State 1
Reference

The Reference State for the Saline Lowland Drained ecological site is representative of the native community phases that establish once the floodplain of a saline drainage is detached from the water during natural stream morphological processes or from channel disturbances. The loss of the natural water table results in a loss of hydrophytic plants and an establishment of upland plants.

Characteristics and indicators. Greasewood and alkali sacaton are present as well as inland saltgrass. Western wheatgrass replaces slender wheatgrass, Sandburg bluegrass will replace alkali bluegrass, and bottlebrush squirreltail and Indian ricegrass have increased in composition. Basin wildrye will persist but will be reduced in the community. Gardner's saltbush establishes once the community is disconnected from the water table, and forbs transition to upland species.

Resilience management. This state is in a state of transition and so although resilient, it is not resistant to change and disturbances can quickly shift this community. Grazing management, drought, natural channel and hydrologic shifts, and disturbances are influences for this state.

Community 1.1
Alkali Sacaton/Greasewood

Figure 8. Alkali sacaton with greasewood are dominant with other native perennial grasses and forbs present.

The Reference Plant Community for the Saline Lowland Drained ecological site evolved with grazing by large herbivores and periodic fires. Potential vegetation composition by cover is is about 70% grasses or grass-like plants, 10% forbs and 20% woody plants. Tall and medium grasses, which can tolerate saline and/or alkali conditions and occasional overflows, dominate this plant community. The major grasses include inland saltgrass, alkali sacaton, rhizomatous wheatgrasses, bottlebrush squirreltail, basin wildrye, and Indian ricegrass. Woody plants are greasewood and Gardner’s saltbush. A variety of forbs also occurs in this community and plant diversity is high (see Plant Composition Table for Community 1.1, Table 21). The total annual production (air-dry weight) of this state is about 525 pounds per acre, but it can range from about 350 lbs./acre in unfavorable years to about 700 lbs./acre in above average years.

Resilience management. This state is stable and well adapted to the arid 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). Typically, relic rill and gullies are visible but are now stable. No recent accelerated erosion should be occurring in this state.

Community 1.2
Rhizomatous wheatgrasses/Greasewood

Figure 11. Rhizomatous wheatgrass, greasewood and other native grasses and forbs increase as alkali sacaton decreases in the community.

This plant community evolved under moderate grazing by domestic livestock and low fire frequency. Saline tolerant grasses make up the majority of the understory. Dominant grasses include rhizomatous wheatgrasses, inland saltgrass, alkali bluegrass, and alkali sacaton. Forbs commonly found in this plant community include wild onion, pursh seepweed, smooth goldaster, and povertyweed. Greasewood may comprise as much as 35% of the total annual production. When compared to the Reference Plant Community (Community Phase 1.1), basin wildrye, Indian ricegrass, rhizomatous wheatgrasses, bottlebrush squirreltail, and alkali sacaton have decreased. Inland saltgrass, blue grama, greasewood and rubber rabbitbrush have increased. The total annual production (air-dry weight) of this state is about 450 pounds per acre, but it can range from about 275 lbs./acre in unfavorable years to about 600 lbs./acre in above average years.

Resilience management. This state 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 CP1.1-1.2
Community 1.1 to 1.2

Alkali Sacaton/Greasewood

Rhizomatous wheatgrasses/Greasewood

Moderate, continuous season-long grazing will convert this plant community to the Rhizomatous Wheatgrasses/Greasewood Plant community (1.2). Prolonged Drought will exacerbate this transition. Rubber rabbitbrush and sagebrush will show effects of grazing pressure. However, greasewood and Gardner's saltbush tend to show very little change through this transition.

Context dependence. This transition can also be a response to further alteration of the hydrologic cycle, especially with the loss of upland overflow moisture. Basin wild rye will decrease rapidly with the loss of hydrology, while other perennial grasses present will transition slower.

Pathway CP1.2-1.1
Community 1.2 to 1.1

Rhizomatous wheatgrasses/Greasewood

Alkali Sacaton/Greasewood

Prescribed grazing designed to provide recovery periods will allow alkali sacaton and basin wildrye to recover, resulting in a plant community very similar to Reference, except that greasewood density will persist. Brush control may be needed to reduce the greasewood and rubber rabbitbrush cover.

Context dependence. Historically, greasewood density was related to fire frequency. The sprouting response of greasewood to fire limits the function of fire in thinning the greasewood canopy. Chemical control and mechanical control are possibilities, but control is challenging. Variability in soil texture and salt content will affect the time required for communities to recover. The heavier the soil texture and the higher the salt content the soil is, the more difficult and more time that may be required to allow for recovery of this plant community to reference.

