State 1
Saltbush/Bunchgrasses

The Reference Communities (1.1 and 1.2) 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 forbs are present in these communities.

Resilience management. The Saltbush/Bunchgrasses State is easily shifted when disturbance occurs and is hard to re-establish once disturbed. However, the ecological site is well adapted to the climatic conditions, allowing quick recovery from drought, making it sustainable.

Community 1.1
Saltbush/Indian ricegrass

Figure 9. Needle and thread and low larkspur are prominent in this community with sagebrush on the fringes of the community where soil properties shift.

Equal composition of Gardner's saltbush and perennial grasses with a minor component of perennial forbs is the signature characteristic of the reference plant community for the Saline Upland Sandy ecological site. The dominant plant community can be found on areas that are properly managed with prescribed grazing including short periods of rest/deferment. Potential vegetation is about 50% grasses or grass-like plants, 10% forbs, and 40% woody plants.

Gardner's saltbush dominates the site with shadscale, winterfat, Indian ricegrass, needle and thread, and prairie junegrass being sub-dominate. Other potential salt tolerant shrubs, namely Greasewood, and spiny hopsage, bottlebrush squirreltail, blue gramma, adn sand dropseed are also common on these sites.

The total annual production (air-dry weight) of this community is about 375 pounds per acre, but it can range from about 200 lbs./acre in unfavorable years to about 650 lbs./acre in above average years.

Resilience management. This state is fragile, but well adapted to the climatic conditions. The diversity in plant species allows for high drought tolerance. This is a sustainable plant community but is difficult to re-establish when damaged, in reference to site/soil stability, watershed function, and biologic integrity.

Community 1.2
Saltbush/Sandberg Bluegrass

Figure 12. Sandberg bluegrass, sand dropseed and an blue grama increasing on an Saline Upland Sandy ecological site.

Figure 13. Sandberg bluegrass community with evident signs of water movement creating gullying on this Saline Upland Sandy ecological site.

Gardner’s saltbush and Sandberg bluegrass are the major composition for this community. Grass species that are common on the site include prairie junegrass, sand dropseed, blue grama, and needle and thread. Forbs commonly found in this plant community include scarlet globemallow, low larkspur, tansyaster, and evening primrose. This plant community maintains diversity, but lacks the structure for cover and wildlife habitat.

When compared to the Reference Community, Sandburg bluegrass and blue grama have increased and plains pricklypear cactus has invaded. Indian ricegrass has decreased and may occur in only trace amounts within the patches of plains pricklypear. Season of use and grazing species has limited or removed winterfat from this community.

Saltbush/Sandberg Bluegrass plant community is found under moderate, season-long grazing by livestock. Prolonged drought will move a reference community to this community phase, and together with continuous season-long grazing this transition can happen more readily.

This community responds to the wet and dry growing seasons with an exaggerated shift in produciton. The fire threat is minimal because of the lack of fine fuels; however, in wet early springs or late fall, bluegrass response may provide the cover and fuels to increase the risk of fire. This plant community is still dominated by Gardner's saltbush and cool-season grasses, while short warm-season grasses and miscellaneous forbs account for the balance of the understory. Under continued drought or intense grazing, this community is at-risk of shifting to a sod-forming, warm-season dominated grass community.

The total annual production (air-dry weight) of this state is about 300 pounds per acre, but it can range from about 100 lbs./acre in unfavorable years to about 650 lbs./acre in above average years.

Resilience management. Rangeland Health Implications/Indicators: This plant community is resistant to change, the herbaceous species present are well adapted to the climatic variability and grazing. The herbaceous component is mostly intact and plant vigor and replacement capabilities are sufficient. Water flow patterns and litter movement may be occurring but only on steeper slopes. Incidence of pedestalling is minimal. Soils are mostly stable and the surface shows minimum soil loss. The watershed is functioning, and the biotic community is intact.

Pathway 1.1A
Community 1.1 to 1.2

Saltbush/Indian ricegrass

Saltbush/Sandberg Bluegrass

Moderate Continuous Season-long Grazing, Drought - Gardner’s saltbush is tolerant to and so resilient under slight and moderate grazing pressures over a period of time. The herbaceous component, however, is weakened under constant use. Indian ricegrass will decrease initially. As the pressure persists, the vigor and frequency of needle and thread, prairie junegrass, and Indian ricegrass will decrease while Sandberg bluegrass and blue grama increase. The transition into community phase 1.2 can be reversed with shifts in management and climatic improvements.

