State 1
Saltbush/Native Grasses

The Reference Communities (1.1., 1.2, and 1.3) for this state have developed under moderate use throughout the year by large ungulates. Although these sites do not provide a large quantity of forage, the value of the saltbush and the interspersed grasses provides a food source for spring and fall grazing when other sites are sensitive.

Characteristics and indicators. This State is characterized by a dominance of Gardner's saltbush and a mixture of mid-stature bunchgrasses and some rhizomatous species. A variety of low-growing forbs are present in these communities.

Resilience management. The Saltbush/Native Grasses State is easily shifted when disturbance occurs, but is well adapted to the climatic conditions. The Saltbush/Native Grasses State can quickly recover from drought, making it sustainable, but hard to reestablish once disturbed.

Community 1.1
Saltbush/Indian Ricegrass

Figure 9. Indian ricegrass and Gardner's saltbush are the key species within the Reference Community Phase 1.1 (Saltbush/Indian Ricegrass).

This community phase, Saltbush/Indian Ricegrass, is described as the Reference Plant Community. This community evolved under moderate grazing by large ungulates and with very droughty soil conditions due to the slower infiltration rates and salt content of the soil. The salt-tolerant, drought-resistant plants that dominate this site are Gardner's saltbush and Indian ricegrass. Bottlebrush squirreltail and birdfoot sagebrush are minor components. A small variety of forbs are found on this site, and are listed on the following plant community tables . The total annual production (air-dry weight) of this state is about 350 pounds per acre, but it can range from about 125 lbs./acre in unfavorable years, to about 500 lbs./acre in above average years.

Resilience management. The Saline Upland Clayey ecological site is extremely stable and well adapted to the climatic conditions. The diversity in plant species allows for high drought resistance. This is a sustainable plant community in relation to soil stability, watershed function, and biologic integrity.

Community 1.2
Saltbush/Squirreltail

Figure 12. Bottlebrush squirreltail will maintain cover as Indian ricegrass decreases, leaving a Saltbush/Squirreltail community.

The bottlebrush squirreltail begins to be the dominant species under moderate, season-long grazing by large ungulates. Prolonged drought can play an important role and will exacerbate these conditions. Gardner’s saltbush and bottlebrush squirreltail are the major components of this plant community. Other cool-season grasses make up the majority of the understory with miscellaneous forbs. Forbs commonly found on this site are wild onion, biscuitroot, smooth woodyaster, leafy wildparsley, and plains pricklypear. When compared to the Reference Community (1.1), shortspine horsebrush has decreased significantly, Indian ricegrass has decreased and may occur in only trace amounts, birdfoot sagebrush may have increased, and alkali seepweed may have established within the site. The total annual production (air-dry weight) of this state is about 200 pounds per acre, but it can range from about 75 lbs./acre in unfavorable years, to about 400 lbs./acre in above average years.

Resilience management. Rangeland Health Indicators: Community Phase 1.2 is relatively resistant to change. The herbaceous species are well adapted to grazing; however, species composition can be altered through long-term overgrazing. The herbaceous component is mostly intact and plant vigor and replacement capabilities are sufficient. Water flow patterns and litter movement may occur, but is not extensive. Incidence of pedestalling is minimal. Soils are mostly stable and the surface shows minimal soil loss. The watershed is functioning and the biotic community is intact, but there is a shift in herbaceous structure.

Community 1.3
Saltbush/Sandberg Bluegrass

Figure 15. The at-risk community within the Reference State is the Saltbush/Sandberg Bluegrass Community (1.3).

Plant Community 1.3, Saltbush/Sandberg Bluegrass, is an at-risk community for the Reference State. As Sandberg bluegrass increases, Indian ricegrass is easily removed from the system. Drought, soil conditions, and seed source can influence the shift between bottlebrush squirreltail and Sandberg bluegrass. Both species are common on the Saline Upland Clayey ecological site as it is degraded. Sandberg bluegrass has higher defenses to tolerate grazing and drought. The total annual production (air-dry weight) of this state is about 175 pounds per acre, but it can range from about 75 lbs./acre in unfavorable years, to about 350 lbs./acre in above-average years.

