Land use 1
Rangeland

Rangeland is the dominant land use for this site and provides the most diverse ecosystem services. Range is land on which the historic and/or introduced vegetation is predominantly grasses, grass-like plants, forbs or shrubs managed as a natural ecosystem. Range may include natural grasslands, savannas, shrublands, tundra, alpine communities, marshes and meadows.

Characteristics and indicators. This landuse consists of diverse native plant communities dominated by basin big sagebrush and perennial cool season grasses that provide for site stability, hydrologic function, and biotic integrity of the site.

State 1.1
Reference State

Figure 7. Overview of drainageway landform

The Reference State consists of three plant communities, the Basin Big Sagebrush/Bunchgrass community, the Bunchgrass/Basin Big Sagebrush community, and the Bunchgrass community. Each plant community differs in percent composition and foliar cover of bunchgrasses and shrubs. The dominant shrub is basin big sagebrush. Dominant bunchgrasses include basin wildrye and slender wheatgrass, Forbs are a minor component. Two important processes occur in the reference state and result in plant community changes: 1) sagebrush-killing disturbances such as fire, herbivory, drought, and flood; and 2) time without those disturbances, generally referred to as "natural succession."

Characteristics and indicators. The shift between plant community phases is dependent upon sagebrush-killing disturbances, and without them it will increase even with proper grazing management that includes light to moderate utilization, adequate recovery, and periodic critical growth period rest. Improper grazing management that includes high utilization, inadequate recovery, and continuous season-long grazing may accelerate the rate of increase for the shrub component. Management actions can and are often used to mimic the natural disturbance regime through mechanical and chemical treatments. Prescribed fire is not often used due to land use and ownership patterns, lack of fine fuels, and adequate burn windows (Clause and Randall, 2014).

Resilience management. This site has moderate resilience due to its ustic bordering on aridic soil moisture regime and frigid bordering on cryic temperature regime (Chambers et.al. 2014). Precipitation is typically adequate with good timing and more effective with cooler temperatures. This site typically recovers after minor disturbances, but is susceptible to delays in recovery during extreme climatic events such as drought. This site has moderately high resistance to invasion by annual grasses because of cold climatic conditions.

Community 1.1.1
Basin Big Sagebrush/Bunchgrass

This community is well adapted to Cool Central Desertic Basins and Plateaus climatic conditions. The diversity in plant species allows for drought tolerance, and natural plant mortality is moderate to low. These plants have strong, healthy root systems that allow production to increase significantly with favorable moisture conditions. Abundant plant litter is available for soil building and moisture retention. Plant litter is properly distributed with very little movement off-site. This plant community provides for soil stability and a properly functioning hydrologic cycle. The soils associated with this site are fertile and hold moderately large amounts of soil moisture, providing a very favorable soil-water-plant relationship. The Basin Big Sagebrush/Bunchgrass Community can occur across the entire ecological site or can occur in a mosaic with the Bunchgrass/Basin Big Sagebrush Community. This plant community occurs in the absence of sagebrush killing disturbances and with grazing that mimics the historic herbivory regime (light, episodic, and associate with mid-size ungulate migration). Basin big sagebrush is dominant. Sagebrush canopy cover ranges from 20 to 30 percent. At this sagebrush canopy level in this precipitation zone, there is some competition between the shrub over-story and the herbaceous understory (Winward, 2007). A Basin Big Sagebrush/Bunchgrass Community with a degraded under-story is an “at-risk” community that could transition to the Grazing Resistant State. Chemical or mechanical treatments are occasionally used to replace natural sagebrush killing events. However, chemical treatments impact non-target species, particularly broad-leafed species (forbs and shrubs) differently than natural events such as drought or fire. Where fire tends to result in a short-term increase in forbs, some chemical treatments result in a short-term (or long-term) reduction in forb density and diversity. Mechanical treatments do not cause a change in plant diversity, however soil disturbance combined with improper grazing techniques has the potential to transition this plant community to either the Disturbed or Eroded States, depending on the severity of disturbance. There are generally few canopy gaps and most basal gaps are small (one to two feet). Rock cover on the soil surface is essentially nonexistent. Many plant interspaces have canopy or litter cover. Production of grasses is much lower than in the Bunchgrass Community and lower than in the Bunchgrass/Basin Big Sagebrush Community.

Community 1.1.2
Bunchgrass/Basin Big Sagebrush

This plant community is well adapted to Cool Central Desertic Basins and Plateaus climatic conditions. The diversity in plant species allows for drought tolerance, and natural plant mortality is very low. Perennial plants that dominate this site have strong, healthy root systems that allow production to increase significantly with favorable moisture conditions. Abundant plant litter is available for soil building and moisture retention. Plant litter is properly distributed with very little movement off-site. This plant community provides for soil stability and a properly functioning hydrologic cycle. The Bunchgrass/Big Sagebrush Community can occur across the entire ecological site or can occur in a mosaic associated with the disturbance cycle at any given time and location with the Big Sagebrush/Bunchgrass Community. This plant community occurs after a recent sagebrush killing disturbances and with grazing that mimics the historic herbivory regime (light, episodic, and associate with mid-size ungulate migration). Tall and mid-stature bunchgrasses dominate and basin big sagebrush is sub-dominant with foliar cover ranging from 10 to 20 percent. At this sagebrush canopy level in this precipitation zone, there is little if any competition between the shrub overstory and the herbaceous understory. In fact, there is evidence to suggest that the understory receives more benefit from the sage overstory than negative effects (Winward, 2007). There are few canopy gaps and basal gaps are generally small (one to two feet). Surface rock fragments in general do not occur and are not a significant source of site stability. Many plant interspaces have canopy or litter cover, which provides site stability. Production of grasses is higher than in the Basin Big Sagebrush/Bunchgrass community, but lower than in the Bunchgrass community.