State 2
Shrub Dominated

The Shrub Dominated State of the Saline Lowland Drained ecological site is a greasewood community with minimal understory. The bare ground and large patch dynamics creates a community that is at risk for invasion and further degradation.

Characteristics and indicators. The plant community is dominated by greasewood with common occurrences of rubber rabbitbrush. Communities in soils that have deeper salts or lower overall salt composition will host scattered amounts of Wyoming big and basin big sagebrush. Remnants of native grasses including bottlebrush squirreltail and six-weeks fescue will occur in the basal cover of greasewood, but very minimal occurrences of grasses occur in the shrub interspaces. Annual and perennial forbs will occur within the greasewood basal cover as well and will extend into the interspaces, especially in wetter years.

Resilience management. Soil crusting, generally higher salt concentrations, especially around the canopy of greasewood, and restrictive soils, natural repopulation of native grasses has not been seen. Invasive encroachment occurs more readily in the open interspaces where seed source is available. The community is stable unless invasion occurs.

Community 2.1
Greasewood/Bare Ground

This plant community evolved under frequent and severe grazing with the absence of fire. 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. Annuals such as six week fescue and wooly plantain fill in the interspaces. Total annual production is mostly from shrubs and these weedy annuals. The total annual production (air-dry weight) of this state is about 350 pounds per acre, but it can range from about 100 lbs./acre in unfavorable years to about 450 lbs./acre in above average years.

Resilience management. This plant community is resistant to change as the stand becomes more decadent. These areas may actually be more resistant to fire as less fine fuels are available and the bare ground between the shrubs is increased. 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. 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 lateral gullies are numerous.

State 3
Sod-bound

The mat-forming growth habit expressed by blue grama and threadleaf sedge create a dense, short, sod-bound community that affects the hydrology and overall function of the community. As the cool-season grasses are removed from the system and the mid-stature warm-season grasses are restricted by use, the short grasses increase to stabilize the community.

Characteristics and indicators. Remnants of alkali sacaton and some cool-season species will persist at the bases of greasewood and scattered across the community. But the dominant grass cover shifts to blue grama or a threadleaf sedge/blue grama mix.

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
Blue grama/Greasewood

This plant community is the result of frequent and severe grazing with periodic overflows and no fire or brush control. This plant community is dominated by a dense sod of inland saltgrass, blue grama and alkali bluegrass and includes a mosaic shrub overstory. Greasewood and rubber rabbitbrush are the dominant overstory but Gardner’s saltbush is also an important shrub in this plant community. Shrubs comprise less than 35% of the annual production and are kept in check by the herbaceous sod understory. When compared to the Reference Plant Community (Community Phase 1.1), the tall- and medium-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. Noxious weeds such as Russian knapweed are present if a seed source is available. The total annual production (air-dry weight) of this state is about 250 pounds per acre, but it can range from about 150 lbs./acre in unfavorable years to about 400 lbs./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 generally not functional as plant diversity is poor especially among the 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 areas and worsens the channelization already present. Water flow patterns are obvious in the bare ground areas and shrubs and sod patches are pedestalled. Rill channels are noticeable in the interspaces and lateral gullies will increase. The watershed is not normally functioning, as runoff is excessive and erosional processes are accelerated.

State 4
Invaded

The Saline Lowland Drained ecological site is vulnerable to invasion by many of the aggressive weedy species threatening the rangelands today. Cheatgrass (downy brome) poses the greatest threat, with annual mustards and clasping pepperweed taking advantage of the open canopy and occasional flushes of overland flow.

Characteristics and indicators. The presence of at least 5 percent cover of an invasive species, dominantly cheatgrass, within the community is the threshold forcing this community into the invaded state.

Resilience management. Managing to maintain the remaining native species while working to reduce the invasive species is the best management practice focus for the Invaded State.

Community 4.1
Greasewood/Invaded/Perennial Grasses

Figure 17. Rhizomatous wheatgrass with an intermixed cover of cheatgrass and clasping pepperweed.

This plant community evolved under frequent and severe grazing with the absence of fire. Greasewood and rubber rabbitbrush are the dominant species of this plant community. Tall- and medium-stature grasses have been eliminated. The interspaces between shrubs have expanded leaving the site open to invasive and aggressive species. The extent of soil surface exposed to erosive elements decreases with increasing coverage of annual species. The annual grasses and forbs, such as foxtail barley, mustards, pepperweeds, and Russian thistle, make up the dominant understory along with invasive weeds such as cheatgrass and halogeton. Total annual production is mostly from shrubs and these weedy annuals. 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 550 lbs./acre in above average years.