Context dependence.Bottlebrush squirreltail and sand dropseed will fluctuate more in response to specific soil characteristics and climate than to use. Production may not be altered depending on the precipitation for the year, but with continued stress the production will decrease as overall diversity and herbaceous cover is reduced.

Pathway 1.2A
Community 1.2 to 1.1

Saltbush/Sandberg Bluegrass

Saltbush/Indian ricegrass

Prescribed Grazing or Long-term Prescribed Grazing - Given there is a viable seed source in close proximity, and with the appropriate rest and recovery time between grazing periods, Indian ricegrass and needle and thread can re-establish. The recovery process is slow because of the variable climate and the limiting soil environment. Recovery may take several years (10-30 years) for recovery with no outside inputs. At this stage, seeding or other mechanical treatments are not suggested. Ground disturbance provides for a higher risk potential for erosion and invasive species.

State 2
Saltbush/Sod-formers

State 2, Saltbush/Sod-formers State, is a prominant plant community group on the landscape. There are several working theories as to why, but the blue grama sod that is the indicator for this plant community is the key to this State. Blue grama forms in small but dense clumps or patches on the ground, altering hydrology and limiting the productivity of the site. The intermixed populations of forbs and Gardner's saltbush with plains pricklypear are the other components to this plant community.

Characteristics and indicators. Low-stature warm-season grasses, commonly (blue grama), and low-stature cool-season grasses (prairie junegrass) have increased in composition, reducing the diversity. Although the state is stable with approximately 30% ground cover by Gardner's Saltbush or salt tolerant shrubs, the production is slightly reduced. The trend noted during sampling was an increase of annual forbs with the decrease of Indian ricegrass and Bottlebrush squirreltail.

Resilience management. A combination of environmental and utilization disturbances has reduced the flexibility of the plant community leading to the shift to the Saltbush/Perennial Grasses State (State 2). Current and historic data has documented extreme swings in productivity between years (on an 8-10 year pattern) for Sandberg Bluegrass and Gardner's Saltbush specifically, but also for many of the species present. (Based on a 50 year data set). This swing in production can provide a false sense that a threshold has been crossed, when in actuality, it is a natural response to drought/climatic changes. These changes are what allow the Reference State and this state (State 2) to be sustainable.

Community 2.1
Saltbush/Blue grama

Figure 16. Gardner's saltbush and blue grama dominated community on a Saline Upland Sandy ecological site.

This plant community is the result of frequent and severe year-long grazing, which has adversely affected the mid-stature cool season grasses. Unlike other communities, the shrub component is less affected, but a change in vigor and stature will occur with continued pressure. The droughty nature of the sod is a response to the thick shallow mat of roots that are unable to reach the moisture as it quickly moves down in the soil profile, and channelizing runoff between established clumps or patches of vegetation. The lack of structure to hold moisture, compounded by drought can reduce the stability of the soil, making erosion a more significant problem.

When compared to the Reference Plant Community (1.1), blue grama has increased. Prickly pear cactus has invaded. All cool-season mid-stature grasses and forbs have been greatly reduced. Production has been significantly decreased.

The total annual production (air-dry weight) of this state is about 250 lbs./acre, but it can range from about 100 lbs./acre in unfavorable years to about 450 lbs./acre in above average years.

Resilience management. Rangeland Health Implications/Indicators: This community is resistant to change and the removal of grazing does not seem to affect the plant composition or structure. The biotic integrity of this community is not functional and plant diversity is extremely low. The plant vigor and replacement capabilities are limited due to the reduced number of cool-season grasses. The sod-bound nature of this plant community is resistant to water infiltration, however the open dissected nature of the "patches" of the site only has a minimal impact on infiltration. Sodded areas are protected by root structure, but impacts off-site areas with excessive runoff that can cause rills and gully erosion. Water flow patterns are obvious in areas of bare ground and pedestalling is apparent along the sod edges. The watershed may or may not be functioning, as runoff may affect adjoining sites.

State 3
Saltbush/Invaded

The Saline Upland site has proven to be more resistant to invasion by many of the aggressive weedy species threatening the rangelands today. However, there are a few species that still present issues as more land is disturbed by development, continued drought, and shifts in use patterns. Cheatgrass (downy brome) poses the greatest threat, with halogeton, and a variety of annual forbs holding their niches in the community. The persistence, resistance and resilience of specific communities within this state will be discussed further below.