Community 1.1.3
Bunchgrass

This plant community is well adapted to Cool Central Desertic Basins and Plateaus climatic conditions. The diversity in plant species allows for drought tolerance, and natural plant mortality is very low. Perennial plants that dominate this site have strong, healthy root systems that allow production to increase significantly with favorable moisture conditions. Abundant plant litter is available for soil building and moisture retention. Plant litter is properly distributed with very little movement off-site. This plant community provides for soil stability and a properly functioning hydrologic cycle. The Bunchgrass/Big Sagebrush Community can occur across the entire ecological site or can occur in a mosaic associated with the disturbance cycle at any given time and location with the Big Sagebrush/Bunchgrass Community. This plant community occurs after a recent sagebrush killing disturbances and with grazing that mimics the historic herbivory regime (light, episodic, and associate with mid-size ungulate migration). Tall and mid-stature bunchgrasses dominate with a minor component of forbs and shrubs. Basin big sagebrush is resent as a part of the community, but is minor with 0 to 10 percent foliar cover. There are more canopy gaps in this plant community compared to the other plant communities in the Reference State, and most basal gaps are generally small (one to two feet). Surface rock fragments in general do not occur and are not a significant source of site stability. Many plant interspaces have canopy or litter cover, which provides site stability. Production of grasses is higher than the other plant communities in the Reference State.

Pathway P1.1.1-1.1.2
Community 1.1.1 to 1.1.2

This pathway occurs after a sagebrush thinning event, such as low intensity fire, prolonged soil saturation, drought, freeze-kill, snow mold, or herbivory from insects or disease. Moderate fire intensity is typically a stand replacing event and results in the Bunchgrass plant community. Brush Management is a conservation practice used to achieve this plant community. Chemical treatment of shrubs has replaced natural sagebrush killing events on many sites in the area. However, chemical treatments impact non-target species, particularly broad-leafed species (forbs and shrubs) differently than natural events such as drought or fire. Where fire tends to result in a short-term increase in forbs, some chemical treatments result in a short-term (or long-term) reduction in forb density and diversity. Chemical treatment of sagebrush with tebuthiuron can have impacts to the under-story, depending on application rate (WWC, 2009). There is a danger of transition to the Disturbed State if multiple consecutive treatments occur.

Context dependence. This pathway relies upon close to normal precipitation and temperature as well as a grazing regime that is low to moderate intensity. If extreme conditions/disturbances such as hot temperatures, drought, catastrophic fire, or high intensity grazing occur, there is risk of a transition to either the Grazing Resistant or Disturbed State depending upon severity and cumulative disturbance. A successful pathway is contingent upon a grazing regime that allows for periodic critical growth period rest (May through June). The historic herbivory regime was light and episodic, sometimes including spring/fall migration patterns by mid-size ungulates who "ride the green wave" from winter to summer ranges (Aikens et.al. 2017).

Pathway P1.1.1-1.1.3
Community 1.1.1 to 1.1.3

Sagebrush killing event such as moderate intensity fire or climatic events such as severe drought, prolonged soil saturation, freeze-kill, snow mold, or herbivory by wildlife, insects, or disease. Anthropogenic sagebrush block treatments such as prescribed fire, chemical (tebuthiuron), or mechanical (mowing, aerator, etc.) can result in a similar pathway. Brush Management is a conservation practice used to achieve this plant community. Chemical treatment of shrubs has replaced natural sagebrush killing events on many sites in the area. However, chemical treatments impact non-target species, particularly broad-leafed species (forbs and shrubs) differently than natural events such as drought or fire. Where fire tends to result in a short-term increase in forbs, some chemical treatments result in a short-term (or long-term) reduction in forb density and diversity. Chemical treatment of sagebrush with tebuthiuron can have impacts to the understory, depending on application rate (WWC, 2009). There is a danger of transition to the Disturbed State if multiple consecutive treatments occur.

Context dependence. This pathway relies upon close to normal precipitation and temperature as well as a grazing regime that is low to moderate intensity. If extreme conditions/disturbances such as hot temperatures, drought, catastrophic fire, or high intensity grazing occur, there is risk of a transition to either the Grazing Resistant or Disturbed State depending upon severity and cumulative disturbance. A successful pathway is contingent upon a grazing regime that allows for periodic critical growth period rest (May through June). The historic herbivory regime was light and episodic, sometimes including spring/fall migration patterns by mid-size ungulates who "ride the green wave" from winter to summer ranges (Aikens et.al. 2017).

Pathway P1.1.2-1.1.1
Community 1.1.2 to 1.1.1

Natural succession (time without sagebrush killing event).

