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 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. Reference State

The Reference State consists of two plant communities: the Big Sagebrush/Bunchgrass community and the Bunchgrass/Big sagebrush community. Each plant community differs in percent composition and foliar cover of bunchgrasses and shrubs. Forbs are a minor component on this site. Shrub canopy cover is less than 25 percent. Dominant shrubs are Wyoming and basin big sagebrush. 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 be used to mimic the natural disturbance regime, however due to the fragile nature of soils are not often used.

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. The site has moderate resistance to invasion by annual grasses because of climate limitations (dry and cold). Coarse soil surface textures lower resistance, but cold climatic conditions provide some resistance. The site is susceptible to invasion during hotter climatic periods. On a local scale, this site is more susceptible to annual weed invasion than sites with heavier soil textures.

Community 1.1.1
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 very 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 coarse soils associated with this site provide a favorable soil-water-plant relationship. The Big Sagebrush/Bunchgrass Community can occur across the entire ecological site or can occur in a mosaic with the Bunchgrass/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). Wyoming and basin big sagebrush are dominant with mountain big sagebrush at the upper end of the precipitation range for this site. Sagebrush canopy cover ranges from 15 to 25 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). Forb diversity is naturally low on this site. A Big Sagebrush/Bunchgrass Community with a degraded understory is an “at-risk” community that could transition to the Grazing Resistant State. Chemical treatment of shrubs is 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 are not often used due to the fragile nature of the coarse-textured soil surface. There are generally few canopy gaps, and most basal gaps are small (one to two feet). Rock fragment (gravels) cover on the soil surface is common. Many plant interspaces have canopy or litter cover. Production of grasses is lower than in the Bunchgrass/Big Sagebrush community.

Community 1.1.2
Bunchgrass/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). Mid-stature cool season bunchgrasses dominate and sagebrush is sub-dominant with foliar cover ranging from 5 to 15 percent. At this sagebrush canopy level in this precipitation zone, there is little, if any, competition between the shrub over-story and the herbaceous understory. In fact, there is evidence to suggest that the understory receives more benefit from the sage over-story than negative effects (Winward, 2007). There are few canopy gaps and basal gaps are generally small (one to two feet). Surface rock fragments 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 Big Sagebrush/Bunchgrass community.

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 to moderate intensity fire, drought, freeze-kill, snow mold, or herbivory from insects or disease. 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 due to the fragile nature of coarse textured soils as well as 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 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 and puts the plant community "at-risk" for transition to the Grazing Resistant State.

State 1.2
Grazing Resistant State

Figure 12. Grazing Resistant State

The Grazing Resistant State consists of two plant communities; the Big Sagebrush/Short-stature Grass community and the Short-stature Grass/Big Sagebrush community. There has been a shift in understory functional/structural group dominance. Due to herbivory pressure or possibly catastrophic drought, there is a shift from mid-stature cool-season bunchgrasses to short-stature cool-season bunchgrasses, rhizomatous wheatgrasses, and grass-likes. Canopy gap interspace and bare ground has increased from the Reference State, while herbaceous foliar cover has decreased.

Characteristics and indicators. There are fewer mid-size bunchgrasses and they are typically found under the shrub canopy where they are protected from herbivory. The shrub canopy interspaces are occupied by grazing tolerant grasses as well as patches of bare ground that are often connected. Needle and thread, a dominant grass in the Reference State, is fairly tolerant to grazing and is typically present. However, Indian ricegrass is a short-lived perennial that relies on an adequate seedbank and is often absent in this state. Annual grasses such as cheatgrass and annual weedy forbs such as desert alyssum may be found in small amounts (less than five percent composition by dry weight). Drier site conditions result in lower productivity and less herbaceous production potential. 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 season-long grazing. However, continual grazing during the critical growth period (roughly May through June) at proper stocking rates will facilitate the transition to this state or 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 such as drought. This state is more drought-prone, and therefore sees wider productivity swings during dry versus wet years and due to coarse soil surface textures is more vulnerable to invasion by annual invasive species. However, existing sagebrush canopy and remnant perennial vegetation provide some amount of resiliency. 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 productivity and litter. Site resistance to invasion by annual grasses and weedy annual forbs is lower due to niches in the understory 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. Localized conditions on this site, including coarse soil textures, further reduce site resistance.

