Natural Resources
Conservation Service
Ecological site R024XY013NV
LOAMY 10-12 P.Z.
Last updated: 3/07/2025
Accessed: 04/11/2025
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.
MLRA notes
Major Land Resource Area (MLRA): 024X–Humboldt Basin and Range Area
Major land resource area (MLRA) 24, the Humboldt Area, covers an area of approximately 8,115,200 acres (12,680 sq. mi.). It is found in the Great Basin Section of the Basin and Range Province of the Intermontane Plateaus. Elevations range from 3,950 to 5,900 feet (1,205 to 1,800 meters) in most of the area, some mountain peaks are more than 8,850 feet (2,700 meters).
A series of widely spaced north-south trending mountain ranges are separated by broad valleys filled with alluvium washed in from adjacent mountain ranges. Most valleys are drained by tributaries to the Humboldt River. However, playas occur in lower elevation valleys with closed drainage systems. Isolated ranges are dissected, uplifted fault-block mountains. Geology is comprised of Mesozoic and Paleozoic volcanic rock and marine and continental sediments. Occasional young andesite and basalt flows (6 to 17 million years old) occur at the margins of the mountains. Dominant soil orders include Aridisols, Entisols, Inceptisols and Mollisols. Soils of the area are generally characterized by a mesic soil temperature regime, an aridic soil moisture regime and mixed geology. They are generally well drained, loamy and very deep.
Approximately 75 percent of MLRA 24 is federally owned, the remainder is primarily used for farming, ranching and mining. Irrigated land makes up about 3 percent of the area; the majority of irrigation water is from surface water sources, such as the Humboldt River and Rye Patch Reservoir. Annual precipitation ranges from 6 to 12 inches (15 to 30 cm) for most of the area, but can be as much as 40 inches (101 cm) in the mountain ranges. The majority of annual precipitation occurs as snow in the winter. Rainfall occurs as high-intensity, convective thunderstorms in the spring and fall.
Ecological site concept
This ecological site is on hills and mountains. Soils are deep, well drained, and formed in residuum and colluvium derived from mixed parent material. The soil profile is characterized by a mollic epipedon, a mesic soil temperature regime and aridic bordering on xeric soil moisture regime. The sagebrush found on this site is primarily basin big sagebrush (ARTRT), with Wyoming sagebrush (ARTRW8) confined to the transitions. The mixing of sagebrush species and the presence of the mollic epipedon are indicative of greater than 10 in (25 cm) of precipitation this site is receiving.
Associated sites
| R024XY005NV |
LOAMY 8-10 P.Z. Important abiotic factors contributing to the presence of this ecological site include limited precipitation and the presence of the argillic horizon that helps retain soil moisture. The fine-textured/clay rich horizons, lying beneath the coarser-textured horizons become impermeable as the swelling matrix closes following wetting. |
|---|---|
| R024XY020NV |
DROUGHTY LOAM 8-10 P.Z. Found on similar landforms at slightly lower elevation. Soils are not characterized by an argillic horizon. Spiny hopsage and bud sagebrush are important associated shrubs and bluebunch wheatgrass is not associated with the plant community. |
Similar sites
| R024XY005NV |
LOAMY 8-10 P.Z. Bluebunch wheatgrass (PSSPS) is an important associated grass. Shadscale and budsage are not associated with the plant community. Spiny hopsage is a minor component, if present. Soils associated with 024XY005NV are characterized by an argillic horizon. |
|---|---|
| R024XY035NV |
SHALLOW LOAM 10-14 P.Z. Less productive site; shallow soil depth. |
| R024XY020NV |
DROUGHTY LOAM 8-10 P.Z. Spiny hopsage (GRSP), bud sagebrush (ARSP5) and shadscale (ATCO) are associated shrubs and bluebunch wheatgrass (PSSPS) is absent. Soils lack an argillic horizon. |
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Artemisia tridentata |
| Herbaceous |
(1) Pseudoroegneria spicata |
Physiographic features
This site is on summits and side slopes of upper fan piedmonts, piedmont slopes, hills, and bordering mountains on all exposures. Slopes range from 8 to 50 percent, but slope gradients of 8 to 30 are most typical. Elevations are 5,000 to 6,800 feet (1,524 to 2,073 m).
Table 2. Representative physiographic features
| Landforms |
(1)
Hill
(2) Mountain (3) Fan |
|---|---|
| Runoff class | Low to very high |
| Ponding frequency | None |
| Elevation | 5,000 – 6,800 ft |
| Slope | 8 – 30% |
| Water table depth | 72 in |
| 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 12 inches (25 to 31 cm). Mean annual air temperature is 43 to 47 degrees F. The average growing season is about 80 to 100 days.
Table 3. Representative climatic features
| Frost-free period (average) | 90 days |
|---|---|
| Freeze-free period (average) | |
| Precipitation total (average) | 11 in |
Figure 1. Monthly precipitation range
Figure 2. Monthly average minimum and maximum temperature
Figure 3. Annual precipitation pattern
Figure 4. Annual average temperature pattern
Influencing water features
There are no influencing water features associated with this site.
