State 1
Reference

The Reference State consists of three Plant Communities: the Big Sagebrush/Bunchgrass Community (1.1) the Bunchgrass/Big sagebrush Plant Community (1.2) and the Bunchgrass Community (1.3). Each community differs in percent composition of bunchgrasses and percent woody canopy cover. Forbs are a minor component on this site. Woody canopy cover is less than 25 percent. The dominant shrub species is Wyoming Big Sagebrush in the Reference State (1). Two important processes occurring in this state result in plant community changes within Reference State: sagebrush killing disturbances (browse, insects, drought, fire) and time without those disturbances. These processes are generally referred to as “natural succession.” The shift from the Bunchgrass Plant Community (1.3) to the Bunchgrass/Big Sagebrush Plant Community (1.2) and subsequently to the Big Sagebrush/Bunchgrass Plant Community is dependent on an increase of woody cover. Without sagebrush killing disturbance, shrubs will increase on this ecological site even with proper grazing management. Improper grazing management may accelerate the rate of increase for woody species and/or result in higher shrub canopy cover than in the Reference State. The shift from the Big Sagebrush/Bunchgrass or Bunchgrass/Big Sagebrush Plant Communities is dependent on sagebrush killing disturbances such as fire, drought, browse, and insects. Management actions can and are often used to mimic these processes through mechanical and chemical treatments. Prescribed fire is not often used on this site due to current land uses and lack of fuels and adequate burn windows.

Community 1.1
Big Sagebrush/Bunchgrass

Figure 6. 1.1

The Sandy site has the potential to be one of the most productive upland sites in this LRU. The Big Sagebrush/Bunchgrass 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. 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. Chemical and mechanical treatment of shrubs has replaced natural sagebrush killing events on many sites in the area. However, chemical treatments can 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 medium-term) reduction in forb density and diversity. The Big Sagebrush/Bunchgrass Community (1.1) can occur across the entire ecological site or can occur in a mosaic. This community can occur over time without disturbances and accelerated with added herbaceous grazing pressure. Big sagebrush is dominant in the Big Sagebrush/Bunchgrass Community (1.1) with sagebrush canopy cover ranging from 15% to 25%. At this sagebrush canopy level in this precipitation zone, there is competition between the shrub overstory and the herbaceous understory (Alma Winward personal communication, 2004). A Big Sagebrush/Bunchgrass Community with a degraded understory is an “at-risk” community. (Define At Risk) In the Big Sagebrush/Bunchgrass Community (1.1), there are generally few canopy gaps great than 6 feet. Rock cover on the soil surface is less than 15%. Many plant interspaces have canopy or litter cover. Production of grasses is much lower than in the Bunchgrass Community (1.3) and slightly lower than in the Bunchgrass/Big Sagebrush Community (1.2). It is typical for shrubs to increase as the community shifts from the Bunchgrass Community (1.1) to the Bunchgrass/Big Sagebrush Community (1.2). Note: POSE in Group 1 refers to larger varieties such as Canby's and big bluegrass. POSE in Group 3 refers to Sandberg bluegrass.

Community 1.2
Bunchgrass/Big Sagebrush

Figure 9. 1.2

The Bunchgrass/Big Sagebrush Community (1.2) can occur across the entire ecological site on a given landscape but more likely occurs in a mosaic pattern associated with the disturbance cycle at any given location. Mid-stature bunchgrasses dominate in the Bunchgrass/Big Sagebrush Community (1.2) and sagebrush is sub-dominant with cover ranging from 5% to 15%. 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) In the Bunchgrass/Big Sagebrush Community (1.2), there are generally few canopy gaps, and most basal gaps are generally (3-6 feet) . Rock cover on the soil surface is less than 15%. Many plant interspaces have canopy or litter cover. Production of grasses is slightly lower and shrub production is higher than in the Bunchgrass Community (1.3). Note: POSE in Group 1 refers to larger varieties such as Canby's and big bluegrass. POSE in Group 3 refers to Sandberg bluegrass.

Community 1.3
Bunchgrass

Figure 12. 1.3

The Bunchgrass Community (1.3) is dominated by mid-stature cool-season bunchgrasses mixed with a minor component of forbs and shrubs. Big sagebrush is present as a part of the community, but is minor with 5 to 15% foliar cover. The Bunchgrass Community (1.3) generally occurs on this site immediately following a sagebrush killing event such as drought, insects, browse, or fire. Note: POSE in Group 1 refers to larger varieties such as Canby's and big bluegrass. POSE in Group 3 refers to Sandberg bluegrass.

