Natural Resources
Conservation Service
Ecological site R025XY028OR
SHRUBBY SOUTH SLOPES 13-16 PZ
Last updated: 4/25/2024
Accessed: 11/13/2024
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): 025X–Owyhee High Plateau
The Owyhee High Plateau, MLRA 25, lies within the Intermontane Plateaus physiographic province. The southern half is found in the Great Basin while the northern half is located in the Columbia Plateaus. The southern section of the Owyhee High Plateau is characterized by isolated, uplifted fault-block mountain ranges separated by narrow, aggraded desert plains. This geologically older terrain has been dissected by numerous streams draining to the Humboldt River. The northern section forms the southern boundary of the extensive Columbia Plateau basalt flows. Deep, narrow canyons drain to the Snake River across the broad volcanic plain.
This MLRA is characteristically cooler and wetter than the neighboring MLRAs of the Great Basin. Elevation ranges from 3,000 to 7,550 feet on rolling plateaus and in gently sloping basins. It is more than 9,840 feet on some steep mountains. The average annual precipitation in most of this area is typically 11 to 22 inches. It increases to as much as 49 inches at the higher elevations. Precipitation occurs mainly as snow in winter. The supply of water from precipitation and streamflow is small and unreliable, except along major rivers. Streamflow depends largely on accumulated snow in the mountains.
The dominant soil orders in this MLRA are Aridisols and Mollisols. The soils in the area dominantly have a mesic or frigid temperature regime and an aridic, arid bordering on xeric, or xeric moisture regime. Most of the soils formed in mixed parent material. Volcanic ash and loess mantle the landscape. Surface soil textures are loam and silt loam, and have ashy texture modifiers in some cases. Argillic horizons occur on the more stable landforms.
Ecological site concept
This ecological site is on south facing side slopes of plateaus, tablelands, and canyonlands associated with volcanic plateau landscapes. Elevations range from 4,500 to 6,000 feet and slopes range from 12 to 70 percent. The soils associated with this site are moderately deep or deep to lithic or paralithic bedrock. The soil climate is frigid (soil temperature regime) and aridic bordering xeric (soil moisture regime). Since this site occurs on south aspects, it receives more solar insolation and thus is slightly drier and warmer than its non-aspect counterpart, resulting in reduced resistance and resilience and annual production. The reference plant community is characterized by bitterbrush and big sagebrush in the overstory with an understory dominated by bluebunch wheatgrass. Idaho fescue is also common. The warmer drier occurrences of this site exhibit greater expression of basin big sagebrush and bluebunch wheatgrass, while dominance shifts to mountain big sagebrush and prevalence of Idaho fescue increases where the site occurs in the cooler wetter portions of the range.
Associated sites
| R025XY034OR |
SHRUBBY NORTH SLOPES 13-16 PZ |
|---|---|
| R025XY065OR |
SHRUBBY LOAM 13-16 PZ |
Similar sites
| R025XY034OR |
SHRUBBY NORTH SLOPES 13-16 PZ North aspected; cooler and wetter (less solar insolation); higher production; Idaho fescue is dominant understory species. |
|---|---|
| R025XY065OR |
SHRUBBY LOAM 13-16 PZ Occurs on non-aspect sites |
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Purshia tridentata |
| Herbaceous |
(1) Pseudoroegneria spicata subsp. spicata |
Physiographic features
This site is on south-facing slopes of tablelands and canyon side slopes. Slopes range from 12 to 70%. Elevation varies from 4,500 to 6,000 feet.
Table 2. Representative physiographic features
| Landforms |
(1)
Lava plateau
> Mountain
(2) Mountains > Mountain slope |
|---|---|
| Runoff class | Very high |
| Flooding frequency | None |
| Ponding frequency | None |
| Elevation | 4,500 – 6,000 ft |
| Slope | 12 – 70% |
| Water table depth | 100 in |
| Aspect | SE, S, SW |
Climatic features
The annual precipitation ranges from 13 to 16 inches, most of which occurs in the form of snow during the months of December through March. Localized convection storms occasionally occur during the summer. The soil temperature regime is frigid. Temperature extremes range from 110 to -30 degrees F. The frost free period ranges from 90 to 120 days. The optimum growth period for native plants is from April through July.
Table 3. Representative climatic features
| Frost-free period (characteristic range) | 90-120 days |
|---|---|
| Freeze-free period (characteristic range) | 75-100 days |
| Precipitation total (characteristic range) | 13-16 in |
| Frost-free period (average) | 110 days |
| Freeze-free period (average) | 95 days |
| Precipitation total (average) | 14 in |
Figure 1. Monthly precipitation range
Figure 2. Monthly minimum temperature range
Figure 3. Monthly maximum temperature range
Figure 4. Monthly average minimum and maximum temperature
Figure 5. Annual precipitation pattern
Figure 6. Annual average temperature pattern
Climate stations used
-
(1) DANNER [USC00352135], Jordan Valley, OR
-
(2) ROCKVILLE 5 N [USC00357277], Adrian, OR
Influencing water features
Site is not influenced by water features.
Site is not connected to a water table.
Soil features
The soils of this site are typically moderately deep to deep and well drained. Typically, the surface layer is an ashy loam to silt loam. The subsoil is a clay loam to clay. Depth to fractured bedrock or paralithic contact is 20 to 60 inches. Permeability is moderate to moderately slow in the surface and slow in the subsoil. The available water holding capacity is about 2 to 5 inches for the profile.