Soil features
The soils associated with this site are deep, well drained and formed in loess and volcanic ash with minor amounts of residuum derived from mixed parent material. The soil profile is characterized by a mollic epipedon, less than 35 percent rock fragments by volume and a aridic bordering on xeric moisture regime. Soil reaction increases with soil depth. Soil series associated with this sire include: Barnard, Quomus, Zevadez, and Zymans.
The representative soil series is Quomus, a Coarse-loamy, mixed, superactive, frigid Duridic Haploxerolls.
Table 4. Representative soil features
| Parent material |
(1)
Loess
(2) Volcanic ash (3) Alluvium |
|---|---|
| Surface texture |
(1) Very fine sandy loam (2) Loam (3) Gravelly sandy loam |
| Family particle size |
(1) Loamy |
| Drainage class | Well drained |
| Permeability class | Slow to moderate |
| Soil depth | 14 – 84 in |
| Surface fragment cover <=3" | 8 – 28% |
| Surface fragment cover >3" | 2% |
| Available water capacity (0-40in) |
2.5 – 5.9 in |
| Calcium carbonate equivalent (0-40in) |
5% |
| Electrical conductivity (0-40in) |
8 mmhos/cm |
| Sodium adsorption ratio (0-40in) |
12 |
| Soil reaction (1:1 water) (0-40in) |
6.6 – 9 |
| Subsurface fragment volume <=3" (Depth not specified) |
45% |
| Subsurface fragment volume >3" (Depth not specified) |
9% |
Ecological dynamics
The plant communities of this site are dynamic in response to changing weather patterns and disturbance regimes. The reference plant community is dominated by Wyoming big sagebrush, mountain big sagebrush, basin big sagebrush and deep-rooted cool season perennial bunchgrasses such as bluebunch wheatgrass and Thurber's needlegrass.
Sagebrush species reproduce from seed and do not sprout from the root crown following disturbance. Sagebrush sets seed in the late summer and fall. Seeds ripen from September through October and fall from the plant. Cold, moist conditions and exposure to light increase germination in the spring (Johnson 2000). Seeds of sagebrush species are best adapted to germinate in habitats with conditions similar to that of the collection site. Survival of sagebrush seedlings is dependent on adequate moisture conditions. Young plants are susceptible to less than desirable condition for several years following germination.
Sagebrush species are generally long-lived, therefore it is not necessary for new individuals to recruit every year for perpetuation of the stand. Infrequent large recruitment events and simultaneous low, continuous recruitment is the foundation of population maintenance (Noy-Meir 1973). Mature properly functioning sagebrush communities have higher infiltration rates and lower sediment production, than degraded systems. Reoccurring disturbances, natural or anthropogenic, will result in decreased sagebrush cover and increased cover of disturbance tolerant shrubs and non-natives. Loss of structural and functional groups effects ecosystem processes and can result in soil loss.
The accumulation and decomposition of litter increase nutrient concentrations under sagebrush shrub canopies. The breakdown of aging roots also contributes to organic matter and nutrient cycling in the sagebrush system. Carbon and nitrogen concentration are higher under sagebrush canopies when compared to interspaces (Chen and Stark 2000). The root systems of sagebrush are well developed and maximizes water uptake with a deep taproot and shallow branching roots. The majority of the roots are in the upper foot of soil with tap roots extending at to 6 feet in depth. The combination of deep and shallow roots also provides excellent soil stabilization. The roots are infected with the vesicular-arbuscular mycorrhizae (VAM) Glomus microcarpus and Gigaspora spp. The presence of these fungi are important for successful establish of seedlings. Areas that lose sagebrush cover due to frequent fire and are dominated by non-native annual grasses lose the mycorrhizae fungi in the soil which may inhibit sagebrush reestablishment (Tirmenstein 1999).
Variability in plant community composition and production depends on soil surface texture and depth. Thurber’s needlegrass will increase on gravelly surfaces, whereas Indian ricegrass will increase with sandy soil surfaces. A weak argillic horizon will promote production of bluebunch wheatgrass. Production increases with soil depth. The amount of sagebrush in the plant community is dependent upon fire frequency, which would be highly infrequent.
At least four or five subspecies of big sagebrush (A. tridentata) have been identified (Tirmenstein 1999). Three subspecies of big sagebrush have been identified on this ecological site. Big sagebrush species commonly hybridize when growing in close proximity. Wyoming big sagebrush is the most drought tolerant of the three major big sagebrush subspecies. Wyoming big sagebrush is a long-lived species with maximum ages upwards of 150 years old (Howard 1999). Mountain big sagebrush typically grows in the wetter and cooler areas occupied by sagebrush species. It usually occurs in the upper elevation range of the big sagebrush zone and is most extensive in the Pinyon-Juniper zone of the Great Basin. A landscape scale study in Wyoming found that soil in topographic depression occupied by mountain big sagebrush had higher organic matter, nutrients and microbial biomass than more exposed soils occupied by basin and Wyoming big sagebrush (Johnson 2000). Basin big sagebrush is found throughout the sagebrush zone, it occurs from the valley floor to timberline, although it is not abundant in all zones. Basin big sagebrush prefers deep, well-drained soils and is capable of attaining heights greater than 10 feet. Variability in plant height occurs along a moisture gradient, with larger plants occurring on more mesic sites (Tirmenstein 1999).
