State 1
Reference

The Reference State of the Saline Lowland ecological site is the native community phases that have historically populated the flood plains of ephemeral and perennial drainages. The community relies on the overland flows/flooding from spring runoff and large precipitation events as well as woody species are utilizing the water table (generally deeper than herbaceous root systems).

Characteristics and indicators. Alkali sacaton and basin wildrye are major components to the community with greasewood as a minor but distinct cover component (less than 15 percent). Bare ground is minimal, with only small interspaces between vegetative cover. A mixture of tall- and mid-stature grasses both warm and cool-season, with a scattering of forbs is key to the Reference State.

Resilience management. The Reference State is diverse in plant composition providing flexibility in responses to fluctuating water tables and drought conditions. This resiliency of the community, however, is limited by the dependency on the fluctuating water table. Once altered, the communities have little resistance to change.

Community 1.1
Alkali Sacaton/Basin Wildrye/Greasewood

Figure 8. Alkali sacaton is prominent in this community with basin wildrye, greasewood, rhizomatous wheatgrasses, and other native perennial grasses present.

The interpretive plant community for the Saline Lowland ecological site is the Alkali Sacaton/Basin Wildrye/Greasewood community phase of the Reference State. This community phase evolved with grazing by large herbivores, supplemental moisture, and saline and/or alkali soils. Potential vegetation is about 70 percent grasses or grass-like plants, 10 percent forbs and 20 percent woody plants. Saline tolerant grasses dominate the state. The major grasses include alkali sacaton, basin wildrye, rhizomatous wheatgrasses, and bottlebrush squirreltail. Woody plants are greasewood and rubber rabbitbrush. A variety of forbs also occurs in this state and plant diversity is high (see Plant Composition Table). The total annual production (air-dry weight) of this state is about 1200 pounds per acre, but it can range from about 700 pounds per acre in unfavorable years to about 1600 pounds per acre in above average years.

Resilience management. This state is stable and well adapted to the Northern Great Plains climatic conditions. The diversity in plant species allows for high drought resistance. This is a sustainable plant community (site/soil stability, watershed function, and biologic integrity).

Community 1.2
Alkali Sacaton/Inland Saltgrass/Greasewood

Figure 11. Inland saltgrass is increasing while alkali sacaton and rhizomatous wheatgrasses remain in this community phase. Basin wildrye has declines and annuals have started to appear (six-weeks fescue).

Historically, this plant community evolved under moderate grazing by large ungulates and low fire frequency. Currently, this site is normally found under a moderate, continuous season-long grazing regime and in the absence of fire or brush control. Prolonged drought can also play an important role and will exacerbate these conditions. Saline and flood tolerant perennial plants make up the dominant species in this plant community. Dominant grasses include alkali sacaton, inland saltgrass, rhizomatous wheatgrasses, blue grama, and mat muhly. Forbs commonly found in this plant community include wild onion, pursh seepweed, smooth woodyaster, and povertyweed. Greasewood and rubber rabbitbrush comprise the majority of the woody species and make up less than 25 percent of the annual production. When compared to the Reference Plant Community (Community Phase 1.1), basin wildrye and rhizomatous wheatgrasses have decreased. Annual weedy plants have increased, but occur in small patches. Inland saltgrass, greasewood, and rubber rabbitbrush have increased. The total annual production (air-dry weight) of this state is about 875 pounds per acre, but it can range from about 500 pounds acre in unfavorable years to about 1100 pounds per acre in above average years.

Resilience management. The Alkali Sacaton/Inland Saltgrass/Greasewood community phase is stable and protected from excessive erosion. The herbaceous component is mostly intact and plant vigor and replacement capabilities are sufficient. Only minimal occurrences of water flow patterns and litter movement is evident. 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 CP 1.1-1.2
Community 1.1 to 1.2

Alkali Sacaton/Basin Wildrye/Greasewood

Alkali Sacaton/Inland Saltgrass/Greasewood

Moderate, continuous season-long grazing reduces the vigor basin wildrye and other cool-season tall and mid-stature grasses, forcing the transition to the Alkali Sacaton/Inland Saltgrass/Greasewood Plant Community. Prolonged Drought will exacerbate this transition.