Community 1.2.1
Big Sagebrush/Short-stature Grass

This plant community is characterized by a dense stand of big sagebrush with a diminished understory. It has a mix of basin big sagebrush and Wyoming big sagebrush, with basin big sagebrush being dominant. The under-story has lost many of the mid-stature cool-season bunchgrasses, although needle and thread remains a dominant due to its high grazing tolerance. Low-stature bunchgrasses, rhizomatous wheatgrasses, and upland sedges have increased in dominance. Shrub canopy cover is often higher than in the reference state, typically making up greater than 40 percent of total annual production (species composition by dry weight), and herbaceous production and foliar cover has decreased. There may be small amounts of annual invasive grasses, mostly less than five percent foliar cover. There is often a slight increase in sprouting shrubs (less than 10 percent composition by weight). The site is susceptible to wind erosion and may have varying amounts of scouring and/or deposition. 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 1,000 pounds per acre with a Representative Value (RV) of 800 pounds per acre. Productivity is highly variable and fluctuates drastically in response to drought and wet cycles.

Community 1.2.2
Short-stature Grass/Big Sagebrush

This plant community is characterized by a dominance of short-stature bunchgrasses, rhizomatous grasses, and upland sedges. A sagebrush killing event has happened recently, and big sagebrush foliar cover is typically less than 15 percent. There could be a mix of basin big sagebrush and Wyoming big sagebrush, with basin big sagebrush being dominant. The under-story has lost many of the mid-stature cool-season bunchgrasses except needle and thread which has a high tolerance for grazing. There is often a slight increase in sprouting shrubs (less than 10 percent composition by weight). The site is susceptible to wind erosion and may have varying amounts of scouring and deposition. Hydrologic Function has been altered through 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 1,000 pounds per acre with a Representative Value (RV) of 800 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

Big Sagebrush/Short-stature Grass

Short-stature Grass/Big Sagebrush

Sagebrush killing event, typically anthropogenic sagebrush treatments, such as chemical (tebuthiuron) or mechanical (mowing, aerator, etc.), and herbivory. Natural climatic events such as 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 under-story.

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 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

Short-stature Grass/Big Sagebrush

Big Sagebrush/Short-stature Grass

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

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 activity, rodent activity, or frequent flooding, which includes occasional irrigation. It may also occur after brush management (or multiple treatments in rapid succession) preceded and followed by improper grazing techniques that include high-intensity grazing use without appropriate recovery periods.

Characteristics and indicators. There is a shift toward sprouting shrub dominance or codominance 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 thickspike wheatgrass (Elymus lanceolatus ssp. lanceolatus) 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 shrub 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 coarse soil surface textures. 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 wind erosion can occur, resulting in scouring and/or deposition. 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 500 to 900 pounds per acre with a Representative Value (RV) of 700 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 under-story has decreased and bare ground exceeds 30 percent. Bunchgrasses are limited to the protected areas under shrubs. The site is typically adequately protected, but wind erosion can occur, resulting in scouring and deposition. 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 500 to 900 pounds per acre with a Representative Value (RV) of 700 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 (drought, etc.), or 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. Disturbances have removed the herbaceous understory and bare ground exceeds 30 percent. The site is prone to wind erosion and often experiences "blow outs" with active erosion.

Characteristics and indicators. In this state, sagebrush canopy varies, but the under-story has seen a decrease in herbaceous grasses/grasslikes and forbs and an increase in bare ground. There will be indicators of reduced soil and site stability as well as reduced hydrologic function, mainly "blow outs" and wind erosion features. Soil surface loss and degradation is likely. Biotic integrity is affected by functional/structural groups not expected for the site, weedy species, and the loss of perennial species and functional/structural groups. The site is more prone to drought with large fluctuations in annual production in response to weather events. The site is less diverse with lower quality habitat for wildlife and pollinators.

Resilience management. Site resilience is lower than all other states because the site hydrology has been modified by the lack of herbaceous perennial under-story and subsequent wind erosion. Annual weedy forbs and invasive grasses are more likely to invade after drought or ground disturbing activities.