Subspecies expression and dominance on this site is determined by elevation and aspect. Wyoming big sagebrush is more prevalent on southern exposures and the lower elevations of this site. Mountain big sagebrush is most common on northern exposures and the higher elevations of this site. Variation in the soil profile also influences subspecies expression. Basin big sagebrush typically occurs on deeper soils that have a loamy texture throughout the profile.
Overgrazing leads to increased sagebrush and a decline in herbaceous understory plants like bluebunch wheatgrass, Thurber’s needlegrass and Indian ricegrass. Squirreltail will increase temporarily with further degradation. Invasion of non-native invasive forbs and cheatgrass could occur with further grazing degradation, leading to a decline in squirreltail and an increase in bare ground. Wetter sites are more resistant to degradation and may result in sagebrush and Sandberg’s bluegrass dominating the site. A combination of overgrazing and prolonged drought leads to soil erosion, increased bare ground and a loss in plant production.
Where site degradation has been fire-induced, rabbitbrush often dominates the site. Repeated burning of the plant community at intervals less than 10 to 15 years results in complete site dominance by non-native annuals (primarily cheatgrass and tansy mustard) and the near total absence of woody plants, including sagebrush.
Fire Ecology:
Big sagebrush communities historically had low fuel loads, and patchy fires that burned in a mosaic pattern were common at 10 to 70 year return intervals (Young et al. 1979, West and Hassan 1985, Bunting et al. 1987). Davies et al. (2007) suggest fire return intervals in big sagebrush communities were around 50 to 100 years. More mesic big sagebrush communities typically experience shorter fire return intervals. The introduction and expansion of cheatgrass has dramatically altered the fire return intervals and restoration potential of big sagebrush plant communities.
Fire is the principal means of renewal for decadent stands of big sagebrush. Depending on site conditions prior to wildfire the perennial grasses and forbs will dominate initially after wildfire. Big sagebrush is killed by fire and establishes after fire from a seedbank. Islands of unburned mature sagebrush plants provide seed and result in faster recovery. Prolific seed production from nearby unburned plants coupled with high germination and survival rates is required to ensure establishment following fire. The VAM upon which big sagebrush depends on for healthy growth are usually harmed by fire and may take several years after fire to recover.
Spiny hopsage is considered to be somewhat fire tolerant and often survives fires that kill sagebrush. Mature spiny hopsage generally resprout after fire. Spiny hopsage is reported to be less susceptible to fire during summer dormancy.
Douglas rabbitbrush and rubber rabbitbrush are fire adapted and may be enhanced by fire. Rabbitbrush is commonly the first species to colonize burned areas by sprouting from the root crown and establishing for off-site seed.
Thurber’s needlegrass is classified as moderately resistant, but depending on season of burn, phenology, and fire severity, it is moderately to severely damaged by fire. Burning has been found to decrease the vegetation and reproductive vigor. Early season burning is more damaging to this needlegrass than late season burning.
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.
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. There is some speculation that Indian ricegrass may sprout from tillers after fire, especially if plant mortality was incomplete. Due to low culm density and below ground plant crowns, this is a fairly fire tolerant species.
State and transition model
Figure 5. State and Transition Model
Figure 6. STM Legend
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Click on state and transition labels to scroll to the respective text
State 1 submodel, plant communities
State 2 submodel, plant communities
State 3 submodel, plant communities
State 4 submodel, plant communities
State 5 submodel, plant communities
State 1
Reference State
The Reference State 1.0 is a representative of the natural range of variability under pristine conditions. The reference state has three general community phases; a shrub-grass dominant phase, a perennial grass dominant phase and a shrub dominant phase. State dynamics are maintained by interactions between climatic patterns and disturbance regimes. Negative feedbacks enhance ecosystem resilience and contribute to the stability of the state. These include the presence of all structural and functional groups, low fine fuel loads, and retention of organic matter and nutrients. Plant community phase changes are primarily driven by fire, periodic drought and/or insect or disease attack.
Community 1.1
Reference Plant Community
The visual aspect of the reference plant community is dominated by an open canopy of soft-woody shrubs with an understory of deep-rooted cool season perennial bunchgrasses. The plant community is dominated by big sagebrush, bluebunch wheatgrass and Thurber’s needlegrass. Bluegrass and basin wildrye are found throughout the site. Forbs such as arrowleaf balsamroot, tapertip hawksbeard and lupine are a conspicuous component of the plant community in the spring and early summer. Potential vegetative composition is about 60 percent grasses, 10 percent forbs and 30 percent shrubs. Approximate ground cover is 25 to 40 percent. Wyoming big sagebrush and Thurber’s needlegrass dominate the site. Indian ricegrass, Sandberg bluegrass and squirreltail are also common. Forbs are present but not abundant.