Pathway CP 1.2-1.1
Community 1.2 to 1.1

Alkali Sacaton/Inland Saltgrass/Greasewood

Alkali Sacaton/Basin Wildrye/Greasewood

Prescribed grazing and possible long-term prescribed grazing will result in a plant community very similar to the Reference Community Phase (1.1), except that greasewood will persist without some form of brush control. Providing a period of recovery following grazing or delaying grazing until the tall- and mid-stature cool-season grasses are able to recover and have a period of growth, will allow them to re-establish or improve over time. Recovery may take a longer duration of time than one or two years, especially during drought conditions.

State 2
Shrub Dominated

The Shrub Dominated State is a greasewood community with significant extents of bare ground and potential for weedy annuals. Rubber rabbitbrush and basin big sagebrush are also common members of this community.

Characteristics and indicators. Greasewood, or a combination of shrubs, will form a significant (greater than 15 percent) cover within the community. Few perennial grasses are present in the community. Those that are able to persist generally are found within the basal cover of the greasewood or other shrub cover. Bare ground is often extensive, comprising between 30 to 50% of the cover. Weedy annuals such as mustards, six-weeks fescue, and annual wheatgrass will often provide some cover in these interspaces. Often, evidence of wind scour and other erosional patterns are present in the interspaces between greasewood.

Resilience management. The shrub cover and exposed salty soils limit the ability for seedling establishment. However, greasewood is persistent even with intensive use. The community is resilient, but is not resistant to invasive by non-native, noxious weeds.

Community 2.1
Dense Shrub/Bare Ground

The Dense Shrub/Bare Ground Plant Community evolved under frequent and severe grazing with the absence of fire and an interruption in overflow or an extended period of drought. Greasewood and rubber rabbitbrush are the dominant species of this plant community. Tall and medium grasses have been eliminated. The interspaces between shrubs have expanded leaving the amount of bare ground more prevalent and more soil surface exposed to erosive elements. The annual grasses and forbs, such as six-weeks fescue, annual wheatgrass, foxtail barley, mustards and woolly plantain, make up the dominant understory. Total annual production is mostly from shrubs and these weedy annuals. Shrubs make up greater than 25 percent of the total annual production. When compared with the Mixed Shrub/Inland Saltgrass Sod Plant Community, the annual production is similar as the shrub production compensates for the decline in the herbaceous production. The total annual production (air-dry weight) of this state is about 450 pounds per acre, but it can range from about 350 pounds per acre in unfavorable years to about 600 pounds per acre in above average years.

Resilience management. 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. Annual grasses, weedy species and bare ground compromise the biotic integrity. Plant diversity is poor and the potential for native grasses to reproduce is absent. The shift in the vegetative structure and function is extreme and the biotic integrity is lost. The soil of this community phase is not well protected as erosion has accelerated because of increased bare ground. Water flow patterns and pedestalling are obvious. Infiltration is reduced and runoff is increased. Rills may be noticeable in the interspaces and gullies may be establishing where rills have concentrated.

State 3
Sod-former

The tillering, mat-forming nature of inland saltgrass forms a sod-bound community that hinders water movement into the soil profile and hinders other native species from establishing or persisting in the community. As the tall- and mid-stature grasses are removed from the community, the short-stature sod-forming grasses increase to stabilize the community.

Characteristics and indicators. Remnants of alkali sacaton will persist with a few less desirable species (little barley, foxtail barley, Baltic rush). Greasewood is generally present, but more scattered across the community.

Resilience management. The dense, tightly rooted sod-forming species are resistant to hoof impact and traffic, as well as drought tolerant. This combination makes for a resilient community with continued disturbances.

