State 1
Reference

State 1 represents sagebrush steppe with no invasive or exotic weed species. All the functional, structural groups have one or more native species. A diverse native perennial community is more resistant to invasive annual species such as cheatgrass. Reference State Community Phases: 1.1 Reference Bluebunch wheatgrass-Wyoming sagebrush 1.2 Bunchgrass Bluebunch wheatgrass 1.3 Heavy sage Wyoming sagebrush-bluebunch wheatgrass 1.4 Depauperate Wyoming sagebrush-Sandberg bluegrass Dominate Reference State Species: Wyoming big sagebrush, bluebunch wheatgrass At-risk Communities: • All communities in the reference state are at risk of moving to State 2. The seed source of cheatgrass is nearby and blowing onto most sites annually • Community Phase 1.4, the depauperate community (sagebrush-Sandberg bluegrass), has little to no bluebunch wheatgrass, and is therefore, at considerable risk of moving to State 3 which is dominated by annual species • Any Stony community is at risk when bluebunch cover is low (less than 10 percent) and cheatgrass cover is becoming co-dominant (40 percent or more). • Any community is at risk when sagebrush cover is high (40 percent plus) and there is little to no bluebunch • Community 1.4, and any site with low cover of bluebunch wheatgrass, and any site with moderate to heavy cover of cheatgrass should be seeded after fire

Community 1.1
Reference - Bluebunch Wheatgrass and Wyoming Big Sagebrush

Reference Community 1.1 is dominated by bluebunch wheatgrass with some sagebrush. Communities 1.1, 1.2, and 1.3 have enough bluebunch wheatgrass to shift to the other two communities and back again. These three community phases have high amounts of bunchgrass cover and are at low risk of moving to State 3

Community 1.2
Bunchgrass Dominated - Bluebunch Wheatgrass and Wyoming Big Sagebrush

Community 1.2 is even more strongly bunchgrass dominated.

Community 1.3
Heavy Sagebrush - Wyoming Big Sagebrush and Bluebunch Wheatgrass

Community 1.3 has a heavy sagebrush canopy but bluebunch remains a vital component in the community.

Community 1.4
Depauperate - Wyoming Big Sagebrush and Sandberg Bluegrass

Community 1.4, Depauperate, is dominated by sagebrush with Sandberg bluegrass as sub-dominant. The are no invasive species in Community 1.4, but there is not enough bluebunch wheatgrass remaining for community 1.4 to shift back to the other communities in the reference state.

Pathway 1.1A
Community 1.1 to 1.2

Result: Shift from reference community to bunchgrass community. Sagebrush cover is all but eliminated, while bluebunch wheatgrass has a moderate increase. The community shifts from a shrub steppe to a bunchgrass appearance. Primary Trigger: Moderate-severity fire is complete enough and hot enough to remove almost all sagebrush. Fire conditions and post-fire grazing management allows bluebunch wheatgrass and other bunchgrasses to thrive and expand. Some areas burn complete while other areas are unburned to lightly burned and fire is not hot enough to affect soil conditions. Fire removes surface vegetation but has no impact on the crown of bunchgrasses. So, bunchgrasses and forbs return post-fire with good vigor. Post-fire the bunchgrasses are now more susceptible to grazing damage. Burned rangeland pastures will need two growing seasons recovery prior to resuming grazing, or to be lightly grazed but only during dormant season the first two years post-fire. Beyond two years for the bunchgrasses to expand, the grazing plan must promote light to moderate grazing intensity, and both critical period and growing season deferments must be implemented on burned pastures. Ecological process: Fire kills sagebrush and it does not have any sprouting ability. A few sagebrush plants remain, but only in patches that did not burn. The reduction in sagebrush releases resources and increases light for grasses and forbs. Bluebunch wheatgrass and other bunchgrasses have good vigor post-fire and expand via tillering and new seedlings.