Context dependence. The time period for this pathway is dependent upon weather events such as drought and above normal precipitation years. Drought results in a faster pathway while favorable precipitation can result in a slower pathway. A grazing regime that mimics the historic regime (light intensity, episodic grazing events) will not alter the pathway, but a continuous grazing regime at moderate to heavy intensity can accelerate the pathway and puts the plant community "at-risk" for transition to the Grazing Resistant State.

Pathway P1.1.2-1.1.3
Community 1.1.2 to 1.1.3

Sagebrush killing event such as moderate intensity fire or climatic events such as severe drought, prolonged soil saturation, freeze-kill, snow mold, or herbivory by wildlife, insects, or disease. Anthropogenic sagebrush block treatments such as prescribed fire, chemical (tebuthiuron), or mechanical (mowing, aerator, etc.) can result in a similar pathway. Brush Management is a conservation practice used to achieve this plant community. Chemical treatment of shrubs has replaced natural sagebrush killing events on many sites in the area. However, chemical treatments impact non-target species, particularly broad-leafed species (forbs and shrubs) differently than natural events such as drought or fire. Where fire tends to result in a short-term increase in forbs, some chemical treatments result in a short-term (or long-term) reduction in forb density and diversity. Chemical treatment of sagebrush with tebuthiuron can have impacts to the understory, depending on application rate (WWC, 2009). There is a danger of transition to the Disturbed State if multiple consecutive treatments occur.

Context dependence. This pathway relies upon close to normal precipitation and temperature as well as a grazing regime that is low to moderate intensity. If extreme conditions/disturbances such as hot temperatures, drought, catastrophic fire, or high intensity grazing occur, there is risk of a transition to either the Grazing Resistant or Disturbed State depending upon severity and cumulative disturbance. A successful pathway is contingent upon a grazing regime that allows for periodic critical growth period rest (May through June). The historic herbivory regime was light and episodic, sometimes including spring/fall migration patterns by mid-size ungulates who "ride the green wave" from winter to summer ranges (Aikens et.al. 2017).

Pathway P1.1.3-1.1.2
Community 1.1.3 to 1.1.2

Natural succession (time without sagebrush killing event).

Context dependence. The time period for this pathway is dependent upon weather events such as drought and above normal precipitation years. Drought results in a faster pathway while favorable precipitation can result in a slower pathway. A grazing regime that mimics the historic regime (light intensity, episodic grazing events) will not alter the pathway, but a continuous grazing regime at moderate to heavy intensity can accelerate the pathway and puts the plant community "at-risk" for transition to the Grazing Resistant State.

State 1.2
Grazing Resistant State

Figure 14. Grazing Resistant State

The Grazing Resistant State consists of two plant communities: the Basin Big Sagebrush/Short-stature Grass community and the Short-stature Grass/Basin Big Sagebrush community. There has been a shift in under-story functional/structural group dominance. Due to herbivory pressure, there is a shift from mid-stature cool-season bunchgrasses to short-stature cool-season bunchgrasses such as Sandberg bluegrass and rhizomatous wheatgrasses such as thickspike and western wheatgrass. Canopy gap interspace and bare ground has increased from the Reference State, while herbaceous foliar cover has decreased.

Characteristics and indicators. There are fewer tall and mid-size bunchgrasses and they are typically found under the shrub canopy where they are protected from herbivory. The shrub canopy inter-spaces are occupied by grazing tolerant grasses as well as patches of bare ground that are sometimes connected. Drier site conditions result in lower productivity and less herbaceous production potential. Decreased infiltration is caused by increased bare ground patch size and lack of litter that acts as mulch in retaining soil moisture and retarding runoff. In many cases, the transition to the Grazing Resistant State may have occurred many decades ago during an era of higher stocking rates and continuous grazing during the growing season. However, continual grazing during the critical growth period (roughly May-June) at proper stocking rates will facilitate the transition to this state and maintain it as a stable state.

Resilience management. Site resilience is lower than the Reference State. Site hydrology has been modified due to moisture being utilized by shallower rooting species. Therefore, the site is drier earlier in the season and unable to recover as quickly after a disturbance. This state is more drought-prone, and therefore therefore sees wider productivity swings during dry vs. wet years. However, existing sagebrush canopy and remnant perennial vegetation provide some amount of resiliency. Rhizomatous grasses provide soil protection by protecting the soil from raindrop impact, decreasing the risk of soil erosion. However, overall soil stability is lower than the reference state, primarily due to a reduction in foliar cover and soil organic matter due to a reduction in litter. Site resistance to invasion by annual grasses is lower due to niches in the under-story for establishment as well as site water availability during the time suited for winter annuals such as cheatgrass (Bromus tectorum). Episodic and limited moisture is more suited to annual life forms. There are a wider range of soil surface textures on this site, and coarser surface textures area more vulnerable to invasion by annual invasive species.