Resilience management. This plant community is resistant to change as the stand increases in percent invasive species. These areas increase in fire potential as fine fuels accumulate and the bare ground between the shrubs is filled with annual species. 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. Soil erosion rates will vary depending on the species of invasion and the amount of litter produced. Water flow patterns and pedestalling are obvious. Infiltration is reduced and runoff is increased. Rill channels may be noticeable in the interspaces and lateral gullies are numerous.

Community 4.2
Invaded Greasewood

Figure 18. Native perennial grasses are near non-existent in the understory of cheatgrass and clasping pepperweed.

This plant community evolved under frequent and severe grazing. Fire may play a minor role in encouraging invasive species and sprouting of shrubs. Greasewood and rubber rabbitbrush are the dominant species of this plant community. Most native perennial grasses have been eliminated. The interspaces between shrubs have expanded leaving the amount of bare ground more prevalent, which allows rapid establishment and dominance of invasive species. The annual grasses and forbs, such as foxtail barley, mustards, and pepperweeds, make up the dominant understory along with invasive weeds such as cheatgrass and halogeton. Total annual production is mostly from shrubs and these weedy annuals. The total annual production (air-dry weight) of this state is about 400 pounds per acre, but it can range from about 100 lbs./acre in unfavorable years to about 600 lbs./acre in above average years.

Resilience management. This plant community is resistant to change as the stand becomes more invaded. 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. Soil erosion is dependent on the species of invasion, but is generally controlled by the annual cover even with increased interspaces between shrubs. Water flow patterns and pedestalling are obvious. Infiltration is maintained or slightly increased by the roots of cheatgrass and other invasive species; however, runoff may increase as litter biomass increases. Rill channels may be noticeable in the interspaces and lateral gullies are numerous.

Pathway CP 4.1-4.2
Community 4.1 to 4.2

Greasewood/Invaded/Perennial Grasses

Invaded Greasewood

In the absence of weed management, continued disturbance or pressure on native species removes them from the system and encourages the invasive species to increase in dominance on the ecological site. Extended or continued drought with exacerbate the degradation of the site as will continued severe grazing and other human disturbances.

Context dependence. The specific species of encroachment will depend on what species are present in the system. Cheatgrass is one of the most prevalent invasive species for the Wind River Basin.

State 5
Altered Lands

Energy development, mining, farming, irrigation canals, drainage laterals, and roads are only a few of the land uses that have had an impact on these arid, salt-affected landscapes.

Characteristics and indicators. The alteration of the soils and removal of the native vegetation are the key indicators for this State. Scaring of the activities completed are visible for significant periods following activities.

Resilience management. Much of this site is deemed unfit or non-productive; attempts to reclaim are marginal, and many attempts have failed. Historic attempts to improve productivity have altered the resilience and response pathways, affecting the site potential and stability.

Community 5.1
Altered Lands

Altered lands have been impacted by human settlement and land use advancement. Many areas within the Wind River Basin were farmed during settlement periods, but as water and times became difficult many homesteads were abandoned. Rangeland improvement projects were completed in the late 1940s and early 1950s by the Bureau of Land Management in conjunction with University of Wyoming. Sections of salt-affected barren landscapes were dissected with water-spreader dikes and seeded with predominantly a variety of grasses. Seeding trails were completed using species including crested wheatgrass, Russian wildrye, wheatgrasses, and Indian ricegrass. The dikes were created to increase water-holding capacity, which in turn improved vigor and production of greasewood and gardner’s saltbush and assisted the establishment of grasses. Remnants of the spreader dikes are still visible and in some areas the seeded grass species are persistent in small scattered populations. Productivity variances were found negligible between treated and untreated locations; however, within the spreader systems, an increase in vigor and production are seen within the immediate vicinity of the dikes. Spaces between the dikes do not show any lasting benefit. Mechanical alteration of these areas in conjunction with seeding of an introduced species carried a lasting effect to hydrology; and even though the introduced species did not persist in all locations, these sites are altered from the Reference State functionality. Similarly, with lands that were farmed or irrigated, then abandoned to return to a natural state of vegetation, they will not be the same as the Reference Community in response to management and natural disturbances. Greasewood, with time, has the potential to return if seed sources and moisture are present to encourage growth.