Figure 7. 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 | 360 | 480 | 600 |
| Shrub/Vine | 180 | 240 | 300 |
| Forb | 60 | 80 | 100 |
| Total | 600 | 800 | 1000 |
Community 1.2
Community Phase
This community phase is characteristic of a post-disturbance, early seral community phase. Thurber’s needlegrass and other perennial grasses dominate. Depending on fire severity or intensity of Aroga moth infestation, patches of intact sagebrush may remain.
Community 1.3
Community Phase
Wyoming big sagebrush increases in the absence of disturbance. Decadent sagebrush dominates the overstory and the deep-rooted perennial bunchgrasses in the understory are reduced either from competition with shrubs and/or from herbivory.
Pathway 1.1a
Community 1.1 to 1.2
Fire would decrease or eliminate the overstory of sagebrush and allow for the perennial bunchgrasses to dominate the site. Fires would typically be small and patchy due to low fuel loads. A fire following an unusually wet spring or a change in management may be more severe and reduce sagebrush cover to trace amounts. A severe infestation of Aroga moth could also cause a large decrease in sagebrush within the community, giving a competitive advantage to the perennial grasses and forbs.
Pathway 1.1b
Community 1.1 to 1.3
Time and lack of disturbance such as fire allows for sagebrush to increase and become decadent. Long-term drought, herbivory, or combinations of these would cause a decline in perennial bunchgrasses and fine fuels and lead to a reduced fire frequency allowing big sagebrush to dominate the site.
Pathway 1.2a
Community 1.2 to 1.1
Absence of disturbance over time would allow for sagebrush to increase.
Pathway 1.3a
Community 1.3 to 1.1
A low severity fire, Aroga moth or combination would reduce the sagebrush overstory and create a sagebrush/grass mosaic with sagebrush and perennial bunchgrasses co-dominant.
Pathway 1.3b
Community 1.3 to 1.2
Fire would decrease or eliminate the overstory of sagebrush and allow for the perennial bunchgrasses to dominate the site. Fires would typically be low severity resulting in a mosaic pattern due to low fine fuel loads. A fire following an unusually wet spring or a change in management favoring an increase in fine fuels, may be more severe and reduce sagebrush cover to trace amounts. A severe infestation of Aroga moth could also cause a large decrease in sagebrush within the community, giving a competitive advantage to the perennial grasses and forbs.
State 2
Current Potential State
This state is similar to the Reference State 1.0. This state has the same three general community phases. Ecological function has not changed, however the resiliency of the state has been reduced by the presence of invasive weeds. Non-natives may increase in abundance but will not become dominant within this State. These non-natives can be highly flammable and can promote fire where historically fire had been infrequent. Negative feedbacks enhance ecosystem resilience and contribute to the stability of the state. These feedbacks include the presence of all structural and functional groups, low fine fuel loads and retention of organic matter and nutrients. Positive feedbacks decrease ecosystem resilience and stability of the state. These include the non-natives’ high seed output, persistent seed bank, rapid growth rate, ability to cross pollinate and adaptations for seed dispersal.
Community 2.1
Community Phase
Wyoming big sagebrush and Thurber’s needlegrass dominate the site. Indian ricegrass and squirreltail may be significant components while Sandberg bluegrass and forbs make up smaller percentages by weight of the understory. Non-native annual species are present.
Community 2.2
Community Phase
This community phase is characteristic of a post-disturbance, early seral community phase. Thurber’s needlegrass and other perennial grasses dominate. Wyoming big sagebrush is present in trace amounts. Depending on fire severity or intensity of Aroga moth infestations, patches of intact sagebrush may remain. Rabbitbrush may be sprouting. Forbs may increase post-fire but will likely return to pre-burn levels within a few years. Annual non-native species generally respond well after fire and may be stable or increasing within the community.
Community 2.3
Community Phase (At-Risk)
This community is at risk of crossing a threshold to another state. Sagebrush dominates the overstory and perennial bunchgrasses in the understory are reduced, either from competition with shrubs or from inappropriate grazing management, or from both. Rabbitbrush may be a significant component. Sandberg bluegrass may increase and become co-dominate with deep rooted bunchgrasses. Annual non-natives species may be stable or increasing due to lack of competition with perennial bunchgrasses. This site is susceptible to further degradation from grazing, drought, and fire.
Pathway 2.1a
Community 2.1 to 2.2
Fire reduces the shrub overstory and allows for perennial bunchgrasses to dominate the site. Fires are typically low severity resulting in a mosaic pattern due to low fuel loads. A fire following an unusually wet spring or a change in management favoring an increase in fine fuels, may be more severe and reduce sagebrush cover to trace amounts. A severe infestation of Aroga moth could also cause a large decrease in sagebrush within the community, giving a competitive advantage to the perennial grasses and forbs. Annual non-native species are likely to increase after fire.