Community 1.2.1
Basin Big Sagebrush/Short-stature Grass

Figure 15. Grazing Resistant (Plant Community 1.2.1)

This plant community is characterized by a dense stand of basin big sagebrush with a diminished under-story. The understory has lost many of the tall and mid-stature cool-season bunchgrasses, and they have been replaced with low-stature bunchgrasses such as Sandberg bluegrass, rhizomatous wheatgrasses, upland sedges, and mat-forming forbs. Shrub foliar cover is often greater than 30 percent, higher than in the Reference State, and typically making up greater than 40 percent of total annual production (species composition by dry weight). Areas that catch and retain snow are more likely to have higher shrub cover. Herbaceous production and foliar cover have decreased. There are often small amounts of annual invasive grasses and weedy forbs, mostly less than 5 percent foliar cover. There is often a slight increase in sprouting shrubs (less than 10 percent composition by dry weight). The site is susceptible to classic gully erosion, has lower soil organic matter, and overall lower Site Stability. Hydrologic Function has been altered through higher than normal sagebrush canopy and more bare ground. Biotic Integrity is reduced due to low vegetative production, relative dominance of structural/functional groups , and potentially invasive species if present. Total annual production ranges from 600 to 1,400 pounds per acre with a Representative Value (RV) of 1,000 pounds per acre. Productivity is highly variable and fluctuates drastically in response to drought and wet cycles. This plant community is at-risk of transitioning to the Eroded State with additional disturbance such as heavy grazing, sagebrush treatment, or ground-disturbing activity.

Community 1.2.2
Short-stature grass/Basin Big Sagebrush

This plant community is characterized by a dominance of short-stature grasses such as Sandberg bluegrass, rhizomatous grasses and grass-likes, and mat-forming forbs. A sagebrush killing event has happened recently, and basin big sagebrush foliar cover is less than 15 percent.There can be an initial flush of invasive annuals and weedy forbs within the first few years of a sagebrush treatment, but they are expected reduce to less than five percent foliar cover within five years. There is often a slight increase in sprouting shrubs (less than 10 percent composition by dry weight). The site is susceptible to classic gully erosion, has lower soil organic matter, and overall lower Site Stability. Hydrologic Function has been altered through a shift in functional/structural groups and higher than normal bare ground. Biotic Integrity is reduced due to low vegetative production, relative dominance of structural/functional groups , and potentially invasive species if present. Total annual production ranges from 600 to 1,400 pounds per acre with a Representative Value (RV) of 1,000 pounds per acre. Productivity is highly variable and fluctuates drastically in response to drought and wet cycles. This plant community is at-risk of transitioning to the Eroded State with additional disturbance such as heavy grazing, sagebrush treatment, or ground-disturbing activity.

Pathway P1.2.1-1.2.2
Community 1.2.1 to 1.2.2

Sagebrush killing event, typically anthropogenic sagebrush treatments such as chemical (tebuthiuron) or mechanical (mowing, aerator, etc.) and herbivory. Natural climatic events such as prolonged soil saturation, drought, freeze-kill, or snow mold can also occur. Fire is not typically a driver in this state due to the lack of fine fuels in the understory.

Context dependence. This pathway relies upon close to normal precipitation and temperature as well as a grazing regime that is low to moderate intensity. If extreme conditions or disturbances such as hot temperatures, drought, catastrophic fire, or high intensity grazing occur, there is risk of a transition to either the Disturbed State or Eroded State depending upon severity and cumulative disturbance.

Pathway P1.2.2-1.2.1
Community 1.2.2 to 1.2.1

Natural succession (time without a sagebrush killing event).

Context dependence. The time period for this pathway is dependent upon weather events such as drought and above normal precipitation years. Drought results in a faster pathway while favorable precipitation can result in a slower pathway. A grazing regime that mimics the historic regime (light intensity, episodic grazing events) will not alter the pathway, but a continuous grazing regime at moderate to heavy intensity can accelerate the pathway.

State 1.3
Disturbed State

Figure 16. Disturbed State

The Disturbed State is a result of soil-disturbing activities outside of the normal disturbance regime expected for this site. Examples are high intensity hoof action, anthropogenic soil-disturbing activities, rodent activity, or frequent flooding, which includes occasional irrigation. It may also occur after brush management preceded followed by improper grazing techniques that include high-intensity grazing use without appropriate recovery periods. A common scenario resulting in this State is multiple consecutive disturbances over a relatively short period of time. Consequences of this are decreased soil organic matter and increased soil erosion, soil crusting, and a decrease in soil surface aggregate stability.

Characteristics and indicators. There is a shift toward sprouting shrub dominance or co-dominance with big sagebrush depending on how long it has been since the disturbance(s). Both green (Chrysothamnus viscidiflorus) and rubber rabbitbrush (Ericameria nauseosus) may be present, but rubber rabbitbrush is typically more dominant. Along with a shift in shrub species, the herbaceous under-story also shifts toward more disturbance tolerant species such as western wheatgrass (Pascopyrum smithii) and needleleaf sedge (Carex duriuscula). Annual weeds such as bur buttercup (Ceratocephala testiculata), flixweed (Descurainia sophia), and lambsquarter (Chenopodium album), and invasive annual grasses such as cheatgrass (Bromus tectorum) are are often present in small amounts (less than five percent composition by dry weight).