Soil series correlated with this site is Arcia.
Table 4. Representative soil features
| Parent material |
(1)
Volcanic ash
(2) Colluvium – volcanic rock (3) Residuum – volcanic rock |
|---|---|
| Surface texture |
(1) Ashy loam (2) Ashy silt loam (3) Loam (4) Silt loam |
| Family particle size |
(1) Fine |
| Drainage class | Well drained |
| Permeability class | Moderate to slow |
| Depth to restrictive layer | 20 – 60 in |
| Soil depth | 20 – 60 in |
| Surface fragment cover <=3" | 15% |
| Surface fragment cover >3" | 5% |
| Available water capacity (0-40in) |
2 – 5 in |
| Soil reaction (1:1 water) (0-40in) |
6.5 – 7.5 |
| Subsurface fragment volume <=3" (0-40in) |
5 – 20% |
| Subsurface fragment volume >3" (0-40in) |
5 – 20% |
Ecological dynamics
The reference plant community is characterized by bitterbrush and big sagebrush in the overstory with an understory dominated by bluebunch wheatgrass. Idaho fescue is also common. The warmer drier occurrences of this site exhibit greater expression of basin big sagebrush and bluebunch wheatgrass, while dominance shifts to mountain big sagebrush and prevalence of Idaho fescue increases where the site occurs in the cooler wetter portions of the range. The site has moderately low resilience to disturbance and resistance to invasion. Resilience is a system’s capacity to regain its structure, processes, and function following stressors or disturbance (e.g. drought or fire). Resistance is the capacity of the system to retain its structure, processes, and function despite stressors or disturbances (including pressure from invasive species) (Chambers 2014). Increased resilience increases with elevation, aspect, increased precipitation, and increased nutrient availability (Stringham et al. 2015); where greater resource availability and more favorable environmental conditions exist for plant growth and reproduction (Chambers 2014).
This ecological site’s lower effective precipitation (aridic bordering xeric soil moisture regime and southern aspect) limits site productivity resulting in more open space for establishment of invasive annual grasses. Since the site occurs on south aspects, it receives more solar insolation and thus is slightly drier and warmer than its non-aspect counterpart. Timing of precipitation also favors invasive annual grasses that are particularly well adapted to cool wet winters and warm dry summers; beginning growth and utilizing resources prior to native species breaking dormancy. The site’s cooler soil temperature regime (frigid) does increase resistance compared to warmer sites but is not cold enough to inhibit invasive annual grasses (Chambers 2014).
This ecological site is dominated by deep-rooted cool season, perennial bunchgrasses and long-lived shrubs (50+ years) with high root to shoot ratios. The dominant shrubs usually root to the full depth of the winter-spring soil moisture recharge, which ranges from 1.0 to over 3.0 m (Dobrowolski et al. 1990). Root length of mature sagebrush plants was measured to a depth of 2 meters in alluvial soils in Utah (Richards and Caldwell 1987). These shrubs have a flexible generalized root system with development of both deep taproots and laterals near the surface (Comstock and Ehleringer 1992).
Periodic drought regularly influences sagebrush ecosystems and drought duration and severity has increased throughout the 20th century in much of the Intermountain West. Major shifts away from historical precipitation patterns have the greatest potential to alter ecosystem function and productivity. Species composition and productivity can be altered by the timing of precipitation and water availability with the soil profile (Bates et al. 2006).
Big sagebrush and antelope bitterbrush 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). Survival of the seedlings is dependent on adequate moisture conditions.
In the Great Basin, the majority of annual precipitation is received during winter and early spring. This continental semiarid climate regime favors growth and development of deep-rooted shrubs and herbaceous cool season plants using the C3 photosynthetic pathway (Comstock and Ehleringer 1992). Winter precipitation and slow melting of snow results in deeper percolation of moisture into the soil profile. Herbaceous plants, more shallow-rooted than shrubs, grow earlier in the growing season and thrive on spring rains, while the deeper rooted shrubs lag in phenological development because they draw from deeply infiltrating moisture from snowmelt the previous winter.
Native insect outbreaks are also important drivers of ecosystem dynamics in sagebrush communities. Climate is generally believed to influence the timing of insect outbreaks especially with regard to Aroga moth (Aroga websteri), a sagebrush defoliator. Aroga moth infestations have occurred in the Great Basin in the 1960s, early 1970s, and have been ongoing in Nevada since 2004 (Bentz, et al 2008). Thousands of acres of big sagebrush have been impacted, with partial to complete die-off observed. Aroga moth can partially or entirely kill individual plants or entire stands of big sagebrush (Furniss and Barr 1975).
The Great Basin sagebrush communities have high spatial and temporal variability in precipitation both among years and within growing seasons. Nutrient availability is typically low but increases with elevation and closely follows moisture availability. The invasibility of plant communities is often linked to resource availability. Disturbance can decrease resource uptake due to damage or mortality of the native species and depressed competition or can increase resource pools by the decomposition of dead plant material following disturbance. The invasion of sagebrush communities by cheatgrass (Bromus tectorum) has been linked to disturbances (fire, abusive grazing) that have resulted in fluctuations in resources (Chambers et al. 2007).