Pathway 2.1b
Community 2.1 to 2.3
Time and lack of disturbance such as fire allows for sagebrush to increase and become decadent. Chronic drought reduces fine fuels and leads to a reduced fire frequency allowing Wyoming big sagebrush to dominate the site. Inappropriate grazing management reduces the perennial bunchgrass understory; conversely Sandberg bluegrass may increase in the understory depending on grazing management. Excessive sheep grazing favors Sandberg bluegrass; however, where cattle and/or horses are the dominant grazers, cheatgrass often increases.
Pathway 2.2a
Community 2.2 to 2.1
Time and lack of disturbance and/or grazing management that favors the establishment and growth of sagebrush allows the shrub component to recover. The establishment of Wyoming big sagebrush can take many years.
Pathway 2.3a
Community 2.3 to 2.1
A change in grazing management that decreases shrubs would allow for the perennial bunchgrasses in the understory to increase. Heavy late-fall/winter grazing may cause mechanical damage and subsequent death to sagebrush, facilitating an increase in the herbaceous understory. An infestation of Aroga moth or a low severity fire would reduce some sagebrush overstory and allow perennial grasses to increase in the community. Brush treatments with minimal soil disturbance would also decrease sagebrush and release the perennial understory. Annual non-native species are present and may increase in the community.
Pathway 2.3b
Community 2.3 to 2.2
Fire would decrease or eliminate the overstory of sagebrush and allow for the perennial bunchgrasses to dominate the site. Fires would typically be small and patchy due to low fuel loads. A fire following an unusually wet spring or a change in management may be more severe and reduce sagebrush cover to trace amounts. A severe infestation of Aroga moth could also cause a large decrease in sagebrush within the community, giving a competitive advantage to the perennial grasses and forbs.
State 3
Shrub State
This state is a product of many years of heavy grazing during time periods harmful to perennial bunchgrasses. Sandberg bluegrass may increase with a reduction in deep rooted perennial bunchgrass competition and may become the dominate grass or the herbaceous understory may be completely eliminated. Sagebrush dominates the overstory and spiny hopsage and/or rabbitbrush may be a significant component. Sagebrush cover exceeds site concept and may be decadent, reflecting stand maturity and lack of seedling establishment due to competition with mature plants. The shrub overstory dominates site resources such that soil water, nutrient capture, nutrient cycling and soil organic matter are temporally and spatially redistributed. Bare ground may be significant with soil redistribution occurring between interspace and canopy locations.
Community 3.1
Community Phase
Wyoming big sagebrush dominates overstory and spiny hopsage and/or rabbitbrush may be a significant component. Deep-rooted perennial bunchgrasses may be present in trace amounts or absent from the community. Sandberg bluegrass may dominate the understory. Annual non-native species are present and may be co-dominant. Bare ground is significant. Utah juniper may be present.
Community 3.2
Community Phase
Bluegrass dominates the site; annual non-native species may be present but are not dominant. Trace amounts of sagebrush may be present. Sprouting shrubs such as spiny hopsage or rabbitbrush may be dominant.
Pathway 3.1a
Community 3.1 to 3.2
Fire, heavy fall grazing causing mechanical damage to shrubs, and/or brush treatments with minimal soil disturbance, will greatly reduce the overstory shrubs to trace amounts and allow for Sandberg bluegrass to dominate the site.
Pathway 3.2a
Community 3.2 to 3.1
Time and lack of disturbance and/or grazing management that favors the establishment and growth of sagebrush allows the shrub component to recover. The re-establishment of Wyoming big sagebrush can take many years. With the dominance of bluegrass this pathway is unlikely to occur.
State 4
Annual State
This community is characterized by the dominance of annual non-native species such as cheatgrass and tansy mustard in the understory. Sprouting shrubs such as rabbitbrush, shadscale, broom snakeweed and spiny hopsage may dominate the overstory.
Community 4.1
Community Phase
Annual non-native plants such as cheatgrass or tansy mustard dominate the site. Rabbitbrush may or may not be present.
Community 4.2
Community Phase
Sprouting shrubs such as spiny hopsage and Rabbitbrush along with broom snakeweed dominate overstory. Wyoming big sagebrush may be a minor component. Annual non-native species dominate understory. Trace amounts of desirable bunchgrasses may be present. Bare ground is significant.
Pathway 4.1a
Community 4.1 to 4.2
Time and lack of fire allows for the sagebrush to establish. Probability of sagebrush establishment is extremely low.
Pathway 4.2a
Community 4.2 to 4.1
Fire removes sagebrush and allows for annual non-native species to dominate the site.
State 5
Seeded State
This state is characterized by the dominance of seeded introduced wheatgrass species. Forage kochia and other desired seeded species including Wyoming big sagebrush and native and non-native forbs may be present. Soil nutrients and soil organic matter distribution and cycling are primarily driven by deep rooted bunchgrasses.
Community 5.1
Community Phase
Introduced wheatgrass species and other non-native species such as forage kochia dominate the community. Native and non-native seeded forbs may be present. Trace amounts of big sagebrush may be present, especially if seeded. Annual non-native species present.
Community 5.2
Community Phase
Wyoming big sagebrush and seeded wheatgrass species co-dominate. Annual non-native species stable to increasing.