Resilience management. Rangeland Health Indicators: This plant community is relatively resistant to change. The herbaceous species are well adapted to grazing; however, species composition can be altered through long-term overgrazing. The herbaceous component is mostly intact, and plant vigor and replacement capabilities are sufficient. Water flow patterns and litter movement occur within the basal inter-spaces, but is not extensive. Incidence of pedestalling is minimal. Soils are mostly stable and the surface shows minimal soil loss. The watershed is functioning and the biotic community is intact. Sandberg bluegrass is a grazing- and drought-tolerant grass that can easily maintain cover and increase with moderate to heavy grazing. Sandberg bluegrass is also tolerant to traffic and other minor surface disturbances, allowing it to maintain cover as other native grasses begin to fall out of the composition. As drought, continued heavy utilization, or ground disturbance increases, Sandberg bluegrass loses vigor and will be removed, making this community prone to invasion or to become dominated by Gardner's saltbush.

Pathway CP1.1-1.2
Community 1.1 to 1.2

Saltbush/Indian Ricegrass

Saltbush/Squirreltail

Drought; moderate, continuous season-long grazing–Prolonged drought will stress Indian ricegrass beyond tolerance, reducing and possibly removing it from the community, especially when conditions are exacerbated by moderate, continuous season-long grazing. The loss of production in Indian ricegrass is initially compensated by bottlebrush squirreltail, and a flush of annual grasses may occur.

Pathway CP1.1-1.3
Community 1.1 to 1.3

Saltbush/Indian Ricegrass

Saltbush/Sandberg Bluegrass

Drought; heavy, continuous season-long grazing–Prolonged drought will stress Indian ricegrass beyond tolerance, reducing and possibly removing it from the community. Drought loss will be exacerbated by heavy, continuous season-long grazing in removing the more desirable species leading to the dominance of Sandberg bluegrass. The loss of production in Indian ricegrass is initially compensated by Sandberg bluegrass, western wheatgrass, and bottlebrush squirrreltail as well as an assortment of forbs.

Context dependence. Existing herbaceous composition will be a determining factor in the Saltbush/Ricegrass Community (Reference) degrading to Community Phase 1.2 or 1.3. If bottlebrush squirreltail is in good vigor and subdominant on a site to Indian ricegrass, degradation of the Reference Community will transition to Community Phase 1.2 rather than Community Phase 1.3. However, if Sandberg bluegrass is the subdominant, the transition will be to Community Phase 1.3.

Pathway CP1.2-1.1
Community 1.2 to 1.1

Saltbush/Squirreltail

Saltbush/Indian Ricegrass

Long-term prescribed grazing; rest–The application of long-term prescribed grazing including rest and rotation of use will allow Indian ricegrass to recover. The small shift in birdfoot sagebrush and alkali seepweed will not disappear, but will be a very minor component on the site.

Context dependence. Recovery of this site with grazing management including rest is dependent on having a seed source in the near proximity of the site for Indian ricegrass. Further consideration has to be given to the soil surface conditions and climatic patterns to be favorable for germination for recovery to be possible.

Pathway CP1.2-1.3
Community 1.2 to 1.3

Saltbush/Squirreltail

Saltbush/Sandberg Bluegrass

Drought; heavy, continuous year-long grazing–Prolonged drought will continue to reduce the vigor and tolerance of this community. As bottlebrush squirreltail is removed by drought or grazing pressure, Sandberg bluegrass will persist. A flush of annual forbs usually responds to the loss of perennial vegetation. When drought lifts, if grazing pressure is not removed, the ability for the perennial vegetation (bottlebrush squirreltail and Indian ricegrass) are limited in their ability to recover.