The introduction of annual weedy species, like cheatgrass, may cause an increase in fire frequency and eventually lead to an annual state. Conversely, as fire frequency decreases, sagebrush will increase and with inappropriate grazing management the perennial bunchgrasses and forbs may be reduced.
Fire Ecology:
Big sagebrush is killed by fire and does not resprout (Blaisdell 1953). Post fire regeneration occurs from seed and will vary depending on site characteristics, seed source, and fire characteristics. Big sagebrush reinvades a site primarily by off-site seed or seed from plants that survive in unburned patches. Approximately 90% of big sagebrush seed is dispersed within 30 feet (9 m) of the parent shrub (Goodrich et al. 1985) with maximum seed dispersal at approximately 108 feet (33 m) from the parent shrub (Shumar and Anderson 1986). Mountain big sagebrush seedlings can grow rapidly and may reach reproductive maturity within 3 to 5 years (Bunting et al. 1987), while basin big sagebrush tends to be slower to regenerate, and it is often eliminated by frequent fires (Bunting et al. 1987). Regeneration of basin big sagebrush after stand replacing fires is difficult and dependent upon proximity of residual mature plants and favorable moisture conditions (Johnson and Payne 1968, Humphrey 1984).
Antelope bitterbrush is moderately fire tolerant (McConnell and Smith 1977). It regenerates by seed and resprouting (Blaisdell and Mueggler 1956, McArthur et al. 1982), however sprouting ability is highly variable and has been attributed to genetics, plant age, phenology, soil moisture and texture and fire severity (Blaisdell and Mueggler 1956, Blaisdell et al. 1982, Clark et al. 1982, Cook et al. 1994). Bitterbrush sprouts from a region on the stem approximately 1.5 inches above and below the soil surface; the plant rarely sprouts if the root crown is killed by fire (Blaisdell and Mueggler 1956). Low intensity fires may allow for bitterbrush to sprout; however, community response also depends on soil moisture levels at time of fire (Murray 1983). Lower soil moisture allows more charring of the stem below ground level (Blaisdell and Mueggler 1956), thus sprouting will usually be more successful after a spring fire than after a fire in summer or fall (Murray 1983, Busse et al. 2000, Kerns et al. 2006). If cheatgrass is present, bitterbrush seedling success is much lower. The factor that most limits establishment of bitterbrush seedlings is competition for water resources with the invasive species cheatgrass (Clements and Young 2002).
The effect of fire on bunchgrasses relates to culm density, culm-leaf morphology, and the size of the plant. The initial condition of bunchgrasses within the site along with seasonality and intensity of the fire all factor into the individual species response. For most forbs and grasses the growing points are located at or below the soil surface providing relative protection from disturbances which decrease above ground biomass, such as grazing or fire. Thus, fire mortality is more correlated to duration and intensity of heat which is related to culm density, culm-leaf morphology, size of plant and abundance of old growth (Wright 1971, Young 1983).
Fire will remove aboveground biomass from bluebunch wheatgrass but plant mortality is generally low (Robberecht and Defossé 1995) because the buds are underground (Conrad and Poulton 1966) or protected by foliage. Uresk et al. (1976) reported burning increased vegetative and reproductive vigor of bluebunch wheatgrass. Thus, bluebunch wheatgrass is considered to experience slight damage to fire but is more susceptible in drought years (Young 1983). Plant response will vary depending on season, fire severity, fire intensity and post-fire soil moisture availability.
Sandberg bluegrass, a minor component of this ecological site, has been found to increase following fire likely due to its low stature and productivity (Daubenmire 1975). Sandberg bluegrass may retard reestablishment of deeper rooted bunchgrass. Reduced bunchgrass vigor or density provides an opportunity for Sandberg bluegrass expansion and/or cheatgrass and other invasive species to occupy interspaces, leading to increased fire frequency and potentially an annual plant community.
Adapted from: Stringham, T.K., P. Novak-Echenique, P. Blackburn, D. Snyder, and A. Wartgow. 2015. Final Report for USDA Ecological Site Description State-and-Transition Models by Disturbance Response Groups, Major Land Resource Area 25 Nevada. University of Nevada Reno, Nevada Agricultural Experiment Station Research Report 2015-02. p. 569
State and transition model
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State 1 submodel, plant communities
State 2 submodel, plant communities
State 3 submodel, plant communities
State 4 submodel, plant communities
State 1
Reference State 1.0
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.
Dominant plant species
-
antelope bitterbrush (Purshia tridentata), shrub
-
big sagebrush (Artemisia tridentata), shrub
-
bluebunch wheatgrass (Pseudoroegneria spicata ssp. spicata), grass
Community 1.1
Reference Community 1.1
Bitterbrush, big sagebrush, and bluebunch wheatgrass dominate the site. Other perennial grasses, and perennial forbs are also common on this site.
Dominant plant species
-
antelope bitterbrush (Purshia tridentata), shrub
-
mountain big sagebrush (Artemisia tridentata ssp. vaseyana), shrub
-
basin big sagebrush (Artemisia tridentata ssp. tridentata), shrub
-
Idaho fescue (Festuca idahoensis), grass
-
bluebunch wheatgrass (Pseudoroegneria spicata ssp. spicata), grass
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 | 755 | 880 | 1010 |
| Shrub/Vine | 340 | 395 | 450 |
| Forb | 105 | 125 | 140 |
| Total | 1200 | 1400 | 1600 |
Community 1.2
Reference Community 1.2
This community phase is characteristic of a post-disturbance, early to mid-seral community phase. Bluebunch wheatgrass, Idaho fescue, and other perennial grasses dominate. Rabbitbrush, snowberry and other sprouting shrubs may be resprouting. Big sagebrush is killed by fire, therefore decreasing within the burned community. Depending on fire severity or intensity of Aroga moth infestations, patches of intact bitterbrush and sagebrush may remain. Perennial forbs may increase post-fire but will likely return to pre-burn levels within a few years.