Pathway 1.1-1.2
Community 1.1 to 1.2

Big Sagebrush/Bunchgrass

Bunchgrass/Big Sagebrush

The driver for community shift 1.1-1.2 is the increase in density and vigor of mid-stature bunchgrasses to the point that they dominate species composition by weight. The trigger for this is a sagebrush killing event, such as drought, insects, and/or disease. In recent history, chemical, mechanical or biological control of sagebrush that favors the existing herbaceous vegetation have been tools to mimic these natural sagebrush killing events. The result of these management actions can have the desired effect of shifting the community from within the Reference State, but they can also accelerate the transition to alternate states depending on current and post-treatment management.

Pathway 1.2-1.1
Community 1.2 to 1.1

Bunchgrass/Big Sagebrush

Big Sagebrush/Bunchgrass

The driver for community shift 1.2-1.1 is natural succession. The trigger for this shift is an increase in shrub canopy cover and decline in overall bunchgrasses. The transition to the Big Sagebrush/Bunchgrass Community (1.1) can be the result of sagebrush naturally increasing its canopy cover along with yearly climatic differences. This transition can be accelerated with proper herbaceous grazing (properly stocked and a grazing system that varies the time and timing of grazing to provide for periodic deferment during the critical growth period) and natural events such as drought/wet cycles.

Pathway 1.2-1.3
Community 1.2 to 1.3

Bunchgrass/Big Sagebrush

Bunchgrass

The driver for community shift 1.2-1.3 is the increase in density and vigor of mid-stature bunchgrasses to the point that they dominate species composition by weight. The trigger for this is a sagebrush killing event, such as drought, insects, and/or disease. In recent history, chemical, mechanical or biological control of sagebrush that favors the existing herbaceous vegetation have been tools to mimic these natural sagebrush killing events. The result of these management actions can have the desired effect of shifting the community from within the Reference State, but they can also accelerate the transition to alternate states depending on current and post-treatment management. Mowing treatments in the Reference State have resulted in increased soil nitrogen (N) but no change in soil organic Carbon (C). Conversely, mowing treatments in the Grazing Resistant State have resulted in no changes in soil N or C (Derner, Schuman, Follett, & Vance, 2014)

Pathway 1.3-1.2
Community 1.3 to 1.2

Bunchgrass

Bunchgrass/Big Sagebrush

The driver for community shift 1.3-1.2 is natural succession. The trigger for this shift is an increase in shrub canopy cover and relative decline in bunchgrasses. The transition to the Bunchgrass/Big Sagebrush Community (1.2) is the result of sagebrush naturally increasing in cover along with yearly climatic differences. This transition can be accelerated with proper herbaceous grazing (fully stocked and a system that varies the time and timing of grazing to provide for periodic deferment during the critical growth period) and natural events such as drought/wet cycles.

State 2
Grazing Resistant

The Grazing Resistant State (2) is characterized by an herbaceous layer dominated by short-statured bunchgrasses such as Sandberg bluegrass and, rhizomatous grasses and grass-likes, such as thickspike wheatgrass and needleaf sedge. Mid-stature bunchgrasses such as Indian ricegrass and needleandthread are scarce or absent. There are two community phases in the Grazing Resistant State: the Big Sagebrush/ Thickspike Wheatgrass Plant Community and the Thickspike Wheatgrass/Big Sagebrush Plant Community. (2.1). The site crosses the threshold to the Grazing Resistant State (2) from the Reference State (1) when desirable mid-stature bunchgrasses lose dominance. Once the key species become scarce, it is unlikely that they have sufficient reproductive capability (seed source, tillering, or resprouting) to recover dominance in a reasonable time frame without extra energy being added to the system. The Big Sagebrush/Thickpsike Wheatgrass Plant Community is very resistant to change and therefore is common on this site. In many cases, the transition to the Grazing Resistant State (2) 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 in this state. While dominance by rhizomatous grasses makes the return to the Reference State (1) plant community difficult, it also makes the site resistant to further degradation except in cases where overstocked or in the case of prolonged drought with full stocking. The main factor creating resiliency of the Big Sagebrush/Thickspike Wheatgrass Plant Community is that rhizomatous grasses are highly grazing tolerant. Sandberg bluegrass and rhizomatous grasses are low to the ground, so, even under heavy grazing, enough biomass remains for the grasses to maintain plant vigor. Rhizomatous grasses successfully reproduce through underground rhizomes. The rhizomatous grasses can form mats that provide soil protection by protecting the soil from raindrop impact, decreasing the risk of soil erosion. However, overall soil health is lower than the reference state, primarily due to a reduction in soil organic matter due to a reduction in litter. The decreased infiltration is due increased bare ground patch size and lack of litter that acts as mulch in retaining soil moisture and retarding runoff. Under high intensity grazing, especially in early season pastures and in small acreage pastures, ground cover can decrease to a point that the site will transition to the Bare Ground State (3), particularly during drought conditions if stocking is not reduced.