Pathway 1.1B
Community 1.1 to 1.3

Result: shift from reference community to heavy sage community. There is a moderate increase in sagebrush while bluebunch wheatgrass has a corresponding moderate decrease. Primary Trigger: With excessive grazing pressure (heavy grazing intensity, season long grazing or frequent late spring grazing) and a period of no fire, sagebrush increases its cover while bluebunch wheatgrass suffers a big decline. Ecological process: With consistent defoliation pressures bluebunch wheatgrass experiences poor plant vigor to such a degree that grass roots begin to die. So, bluebunch wheatgrass experiences shrinking crowns and some mortality. This gives sagebrush the opportunity to set new seedlings and expand its cover. Increased shade from the new sagebrush plants also plays a role in this process.

Pathway 1.2A
Community 1.2 to 1.1

Result: Shift from bunchgrass community to reference community. There is a moderate reduction of bluebunch wheatgrass cover and a corresponding increase of sagebrush. Primary Trigger: Over time with no fire, sagebrush will re-enter the community even with good bunchgrass vigor. Ecological process: Spots with soil disturbance receive sagebrush seed from remnant plants in unburned patches or from adjacent sites, seed germinates in the spring and a few sagebrush seedlings establish. For most locations it may take up to 10 years for sagebrush to re-enter the community. But in Douglas County the re-entry period may only be two to five years. With a slight increase in shade perennial bunchgrasses experience a slight decline.

Pathway 1.3A
Community 1.3 to 1.1

Result: Shift from heavy sage community to reference community. There is a major decrease in sagebrush cover and a considerable increase in the cover of bluebunch wheatgrass. The community shift is from sagebrush dominance to bunchgrass dominance. Primary Trigger: Moderate-severity fire is patchy, dependent on temperature, wind, fuel load and fuel moisture. In areas that burn the fire is complete enough and hot enough to remove most sagebrush. Most areas burn complete while other areas are unburned to lightly burned and fire is not hot enough to affect soil conditions. Fire removes surface vegetation but has no impact on the root crown of bunchgrasses. So, bunchgrasses and forbs return post-fire with good vigor. Post-fire the bunchgrasses are now more susceptible to grazing damage. Burned rangeland pastures will need two growing seasons recovery prior to resuming grazing, or to be lightly grazed but only during dormant season the first two years post-fire. Beyond two years, for the bunchgrasses to expand, the grazing plan must moderate grazing intensity, and both critical period & growing season deferments must be implemented on and burned pastures. Ecological process: Fire kills sagebrush and it does not have any sprouting ability. Some sagebrush remains, but only in patches that did not burn. The reduction in sagebrush releases resources and, increases light for grasses and forbs. Fire conditions and post-fire grazing management allows bluebunch wheatgrass and other bunchgrasses to thrive and expand via tillering and new seedlings.

Pathway 1.3B
Community 1.3 to 1.4

Result: Shift from heavy sage community to depauperate community. Sagebrush has a moderate increase while bluebunch is all but eliminated from the community. Invasive annual grasses have not invaded, but Community 1.4 is most at risk to invasion and is the segue between States 1 and 2, and States 1 and 3. Pathway 1.2c is a continuation of the process that started with Pathway 1.2b. Primary Trigger: With excessive grazing pressure (heavy grazing intensity, season long grazing or frequent late spring grazing) and a period of no fire, sagebrush increases its cover while bluebunch wheatgrass bunchgrasses suffers a big decline. Grazing animals selectively target the remaining bluebunch wheatgrass plants eliminating most of the bluebunch wheatgrass plants from the community. Ecological process: With consistent defoliation pressure bluebunch wheatgrass has low vigor, shrinking crowns and a lot of mortality. This gives sagebrush opportunity to set new seedlings and expand its cover. A few bluebunch wheatgrass plants may survive.

State 2
Sagebrush Steppe with Invasive Species

State 2 is very similar to the Reference state, however, invasive species such as cheatgrass, medusahead, and ventenata are present.