Community 1.3
Reference Community 1.3
Bitterbrush and big sagebrush increase in the absence of disturbance. Decadent shrubs dominate the overstory and the deep-rooted perennial bunchgrasses in the understory are reduced either from competition with shrubs or from herbivory. Sandberg bluegrass will likely increase in the understory and may be the dominant grass on the site.
Pathway P1.1a
Community 1.1 to 1.2
Fire decreases or eliminates the overstory of bitterbrush and sagebrush and allows 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 shrub 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 P1.1b
Community 1.1 to 1.3
Long-term drought, time and/or herbivory favor an increase in shrubs over deep-rooted perennial bunchgrasses. Combinations of these would allow the shrub overstory to increase and dominate the site, causing a reduction in the perennial bunchgrasses. Sandberg bluegrass may increase in density depending on the grazing management.
Pathway P1.2a
Community 1.2 to 1.1
Time and lack of disturbance allows for bitterbrush and sagebrush to reestablish.
Pathway P1.3a
Community 1.3 to 1.1
A low severity fire, Aroga moth or combinations will reduce the shrub overstory and create a shrub/grass mosaic with bitterbrush/sagebrush and perennial bunchgrasses codominant.
Pathway P1.3b
Community 1.3 to 1.2
Fire decreases or eliminates the overstory of bitterbrush and sagebrush and allows 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 shrub 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 2.0
This state is similar to the Reference State 1.0. Ecological function has not changed, however the resiliency of the state has been reduced by the presence of invasive weeds. This state has the same three general community phases. 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. 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. Additionally, the presence of highly flammable, non-native species reduces State resilience because these species can promote fire where historically fire has been infrequent leading to positive feedbacks that further the degradation of the system.
Community 2.1
Community 2.1
Bitterbrush, big sagebrush, and Bluebunch wheatgrass dominate the site. Idaho fescue and other perennial grasses, and perennial forbs are also common on this site. Non-native annual species are present in minor amounts.
Community 2.2
Community 2.2
This community phase is characteristic of a post-disturbance, early to mid-seral community phase. Bluebunch wheatgrass, Idaho fescue, and other perennial grasses dominate. Rabbitbrush, snowberry and other sprouting shrubs may be resprouting. Big sagebrush is killed by fire, therefore decreasing within the burned community. Depending on fire severity or intensity of Aroga moth infestations, patches of intact bitterbrush and sagebrush may remain. Perennial 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 2.3 (at risk)
Bitterbrush and big sagebrush increase in the absence of disturbance. Decadent shrubs dominate the overstory and the deep-rooted perennial bunchgrasses in the understory are reduced either from competition with shrubs or from herbivory. Sandberg bluegrass will likely increase in the understory and may be the dominant grass on the site. Annual non-native species present.
Pathway P2.1a
Community 2.1 to 2.2
Fire decreases or eliminates the overstory of bitterbrush and sagebrush and allows 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 shrub 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 P2.1b
Community 2.1 to 2.3
Time, long-term drought, grazing management that favors shrubs or combinations of these would allow the sagebrush overstory to increase and dominate the site, causing a reduction in the perennial bunchgrasses. However, Sandberg bluegrass and/or squirreltail may increase in the understory depending on the grazing management. Heavy spring grazing will favor an increase in shrubs. Annual non-native species may be stable or increasing within the understory.
Pathway P2.2a
Community 2.2 to 2.1
Absence of disturbance over time allows for the bitterbrush and sagebrush to recover, or grazing management that favors shrubs.
Pathway P2.3a
Community 2.3 to 2.1
Low severity fire or Aroga moth infestation creates shrub/grass mosaic.
Pathway P2.3b
Community 2.3 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.
State 3
Shrub State 3.0
This state has two community phases; a bitterbrush/big sagebrush dominated phase and a sprouting shrub dominated phase. This state is a product of many years of heavy grazing during time periods harmful to perennial bunchgrasses. Sandberg bluegrass will increase with a reduction in deep rooted perennial bunchgrass competition and become the dominant grass. Bitterbrush/sagebrush dominates the overstory and rabbitbrush may be a significant component. Bitterbrush/sagebrush canopy cover is high and shrubs may be decadent, reflecting stand maturity and lack of seedling establishment due to competition with mature plants. The shrub overstory and Sandberg bluegrass understory dominate site resources such that soil water, nutrient capture, nutrient cycling and soil organic matter are temporally and spatially redistributed.
Community 3.1
Community 3.1
This site has crossed a biotic threshold and site processes (soil hydrology, nutrient cycling, and energy capture) are being controlled by the shrub component of the plant community along with Sandberg bluegrass in the understory. Decadent bitterbrush and sagebrush, or rabbitbrush dominate the overstory. Deep-rooted perennial bunchgrasses may be present in trace amounts or absent from the community. Sandberg bluegrass and annual non-native species increase, and the amount of bare ground increases.