Characteristics and indicators. Gardner's saltbush is fairly constant in the community with shifts in productivity of individual plants under different stress conditions. The composition of native and invasive herbaceous species is the indicator for this community. A threshold of 5% composition of a non-native invader species was established to mark when a community has crossed into this State. As this community continues to degrade, the invasive species will increase.

Resilience management. Once non-native species, specifically cheatgrass, invades the saltbush community, it is difficult to remove, and successful eradication without significant alteration has not been achieved at this time. As the invasive species become dominant in the community, the state becomes resistant to change and is very resilient to further disturbance.

Community 3.1
Saltbush/Native Grasses/Invasives

Figure 18. A strong cover of native herbaceous cover exists within the cheatgrass canopy.

This Community phase will resemble the reference state communities (1.1 and 1.2) but will have the presence (5% or greater) of invasive species such as cheatgrass. 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 or other disturbances.

Fire risk is minimal, however, the added fuels created by cheatgrass, can provide the needed conditions to allow a fire to occur. The known fire frequency is rare and is not considered a major risk to Gardner's saltbush.

The variability in composition commonly found with cheatgrass limit the ability to estimate 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. 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.

Community 3.2
Saltbush/Invasives

Figure 19. Cheatgrass and Russian thistle have invaded this community, with Garner's saltbush and only remnants of native grasses.

As annuals or other invasive species increase the native grasses are weakened and eventually will be removed from the site. The Saltbush/Invader community retains Gardner's saltbush as the dominant species with an invasive partner. Cheatgrass is the common threat to the ecological site; however, as other invasive species are brought into the Basin, the dynamics of this site will vary depending on the specific species. At this time, there has been no production data collected on this isolated and small stature community, so no productivity is estimated for this community.

Resilience management. The resistance to change increases as the stand becomes more decadent. Continued frequent and severe (continuous, season-long) grazing or no 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 3.1A
Community 3.1 to 3.2

Saltbush/Native Grasses/Invasives

Saltbush/Invasives

Drought, Non-Use, Disturbance, or Frequent or Severe (Continuous, Season-long) Grazing – After crossing the threshold into an invaded state, the community will continue to degrade if disturbance continues or no weed management is implemented. Drought and non-use can leave soils dispersed and susceptible to invasion and loss of perennial grasses. Once an invasive species has gained a niche within a community and is able to begin to establish and propagate, the transition from the initial phase in this state to a more degraded phase may happen quickly when multiple factors are influencing the community. However, the transition can be stable and resistant to further degradation in many management situations. Proactive early detection and rapid response can be an effective tool at this stage to prevent this transition.

Pathway 3.2A
Community 3.2 to 3.1

Saltbush/Invasives

Saltbush/Native Grasses/Invasives

Integrated Pest Management with Prescribed Grazing – The native grasses displaced by the invasive species generally will persist in remnant populations within the crowns of the Gardner's saltbush and plains pricklypear, or scattered in small pockets on the landscape. If a site is addressed in the preliminary stages of the transition to this phase, there is a higher likelihood that integrated pest management (weed control) and grazing management will encourage the perennial grasses to increase or persist on the landscape. But as the site continues to degrade or transition to an invasive dominated community, the ability to recover becomes more and more minimal.

State 4
Disturbed

The majority of the sites identified have been impacted by vehicle use (roads/trails), including recreational vehicles. The level and extent of disturbance varies from the clayey and loamy counterparts to this ecological site. Climate, degree of disturbance, type of disturbance and the resources surrounding each location must be considered with this state. Also, the size of the community is generally small and in difficult areas to access with equipment, making the overall footprint and need to reclaim lower in priority than other larger scale ecological sites.

Characteristics and indicators. This state is to capture areas where surface disturbance has removed the native vegetation or where the site has been treated to improve/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.. The coarse soil textures make this ecological site susceptible to erosion, by wind especially, reducing the viability of seeds and seedlings in the early stages of establishment. Intensity and timing of precipitation has proved risky and nearly impossible to achieve a high level of success

Community 4.1
Altered

Small acres of abandoned lands have been created over an extended period of time. Changes in irrigation systems or land use, land management/ownership, to drought cycles have proven to shift these soils to a degraded state. The location and incidental (small isolated patches) of this ecological site lends it to be a sacrifice or bleed over area on the landscape. As fields are switched from flood irrigation to pivots, the path of irrigation either hits or misses, rarely is it included with intent. Once the soil has been tilled or mechanically worked, the structure and function of the site is altered. These changes, prevents 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 existed prior to disturbance.