Context dependence. This community pathway (1.2-1.3) is dependent on the presence of Sandberg bluegrass, and the level of disturbance. If Sandberg bluegrass is not present in the community, then this pathway will lead to a different community phase not identified, or it may force a transition to State 2.1 Saltbush/Bare Ground.

State 2
Saltbush/Bare Ground

The loss of most of the perennial grass species within this state has created an at-risk community that is vulnerable to invasive species, but also is resilient and resistant to change. This creates a difficult scenario, and coupled with the low productivity of the land, many managers do not attempt to improve or manage these landscapes.

Characteristics and indicators. The Saltbush/Bare Ground State (State 2) consists predominately of Gardner's saltbush with pricklypear cactus or a few other scattered forbs, but very little other vegetation on the site.

Resilience management. As described before, the protein value of gardner’s saltbush provides an excellent source of feed at specific times of the year. If managed properly, saltbush can be a great spring or fall food source for livestock and wildlife.

Community 2.1
Saltbush/Bare Ground

Figure 18. Saline Upland Clayey ecological site transitioned to a Saltbush/Bare Ground community.

The persistence and resilience of Gardner's saltbush helps to create a stable plant community. This community will occur where sites are subjected to continuous year-long grazing. Gardner’s saltbush will dominate this site, and in some cases may comprise 100 percent of the plant community. The interspaces between plants have expanded significantly, leaving the amount of bare ground prevalent and the soil surface exposed to erosional elements. Birdfoot sagebrush will continue to persist with Gardner's saltbush and may help to protect the inter-spaces to a degree, but the site is more prone to erosion. Cool-season grasses have been greatly reduced and commonly are eliminated. With the lack of competition this site is vulnerable to invasion by noxious weed species such as clasping pepperweed and halogeton. When compared to the Reference Community 1.1, plant composition and structure are lacking, and productivity is diminished due to the excessive amount of bare ground. The total annual production (air-dry weight) of this community is about 250 pounds per acre, but it can range from about 50 lbs./acre in unfavorable years, to about 400 lbs./acre in above average years.

Resilience management. Rangeland Health Indicators: The Saltbush/Bare Ground community is resistant to change as the stand becomes more decadent. Fire is not a factor with the lack of fine fuels. Plant diversity is extremely low. The plant vigor is diminished and replacement capabilities are severely reduced due to the decrease in the number of cool-season grasses. Plant litter is noticeably less when compared to the Reference State (Plant Communities 1.1 and 1.2). Continued frequent and severe grazing has minimal effect on the persistent cover of Gardner's saltbush; however, the structure and vigor of the shrub will become stunted. University of Wyoming exclosure studies established in the 1950s were analyzed, and the removal of grazing has not shown any potential improvement for the plant composition or structure once degraded. Soil erosion is accelerated because of increased bare ground. Water flow patterns and pedestalling are obvious. Infiltration is reduced and runoff is increased. Rill channels may be noticeable in the interspaces and gullies may be establishing where rills have concentrated down slope.

State 3
Invaded

The major invasive species that are moving into the Big Horn Basin are cheatgrass, halogeton, Russian knapweed, and a variety of thistles. Many of these sites are used frequently by recreationalists for ATV/ORVs, shooting, etc., due to the open, barren nature. The heavy clay soils are attractive for mudding and other 4-wheel drive activities. With the increased “traffic” and the soil surface disturbance, not only is the ground opened to allow establishment, but weed seed sources are readily transported from one area to another.

Characteristics and indicators. The Invaded State will maintain the Gardner's saltbush as well as birdfoot sagebrush, with varying composition of the native herbaceous species. The dominant or significant herbaceous composition will transition to an introduced or invasive species. Halogeton is the major threat to the Saline Upland Clayey ecological site. However, cheatgrass will establish in the barren interspaces.