Community 2.1
Big Sagebrush/Thickspike Wheatgrass

The Big Sagebrush/Thickspike Wheatgrass Plant Community (2.1) is shrub-dominated with an herbaceous component dominated by thickspike wheatgrass and other low-growing, grazing tolerant species such as needleleaf sedge. Once the mid-stature bunch grasses becomes scarce, it is unlikely to have sufficient reproductive capability (seed source, tillering, or resprouting) to recover dominance in a reasonable time frame without extra energy being added to the system. The plant community is highly resistant to changes in composition, due to the dominance and competition of established low stature and rhizomatous species. However, the community can be restored back to the Reference State over time with appropriate sagebrush treatment and a grazing regime that includes periodic critical growth period deferment. This community is shrub dominated. Sagebrush canopy is greater than 25 percent. The dominant shrub is Wyoming big sagebrush. The Big Sagebrush/Thickspike Wheatgrass Plant Community occurs if the herbaceous component has been degraded. Areas that catch and retain snow are more likely to have the highest shrub cover. Range Health Indicators: Production is considerably lower than in Reference State (1), leading to lower soil organic matter content and therefore lower soil stability than in the Reference State. Ground cover is still high. Infiltration is lower than in the Reference State and the water cycle has reduced function due to decreased soil organic matter. Note: POSE in Group 1 refers to larger varieties such as Canby's and big bluegrass. POSE in Group 3 refers to Sandberg bluegrass.

Community 2.2
Thickspike Wheatgrass/Big Sagebrush

The Thickspike Wheatgrass/Big Sagebrush Community (2.2) is characterized by an herbaceous component dominated by low-stature and rhizomatous species such as thickspike wheatgrass and needleleaf sedge. Once mid-stature bunchgrasses becomes scarce, they are unlikely to have sufficient reproductive capability (seed source, tillering, or re-sprouting) to recover dominance in a reasonable time frame without extra energy being added to the system. The plant community is highly resistant to changes in composition, due to the dominance and competition of grazing tolerant species. However, the community can shift back to the Reference State (1) with grazing deferment followed by a grazing system that allows periodic rest during the critical growth period. Seeding maybe needed in some instances to achieve desired results. Thickspike wheatgrass (Elymus lanceolatus ssp. lanceolatus) dominates, and Wyoming big sagebrush foliar cover is typically 5% to 25%. The Rhizomatous Wheatgrass/Big Sagebrush Community occurs if there is a sagebrush killing event after the herbaceous component has already been degraded. Biological soil crusts have greatly diminished, further exposing the soil surface to erosional forces as well as impairing carbon, nutrient, and water cycles. Productivity is highly variable and fluctuates drastically in response to drought and wet cycles. Production is lower than in Reference State (1), leading to lower soil organic matter and nitrogen content and therefore lower soil stability than in the Reference State. Ground cover is still high, but infiltration is lower than in the Reference State and hydrologic function is impaired due to decreased soil organic matter. Note: POSE in Group 1 refers to larger varieties such as Canby's and big bluegrass. POSE in Group 3 refers to Sandberg bluegrass.

Pathway 2.1-2.2
Community 2.1 to 2.2

Sagebrush killing event, typically a mechanical or chemical treatment. Due to low fine fuels, fire is seldom a driver in this state.

Pathway 2.2-2.1
Community 2.2 to 2.1

The trigger for a community shift from the Thickspike Wheatgrass/Big Sagebrush Plant Community (2.2) to the Big Sagebrush/Thickspike Wheatgrass Plant Community (2.1) is time without sagebrush killing disturbances. This shift can be accelerated with high utilization levels by grazers, particularly during the critical growth period.