Community 5.3
Community Phase (At-Risk)
This community phase is at-risk of crossing a threshold to another state. Wyoming big sagebrush dominates. Rabbitbrush may be a significant component. Wheatgrass vigor and density reduced. Annual non-native species stable to increasing.
Pathway 5.1a
Community 5.1 to 5.2
Inappropriate grazing management particularly during the growing season reduces perennial bunchgrass vigor and density and facilitates shrub establishment. Absence of shrub removal disturbances over time coupled with inappropriate grazing management facilitates shrub dominance.
Pathway 5.2a
Community 5.2 to 5.1
Low severity fire, brush management, and/or Aroga moth infestation would reduce the sagebrush overstory and allow seeded wheatgrass species to become dominant.
Pathway 5.2b
Community 5.2 to 5.3
Absence of shrub removal disturbances over time coupled with inappropriate grazing management that promotes a reduction in perennial bunchgrasses and facilitates shrub dominance.
Pathway 5.3a
Community 5.3 to 5.1
Fire eliminates/decreases the overstory of sagebrush and allows for the understory perennial grasses to increase. Fires would typically be low severity resulting in a mosaic pattern due to low fine fuel loads. A fire following an unusually wet spring or change in management favoring an increase in fine fuels, may be more severe and reduce the shrub component to trace amounts. A severe infestation of Aroga moth would also cause a large decrease in sagebrush within the community, giving a competitive advantage to the perennial grasses and forbs. Brush treatments with minimal soil disturbance would also decrease sagebrush and release the perennial understory. Annual non-native species respond well to fire and may increase post-burn.
Transition T1A
State 1 to 2
Trigger: This transition is caused by the introduction of non-native annual weeds, such as cheatgrass, mustards, bur buttercup and halogeton. Slow variables: Over time the annual non-native plants will increase within the community. Threshold: Any amount of introduced non-native species causes an immediate decrease in the resilience of the site. Annual non-native species cannot be easily removed from the system and have the potential to significantly alter disturbance regimes from their historic range of variation.
Transition T2A
State 2 to 3
Trigger: Inappropriate, long-term grazing of perennial bunchgrasses during the growing season would favor sagebrush. Slow variables: Long term decrease in deep-rooted perennial grass density. Threshold: Loss of deep-rooted perennial bunchgrasses changes spatial and temporal nutrient cycling and nutrient redistribution, and reduces soil organic matter.
Transition T2B
State 2 to 4
Trigger: To Community Phase 4.1: Severe fire and/or soil disturbing treatments. To Community Phase 4.2: Inappropriate grazing management that favors shrubs in the presence of non-native species. Slow variables: Increased production and cover of non-native annual species. Threshold: Loss of deep-rooted perennial bunchgrasses and shrubs truncates, spatially and temporally, nutrient capture and cycling within the community. Increased, continuous fine fuels from annual non-native plants modify the fire regime by changing intensity, size and spatial variability of fires.
Restoration pathway R3A
State 3 to 2
Brush management with minimal soil disturbance, coupled with seeding of deep rooted perennial native bunchgrasses. Probability of success very low.
Transition T3A
State 3 to 4
Trigger: To Community Phase 4.1: Severe fire and/or soil disturbing treatments. To Community Phase 4.2: Inappropriate grazing management in the presence of annual non-native species. Slow variables: Increased production and cover of non-native annual species. Threshold: Increased, continuous fine fuels modify the fire regime by changing intensity, size and spatial variability of fires. Changes in plant community composition and spatial variability of vegetation due to the loss of perennial bunchgrasses and sagebrush truncate energy capture spatially and temporally thus impacting nutrient cycling and distribution.
Restoration pathway R3B
State 3 to 5
Brush management with minimal soil disturbance, coupled with seeding of desired species, usually wheatgrasses (5.1 or 5.2). Restoration attempts causing soil disturbance will likely initiate a transition to an annual state. Probability of success very low.
Restoration pathway R4A
State 4 to 5
Seeding of deep-rooted introduced bunchgrasses and other desired species; may be coupled with brush management and/or herbicide. Probability of success is extremely low.