Community 3.1
Inland Saltgrass/Greasewood

This plant community is the result of frequent and severe grazing with periodic overflows and no brush control. This plant community is dominated by a dense short grass sod and includes a mosaic shrub overstory. Greasewood and rubber rabbitbrush are the primary overstory species in this plant community. Shrubs comprise less than 25 percent of the annual production. The dominant grasses are inland saltgrass and blue grama. Historically, mat muhly was recorded on these sites, but has not be identified in current inventories. Plant diversity is moderate to poor. When compared with Reference Plant Communities, the annual production is similar, as the shrub production compensates for the decline in the herbaceous production. When compared to the Reference State, the tall- and mid-stature grasses are absent. Short-stature warm-season grasses are dominant and weedy annuals are common. Shrubs will have increased as a percentage of the total production, but will not dominate as the sod prevents a homogeneous shrub cover. Areas of bare ground may have increased in patches and total production has decreased. The total annual production (air-dry weight) of this state is about 480 pounds per acre, but it can range from about 300 pounds per acre in unfavorable years to about 600 pounds per acre in above average years.

Resilience management. The sod component of this plant community is extremely resistant to change and continued frequent and severe grazing or the removal of grazing does not seem to affect the plant composition or structure of the plant community. The biotic integrity of this state is mostly not functional as plant diversity is poor especially the amount of herbaceous species. However, the vegetative structure may still be partially intact as the shrub component is still within a reasonable percentage of the total composition. This sod bound plant community is very resistant to water infiltration. While this sod protects the site itself, excessive runoff increases erosion on bare ground and can cause rills, channels and gully erosion. Water flow patterns are obvious in the bare ground areas and shrubs and sod patches are pedestalled. Rills are noticeable in the interspaces and gullies may be establishing where rills have concentrated. The watershed may or may not be functioning, as runoff is excessive and erosional processes are accelerated.

Community 3.2
Inland Saltgrass

The Inland Saltgrass Community Phase is the result of long-term improper grazing use plus some form of brush removal. This community phase is dominated by inland saltgrass sod. Intermittent areas of bare ground have increased and extend between the patches of sod. When compared to the Reference State, the tall- and mid- stature grasses are absent. Short-stature warm-season grasses are dominant and weedy annuals are common. Greasewood and other common shrubs (rubber rabbitbrush and basin big sagebrush) are absent from the community. The total annual production (air-dry weight) of this state is about 280 pounds per acre, but it can range from about 100 pounds per acre in unfavorable years to about 350 pounds per acre in above average years.

Resilience management. This sod is extremely resistant to change and continued frequent and severe grazing or the removal of grazing does not seem to affect the plant composition or structure of the plant community. The biotic integrity is not functional and plant diversity is extremely low. This sod bound plant community is very resistant to water infiltration. While this sod protects the site itself, excessive runoff increases erosion on bare ground areas and can cause rills, channels and gully erosion. Water flow patterns are obvious in the bare ground areas and pedestalling is apparent along the sod edges. Rills are noticeable in the interspaces and gullies may be establishing where rills have concentrated. The watershed is not normally functioning, as runoff is excessive and erosional processes are accelerated.

Pathway CP 3.1-3.2
Community 3.1 to 3.2

Continued impacts from frequent and continuous year-long grazing removes remaining tall- and mid-stature grasses and shrubs. Drought with further exacerbate the loss of shrubs in the community with the loss of overflow, lower water tables, and increased risk of insect and disease. Traffic or shrub treatments may also transition the community to a sod-dominated community with the loss of shrub cover.

Pathway CP 3.2-3.1
Community 3.2 to 3.1

Development of a grazing prescription to allow recovery of desirable tall- and mid-stature grasses as well as to encourage the recovery of the shrub species (greasewood and rubber rabbitbrush) will bring this transition with time. The plan may require a longer period of time, especially with on-going drought. In some instances, seeding or planting of shrubs may be necessary to begin the recovery process.