Resilience management. Site resilience is lower than the Reference State or Grazing Resistant State, but higher than the Eroded State. Site hydrology has been modified due to moisture being utilized by shallower rooting species. Therefore, the site is drier earlier in the season and unable to recover as quickly after a disturbance. However, existing sagebrush canopy and remnant perennial vegetation provide some amount of resiliency. Site resistance to invasion by annual grasses is lower due to niches in the under-story for establishment as well as site water availability during the time suited for winter annuals such as cheatgrass (Bromus tectorum). Episodic moisture is more suited to annual life forms during drought.

Community 1.3.1
Basin Big Sagebrush/Rabbitbrush

Basin big sagebrush and rabbitbrush dominate with foliar cover often exceeding 30 percent, typically making up over 50 percent of total annual production (species composition by dry weight). The understory has decreased and bare ground often exceeds 30 percent. Dominant perennial grasses include rhizomatous species that are resistant to soil disturbance. Bunchgrasses are limited to the protected areas under shrubs. Annuals grasses and forbs may be present, but are not dominant. Common annuals include desert alyssum, flixweed, and occasionally cheatgrass if a seed source has been introduced to the site. The site is typically adequately protected, but erosion can occur during high runoff events. The watershed is functioning-at-risk. Biotic Integrity is reduced due to low vegetative production, relative dominance and unexpected structural/functional groups, and potentially invasive species if present. Total annual production ranges from 600 to 1,000 pounds per acre with a Representative Value (RV) of 1,400 pounds per acre.

Community 1.3.2
Rabbitbrush/Rhizomatous Wheatgrass

Rabbitbrush dominates with foliar cover often exceeding 20 percent, typically making up over 30 percent of total annual production (species composition by dry weight). Rhizomatous wheatgrasses are the dominant perennial grass, and annual grasses and forbs are often present. Common annuals include desert alyssum, flixweed, and occasionally cheatgrass if a seed source has been introduced to the site. The understory has decreased and bare ground exceeds 30 percent. Bunchgrasses are limited to the protected areas under shrubs. The site is typically adequately protected, but erosion can occur during high runoff events. The watershed is functioning-at-risk. Biotic Integrity is reduced due to low vegetative production, relative dominance and unexpected structural/functional groups, and potentially invasive species if present. Total annual production ranges from 600 to 1,000 pounds per acre with a Representative Value (RV) of 1,400 pounds per acre.

Pathway P1.3.1-1.3.2
Community 1.3.1 to 1.3.2

Sagebrush killing event, typically high intensity fire or consecutive climatic events (flooding, drought, etc.), and anthropogenic sagebrush treatments such as chemical (tebuthiuron) or mechanical (mowing, aerator, etc.).

Context dependence. Continued disturbances can maintain this plant community for long periods of time. Prolonged drought and improper grazing (high intensity, season-long) can accelerate the pathway back to a sagebrush dominated plant community.

Pathway P1.3.2-1.3.1
Community 1.3.2 to 1.3.1

Natural succession (time without sagebrush killing event). Sagebrush and rabbitbrush will eventually become co-dominant.

Context dependence. The time period for this pathway is dependent upon weather events such as drought and above normal precipitation years. Drought results in a faster pathway while favorable precipitation can result in a slower pathway. A grazing regime that mimics the historic regime (light intensity, episodic grazing events) will not alter the pathway, but a continuous grazing regime at moderate to heavy intensity can accelerate the pathway.

State 1.4
Eroded State

The Eroded State has seen a shift in functional/structural group dominance to a monotypic old-aged, decadent basin big sagebrush stand with very little perennial herbaceous understory. Due to classic gully erosion, the ecological dynamics have been altered to prevent prolonged soil saturation, which is a major driver in sited dynamics in the reference state.

Characteristics and indicators. Site productivity is lower and is dominated by even-aged stands of old, decadent basin big sagebrush. The understory is sparse and can resemble many other states described for this site, but the defining indicator is gully erosion that effectively drains this site, changing site hydrology.

Resilience management. Site resilience is much lower than the all other states. Site hydrology has been modified due to classic gully erosion. Therefore, the site is drier earlier in the season and unable to turn over sagebrush communities. This state is more drought-prone, and therefore more vulnerable to invasion by annual invasive species. Overall soil stability is much lower than the reference state due to a reduction in litter resulting in lower soil organic matter. Site resistance to invasion by annual grasses is lower due to niches in the under-story for establishment as well as site water availability during the time suited for winter annuals such as cheatgrass (Bromus tectorum). Episodic and limited moisture is more suited to annual life forms.

Community 1.4.1
Basin Big Sagebrush/Annuals

This plant community is characterized by a dense stand of basin big sagebrush with a sparse understory. The site has lost its hydrology. Shrub foliar cover often exceeds 30 percent, higher than in the reference state, typically making up over 50 percent of total annual production (species composition by dry weight). The under-story has decreased and bare ground exceeds 30 percent. Perennial grass and forbs are sparse and bunchgrasses are limited to the protected areas under shrubs. Annuals grass and forb dominates herbaceous understory cover. Common annuals include desert alyssum, flixweed, and occasionally cheatgrass if a seed source has been introduced to the site. The site is experiencing classic gully erosion and Site Stability is Moderate or greater departure from the Reference State. Hydrologic Function is impaired due to altered hydrology from classic gully erosion. Biotic integrity is affected by the change in functional/structural group dominance. More recently, there have been efforts to promote economical restoration activities due to high production potential for this site and high rates of degradation from a myriad of competing uses. Recommended restoration activities include Low-Tech Mesic Restoration techniques such as Zeedyk structures. For more information, see: https://www.sagegrouseinitiative.com/mesic/ Total annual production ranges from 400 to 1,200 pounds per acre with a Representative Value (RV) of 800 pounds per acre.