Community 3.2
Community 3.2
Sandberg bluegrass dominates the understory; annual non-natives are present but are not dominant. Trace amounts of bitterbrush/sagebrush may be present. Sprouting shrubs may dominate for a number of years following fire.
Pathway P3.1a
Community 3.1 to 3.2
Fire decreases or eliminates the overstory of bitterbrush/sagebrush. A severe infestation of Aroga moth could also cause a large decrease in sagebrush within the community, giving a competitive advantage to the Sandberg bluegrass, forbs and sprouting shrubs. Heavy fall grazing causing mechanical damage to shrubs, and/or brush treatments with minimal soil disturbance, would greatly reduce the overstory shrubs and allow for Sandberg bluegrass to dominate the site.
Pathway P3.2a
Community 3.2 to 3.1
Absence of disturbance over time would allow for bitterbrush/sagebrush and other shrubs to recover.
State 4
Annual State 4.0
This state has two community phases; one dominated by annual non-native species and the other is a shrub dominated site. This state is characterized by the dominance of annual non-native species such as cheatgrass and tansy mustard in the understory. Bitterbrush/sagebrush and/or rabbitbrush may dominate the overstory. Annual non-native species and squirreltail dominate the understory.
Community 4.1
Community 4.1
Annual non-native plants such as cheatgrass or tansy mustard dominate the site.
Community 4.2
Community 4.2
Bitterbrush, big sagebrush and/or sprouting shrubs remain in the overstory with annual non-native species, likely cheatgrass, dominating the understory. Trace amounts of desirable bunchgrasses may be present.
Pathway P4.1a
Community 4.1 to 4.2
Time and lack of disturbance allows for shrubs to reestablish. Sprouting shrubs such as rabbitbrush will be the first to reappear after fire. Probability of bitterbrush/sagebrush establishment is extremely low.
Pathway P4.2a
Community 4.2 to 4.1
Fire allows for annual non-native species to dominate site.
Transition T1A
State 1 to 2
Trigger: This transition is caused by the introduction of non-native species. Slow variables: Over time the annual non-native plants will increase within the community decreasing organic matter inputs from deep-rooted perennial bunchgrasses resulting in reductions in soil water availability for perennial bunchgrasses. 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 growing season would favor shrubs and initiate transition to Community Phase 3.1. Severe fire would cause a transition to Community Phase 3.2. Slow variables: Long term decrease in deep-rooted perennial grass density resulting in a decrease in organic matter inputs and subsequent soil water decline. 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: Multiple fires lead to plant community phase 4.1. Inappropriate grazing management that favors shrubs in the presence of non-native annual species leads to community phase 4.2. Slow variables: Increased production and cover of non-native annual species. Threshold: Loss of deep-rooted perennial bunchgrasses and shrubs changes nutrient capture and cycling within the community. Increased, continuous fine fuels modify the fire regime by changing intensity, size and spatial variability of fires.
Restoration pathway R3A
State 3 to 2
Brush management, herbicide or sub-soiling of Sandberg bluegrass and seeding of desired perennial bunchgrass.
Transition T3A
State 3 to 4
Trigger: Severe fire will transition to 4.1. Inappropriate grazing management in the presence of annual non-native species will transition to 4.2. Slow variable: Increased seed production and cover of annual non-native 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 and impact the nutrient cycling and distribution.
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 | Dominant deep rooted perennial grasses | 490–630 | ||||
| bluebunch wheatgrass | PSSPS | Pseudoroegneria spicata ssp. spicata | 490–630 | – | ||
| 2 | Subdominant deep rooted perennial grasses | 140–350 | ||||
| Idaho fescue | FEID | Festuca idahoensis | 140–350 | – | ||
| 3 | Sub-dominant shallow rooted perennial grasses | 28–70 | ||||
| Sandberg bluegrass | POSE | Poa secunda | 28–70 | – | ||
| 4 | Other perennial grasses | 0–112 | ||||
| basin wildrye | LECI4 | Leymus cinereus | 0–28 | – | ||
| Cusick's bluegrass | POCU3 | Poa cusickii | 0–28 | – | ||
| Thurber's needlegrass | ACTH7 | Achnatherum thurberianum | 0–28 | – | ||
| squirreltail | ELEL5 | Elymus elymoides | 0–28 | – | ||
|
Forb
|
||||||
| 5 | Dominant, perennial forbs | 56–126 | ||||
| arrowleaf balsamroot | BASA3 | Balsamorhiza sagittata | 14–42 | – | ||
| tapertip hawksbeard | CRAC2 | Crepis acuminata | 14–28 | – | ||
| lupine | LUPIN | Lupinus | 14–28 | – | ||
| milkvetch | ASTRA | Astragalus | 14–28 | – | ||
| 6 | Other perennial forbs | 0–70 | ||||
| buckwheat | ERIOG | Eriogonum | 0–14 | – | ||
| desertparsley | LOMAT | Lomatium | 0–14 | – | ||
| phlox | PHLOX | Phlox | 0–14 | – | ||
| fleabane | ERIGE2 | Erigeron | 0–14 | – | ||
| common yarrow | ACMI2 | Achillea millefolium | 0–14 | – | ||
| agoseris | AGOSE | Agoseris | 0–14 | – | ||
| stoneseed | LITHO3 | Lithospermum | 0–14 | – | ||
| phacelia | PHACE | Phacelia | 0–14 | – | ||
| deathcamas | ZIGAD | Zigadenus | 0–14 | – | ||
| onion | ALLIU | Allium | 0–14 | – | ||
| pussytoes | ANTEN | Antennaria | 0–14 | – | ||
|
Shrub/Vine
|
||||||
| 7 | Dominant, perennial shrubs | 140–280 | ||||
| antelope bitterbrush | PUTR2 | Purshia tridentata | 140–280 | – | ||
| 8 | Sub-dominant, perennial shrubs | 98–210 | ||||
| mountain big sagebrush | ARTRV | Artemisia tridentata ssp. vaseyana | 70–140 | – | ||
| basin big sagebrush | ARTRT | Artemisia tridentata ssp. tridentata | 28–70 | – | ||
| 9 | All other perennial shrubs | 0–84 | ||||
| Saskatoon serviceberry | AMAL2 | Amelanchier alnifolia | 0–28 | – | ||
| bitter cherry | PREM | Prunus emarginata | 0–28 | – | ||
| wax currant | RICE | Ribes cereum | 0–28 | – | ||
| mountain snowberry | SYOR2 | Symphoricarpos oreophilus | 0–28 | – | ||
| yellow rabbitbrush | CHVI8 | Chrysothamnus viscidiflorus | 0–28 | – | ||
| rubber rabbitbrush | ERNA10 | Ericameria nauseosa | 0–28 | – | ||
Interpretations
Animal community
This site is suitable for grazing. Grazing management considerations include timing, duration and intensity of grazing.