Community 1.4.1
Basin Big Sagebrush/Annuals

Basin big sagebrush and rabbitbrush are dominant with foliar cover often exceeding 30 percent, typically making up over 50 percent of total annual production (species composition by dry weight). The under-story has decreased and bare ground exceeds 40 percent. Perennial grass and forbs are sparse and bunchgrasses are limited to the protected areas under shrubs. Annual grasses and forbs 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 not well protected from wind erosion and Site Stability is Moderate or greater departure from the Reference State. Biotic integrity is affected by the change in functional/structural group dominance. Due to the fragile nature of soils, it is difficult to restore this plant community. Total annual production ranges from 400 to 800 pounds per acre with a Representative Value (RV) of 600 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. Warmer and drier climate trends contribute to uncertainty of restoration efforts. Coarse soil textures put this site at risk of transitioning to the Disturbed State with continued or additive disturbances.

Transition T1.1-1.3
State 1.1 to 1.3

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.

Restoration pathway R2-1
State 1.2 to 1.1

Grazing Resistant State

Reference State

The drivers for this restoration pathway are reduction in woody species and restoration of native herbaceous species by mechanical or chemical treatment of sagebrush, and a rotational grazing system that incorporates periodic rest during the critical growth period (May through June).

Context dependence. If some mid-stature bunchgrasses remain under the sagebrush canopy, proper grazing management can move the site back to the Reference State combined with a mechanical or chemical sagebrush treatment. Due to the fragile nature of soils, care must be taken to appropriately prescribe the treatment to avoid excessive soil disturbance or over application of chemicals that may be more active with coarser soil textures such as tebuthiuron. Restoration could take multiple generations of management or could be accelerated with rest or deferment combined with successive wet springs conducive to seed germination and seedling establishment. (Derner, Schuman, Follett, & Vance, 2014).

Transition T1.2-1.3
State 1.2 to 1.3

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

Extreme herbivory pressure in excess of normal Reference State, livestock husbandry practices, or concentrated animal use result in conditions that remove the herbaceous understory. Typical scenarios include high intensity season-long grazing and bedding activities.

Constraints to recovery. As bare ground increases, the site is prone to wind erosion and blowouts. 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 prolonged high intensity grazing and concentrated animal use for grazing and bedding. Warmer and drier climate trends contribute to uncertainty of restoration efforts.

Transition T1.3-1.4
State 1.3 to 1.4

Extreme herbivory pressure in excess of normal Reference State, livestock husbandry practices, or concentrated animal use result in conditions that remove the herbaceous understory. Typical scenarios include high intensity season-long grazing and bedding activities.

Constraints to recovery. As bare ground increases, the site is prone to wind erosion and blowouts. 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 prolonged high intensity grazing and concentrated animal use for grazing and bedding. Warmer and drier climate trends contribute to uncertainty of restoration efforts.

Restoration pathway R4-3
State 1.4 to 1.3

The drivers for this restoration pathway are reduction in woody species and restoration of native herbaceous species by mechanical or chemical treatment of sagebrush, and a rotational grazing system that incorporates periodic rest during the critical growth period (May through June).

Context dependence. If some mid-stature bunchgrasses remain under the sage canopy, proper grazing management can move the site back to the Reference State combined with a mechanical or chemical sagebrush treatment. Due to the fragile nature of soils, care must be taken to appropriately prescribe the treatment to avoid excessive soil disturbance or over application of chemicals that may be more active with coarser soil textures such as tebuthiuron. Restoration could take multiple generations of management or could be accelerated with rest or deferment combined with successive wet springs conducive to seed germination and seedling establishment. (Derner, Schuman, Follett, & Vance, 2014).

Land use 2
Pastureland

This is a moderately deep to very deep site with some limitations for agriculture production, mainly low available water-holding capacity (AWC). Therefore, this site is not often converted to irrigated pasture, but pasture occasionally occurs when supported by 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

This site belongs to the Sandy, Dry Forage Suitability Group (FSG) which covers coarse textured soils with 3 to 6 inches available water-holding capacity (AWC) in the top 60 inches of the soil profile with rapid permeability. Production expected to range from 2,000 to 4,000 pounds per acre. with representative value (RV) of 3,000 pounds per acre. 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 Sandy, Dry 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_sandy_dry_lru_E_.pdf

Characteristics and indicators. Irrigated pasture on this site is varies from a very diverse mix of forage species to a monoculture of creeping meadow foxtail. 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 five 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 or stored too deep resulting in fewer soil microorganisms. Over time, basin or Wyoming 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. Due to coarse surface textures, 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, 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 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 2.5 to 20 cm 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 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.