Community 2.1
Reference with Invasives

Trace, 1 percent cheatgrass

Community 2.2
Bunchgrass Community with Invasives

Trace 1 percent cheatgrass

Community 2.3
Heavy Sagebrush Community with Invasives

5 percent cheatgrass

Community 2.4
Depauperate Community with Invasives

20 percent cheatgrass

Pathway 2.1A
Community 2.1 to 2.2

Result: Shift from the near reference community to bunchgrass community. Sagebrush cover is all but eliminated, while bluebunch wheatgrass has a moderate increase. The community shifts from a shrub steppe to a bunchgrass appearance. Primary Trigger: Moderate-severity fire is complete enough and hot enough to remove almost all sagebrush. Fire conditions and post-fire grazing management allows bluebunch wheatgrass and other bunchgrasses to thrive and expand. Some areas burn complete while other areas are unburned to lightly burned and fire is not hot enough to affect soil conditions. Fire removes surface vegetation but has no impact on the crown of bunchgrasses. So, bunchgrasses and forbs return post-fire with good vigor. Post-fire the bunchgrasses are now more susceptible to grazing damage. Burned rangeland pastures will need two growing seasons recovery prior to resuming grazing, or to be lightly grazed but only during dormant season the first two years post-fire. Beyond two years for the bunchgrasses to expand, the grazing plan must promote light to moderate grazing intensity, and both critical period and growing season deferments must be implemented on burned pastures. Ecological process: Fire kills sagebrush and it does not have any sprouting ability. A few sagebrush plants remain, but only in patches that did not burn. The reduction in sagebrush releases resources and increases light for grasses and forbs. Bluebunch wheatgrass and other bunchgrasses have good vigor post-fire and expand via tillering and new seedlings.

Pathway 2.1B
Community 2.1 to 2.3

Result: shift from reference community to heavy sagebrush community. There is a moderate increase in sagebrush while bluebunch wheatgrass has a corresponding moderate decrease. Primary Trigger: With excessive grazing pressure (heavy grazing intensity, season long grazing or frequent late spring grazing) and a period of no fire, sagebrush increases its cover while bluebunch wheatgrass suffers a big decline. Ecological process: With consistent defoliation pressures bluebunch wheatgrass experiences poor plant vigor to such a degree that grass roots begin to die. So, bluebunch wheatgrass experiences shrinking crowns and some mortality. This gives sagebrush the opportunity to set new seedlings and expand its cover. Increased shade from the new sagebrush plants also plays a role in this process.

Pathway 2.2A
Community 2.2 to 2.1

Result: Shift from Bunchgrass community to near Reference community. There is a moderate reduction of bluebunch wheatgrass cover and a corresponding increase of sagebrush. Primary Trigger: Over time with no fire, sagebrush will re-enter the community even with good bunchgrass vigor. Ecological process: Spots with soil disturbance receive sagebrush seed from remnant plants in unburned patches or from adjacent sites, seed germinates in the spring and a few sagebrush seedlings establish. For most locations it may take up to 10 years for sagebrush to re-enter the community. But in Douglas County the re-entry period may only be 2-5 years. With a slight increase in shade perennial bunchgrasses experience a slight decline.

Pathway 2.3A
Community 2.3 to 2.1

Result: Shift from heavy sagebrush community to reference community. There is a major decrease in sagebrush cover and a considerable increase in the cover of bluebunch wheatgrass. The community shift is from sagebrush dominance to bunchgrass dominance. Primary Trigger: Moderate-severity fire is patchy, dependent on temperature, wind, fuel load and fuel moisture. In areas that burn the fire is complete enough and hot enough to remove most sagebrush. Most areas burn complete while other areas are unburned to lightly burned and fire is not hot enough to affect soil conditions. Fire removes surface vegetation but has no impact on the root crown of bunchgrasses. So, bunchgrasses and forbs return post-fire with good vigor. Post-fire the bunchgrasses are now more susceptible to grazing damage. Burned rangeland pastures will need two growing seasons recovery prior to resuming grazing, or to be lightly grazed but only during dormant season the first two years post-fire. Beyond two years, for the bunchgrasses to expand, the grazing plan must moderate grazing intensity, and both critical period & growing season deferments must be implemented on burned pastures. Ecological process: Fire kills sagebrush and it does not have any sprouting ability. Some sagebrush remains, but only in patches that did not burn. The reduction in sagebrush releases resources and, increases light for grasses and forbs. Fire conditions and post-fire grazing management allows bluebunch wheatgrass and other bunchgrasses to thrive and expand via tillering and new seedlings.