Transition T1.1-1.2
State 1.1 to 1.2

Reference State

Grazing Resistant State

Herbivory pressure in excess of normal Reference State conditions. Typical scenarios include moderate to high intensity continuous spring grazing or low intensity season-long grazing.

Constraints to recovery. Recovery is inhibited by continued herbivory pressure, reduced seedbank, and drought conditions. Annual grasses and forbs may occur in the shrub understory.

Context dependence. Because this site receives additional moisture through overland flow, chances of restoration are higher. However, warmer and drier climate trends contribute to uncertainty of restoration efforts. Animals concentrate on these sites, further reducing the likelihood of restoration.

Transition T1.1-1.3
State 1.1 to 1.3

Reference State

Disturbed State

Soil-disturbance outside of the normal disturbance regime expected for this site. Examples include high intensity fire, high intensity hoof action, anthropogenic activity (e.g. mechanical and chemical treatments), rodent activity, or prolonged soil saturation, typically occasional irrigation. Extreme herbivory in combination with catastrophic drought may be a trigger for this transition as well.

Constraints to recovery. Persistent drought conditions, and herbivory pressure are constraints to recovery to the Reference State. Recovery is further inhibited by consecutive disturbances repeated over a relatively short time period and prolonged drought conditions. There is a risk of annual grass and forb invasion.

Context dependence. This transition typically occurs after multiple consecutive disturbances. Warmer and drier climate trends contribute to uncertainty of restoration efforts.

Transition T1.1-1.4
State 1.1 to 1.4

Classic gully erosion is primary driver of this transition which is caused by large precipitation events outside of normal reference conditions in combination with herbivory pressure.

Constraints to recovery. Hydrology is altered, and the site lacks the ability to hold additional moisture on the site. This effectively interrupts site dynamics, lowers productivity potential, and prevents the normal ecological dynamics of sagebrush-killing events due to prolonged soil moisture.

Context dependence. Large precipitation events that would have resulted in prolonged soil saturation and caused sagebrush mortality instead result in additional soil erosion and head-cutting in drainageways with little to no sagebrush mortality and conditions that do not promote understory recruitment. The resulting plant community is dominated by sagebrush with a reduced herbaceous understory. Herbivory pressure further exacerbates sparse understory conditions.

Transition T1.2-1.3
State 1.2 to 1.3

Grazing Resistant State

Disturbed State

Soil-disturbance outside of the normal disturbance regime expected for this site. Examples include high intensity fire, high intensity hoof action, anthropogenic activity (e.g. mechanical and chemical treatments), rodent activity, or prolonged soil saturation, typically occasional irrigation. Extreme herbivory in combination with catastrophic drought may be a trigger for this transition as well.

Constraints to recovery. Persistent drought conditions, and herbivory pressure are constraints to recovery to the Reference State. Recovery is further inhibited by consecutive disturbances repeated over a relatively short time period and prolonged drought conditions. There is a risk of annual grass and forb invasion.

Context dependence. This transition typically occurs after multiple consecutive disturbances. Warmer and drier climate trends contribute to uncertainty of restoration efforts.

Transition T1.2-1.4
State 1.2 to 1.4

Classic gully erosion is primary driver of this transition which is caused by large precipitation events outside of normal reference conditions in combination with herbivory pressure.

Constraints to recovery. Hydrology is altered, and the site lacks the ability to hold additional moisture on the site. This effectively interrupts site dynamics, lowers productivity potential, and prevents the normal ecological dynamics of sagebrush-killing events due to prolonged soil moisture.

Context dependence. Large precipitation events that would have resulted in prolonged soil saturation and caused sagebrush mortality instead result in additional soil erosion and head-cutting in drainageways with little to no sagebrush mortality and conditions that do not promote understory recruitment. The resulting plant community is dominated by sagebrush with a reduced herbaceous understory. Herbivory pressure further exacerbates sparse understory conditions.

Transition T1.3-1.4
State 1.3 to 1.4

Classic gully erosion is primary driver of this transition which is caused by large precipitation events outside of normal reference conditions in combination with herbivory pressure.

Constraints to recovery. Hydrology is altered, and the site lacks the ability to hold additional moisture on the site. This effectively interrupts site dynamics, lowers productivity potential, and prevents the normal ecological dynamics of sagebrush-killing events due to prolonged soil moisture. Because the site previously experienced soil disturbing activities, the dominant shrub may be rabbitbrush or after a long period of time sagebrush may be co-dominant with rabbitbrush.

Context dependence. Large precipitation events that would have resulted in prolonged soil saturation and caused sagebrush mortality instead result in additional soil erosion and head-cutting in drainageways with little to no sagebrush mortality and conditions that do not promote understory recruitment. The resulting plant community is dominated by sagebrush and/or rabbitbrush with a reduced herbaceous understory. Herbivory pressure further exacerbates sparse understory conditions.