State 3
Bare Ground

This state contains one community, the Big Sagebrush/Bare Ground Community (3.1). It is characterized by sparse herbaceous plant cover dominated by big sagebrush and bare ground. Communities in the Bare Ground State (3) have crossed a threshold (T1-3 or T2-3) because of soil erosion, loss of soil fertility, and/or degradation of soil properties. Soil erosion affects the hydrology, soil chemistry, soil microorganisms, and soil physics to the point where intensive restoration is required to restore the site to another state or community. Simply changing grazing management may not create sufficient change to restore the site within a reasonable period. It will require a considerable input of energy to move the site back to the Reference State (1). The Bare Ground State (3.0) is at high risk of weed invasion due to the high percentage of bare ground. Many invasive species are adapted to low soil fertility, high soil temperatures and low soil moisture content. This puts the community at risk of transitioning to the Disturbed State (4).

Community 3.1
Big Sagebrush/Bare Ground

Herbaceous canopy cover in the Big Sagebrush/Bare Ground Community (3.1) is significantly reduced. Annual production is approximately half of the Bunchgrass Plant Community (1.1). Perennial grasses may exist only in patches and are typically low in vigor. This community tends to be dominated by big sagebrush (>25% cover) and bare ground in large patches in the interspaces of the shrub canopy. The majority of annual production is from big sagebrush so this site provides very little value for livestock grazing. There is some value to wintering big game, but the lack of an herbaceous understory results in poor wildlife values overall. The Big Sagebrush/Bare Ground Community (3.1) rarely produces sufficient quantity of fine fuels necessary to carry a fire. Therefore, fire no longer influences community dynamics. The Big Sagebrush/Bare Ground Community (3.1) differs from other communities, because it is characterized by sparse plant cover and soil surface erosion. Sparse vegetation creates low levels of foliar and basal cover. This, in turn, leads to low litter production, which is combined with reduced ability to retain litter on site. Soil is exposed to wind and water erosion in the plant interspaces. These factors combine to create a decrease in soil organic matter. Reduced litter cover, combined with reduced herbaceous cover, results in higher soil temperature, poor water infiltration rates, and high evaporation, thus favoring species which are more adapted to drier conditions. Soil fertility is reduced, soil compaction is increased, and resistance to soil surface erosion has declined compared to the other states. This community has lost most, if not all, of the attributes of a functioning, healthy rangeland, including good infiltration, minimal erosion and runoff, nutrient cycling, and energy flow.

State 4
Disturbed

This state is characterized by the amount of rabbitbrush on the site. It also has a component of annual forbs and substantial bare ground. It occurs with multiple sagebrush killing events in rapid succession outside the normal disturbance regime for this site (see Reference State for discussion). It could be mechanical (including heavy equipment/construction or a mowing/chaining/harrow type sage treatment), chemical (including 2,4-D or tebuthiuron), or biological (including browse and/or insects). Fire could be a factor in maintaining this plant community perpetually by stimulating sprouting shrubs (rabbitbrush) and killing sagebrush. This is usually only a concern when annual weeds are prolific on the site during wet cycles that boost their production. Removal of shrubs without proper grazing management can lead to an increase in bare ground and erosion of the upper soil horizon. Consequences of this are decreased soil fertility or even soil erosion, soil crusting, and decrease of soil surface aggregate stability.

Community 4.1
Sprouting Shrub/Thickspike Wheatgrass

The plant community is in a perpetual state of disturbance when maintained long-term on a site. The disturbance regime of the site has been accelerated often with the addition of ground disturbing activities (i.e. gravel pits, pasture corners where livestock are gathered, continual sagebrush removal techniques, and rapid succession fire). Seeding may be used to restore Reference State functional structural groups, but it is unlikely that the Reference soil site stability can be achieved, and so any restoration efforts of this State will result in transition to the Reclaimed Plant Community of the Highly Disturbed State.

State 5
Highly Disturbed

Community 5.1
Annuals/Bare Ground

As part of succession, all sites that are severely disturbed will go through this plant community as part of their restoration. Weather is the largest determining factor in how long a site will be in this plant community phase, but is approximately 2-5 years on sites that use Best Management Practices for site restoration (http://www.uwyo.edu/wrrc/).