Resilience management. Preliminary studies completed by the Wyoming Bureau of Land Management (BLM) and University of Wyoming have shown examples of halogeton outcompeting Gardner's saltbush to be the only species on a location. However, no final publication has been found detailing the final outcome. Presentations have suggested that Gardner's saltbush may still be present in the understory, and with the removal or suppression of halogeton, saltbush may be able to recover. With other weedy species, no wide or monoculture stands have been located. The risk of going to a cheatgrass-only composition is minimal, unless intense ground disturbance (tillage, scraping, etc) occurs, removing the persistent saltbush cover. Once these communities have lost the native components, especially Gardner's saltbush, it is extremely difficult to reverse the community. Seeding is difficult due to the heavy-textured, salt-burdened, droughty soils.

Community 3.1
Grasses/Invaders/Saltbush

Figure 21. Gardner's saltbush, western wheatgrass, and Sandberg bluegrass community with a cheatgrass component.

Figure 22. Wildfire burn scars in a Saline Upland Clayey site with an component of cheatgrass and black greasewood.

This Community phase will resemble the Reference State communities (1.1, 1.2, and 1.3) but will have the presence of invasive species such as cheatgrass, halogeton, and knapweeds. The herbaceous species structural and functional groups still exist, but are decreasing in vigor and composition. If managed, the weed invasion can be minimal and change of this site may occur very slowly. Degradation of the site could be exacerbated by prolonged drought conditions, fire, or other disturbances. Fire in the Saline Upland Clayey ecological site was said to be not a risk. However, the added fuels of invasive species, namely cheatgrass, can provide the needed conditions to allow a fire to occur. In 2018, a lightening strike within the Oregon Basin of Wyoming, produced a fire the burned several hundred acres, included a sizable patch of Saline Upland Clayey. This community was in the Grasses/Invaded/Saltbush community 3.1. This community had a small cover of black greasewood with an understory component of cheatgrass. The fire burned quickly across the landscape, but the low structure and fuels under the saltbush and greasewood allowed hot spots that created significant burn scars in these areas. The site will be evaluated as healing and succession occurs to determine the long-term effects of a fire. So although it occurs, fire is still rare on these communities and is not considered a major risk overall. The variability in composition between other weedy species that are commonly found with cheatgrass affect the production of these sites, so at this time, sufficient data has not been collected to provide an average production figure. Site specific analysis is recommended for planning.

Resilience management. Rangeland Health Indicators: The plant community is relatively resistant to change; however, the invasive species will continue to increase if not managed. The other herbaceous species are well adapted to grazing and drought conditions. The plant composition is mostly intact and plant vigor and replacement capabilities are reduced but sufficient. Water flow patterns and litter movement may occur, but is not extensive. Instances of pedestalling is minimal. Soils are mostly stable and the surface shows minimal soil loss. The watershed is functioning and the biotic community is intact. The weedy species that encroach into this community determine the benefits or risks associated. Invasive species, in general, are able to colonize in the inter-spaces of the community, reducing bare ground, increasing water infiltration, and ultimately creating a more stable soil. The consequence is an increase in fire risk due to the added bio-fuels. This is especially true with cheatgrass.

Community 3.2
Invaders/Saltbush

Figure 24. Cheatgrass and saltbush dominated community on the Saline Upland Clayey ecological site.

As annuals or other invasive species increase, the native grasses are weakened and eventually will be removed from the site. This will leave a saltbush community that has a dominant invasive partner. Cheatgrass may be a common threat on this site, but unlike the sagebrush counterpart, the Gardner’s saltbush is able to maintain and prevent the dense monoculture stands of cheatgrass that increases the fire risk, reducing the risk of the loss of Gardner’s saltbush from this community. However, Halogeton has recently been found to take over and slowly remove saltbush from a location, especially in the fine textured soils of this site. As other invasive species are brought into the Basin, the dynamics of this site will vary depending on the specific species. Due to the variable productivity and the extent of interaction with saltbush, it is difficult to identify the potential productivity without completing a site specific evaluation.