State 4
Invaded

Deterioration of the reference community opens the soil to invasion by undesirable species. Migration of wildlife, use by livestock, and water flow events provide seed sources to encourage invasive species to establish in the disturbed communities. This disturbance with a seed source present is what allows establishment to a significant level to occur.

Characteristics and indicators. When the community is comprised of five percent or greater of invasive (non-native) species, the threshold has been crossed into the Invaded State. Cheatgrass, salt cedar, and Russian Olive are among potential species of invasion; however, whitetop, knapweeds, and thistle are also prevalent.

Resilience management. The inability to eradicate cheatgrass, and the challenges to maintain high levels of weed control limit the ability for this State to improve, making it resistant to change. The ability for the invasive species to adapt and recover following disturbance make this state resilient.

Community 4.1
Invasive Species/Greasewood

Figure 14. Saltcedar (Tamarisk) and cheatgrass are dominant in this Saline Lowland community.

The Invasive Species/Greasewood Community Phase is capturing a wide array of potential transitions in one community phase. It is necessary to complete a site specific inventory to know the exent of invasion and the potential of the community. Each invasive species has different management challenges that will determine the risk to the community. Initially, this community may resemble the Reference State, but as invasive species increase, fewer native species are able to persist in the community. The basal cover of greasewood provides potential niches for natives to reside, but the remaining community will transition to invasive species.

Resilience management. The strategy for managing this community phase focusing on minimizing the spread or increase of invasive species while protecting and hopefully encouraging the native species to increase within the community. Timing of grazing to utilize invasive species while the native grasses are dormant and integrated weed management can maintain and strive to improve this plant community.

State 5
Altered Lands

Mining, energy development, irrigation conveyance lines, irrigation, and livestock operating facilities are a few activities that have created a change to this ecological site. The soil disturbance, removal of greasewood and other vegetation, as well as impacts to they hydrology of this ecological site has left scars on the landscape.

Characteristics and indicators. Outside of the visible evidence of soil movement, seeding, or development the altered/disturbed community is comprised of non-native or improved varieties and varying successional species such as weedy annuals (Russian thistle, sunflower or other asters) and foxtail barley.

Resilience management. Frequency of disturbance, species established, level of management, and remaining hydrology determines the resistance and resiliency of the Altered State.

Community 5.1
Altered Lands

Figure 15. Evidence of the old road bed in the upper portion of the photo and the current road bed with the remnants of an old head gate are a few of the disturbances to this site.

Altered lands have been impacted by human settlement and land use advancement. Many areas within the Wind River Basin were farmed during early settlement periods. Water collection structures and conveyance ditches were cut through the channel systems to move water across the landscape for irrigation. Diversion structures, culverts, and intensive use of the riparian systems impacted the water flow and channel stability, causing downcutting and other erosional processes to occur. These alterations with changes in the precipitation and runoff into the system had an impact on the system and over time many ditches and irrigation systems were abandoned. Remnants of old mining towns, farmsteads, and corrals are visible along sections of these drainages today. Mechanical alteration of these areas in conjunction with the introduction of species from hayfields and in attempts to stabilize areas created these altered lands.

Resilience management. The persistence of an introduce non-native species is a very indicative that will assist in identify this community phase. These non-native species are not invasive, although they may be persistent and aggressive species. Crested wheatgrass, varieties of wildrye, and hybrid wheatgrasses are a few cultivars that have been planted that have persisted on the landscape. The preparation of the seedbed as well as any original soil disturbance have altered the soil function and site characteristics. Productivity of these sites varies greatly depending on the exact disturbance, age and successional stage of recovery from this disturbance, and what, if any, species were seeded into the site. Composition variability of this plant community limits the ability to provided accurate averages and growth curves, so no production values are provided for this community phase.