Overgrazing leads to an increase in sagebrush, a decline in antelope bitterbrush, and a decline in understory plants like Idaho fescue and bluebunch wheatgrass. Squirreltail or Sandberg bluegrass will increase temporarily with further degradation. Invasion of annual weedy forbs and cheatgrass could occur with further grazing degradation, leading to a decline in squirreltail and bluegrasses and an increase in bare ground. A combination of overgrazing and prolonged drought leads to soil erosion, increased bare ground and a loss in plant production.
Antelope bitterbrush is an important shrub species to a variety of animals, such as domestic livestock, antelope, deer, and elk. Bitterbrush is critical browse for mule deer, as well as domestic livestock, antelope, and elk (Wood 1995). Antelope bitterbrush is most commonly found on soils which provide minimal restriction to deep root penetration such as coarse textured soil, or finer textured soil with high stone content (Driscoll 1964, Clements and Young 2002). Grazing tolerance of antelope bitterbrush is dependent on site conditions (Garrison 1953).
Idaho fescue is valuable forage for livestock and wildlife. However, Idaho fescue decreases under heavy grazing by livestock (Eckert and Spencer 1986, Eckert and Spencer 1987) and wildlife (Gaffney 1941).
Bluebunch wheatgrass is moderately grazing tolerant and is very sensitive to defoliation during the active growth period (Blaisdell and Pechanec 1949, Laycock 1967, Anderson and Scherzinger 1975). Herbage and flower stalk production was reduced with clipping at all times during the growing season; however, clipping was most harmful during the boot stage (Blaisdell and Pechanec 1949, Britton et al. 1990) Tiller production and growth of bluebunch was greatly reduced when clipping was coupled with drought (Busso and Richards 1995). Mueggler (1975) estimated that low vigor bluebunch wheatgrass may need up to 8 years rest to recover. Although an important forage species, it is not always the preferred species by livestock and wildlife.
Reduced bunchgrass vigor or density provides an opportunity for Sandberg bluegrass expansion and/or cheatgrass and other invasive species such as halogeton (Halogeton glomeratus), bur buttercup (Ceratocephala testiculata) and annual mustards to occupy interspaces. Sandberg bluegrass increases under grazing pressure (Tisdale and Hironaka 1981) and is capable of co-existing with cheatgrass. Excessive sheep grazing favors Sandberg bluegrass; however, where cattle are the dominant grazers, cheatgrass often dominates (Daubenmire 1970). Thus, depending on the season of use, the grazer and site conditions, either Sandberg bluegrass or cheatgrass may become the dominant understory with inappropriate grazing management.
Supporting information
Inventory data references
Vale District BLM Ecological Site Inventory
NASIS component and pedon data
Range Site Descriptions
Field knowledge of range-trained personnel
Other references
Anderson, E. W. and R. J. Scherzinger. 1975. Improving quality of winter forage for elk by cattle grazing. Journal of Range Management 28:120-125.
Barrington, M., S. Bunting, and G. Wright. 1988. A fire management plan for Craters of the Moon National Monument. Cooperative Agreement CA-9000-8-0005. Moscow, ID: University of Idaho, Range Resources Department. 52 p. Draft.
Bates, J. D., T. Svejcar, R. F. Miller, and R. A. Angell. 2006. The effects of precipitation timing on sagebrush steppe vegetation. Journal of Arid Environments 64:670-697.
Bentz, B., D. Alston, and T. Evans. 2008. Great Basin Insect Outbreaks. In: J. Chambers, N. Devoe, A. Evenden [eds]. Collaborative Management and Research in the Great Basin -- Examining the issues and developing a framework for action Gen. Tech. Rep. RMRS-GTR-204. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fort Collins, CO. p. 45-48
Blaisdell, J. P. and J. F. Pechanec. 1949. Effects of Herbage Removal at Various Dates on Vigor of Bluebunch Wheatgrass and Arrowleaf Balsamroot. Ecology 30:298-305.