Resilience management. Rangeland Health Indicators: This plant community is resistant to change as the stand becomes more decadent. Continued frequent and severe grazing or the removal of grazing does not seem to affect the plant composition or structure of the plant community. Plant diversity is greatly altered and the herbaceous component is not intact. Recruitment of perennial grasses is not occurring and the replacement potential is minimal. The biotic integrity is missing.

Pathway CP3.1-3.2
Community 3.1 to 3.2

Grasses/Invaders/Saltbush

Invaders/Saltbush

No use/management, persistent drought, frequent and severe grazing, further disturbance–Once invasive species have gained a niche in a community no use is comparable to no management or over use. Drought on its own can force a community to change very quickly. Disturbances such as energy development, mining, or recreation, assist in providing a seed source. Soil disturbance opens the seedbed to initiate the establishment invasive species, allowing the problem to quickly across the landscape.

Pathway CP3.2-3.1
Community 3.2 to 3.1

Invaders/Saltbush

Grasses/Invaders/Saltbush

Integrated pest management or invasive species control with long-term prescribed grazing–In areas where there are still remnant populations of the cool-season perennial grasses, if weed control is put into place and grazing management occurs to protect the perennial grass species, this site has the potential to improve slightly.

State 4
Altered

Many of the sites identified have been near areas that are actively mined for bentonite, oil and gas, or have been used for recreational vehicles. The level and extent of disturbance varies greatly between each of these uses. Climate, degree of disturbance, type of disturbance, and the resources surrounding each location must be considered with this state.

Characteristics and indicators. The Altered State is to capture areas where surface disturbance has removed the native vegetation or where the site has been treated to improve or enhance the native community resulting in a non-native composition.

Resilience management. Climatic conditions and soil limitations restrict the feasibility of manipulating the native vegetation or degraded sites with much success. Additional inputs to help improve soil quality as well as artificial watering systems to assist in seedling establishment have been costly, and troublesome. Irrigating these sites has created issues with surface crusting, inhibiting seedling emergence. Intensity and timing of precipitation has proved risky and nearly impossible to achieve a high level of success. However, some areas have had acceptable establishment with introduced or improved varieties of species.

Community 4.1
Altered

Small acreages of abandoned lands have been created over an extended period of time. Changes in irrigation systems, land management or ownership, as well as extended periods of drought have shifted acres of the Saline Upland Clayey ecological site to a degraded state. Irrigation of these sites is difficult, and many times attempts to farm these areas are short lived, but the change to the soil or plants are long-lasting. Once the soil has been tilled or mechanically worked, the structure and function of the site is altered. These changes prevent the site from returning to a true Reference State. Many times the disturbances are due to vehicle traffic from mining, farming, or recreation. Over time the saltbush is degraded and then removed from the site. Oil and gas development remove all vegetation to create pad sites, leaving raw and compacted soils susceptible to weeds. Many times when these locations are left to recover by natural forces, they become weed-dominated or slowly transition through several stages of primary succession, creating a community that is variable with productivity related closer to the disturbance rather than to the communities that exist. In select locations introduced seedings were completed and then were left to adapt to the climate. Many of these sites are still visible on the landscape with a distinctive community or a row pattern in the vegetation. Crested wheatgrasses and Russian wildrye were the primary species utilized in the seedings during the late 1940s to the early 1980s. The persistence of these species and the furrows or drill rows help to quickly identify these locations. In other instances, the edge of the pad site, or edge effect of fields, roads, etc. are still visible on aerial photography. Because of the noted variability, estimation or average production has not been attempted. The selected growth curve is typical for the climate, not taking into consideration the variety of plant species that are present. Site-specific evaluation needs completed to accurately capture the potential productivity and growth curves.

Resilience management. The climatic challenges (low amount, high-intensity, scattered rainfall and variable spring temperatures) with the soil limitations (heavy textures prone to surface sealing and high salt, sodium, or gypsum content) make seeding or reestablishing vegetation challenging. There are new cultivars that will tolerate the conditions, but the cost and risk analysis must be considered in the reclamation process. This community has not been identified to recover to a natural community within a specified time frame.