Resilience management. The persistence of an introduced, non-native species is a very indicative trait that will assist in identifying 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, altering the site. The act of seedbed preparation alone, without consideration of the original disturbance can be seen as an alteration to the soil function. 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 provide accurate averages and grow curves, so no production values or growth curves are provided for this community phase.

Transition T1-2
State 1 to 2

Continuous, season-long grazing, ground disturbance, and drought can facilitate the loss of herbaceous cover and create a greasewood/bare ground community. Hoof impact as well as lack of recovery for all perennial grass species weakens their resiliency in the community. Remnants of these species may persist in the protective bases of greasewood, but are otherwise removed from the system. Drought assists with the weakening and removal of the herbaceous as well as shrub species. Ground disturbance will remove the herbaceous cover and in many instances encourage the sprouting of greasewood further exacerbating the concern.

Constraints to recovery. Lack of seed source in conjunction with a harsh climate for seedling establishment inhibit natural recovery of this community. Shrub density can also have an impact on herbaceous recovery.

Transition T1-3
State 1 to 3

Continuous, season-long use or repetitive timing of use during early growing season will reduce the mid-stature cool-season grasses and encourage the short sod-forming grasses to establish. Drought will exacerbate this process.

Constraints to recovery. The dense root mat of sod forming species alters water flow across the site and inhibits infiltration causing dry subsoil conditions (droughty). This alteration in hydrology and resistance of the root mat to degradation creates a hostile environment for other species to establish.

Restoration pathway R2-1
State 2 to 1

Prescribed grazing and management to reduce pressure on the plant community during the early growing season will provide the native perennial cool-season grasses to establish and to recover within the community. Inland saltgrass and alkali sacaton will respond with hoof action to stimulate the basal growth and rest during the mid to late growing season. The time required for recovery will vary depending on texture and salt content. Shifts in the community will be slow but obvious in the health and vigor of the existing species. Density of shrubs may require mechanical or chemical treatment to thin them to an acceptable level of cover.

Transition T2-3
State 2 to 3

A shift in grazing management, specifically to a grazing pattern favoring warm season species, will allow recovery of blue grama and threadleaf sedge. With time, the community will recover to a sod-former community. Precipitation pattern changes can also be a factor in this shift.

Constraints to recovery. Sod forming species are resistant to change and resilient making it challenging to break the root mat to allow other native species to establish. The shift in hydrology caused by the root mat (filtering water off site, causing dryer subsurface conditions) also limits recovery of other native grasses.

Context dependence. The presence of these sod forming species must exist in the community before the shift occurs for this transition to occur.

Transition T2-4
State 2 to 4

The open gaps between greasewood canopy is open to invasive species. Once disturbed by hoof action or human disturbance, the soil is vulnerable to invasive species when seed sources are available.

Constraints to recovery. The lack of successful eradication of invasive species and the harsh soil conditions are the two limiting factors to recovery.

Transition T3-4
State 3 to 4

Continuous, season-long grazing weakens the sod-bound community opening a niche for invasive species to establish. Prolonged drought or soil disturbance (traffic) will also reduce the resistance of the sod former species allowing invasive species to establish when the seed source is available. Roadways and trails are common sources. However, proximity to the water source also serves as a source via water transmission as well as animal movement through the community.

Constraints to recovery. The inability to eradicate most invasive species is the main limiting factor to recovery. However, the harsh growth environment of the climate and soils also restricts recovery.

Restoration pathway R4-5
State 4 to 5

Once a community becomes invaded (greater than 5% composition of non-native invasive species), eradication or significant control of invasive species must occur to recover the community. In many instances this may require cultural practices to achieve success. Seeding of the community with integrated weed control to minimize the chance of re-establishment is needed to move the community towards a reference community. Once soil disturbance occurs, the response to management and natural disturbance regimes are not the same as reference. The species seeded will also be improved varieties and will respond to management differently than native populations. So although the community may resemble reference, it will maintain as a disturbed or altered community.

Transition T5-4
State 5 to 4

Continued ground disturbance, natural or man-induced, with a seed source present will revert an abandoned or disturbed landscape to the invaded state. The generally challenging soils and climate of the basin make reclamation a risky venture. When failure with seeding or improvement projects occur, invasive weeds are quick to establish in the disturbed soils. Wildlife and livestock moving through the Saline Lowland Drained ecological site are great vectors for seed dispersal.

Constraints to recovery. Cheatgrass is the most prominent invader that is found. Control of cheatgrass as well as many invasive species, is difficult and holds a low success rate, let a lone eradication. This inability to out-compete the invasive species is the main constraint to recovery. However, the hostile growth environment of the soils also limits successful recovery.