Transition T5A
State 5 to 4
Trigger: Fire Slow variables: Increased production and cover of non-native annual species Threshold: Cheatgrass or other non-native annuals dominate understory
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 | 432–664 | ||||
| bluebunch wheatgrass | PSSPS | Pseudoroegneria spicata ssp. spicata | 240–320 | – | ||
| Thurber's needlegrass | ACTH7 | Achnatherum thurberianum | 160–240 | – | ||
| bluegrass | POA | Poa | 16–64 | – | ||
| basin wildrye | LECI4 | Leymus cinereus | 16–40 | – | ||
| 2 | Secondary Perennial Grasses | 16–64 | ||||
| Indian ricegrass | ACHY | Achnatherum hymenoides | 4–24 | – | ||
| squirreltail | ELEL5 | Elymus elymoides | 4–24 | – | ||
| thickspike wheatgrass | ELLAL | Elymus lanceolatus ssp. lanceolatus | 4–24 | – | ||
| Idaho fescue | FEID | Festuca idahoensis | 4–24 | – | ||
|
Forb
|
||||||
| 3 | Perennial Forbs | 20–120 | ||||
| arrowleaf balsamroot | BASA3 | Balsamorhiza sagittata | 4–24 | – | ||
| tapertip hawksbeard | CRAC2 | Crepis acuminata | 4–24 | – | ||
| buckwheat | ERIOG | Eriogonum | 4–24 | – | ||
| lupine | LUPIN | Lupinus | 4–24 | – | ||
| phlox | PHLOX | Phlox | 4–24 | – | ||
|
Shrub/Vine
|
||||||
| 4 | Primary Perennial Shrubs | 80–160 | ||||
| basin big sagebrush | ARTRT | Artemisia tridentata ssp. tridentata | 26–54 | – | ||
| mountain big sagebrush | ARTRV | Artemisia tridentata ssp. vaseyana | 27–53 | – | ||
| Wyoming big sagebrush | ARTRW8 | Artemisia tridentata ssp. wyomingensis | 27–53 | – | ||
| 5 | Secondary Shrubs | 20–80 | ||||
| yellow rabbitbrush | CHVI8 | Chrysothamnus viscidiflorus | 8–16 | – | ||
| rubber rabbitbrush | ERNAN5 | Ericameria nauseosa ssp. nauseosa var. nauseosa | 8–16 | – | ||
| spiny hopsage | GRSP | Grayia spinosa | 8–16 | – | ||
Interpretations
Animal community
Livestock Interpretations:
This site is suitable for livestock grazing. Grazing management should be keyed to dominant grasses and palatable shrub production. Big sagebrush is eaten by domestic sheep and cattle, but has long been considered to be of low palatability to domestic livestock, a competitor with more desirable species, and a physical impediment to grazing. 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. The early growth and abundant production of basin wildrye make it a valuable source of forage for livestock. It is important forage for cattle and is readily grazed by cattle and horses in early spring and fall. Though coarse-textured during the winter, basin wildrye may be utilized more frequently by livestock and wildlife when snow has covered low shrubs and other grasses.
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:
Big sagebrush is highly preferred and nutritious winter forage for mule deer. Sage grouse are also highly dependent on big sagebrush for both food and 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. Basin wildrye provides winter forage for mule deer, though use is often low compared to other native grasses. Basin wildrye provides summer forage for black-tailed jackrabbits. Because basin wildrye remains green throughout early summer, it remains available for small mammal forage for longer time than other grasses. Sagebrush-grassland communities provide critical sage-grouse breeding and nesting habitats. Sagebrush is a crucial component of their diet year-round, and sage-grouse select sagebrush almost exclusively for cover. Sage-grouse prefer mountain big sagebrush and Wyoming big sagebrush communities to basin big sagebrush communities.
Hydrological functions
Runoff is low to medium. Permeability is slow to moderate. Hydrologic soil groups are B, C, and D. Rills are none to rare. A few rills can be expected on steeper slopes in areas subjected to summer convection storms or rapid spring snowmelt. Water flow patterns are none to rare but can be expected in areas subjected to summer convection storms or rapid snowmelt usually on steeper slopes. Pedestals are none to rare. Occurrence is usually limited to areas of water flow patterns. Frost heaving of shallow rooted plants should not be considered a "normal" condition. Gullies are none to rare. Perennial herbaceous plants (especially deep-rooted bunchgrasses [i.e., bluebunch wheatgrass] 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 has potential for upland bird and big game hunting.
Other products
Basin wildrye was used as bedding for various Native American ceremonies, providing a cool place for dancers to stand.
Other information
Basin wildrye is useful in mine reclamation, fire rehabilitation and stabilizing disturbed areas. Its usefulness in range seeding, however, may be limited by initially weak stand establishment.
Supporting information
Inventory data references
NASIS soil component data.
Type locality
| Location 1: Humboldt County, NV | |
|---|---|
| Township/Range/Section | T38N R38E S19 |
| UTM zone | N |
| UTM northing | 4556247 |
| UTM easting | 437496 |
| Latitude | 41° 9′ 18″ |
| Longitude | 117° 44′ 41″ |
| General legal description | SW¼ East side of Bloody Run Hills, about 12 miles north of Winnemucca, Humboldt County, Nevada. This site also occurs in Eureka, Lander, and Pershing Counties, Nevada. |
Other references
Anderson, E.W. and R.J. Scherzinger. 1975. Improving quality of winter forage for elk by cattle grazing. Journal of Range Management 28(2):120-125.
Blaisdell, J.P. and J.F. Pechanec. 1949. Effects of herbage removal at various dates on vigor of bluebunch wheatgrass and arrowleaf balsamroot. Ecology 30(3):298-305.
Britton, C.M., G.R. McPherson and F.A. Sneva. 1990. Effects of burning and clipping on five bunchgrasses in eastern Oregon. The Great Basin Naturalist 50(2):115-120.
Bunting, S.C., B.M. Kilgore, and C.L. Bushey. 1987. Guidelines for prescribed burning sagebrush-grass rangelands in the northern Great Basin. Gen. Tech. Rep. INT-231. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 33 p.
