is available. Desert needlegrass is an important forage species for several wildlife species in the spring. 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 low.

Other products

Native Americans made tea from big sagebrush leaves. They used the tea as a tonic, an antiseptic, for treating colds, diarrhea, and sore eyes and as a rinse to ward off ticks. Big sagebrush seeds were eaten raw or made into meal. Some Native American peoples traditionally ground parched seeds of spiny hopsage to make pinole flour. Native Americans used Nevada ephedra as a tea to treat stomach and kidney ailments. Indian ricegrass was traditionally eaten by some Native Americans. The Paiutes used seed as a reserve food source.

Other information

Wyoming big sagebrush is used for stabilizing slopes and gullies and for restoring degraded wildlife habitat, rangelands, mine spoils and other disturbed sites. It is particularly recommended on dry upland sites where other shrubs are difficult to establish. Spiny hopsage has moderate potential for erosion control and low to high potential for long-term revegetation projects. It can improve forage, control wind erosion, and increase soil stability on gentle to moderate slopes. Spiny hopsage is suitable for highway plantings on dry sites in Nevada. Nevada ephedra is useful for erosion control, and seedlings have been successfully planted onto reclaimed strip mines, with survival ranging from 12 to 94%. Atrazine may be effective in controlling Nevada ephedra, though some plants can survive through crown sprouting. Irrigation may increase control by atrazine.
Desert needlegrass seeds are easily germinated and have potential for commercial use. Desert needlegrass may be used for groundcover in areas of light disturbance, but it is susceptible to excessive trampling.

Supporting information

Inventory data references

NASIS soil component data.

Type locality

Location 1: Mineral County, NV
Township/Range/Section	T7N R34E S29
General legal description	About 6 miles northwest of Mina, Black Dyke Mountain area, Garfield Hills, Mineral County Nevada. This site also occurs in Churchill, Esmeralda, Lyon, Nye and Pershing Counties, Nevada.
Location 2: Pershing County, NV
Township/Range/Section	T26N R26E S9
General legal description	Sahwave Mountains, Pershing County, Nevada. This site also occurs in Churchill, Esmeralda, Lyon, Mineral, and Nye Counties, 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

GED/FR

Approval

Kendra Moseley, 6/03/2024

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)	G. Brackley
Contact for lead author	State Rangeland Management Specialist
Date	02/08/2007
Approved by	Kendra Moseley
Approval date
Composition (Indicators 10 and 12) based on	Annual Production

Indicators

Number and extent of rills:
Rills may occur on steeper slopes and most frequently occur in areas subjected to summer convection storms or rapid spring melt.
Presence of water flow patterns:
Wate flow patterns are rare to slight.
Number and height of erosional pedestals or terracettes:
Pedestals are rare to slight and most frequently occur in areas subjected to summer convection storms or rapid spring snowmelt.
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
50 to 60 percent
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, forbs and shrubs) expected to move distance of slope length duriing intense summer storms. Persistent litter (large woody material) will remain in place except during catastrophic 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 4 to 6 on most surface soil textures found on this site.
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Surface structure is single grain, weak subangular blocky or massive. Soil surface colors are light and soils are typified byb an ochric epipedon. Organic carbon of the surface 2 to 3 inches is typically less than 1 percent dropping off quickly below.
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 [Desert needlegrass and Indian ricegrass] 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):
None. Subsoil argillic horizons are not to 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:
Reference Plant Community: Deep-rooted, cool season, perennial bunchgrasses >> evergreen and deciduous shrubs

Sub-dominant:
shallow-rooted, cool season perennial grasses = deep-rooted cool season perennial forbs = fibrous, shallow-rooted cool seaso, annual and perennial forbs > shallow-rooted, warm season grasses.

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 30% of total woody canopy. Some of the mature bunchgrasses (<25%) have dead centers.
Average percent litter cover (%) and depth ( in):
Mostly under the canopy
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:
Cheatgrass, annual mustards, halogeton, and Russian thistle are invaders on this site. Douglas rabbitbrush, Utah juniper and singleleaf pinyon are increasers on this site.
Perennial plant reproductive capability:
All functional groups should reproduce in average (normal) and above average growing seasons.

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