Transition T1-2
State 1 to 2

Frequent, severe grazing and drought–When these communities are used year-long with no recovery and multiple uses per growing season, the mid-stature cool-season grasses will be removed or reduced to a very trace composition on the site. If it is again exacerbated with prolonged drought, the community will become a saltbush-dominant or monoculture stand.

Constraints to recovery. The lack of seed source and the harsh environment created by the heavy clay soils limits the ability for seedling establishment.

Transition T1-3
State 1 to 3

Drought, disturbance or overuse with seed source present–When drought or a disturbance such as overuse by grazers occurs, the vulnerability of the state is opened and when there is a seed source present, invasive species can gain a foothold quickly due to the open canopy and low plant density.

Constraints to recovery. The difficulty to eradicate invasive species hinders the ability for the recovery of this State.

Restoration pathway R2-1
State 2 to 1

Long-term prescribed grazing; seeding with no to only minimal ground disturbance, cultural seeding practices–With extended grazing management, allowing rest and rotation, these sites may be prevented from further degradation, and will see a return to the Reference State composition over very extended periods. Trials have been completed on an informal basis of broadcast seeding sites in the fall and winter, and then feeding hay over them. This works to incorporate organics that will increase infiltration, provide nutrients to the site as well as prevent erosion, and allow for a small amount of establishment of species. Although the scientific studies have not addressed this in the Basin, it has been seen to have a small success in isolated areas.

Transition T2-3
State 2 to 3

Disturbance with seed source present, drought–Ground disturbance from recreation, energy development, or other activities provides a means to introduce a seed source into an already vulnerable community with the high bare ground and open canopy. Drought provides further stress on the saltbush, reducing vigor, and allowing species such as halogeton and cheatgrass to gain a foothold in the community.

Constraints to recovery. The difficulty to eradicate weeds limits the recovery potential of this community.

Transition T2-4
State 2 to 4

Mechanical grazing land treatment (furrowing or pitting), seeding–Several locations throughout the Big Horn Basin have been contour furrowed with a range plow with a 5-foot interval. In some areas non-native seedings were implemented while others had no seedings completed. The furrows assisted in catching and holding more moisture and provided a zone where establishment could take place. Overall improvements were seen to persist on these treated locations for over 20 years; however, the process is quite expensive with low returns (long-term species response).

Constraints to recovery. The limitations of the soil for seedling establishment is the major constraint to recovery. With the use of newer seeding techniques and soil amendments with salt-affected, heavy textured soils, better success rates are being seen.

Restoration pathway R3-2
State 3 to 2

Integrated pest management, invasive weed control, long-term prescribed grazing - As was mentioned previously, it is known that with favorable weather and management, Gardner’s saltbush will respond and gain productivity, if a presence is there before treatments begin. The process is very slow and requires continual maintenance of the site to prevent halogeton from returning.

Context dependence. If cheatgrass is the invasive species of concern, then recovery is not a potential, but halogeton is containable to allow recovery of this State.

Restoration pathway R3-4
State 3 to 4

Integrated pest management or invasive species control, grazing land mechanical treatment, seeding–With the improved varieties of plant materials that are available for salt-affected soils, seeding sites has become a more feasible solution. However, control of the invasive species with long-term grazing management as well as mechanical preparation and seeding will be required to have any level of success. Success will still be minimal due to the limiting climatic conditions that exist within the Big Horn Basin.

Transition T4-3
State 4 to 3

Continued disturbance or lack of use or management with seed source present –If a site is vulnerable and not established or if it is in a degraded state, many times these sites will be repeatedly misused or abused by vehicle traffic. These at-risk sites are vulnerable to weeds especially the aggressive invasive species that are within the Basin. Knapweed and halogeton, as well as cheatgrass have seed sources readily available and easily transported on tires, undercarriages, animals, and humans themselves.