Community 5.2
Reclaimed

This plant community is highly variable based on weather conditions during restoration activities, the management practices used to implement the restoration, the seed mix, and how soil was stockpiled during the disturbance.

Transition 1-2
State 1 to 2

The driver for Transition T1-2 is continuous spring grazing and/or long-term drought. Continuous spring grazing and/or drought can lead to a decline in palatable mid-stature bunchgrasses. Indian ricegrass, a short-lived perennial that requires more frequent seed production to provide an adequate seedbank, is typically the first species to decline (Natural Resources Conservation Service, 2007). Needleandthread is more grazing tolerant, but will eventually decline in plant density and vigor. As bunchgrasses diminish or die during periods of stress, low- stature bunchgrasses and rhizomatous grasses gain a competitive advantage, creating a shift in species composition toward less productive species. While bare ground may not change, the pattern of bare ground will shift to larger gaps in the canopy and fewer herbaceous plants between shrubs. Many of the remaining desirable bunchgrasses will be only found in the understory of the sagebrush canopy. Once mid-stature bunchgrasses species become scarce, it is unlikely that they have sufficient reproductive capability (seed source, tillering, or resprouting) to recover dominance in a reasonable time frame without extra energy being added to the system. When the understory vegetation has been degraded to this point, the transition to the Grazing Resistant State (2) can occur from either the Bunchgrass/Big Sagebrush Plant Community (1.2) or the Big Sagebrush/Bunchgrass Plant Community (1.1). The transition is not dependent on the increase of woody canopy cover, but rather on the lack of mid-stature bunchgrasses in the canopy interspaces. Management should focus on grazing management strategies that will prevent further degradation. This can be achieved through a grazing management scheme that varies the season of use to provide periodic deferment during the critical growth period (roughly May-June). Forage quantity and/or quality in the Grazing Resistant State (2) may be substantially reduced compared to the Reference State.

Transition 1-3
State 1 to 3

The driver for Transition T1-3 is continuous high intensity grazing and/or long-term drought. The Reference State (1) transitions to the Eroded State (3) if plant canopy cover declines significantly or total annual aboveground biomass production falls below 300 pounds per acre. The trigger for this transition is the loss of understory, which creates open spots with bare soil. Soil erosion is accompanied by decreased soil fertility driving the transitions to the Bare Ground State. Several other key factors signal the approach of transition T1B: an increase in soil physical crusting, a decrease in soil surface aggregate stability, and/or evidence of erosion, including water flow patterns, development of plant pedestals, and litter movement.

Transition 1-4
State 1 to 4

The driver for this transition is an increase in the disturbance cycle (i.e. grazing, drought, fire, mechanical, chemical or biological treatments) often in combination with grazing management that does not provide periodic deferment during the critical growth period. The Reference State (1) may transition to the Disturbed State (4) if a soil disturbing activity has occurred. Sprouting shrubs such as rabbitbrush increase from ground disturbances that could be either natural (i.e. water movement) or manmade (i.e. high density/high frequency stocking, mechanical treatments or heavy equipment operations). If a seed source exists, aggressive invasive species, such as cheatgrass, may be present, but are not expected to dominate the site. However, it is projected that annual invasives may effect site dynamics under future climate change scenarios. To prevent this transition, the site will require proper reclamation using the most current science and technology available to restore native vegetation and prevent invasive dominance. In some instances, it may not be possible to prevent this transition. In cases where total topsoil loss occurs, it may be unavoidable to prevent this transition. Long-term stress conditions for native species (e.g., improper grazing management, drought, and fire) will alter plant community composition and production over time and may hasten a transition to the Disturbed State (4). The resulting lower biomass production, reduced litter, and increased bare ground in this community can promote invasion of undesirable species. The site transitions to the Disturbed State when populations of invasive species reach critical levels.

Restoration pathway 2-1
State 2 to 1

The drivers for this restoration pathway are removal of woody species and restoration of native herbaceous species by mechanical or chemical treatment of sagebrush, and grazing rest or deferment. If some mid- stature bunchgrasses remain under the sage canopy, proper grazing management can move the site back to the Reference State (1) combined with a mechanical or chemical sagebrush treatment. This 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 2-3
State 2 to 3

The driver for transition to the Bare Ground State is continuous high intensity grazing. Examples include calving pastures and small acreage horse pastures where rotational grazing is not employed. Extended drought period may provide a trigger to accelerate this process. The Bare Ground State is typified by old age sagebrush stands with very little herbaceous understory. Bare ground patch size has increased to the majority of the interspaces between sagebrush plants.