Restoration pathway R4-2
State 1.4 to 1.2

More recently, there have been efforts to promote economical restoration activities due to high production potential for this site and high rates of degradation from a myriad of competing uses. Recommended restoration activities include Low-Tech Mesic Restoration techniques such as Zeedyk structures. The NRCS Conservation Practice is (643) Restoration of Rare or Declining Habitats. See the Conservation Practice Standard (CPS) at: https://efotg.sc.egov.usda.gov/api/CPSFile/3533/643_WY_CPS_Restoration_of_Rare_or_Declining_Natural_Communities_2018

Context dependence. Restoration to the Grazing Resistant State is likely possible without drastic changes in grazing management, but recovery will be slow and episodic with climatic conditions. Favorable weather (above normal precipitation) can result in more accelerated restoration while drought conditions can delay recovery.

Restoration pathway R4-3
State 1.4 to 1.3

More recently, there have been efforts to promote economical restoration activities due to high production potential for this site and high rates of degradation from a myriad of competing uses. Recommended restoration activities include Low-Tech Mesic Restoration techniques such as Zeedyk structures. The NRCS Conservation Practice is (643) Restoration of Rare or Declining Habitats. See the Conservation Practice Standard (CPS) at: https://efotg.sc.egov.usda.gov/api/CPSFile/3533/643_WY_CPS_Restoration_of_Rare_or_Declining_Natural_Communities_2018

Context dependence. Restoration to the Disturbed State is likely if the site was previously degraded from the Disturbed State to the Eroded State. It can likely occur without drastic changes in grazing management, but recovery will be slow and episodic with climatic conditions. Favorable weather (above normal precipitation) can result in more accelerated restoration while drought conditions can delay recovery.

Land use 2
Pastureland

This is a deep to very deep site with very few limitations for agriculture production, and therefore is often converted to irrigated pasture due to high water holding capacity, low slopes, and landscape position that lends itself to tillage and irrigation practices. Pasture is land composed of introduced or domesticated native forage species that is used primarily for the production of livestock. Pastures receive periodic renovation and cultural treatments, such as tillage, fertilization, mowing/haying, weed control, and may be irrigated. Pastures are not in rotation with annual crops.

Characteristics and indicators. Plant communities can be very diverse with a mixture of native and non-native forage species or as a monoculture of a highly competitive forage grass such as creeping meadow foxtail. Hay production with aftermath grazing is the most common management scenario, but pastures on this site can also managed for grazing throughout the growing season with some dormant season grazing as well.

State 2.1
Irrigated Pasture

Figure 17. Pasture Land Use

This site belongs to the Deep Sub-irrigated, Loamy Forage Suitability Group (FSG) which covers deep to very deep soils with medium soil textures and greater than 6" available water-holding capacity (AWC) in the top 60" of the soil profile. A water table is often present at 48 to 72 inches in the soil profile. Production expected to range from 3,000 to 6,000 lbs./ac. with representative value (RV) of 4,500 lbs./ac. Adapted species for use as irrigated pasture include native species such as prairie junegrass, Canby's bluegrass, basin wildrye, slender wheatgrass, and western wheatgrass; introduced species including meadow brome, timothy, beardless wildrye, Altai wildrye, red fescue, sheep fescue, tall fescue, creeping meadow foxtail, Canada bluegrass, and Kentucky bluegrass; legume and forb species such as cicer milkvetch, birdsfoot trefoil, small burnett, white clover, alsike clover, red clover, and strawberry clover. Since this site is well-drained it is capable of supporting certain varieties of alfalfa when under an improved irrigation system such as sprinkler. Selection of species should be based on production goals and intended use (goals and objectives). More information regarding preferred varieties for irrigated pasture can be found at http://animalrange.montana.edu/documents/extension/mteb99.pdf AND https://www.nrcs.usda.gov/Internet/FSE_PLANTMATERIALS/publications/mtpmctn10704.pdf See the description for Deep Sub-irrigated, Loamy FSG for MLRA 34A LRU E (10-14" ppt, <70 day growing season) for more information at Wyoming's electronic Field Office Technical Guide, Section II, Forage Suitability Groups https://efotg.sc.egov.usda.gov/references/public/WY/mlra34A_fsg_deep_sub_irrigated_loamy_lru_E_.pdf

Characteristics and indicators. Irrigated pasture on this site is varies from a very diverse mix of native wetland plants to a monoculture of creeping meadow foxtail. Flood irrigation water management often results in hydric soil and hydrophytic vegetation. Improved irrigation systems allow for legume production.

Resilience management. Resilience on this site when in irrigated pasture is much higher than Reference State due to the additional moisture available for site recovery after disturbance. Resistance to weed invasion is typically much higher than the reference state. However, improper grazing or irrigation water management techniques could result in noxious weed invasion by perennials such as whitetop, perennial pepperweed, musk thistle, and Canada thistle.

Land use 3
Other - Mineral Extraction Lands

Land that is barren, sandy, rocky, or that is impacted by the extraction of natural resources, such as minerals, gravel or sand, coal, shale, rock, oil, or natural gas.