Pathway 2.3B
Community 2.3 to 2.4

Result: Shift from heavy sagebrush community to depauperate community. Sagebrush has a moderate increase while bluebunch is all but eliminated from the community. Invasive annual grasses have not invaded, but Community 1.4 is most at risk to invasion and is the segue between States 1 and 2, and States 1 and 3. Pathway 1.2c is a continuation of the process that started with Pathway 1.2b. Primary Trigger: With excessive grazing pressure (heavy grazing intensity, season long grazing or frequent late spring grazing) and a period of no fire, sagebrush increases its cover while bluebunch wheatgrass bunchgrasses suffers a big decline. Grazing animals selectively target the remaining bluebunch wheatgrass plants eliminating most of the bluebunch wheatgrass plants from the community. Ecological process: With consistent defoliation pressure bluebunch wheatgrass has low vigor, shrinking crowns and a lot of mortality. This gives sagebrush opportunity to set new seedlings and expand its cover. A few bluebunch wheatgrass plants may survive.

State 3
Invasive Annuals

State 3 represents communities dominated by invasive annual species and has crossed a biological threshold. Virtually all the native functional, structural groups are missing. Community Phases for State 3: 3.1 Shrub – Annual Grass Sagebrush – cheatgrass 3.2 Annual Grass Cheatgrass Dominate State 3 Species: Cheatgrass with or without sagebrush The main species can include annual bromes, medusahead, ventenata, mustard, prickly lettuce and diffuse knapweed. This state can occur with or without sagebrush.

Community 3.1
Wyoming Big Sagebrush and Cheatgrass

Community 3.2
Cheatgrass

Pathway 3.1A
Community 3.1 to 3.2

Result: shift from shrub-cheatgrass to cheatgrass. Primary Trigger: Moderate intensity fire kills most or all sagebrush. Ecological process: due to a lack of native species in the community there is limited competition and invasive annuals such as cheatgrass fully occupy the site.

State 4
Seeded Grass

Note: Stony ecological sites have mild to moderate equipment limitations due to surface rock. State 4 Narrative: State 4 represents a site that has been seeded to desirable grasses such as Secar Snake River wheatgrass, Sherman big bluegrass, crested wheatgrass or intermediate wheatgrass. State 4 has two community phases that are stable if they maintain 0.8 plant per square feet or greater of the desired bunchgrasses Community Phases for State 4: 4.1 Seeded Grasses 4.2 Shrub – Seeded Grasses Dominate State 4 Species: Desirable seeded grasses with or without sagebrush and legumes

Community 4.1
Seeded Grass

Community 4.2
Shrubs and Seeded Grass

Pathway 4.1A
Community 4.1 to 4.2

Result: Shift from seeded grass to shrub – seeded grass community. Shrubs colonize the site and increase cover and density while seeded grasses decline Primary Trigger site has not burned. Heavy grazing pressure on seeded grasses reduce plant vigor. Ecological process: Consistent defoliation pressures that reduced plant vigor to such a degree that that grass roots begin to die, seeded grass crowns shrink, and some seeded grasses die. This opens the soil for seedling shrubs to establish.