Transition 2-4
State 2 to 4

The driver for transition to the Disturbed State is an increase in the disturbance cycle (i.e. grazing, drought, fire, mechanical, chemical, biological treatments). Removal of shrubs without proper grazing management can lead to an increase in bare ground and erosion of the upper soil horizon, and the site can degrade to the Disturbed State (4). Consequences of this transition are decreased soil fertility or even soil erosion, soil crusting, and decrease of soil surface aggregate stability.

Restoration pathway 3-1
State 3 to 1

This state has lost soil or vegetation attributes to the point that recovery to the Reference State will require a combination of long-term grazing management (changing season of use to allow frequent rest or deferment during the critical growth period) and chemical, biological or mechanical treatments, and often re-seeding. Seeding may become cost prohibiting as a restoration practice used alone. With reduced organic matter and loss of soil, soil amendments may be needed to have a successful seeding. Care must be taken with any re-seeding operation to prevent the introduction of invasive species, such as cheatgrass, to areas where these species are not currently present.

Restoration pathway 3-2
State 3 to 2

The drivers for this restoration pathway are mechanical, biological and chemical treatments with only temporary rest or deferment post-treatment. Due to loss of soil fertility, structure, and organic matter, reference community plants are slow to repopulate the site. Success of this restoration is highly dependent upon climatic factors.

Transition 3-4
State 3 to 4

The driver for this transition is multiple sagebrush killing events in rapid succession outside the normal disturbance regime for this site (see Reference State for discussion). It could be mechanical (including heavy equipment/construction or a mowing/chaining/harrow type sage treatment), chemical (including 2,4-D or tebuthiuron), or biological (including browse and/or insects). Fire is not usually possible due to lack of understory fuels to carry the fire. In fact, the Eroded State is characterized by monotypic decadent sagebrush stands because they are fireproof.

Restoration pathway 5-1
State 5 to 1

The Highly Disturbed State (5) can be restored to the Reference State (1) if appropriate seedbed preparation and seed mixes are used, and weather conditions are conducive to seedling establishment. This most often occurs through achieving the Bunchgrass Plant Community first. Weather is the largest determining factor in determining time and success, but the process can be accelerated with Best Management Practices for site restoration (http://www.uwyo.edu/wrrc/). There is low potential for recovery without significant inputs of energy and resources if topsoil has been removed. Seeding is needed to restore functional structural groups, and proper seedbed preparation is key to restoring ecological processes on the site.

Restoration pathway 5-2
State 5 to 2

The Highly Disturbed State (5) is often restored to the Grazing Resistant State (2) unintentionally when inappropriate seed mixes are used and post-seeding grazing does not provide adequate and periodic critical growth period rest. There is low potential for recovery without significant inputs of energy and resources 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) will often result in a plant community resembling the Grazing Resistant State (2) due to pre and post-seeding grazing management of the area.

Restoration pathway 5-3
State 5 to 3

The Highly Disturbed State (5) can transition the Eroded State (3) if disturbed areas result in total topsoil removal, are abandoned (no re-seeding) and climate is favorable for sagebrush seedling establishment. Wyoming big sagebrush will eventually colonize the site, but because soil conditions are severely altered, little to no under-story can be found. An example of this transition can be found on abandoned oil and gas wells that are 30+ years old where topsoil was not stockpiled and re-spread on the site after proper contouring and ripping, and either no seeding was done or the planting was a failure. If topsoil was not physically removed, and there is a viable seedbank in the soil, recovery is possible without re-seeding as long as adequate rest from herbivory is provided to allow seedling establishment. Rest from herbivory is recommended during dry years to prevent further soil loss as well as in wet years to allow seedling establishment.

Restoration pathway 5-4
State 5 to 4

The Highly Disturbed State (5) can transition the Disturbed State (4) if disturbed areas result in only partial topsoil removal, leaving rootstock available for sprouting species such as rabbitbrush. This is common for gravel pits and areas disturbed as stockpile areas where soil is placed on the area for any amount of time, and then removed with equipment that scrapes some of the soil surface during the removal process.