Transition T1-2
State 1 to 2

Repeated frequent and severe grazing, especially year-long or continuous, will weaken the herbaceous cover. Frequent years with reduced or no overflow will convert this plant community to the Dense Shrub/Bare Ground Sod Community phase. Prolonged Drought will exacerbate this transition. The lack of extra effective moisture and the lack of recovery time for the perennial grasses remove them from the community and allow greasewood and rubber rabbitbrush to persist.

Constraints to recovery. The harsh environment created by salt-laden soils and the potential for compaction limits the ability for grasses and other herbaceous species to establish. The droughty conditions that created the transition also limit seedling establishment. Over time, the lack of seed-source for desired perennial grasses becomes scarce further limiting the ability for the community to recover.

Transition T1-3
State 1 to 3

Frequent and severe grazing with brush management or disturbance to brush cover will convert this plant community to the Sod Bound State. The loss of overflow conditions or high traffic aids in this conversion.

Constraints to recovery. The competitive nature of inland saltgrass and its tillering root structure limits the ability for other native species to propagate and compete in these communities.

Restoration pathway R2-1
State 2 to 1

Grazing land mechanical treatment (chiseling, etc.) and brush management followed by prescribed grazing and if necessary seeding will return this plant community to near Reference. Return of overflow conditions and restored water table assists with recovery of this site as well. The time required for a transition will be determined by climatic factors and seed sources present.

Context dependence. Extent of soil disturbance determines if the site is able to move towards the Reference State, or if hydrology and soils are altered enough that the site becomes disturbed or the Altered State.

Transition T2-3
State 2 to 3

Mechanical disturbance to eradicate or reduce the cover of greasewood and other woody species, while providing opportunity for resilient species to establish with prescribed grazing and time, helps this site to transition to the Sod-Bound State. Disease, drought, and other disturbances are also responsible for the removal of shrub cover that will also allow inland saltgrass to establish, when it is prominent in the understory or seedbank.

Constraints to recovery. The nature of tillering plants, i.e. inland saltgrass, restrict other native grasses and forbs from establishing in the community. This cover is also restrictive to shrub recovery. Recovery to Reference is highly unlikely due to the lack of key species and the restrictive nature of the sod cover. The removal of the sod cover is highly unlikely to occur without major disturbance that would alter the function of the site, transitioning to the Altered State.

Transition T2-4
State 2 to 4

The open nature of the Shrub Dominated State provides opportunity for invasive species to gain a foothold in a community. The lack of ground cover, and the on-going disturbances in this state provide a seed-source as well as seed-soil contact to encourage establishment. Livestock and wildlife movement through the site, human traffic, as well as wind and water aid in providing seed sources.

Constraints to recovery. Once most invasive species establish in a community, on going disturbances, encourage further spread and prominence. The difficulty to control, let alone eradicate, most invasive species limits the potential for recovery once a community becomes invaded.

Transition T3-4
State 3 to 4

Ground disturbance and drought assist to weaken inland saltgrass, providing opportunity for invasive species to establish. Traffic, human and animal, as well as wind and water provide seed sources for invasive species to the community.

Constraints to recovery. The challenge to control (maintain) or eradicate invasive species is the major constraint to the recovery from this transition.

Restoration pathway R4-5
State 4 to 5

An integrated approach, generally including chemical treatment of invasive species, mechanical working of the soil and seeding or planting native or improved varieties to provide perennial cover of desirable species is applied to improve this community. Continued weed or integrated pest control as well as grazing management is needed to prevent further regression or invasion of the site.

Context dependence. The extent of treatment and necessary procedures will be determined by the exact species of invasion within the community, the accessibility of the community, and native species remaining in the community.

Transition T5-4
State 5 to 4

Seeding failure or lack of management following seeding are common mechanisms that allow for the re-establishment or establishment of weeding species in an altered community. Continued disturbance or new disturbances to a community provide opportunity for new or reoccurring invasion.

Constraints to recovery. Weed control is the limiting factor to recovery for this site.