Chen, J. and J.M. Stark. 2002. Plant species effects and carbon and nitrogen cycling in a sagebrush-crested wheatgrass soil. Soil Biology and Biochemistry 32(1):47-57.
Conrad, C.E. and C.E. Poulton. 1966. Effect of a wildfire on Idaho fescue and bluebunch wheatgrass. Journal of Range Management 19(3):138-141.
Davies, K.W., J.D. Bates and R.F. Miller. 2007. Short-term effects of burning Wyoming big sagebrush steppe in southeast Oregon. Rangeland Ecol. Mgt 60(5): 515-522.
Ganskopp, D. 1988. Defoliation of Thurber needlegrass: herbage and root responses. Journal of Range Management 41(6):472-476.
Green, L.R., L.A. Sharp, C.W. Cook, and L.E. Harris. 1951. Utilization of winter range forage by sheep. Journal of Range Management 4:233-241.
Howard, J. L. 1999. Artemisia tridentata subsp. wyomingensis. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Johnson, Kathleen A. 2000. Artemisia tridentata subsp. vaseyana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Koniak, S. 1985. Succession in pinyon-juniper woodlands following wildfire in the Great Basin. The Great Basin Naturalist 45(3):556-566.
Laycock, W.A. 1967. How heavy grazing and protection affect sagebrush-grass ranges. Journal of Range Management 20:206-213.
Noy-Meir, I. 1973 Desert ecosystems: environment and producers. Annu. Rev. Ecol. Syst. 4: 25-52.
Quinones, F.A. 1981. Indian ricegrass evaluation and breeding. Bulletin 681. Las Cruces, NM: New Mexico State University, Agricultural Experiment Station. 19 p.
Robberecht, R. and G.E. Defosse. 1995. The relative sensitivity of two bunchgrass species to fire. International Journal of Wildland Fire 5(3):127-134.
Smith, M.A. and F. Busby. 1981. Prescribed burning: effective control of sagebrush in Wyoming. RJ-165. Laramie, WY: University of Wyoming, Agricultural Experiment Station. 12 p.
Stubbendieck, J., J.T. Nichols, and K.K. Roberts. 1985. Nebraska range and pasture grasses (including grass-like plants). E.C. 85-170. Lincoln, NE: University of Nebraska, Department of Agriculture, Cooperative Extension Service. 75 p.
Tirmenstein, D. 1999. Artemisia tridentata spp. tridentata. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
USDA-SCS. 1993. Determining success of forage production seedings. TN- Plant Materials No. 32. Reno NV.
West, N.E. 1994. Effects of fire on salt-desert shrub rangelands. In: Monsen, S.B. and S.G. Kitchen (compilers). Proceedings--ecology and management of annual rangelands; 1992 May 18-22; Boise, ID. Gen. Tech. Rep. INT-GTR-313. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: Pgs 71-74.
West, N.E. and M.A. Hassan. 1985. Recovery of sagebrush-grass vegetation following wildfire. Journal of Range Management 38(2):131-134.
Young, J.A., R.E. Eckert, Jr., R.A. Evans. 1979. Historical perspectives regarding the sagebrush ecosystem. In: The sagebrush ecosystem: a symposium: Proceedings; 1978 April; Logan, UT. Logan, UT: Utah State University, College of Natural Resources: 1-13.
Contributors
CP
TK Stringham
Approval
Kendra Moseley, 3/07/2025
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) | Patti Novak-Echenique |
|---|---|
| Contact for lead author | State Rangeland Management Specialist |
| Date | 02/02/2010 |
| Approved by | Kendra Moseley |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
Rills are none to rare. A few rills (short <1 m) 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 none to rare but can be expected in areas subjected to summer convection storms or rapid snowmelt usually on steeper slopes. These will be short (<1m), meandering and disconnected. -
Number and height of erosional pedestals or terracettes:
Pedestals are none to 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 ± 40% 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. Soil surface colors are dark and soils are typified by an ochric epipedon. Organic matter of the surface 2 to 4 inches is typically <1 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 [i.e., bluebunch wheatgrass] 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, subangular blocky, prismatic, or massive sub-surface horizons, subsoil argillic horizons or duripans 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 bunchgrassesSub-dominant:
tall shrubs (big sagebrush) > associated shrubs > shallow-rooted, cool season, perennial bunchgrasses > deep-rooted, cool season, perennial forbs > fibrous, shallow-rooted, cool season, perennial and annual forbsOther:
succulents, microbiotic crustsAdditional:
with an extended fire return interval, the shrub component will increase at the expense of the herbaceous component. -
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):
Between plant interspaces (± 15-25%) and litter depth is < ½ 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) ± 800 lbs/ac; Spring moisture significantly affects total production. Favorable years ± 1000 lbs/ac and unfavorable years ± 600 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, snakeweed, halogeton, Russian thistle, annual mustards, singleleaf pinyon, and Utah juniper. -
Perennial plant reproductive capability:
All functional groups should reproduce in average (or normal) and above average growing season years. Reduced growth and reproduction occur during extreme or extended drought periods.
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