Blaisdell, J. P. 1953. Ecological effects of planned burning of sagebrush-grass range on the upper Snake River Plains. US Dept. of Agriculture.
Blaisdell, J. P. and W. F. Mueggler. 1956. Sprouting of bitterbrush (Purshia tridentata) following burning or top removal. Ecology 37:365-370.
Blaisdell, J. P., R. B. Murray, and E. D. McArthur. 1982. Managing intermountain rangelands-sagebrush grass ranges. USDA Forest Serv. Intermountain Forest and Range Exp. Sta. Gen. Tech. Rep. INT-134.
Britton, C. M., G. R. McPherson, and F. A. Sneva. 1990. Effects of burning and clipping on five bunchgrasses in eastern Oregon. Great Basin Naturalist 50:115-120.
Bunting, S. C., B. M. Kilgore, and C. L. Bushey. 1987. Guidelines for prescribed burning sagebrush-grass rangelands in the northern Great Basin. US Department of Agriculture, Forest Service, Intermountain Research Station Ogden, UT, USA.
Burkhardt, J. W. and E. Tisdale. 1969. Nature and successional status of western juniper vegetation in Idaho. Journal of Range Management:264-270.
Busse, D., A. Simon, and M. Riegel. 2000. Tree-growth and understory responses to low-severity prescribed burning in thinned Pinus ponderosa forests of central Oregon. Forest Science 46:258- 268.
Busso, C. A. and J. H. Richards. 1995. Drought and clipping effects on tiller demography andgrowth of two tussock grasses in Utah. Journal of Arid Environments 29:239-251.
Chambers, J. C., B. A. Roundy, R. R. Blank, S. E. Meyer, and A. Whittaker. 2007. What makes great basin sagebrush ecosystems invasible by Bromus tectorum? Ecological Monographs 77:117-145.
Chambers, Jeanne C.; Pyke, David A.; Maestas, Jeremy D.; Pellant, Mike; Boyd, Chad S.; Campbell, Steven B.; Espinosa, Shawn; Havlina, Douglas W.; Mayer, Kenneth E.; Wuenschel, Amarina. 2014. Using resistance and resilience concepts to reduce impacts of invasive annual grasses and altered fire regimes on the sagebrush ecosystem and greater sage-grouse: A strategic multi-scale approach. Gen. Tech. Rep. RMRS-GTR-326. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 73 p.
Clark, R. G., M. B. Carlton, and F. A. Sneva. 1982. Mortality of bitterbrush after burning and clipping in eastern Oregon. Journal of Range Management 35:711-714.
Clements, C. D. and J. A. Young. 2002. Restoring antelope bitterbrush. Rangelands 24:3-6.
Comstock, J. P. and J. R. Ehleringer. 1992. Plant adaptation in the Great Basin and Colorado plateau. Western North American Naturalist 52:195-215.
Conrad, C. E. and C. E. Poulton. 1966. Effect of a wildfire on Idaho fescue and bluebunch wheatgrass. Journal of Range Management:138-141.
Cook, J. G., T. J. Hershey, and L. L. Irwin. 1994. Vegetative response to burning on Wyoming mountain shrub big game ranges.. Journal of Range Management 47:296-302.
Daubenmire, R. 1970. Steppe vegetation of Washington.131 pp.
Daubenmire, R. 1975. Plant succession on abandoned fields, and fire influences in a steppe area in southeastern Washington. Northwest Science 49:36-48.
Dobrowolski, J. P., M. M. Caldwell, and J. H. Richards. 1990. Basin hydrology and plant root systems. In: C. B. Osmand, L. F. Pitelka, G. M. Hildy [eds]. Plant biology of the Basin and range. Ecological Studies. 80: 243-292
Driscoll, R. S. 1964. A Relict Area in the Central Oregon Juniper Zone. Ecology 45:345-353.
Eckert Jr, R. E. and J. S. Spencer. 1986. Vegetation response on allotments grazed under rest-rotation management. Journal of Range Management:166-174.
Eckert, R. E., Jr. and J. S. Spencer. 1987. Growth and reproduction of grasses heavily grazed under restoration management. Journal of Range Management 40:156-159.
Furniss, M. M. and W. F. Barr. 1975. Insects affecting important native shrubs of the northwestern United States General Technical Report INT-19. Intermountain Forest and Range Experiment Station, U.S. Department of Agriculture, Forest Service. Ogden, UT. p. 68
Gaffney, W. S. 1941. The effects of winter elk browsing, South Fork of the Flathead River, Montana. The Journal of Wildlife Management 5:427-453.
Garrison, G. A. 1953. Effects of Clipping on Some Range Shrubs. Journal of Range Management 6:309-317.
Houston, D. B. 1973. Wildfires in northern Yellowstone National Park. Ecology 54:1111-1117.
Johnson, C. G., R. R. Clausnitzer, P. J. Mehringer, and C. Oilver. 1994. Biotic and abiotic processes of eastside ecosystems: The effects of management on plant and community ecology, and on stand and landscape vegetation dynamics. Forest Service general technical report. Forest Service, Portland, OR (United States). Pacific Northwest Research Station.