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/or Russian wildrye were the primary species utilized in the seedings during the late 1940s to the early 1980s. The persistence of these species help to quickly identify these locations. The susceptiblity to wind erosion on these sites has quickly removed or hidden the otherwise evidence of drill rows or furrows on this soil. 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 a typical for the climate, not taking into consideration the variety of plant species that are present. Site specific evaluation needs to be 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 (coarse textures prone to erosion and salt/sodium/gypsum content) make seeding or re-establishing vegetation challenging. There are new cultivars that will tolerate the conditions, but the cost and risk analysis must be considered in the reclamation process. No known trials on this ecological site have been identified.

Transition T1A
State 1 to 2

Drought, Frequent or Severe Grazing – Extended periods of drought have the ability to weaken the plant community's resilience, forcing the community over the threshold into the next state. Drought with added stress of frequent or severe (continuous, season-long) grazing can expedite the process, removing the key species (Indian ricegrass, needle and thread), leaving the site dominated by tillering grass species (blue grama). Review of long term exclosure data also shows a natural shift to blue grama that is correlating with shifts in the precipitation occurring later in the season with warming spring temperatures. This is still under review to determine other factors influencing this transition.

Constraints to recovery.The mat-forming blue grama alters hydrology and creates a difficult environment for other natives to compete. The dense root system also makes blue grama highly tolerable to grazing and hoof impacts, making it difficult to remove or effectively reduce its composition in the community.

Transition T1B
State 1 to 3

Frequent and Severe Grazing, Drought, Non-Use, or Ground Disturbance (with Seed Source Present) – Halogeton, cheatgrass (downy brome), and many of the invasive weeds that are present in the Big Horn Basin are drought tolerant and able to establish in poor soils and growing conditions. The barren, open canopy that is typical with Saline Upland landscapes are a prime target for these invaders. Given any level of disturbance, whether it is from heavy and frequent grazing use, drought or other ground disturbances, if there is a seed source present, these invaders will find a niche for establishment. The dispersed nature of salt affected soils, especially in the absence of compaction by hoof action or traffic, allows for any variety of invasive species to quickly transition the reference state into an invaded state.

Constraints to recovery.The inability to eradicate most invasive species, specifically cheatgrass, block the recovery of this state to another state without major soil disturbances, seeding and high intensity weed management. A successful trial has not occurred on these soil-limited communities.

Transition T2A
State 2 to 3

Drought, Ground Disturbance, Frequent or Severe Grazing or Non-use with a seed source present – The vulnerability of this state to transition to an invaded state is increased as the canopy is opened with further disturbance, drought or grazing use. If the seed source is present (in the area), drought or abnormal precipitation patterns provide the opportunity for invasive species to establish. Many of the sources of disturbance (recreational vehicles, animals, and development activities) provide a source to bring invasive species into an area.

Constraints to recovery.The difficulty of removing or reducing the composition of the non-native or invasive species and encouraging the establishment of native species is the major factor limiting the ability to return the invaded community back to the previous state.

Restoration pathway R3A
State 3 to 4

Integrated Pest Management, Grazing Land Mechanical Treatment, or Rangeland Seeding with Prescribed Grazing – Once a community has degraded to an invaded state, especially if cheatgrass is dominant; eradication is not a feasible option, preventing restoration to a Reference state. An invaded site, however, can be restored to a functional plant community through intensive and integrated pest management and grazing land mechanical treatments. Removal of or reducing existing populations and establishment of forage species that are desirable and able to tolerate/compete with the invasive species helps to improve the function of the landscape. When a community has been significantly invaded, losing all of the key grazing species, re- seeding the site to a competitive species may be the only option. Establishment will be slow and the variety of available seed sources for salt-affected soil conditions is minimal, but small scale projects have been achieved with marginal success.

Transition T4A
State 4 to 3

Drought, Severe and Frequent Grazing, Ground Disturbance, or Non-Use with seed source present – Loose soils as a result of no hoof action during non-use or the decrease in key herbaceous species due to severe and frequent grazing, drought or disturbance opens the canopy and provides opportunity for invasive species to establish. With continued stress or addition of undesirable species will weaken this community even further.

Constraints to recovery.Weed removal or control is the main constraint to recovery for this community and state.