Characteristics and indicators. This land use can be many things, but in this LRU is most often associated with oil and gas development. Barren land. A land cover/use category used to classify lands with limited capacity to support life and having less than 5 percent vegetative cover. Vegetation, if present, is widely spaced. [NRI-87] Typically, the surface of barren land is sand, rock, exposed subsoil, or salt-affected soils. Subcategories include salt flats; sand dunes; mud flats; beaches; bare exposed rock; quarries, strip mines, gravel pits, and borrow pits; river wash; oil wasteland; mixed barren lands; and other barren land. [NRI-92]

State 3.1
Reclaimed

The Reclaimed State is highly variable based on weather conditions during reclamation activities, the management practices used to implement the reclamation, the seed mix, and timing/method of stockpiling topsoil during the disturbance.

Characteristics and indicators. The most common scenario is a reclaimed oil and gas well pad planted to crested wheatgrass (Agropyron cristatum) without appropriate topsoil stockpiling. If topsoil is stockpiled, it may have been stored for too long and/or stored too deep resulting in fewer soil microorganisms. Over time, basin big sagebrush will spread into the reclaimed area, but the understory will be dominated by introduced species. Biological soil crusts are minimal, further exposing the soil surface to erosional forces as well as impairing carbon, nutrient, and water cycles.

Resilience management. Resilience is lower than the Reference State, but with best management practices, a certain amount of resilience can be restored. Successful reclamation will result in reduced soil erosion and improved hydrologic function. Biotic integrity is highly variable. Because soil disturbance previously occurred on the site, resistance to invasive species is lower unless reclamation is highly successful with all available niches occupied by desirable perennial species.

State 3.2
Annuals/Bare Ground

The Annuals/Bare Ground community occurs after severe disturbance, most often physical soil disturbance that removes topsoil, but it can also occur as a transition from the Eroded State after severe drought, flooding, pests, or disease, leaving the site with no perennial vegetation.

Characteristics and indicators. Populations of annual weedy forbs can reach critical levels and impact the ecological processes on the site until restoration or reclamation of the site occurs. As part of succession, all sites that are severely disturbed go through this plant community as part of the restoration process, but the time in this plant community phase is largely dependent on the use of restoration Best Management Practices (BPMs) and climate cycles. Biological soil crusts are non-existent, further exposing the soil surface to erosional forces as well as impairing carbon, nutrient, and water cycles.

Resilience management. Site resilience is at its lowest, and recovery is largely dependent on management practices and weather patterns. Resistance to invasion is at its lowest, and the site is vulnerable to all of the common annual weedy forbs such as Russian thistle (Salsola tragus)), flixweed (Descurainia sophia), lambsquarter (Chenopodium album), and halogeton (Halogeton glomeraturs) as well as existing or newly emerging noxious weed threats. When soil surface textures are coarse (sandy loam), this site is particularly susceptible to cheatgrass (Bromus tectorum).

Restoration pathway R3.2-3.1
State 3.2 to 3.1

Reclamation efforts include re-seeding. In cases where heavy equipment caused the disturbance, contouring and/or deep ripping may be necessary to provide a suitable site for re-seeding. Care must be taken to stockpile and replace surface layers separately from the subsurface. Prescribed grazing and restricting vehicle traffic on the site is necessary to facilitate successful seeding of perennial species.

Context dependence. Drought conditions and/or herbivory pressure may hinder restoration efforts, and multiple seeding efforts may be necessary if failure is caused by drought. Mulch can be effective for soil moisture retention and erosion control.

Conversion C1-2
Land use 1 to 2

Most range conversion to pasture occurred at the beginning of the 20th century through the use of horse-drawn implements and hand tools. Flood irrigation infrastructure was installed and introduced species, such as Kentucky bluegrass and clover, were planted. Wild flooding, or "Mountain Meadow Flooding," is the most common irrigation system which has little directional control and low efficiency. Land smoothing and land leveling are not common practices due to the potential of a thin topsoil or the economic cost for an area with such a short growing season. Because of the undulating natural surface, resulting microtopography ranges from 2.5cm to 20cm and sometimes greater. The field is over-irrigated to increase the water table, a practice called "sub-irrigating," or locally referred to as "getting the sub up," that results in hydrophytic vegetation and hydric soil development in the lower landscape positions. The goal with this irrigation system is to saturate the soil with enough water to supplement the higher areas. Over the years, willows have colonized the ditch systems and provide additional wildlife habitat. Late season return flow to streams are often cited as another added benefit to this type of system.

Conversion C1-3
Land use 1 to 3

The conversion from Range to Other - Mineral Extraction Lands occurs when vegetation and soil is manipulated for the purpose of mineral extraction. Common practices are oil and natural gas pad and pipeline infrastructure, gravel pits, and road construction. Vegetation and topsoil is removed and topsoil is often stockpiled for on or off-site reclamation.

Conversion C3-1
Land use 3 to 1

Conversion from Other - Mineral Extraction Lands to Range occurs, sometimes over a long period of time, as part of the reclamation and/or restoration process after mineral extraction. There is low potential for recovery without significant inputs of energy and resources, especially if topsoil has been removed. Seed mixes that mimic an adjacent “reference area” rather than the site potential as described in the Reference State (1.1) will often result in a plant community resembling the Grazing Resistant State (1.2) due to inappropriate seed mixes and pre- and post-seeding grazing management that does not provide adequate recovery and periodic critical growth period rest.