Kerns, B. K., W. G. Thies, and C. G. Niwa. 2006. Season and severity of prescribed burn in ponderosa pine forests: implications for understory native and exotic plants. Ecoscience 13:44-55.
Laycock, W. A. 1967. How heavy grazing and protection affect sagebrush-grass ranges. Journal of Range Management:206-213.
McArthur, E. D., A. Blaner, A. P. Plummer, and R. Stevens. 1982. Characteristics and hybridization of important Intermountain shrubs: 3. Sunflower family. U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. Research Paper INT-177 43.
McConnell, B. R. and J. G. Smith. 1977. Influence of grazing on age-yield interactions in bitterbrush. Journal of Range Management 30:91-93.
Miller, R. F. R. J. T. 2000. The role of fire in juniper and pinyon woodlands: a descriptive analysis. Pages p. 15-30 in Proceedings of the invasive species workshop: the role of fire in the control and spread of invasive species., Tallahassee, Florida.
Miller, R. F. and E. K. Heyerdahl. 2008. Fine-scale variation of historical fire regimes in sagebrush-steppe and juniper woodland: an example from California, USA. International Journal of Wildland Fire 17:245-254.
Mueggler, W. F. 1975. Rate and Pattern of Vigor Recovery in Idaho Fescue and Bluebunch Wheatgrass. Journal of Range Management 28:198-204.
Murray, R. 1983. Response of antelope bitterbrush to burning and spraying in southeastern Idaho. Tiedemann, Arthur R.; Johnson, Kendall L., compilers. Research and management of bitterbrush and cliffrose in western North America. General Technical Report INT-152. Ogden, UT: US Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station:142-152.
Neuenschwander, L. 1980. Broadcast burning of sagebrush in the winter. Journal of Range Management:233-236.
Noy-Meir, I. 1973. Desert Ecosystems: Environment and Producers. Annual Review of Ecology and Systematics. Vol. 4:25-51.
Richards, J. H. and M. M. Caldwell. 1987. Hydraulic lift: Substantial nocturnal water transport between soil layers by Artemisia tridentata roots. Oecologia 73:486-489.
Robberecht, R. and G. Defossé. 1995. The relative sensitivity of two bunchgrass species to fire. International Journal of Wildland Fire 5:127-134.
Stringham, T.K., P. Novak-Echenique, P. Blackburn, D. Snyder, and A. Wartgow. 2015. Final Report for USDA Ecological Site Description State-and-Transition Models by Disturbance Response Groups, Major Land Resource Area 25 Nevada. University of Nevada Reno, Nevada Agricultural Experiment Station Research Report 2015-02. p. 569
Tisdale, E. W. and M. Hironaka. 1981. The sagebrush-grass region: A review of the ecological literature. University of Idaho, Forest, Wildlife and Range Experiment Station.
Uresk, D. W., J. F. Cline, and W. H. Rickard. 1976. Impact of wildfire on three perennial grasses in southcentral Washington. Journal of Range Management 29:309-310.
Wood, M. K., Bruce A. Buchanan, & William Skeet. 1995. Shrub preference and utilization by big game on New Mexico reclaimed mine land. Journal of Range Management 48:431-437.
Wright, H. A. 1971. Why Squirreltail Is More Tolerant to Burning than Needle-and-Thread. Journal of Range Management 24:277-284.
Wright, H.A., L.F. Neuenschwander, and C.M. Britton. 1979. The role and use of fire in sagebrush-grass and pinyon-juniper plant communities: A state-of-the-art review. Gen. Tech. Rep. INT-58. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 48 p.
Young, R. P. 1983. Fire as a vegetation management tool in rangelands of the intermountain region. Pages 18-31 in Managing intermountain rangelands - improvement of range and wildlife habitats. USDA, Forest Service.
Ziegenhagen, L. L. 2003. Shrub reestablishment following fire in the mountain big sagebrush (Artemisia tridentata Nutt. ssp. vaseyana (Rydb.) Beetle) alliance. M.S. Oregon State University.
Ziegenhagen, L. L. and R. F. Miller. 2009. Postfire recovery of two shrubs in the interiors of large burns in the Intermountain West, USA. Western North American Naturalist 69:195-205.
Contributors
C.D. Tackman, R.B. Williams & C.L. Landing
Jennifer Moffitt
Approval
Kendra Moseley, 4/25/2024
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) | |
|---|---|
| Contact for lead author | |
| Date | 04/26/2024 |
| Approved by | Kendra Moseley |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
-
Presence of water flow patterns:
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Number and height of erosional pedestals or terracettes:
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Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
-
Number of gullies and erosion associated with gullies:
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Extent of wind scoured, blowouts and/or depositional areas:
-
Amount of litter movement (describe size and distance expected to travel):
-
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
-
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
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Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
-
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
-
Functional/Structural Groups (list in order of descending dominance by above-ground annual-production or live foliar cover using symbols: >>, >, = to indicate much greater than, greater than, and equal to):
Dominant:
Sub-dominant:
Other:
Additional:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
-
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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Potential invasive (including noxious) species (native and non-native). List species which BOTH characterize degraded states and have the potential to become a dominant or co-dominant species on the ecological site if their future establishment and growth is not actively controlled by management interventions. Species that become dominant for only one to several years (e.g., short-term response to drought or wildfire) are not invasive plants. Note that unlike other indicators, we are describing what is NOT expected in the reference state for the ecological site:
-
Perennial plant reproductive capability:
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