Pathway 4.2A
Community 4.2 to 4.1

Result: Shift from shrub-grass to seeded grass community. Shrubs are decreased to all but eliminated and grasses increase to dominate the community. Primary Trigger: community treatment activities. (1) For communities with fire sensitive shrubs (sagebrush, bitterbrush) and a good population of desirable grasses, the best course of action is to reduce the shrubs by fire, chemical or mechanical treatment, and use proper grazing management to ensure grasses recover. (2) For communities with fire tolerant shrubs (rabbitbrush, three-tip sage) and a good population of desirable grasses, the best course of action is to reduce the shrubs by chemical treatment and use proper grazing management to ensure grasses recover. (3) Communities that do not have much seeded grass remaining will require a seedbed to be prepared and a seeding operation. Seedbed preparation can use a combination of fire, mechanical tillage and chemical application. Post-seeding the site will need 1 to 2 years of rest while the seeded grasses are established. Broadleaf weed control may also be necessary. Afterward, proper grazing must be used to maintain the stand. Ecological Process: with removal of the shrub layer the vigorous seeded grasses increase via tillering and new seedlings

Transition T1A
State 1 to 2

Result: transition from Reference State to State 2 (shrub steppe w/ a few annuals). The Reference State does not have invasive species. State 2 has the same communities but with minor additions of invasive annual grasses such as cheatgrass. Ecological process. Most sites in the Reference State have some scattered cheatgrass seed. This seed is waiting for enough moisture to germinate and to compete with the native species for space, light and moisture. When the right year happens even pristine communities in the Reference State are susceptible to colonization by cheatgrass. Primary Trigger: The transition occurs during a high moisture year that causes a micro-flush of cheatgrass and is the principle means of colonization. A second trigger would be spots of soil disturbance. Indicators: The occurrence of annual grasses on sites where they had been absent.

Transition T2A
State 2 to 3

Result: Transition from State 2 to State 3 which is dominated by annuals. This transition occurs once the cover of bluebunch wheatgrass decline to less than 10% while invasive species cover is at least 40%. This transition can occur with or without sagebrush in the community. Community 2.4 has limited amount of bluebunch and is the community most at risk and is also the pathway for crossing the threshold from State 2 into State 3. Community 2.4 is the segue between State 2 and State 3. Primary Trigger: Chronic heavy grazing, season-long grazing, or late spring grazing. Native species are all but eliminated. Note: chronic season-long grazing in 1880s-1940s created thousands of acres of annual grass-sagebrush community, and then fire turned that into annual grasses. A secondary trigger would be frequent fires that weaken the entire community. In either case, annuals such as cheatgrass have the competitive advantage. The site has lost its primary species that stabilize and protect the soil from wind and water erosion and has also lost the ability to retain sufficient soil moisture for many of the native perennial species. Ecological Process: Consistent defoliation pressure to bluebunch wheatgrass causes poor vigor, shrinking crowns and plant mortality. With more and more of the soil surface and upper soil rooting surface open, opportunistic, exotic weeds that take advantage of the available niche space to colonize and expand until the dominate the community. Indicators: Decreasing cover of bluebunch wheatgrass and increasing cover of invasive annual species. Increasing distance between native bunchgrasses. Decreasing soil organic matter, soil water retention, limited water infiltration and percolation in the soil profile.

Restoration pathway R3A
State 3 to 4

Most Stony, sagebrush ecological site soils have surface rock and rock throughout the profile. Other soils do not have surface rock but are shallow to bedrock. Equipment limitations that will cause issues and some treatment options may not be feasible on some sites. R1 Result: Shift from State 3 (a community dominated by invasive annual species) to State 4, which is predominately desirable seeded grasses. This transition occurs when active management decisions are attempted to alter the annual dominated state to one with persistent perennial bunchgrasses, even if they are not native ones. This requires a commitment of two years or more for weed control. Care must be taken to maintain soil structure so that the seedbed has many safe sites for the seed. Seed placement must be managed to achieve seed-soil contact at very shallow depth (about 1/8 inch is desired). Proper grazing management is essential to maintain the stand post-seeding. Secar Snake River wheatgrass, thickspike wheatgrass, Sherman big bluegrass, Sandberg bluegrass, and crested or Siberian wheatgrass are typical species seeded on Stony ecological site. The actual transition occurs when the seeded species have successfully established and are outcompeting the annual species for cover and dominance of resources.

Restoration pathway R4A
State 4 to 2

Result: Shift from State 3 back to State 2. This restoration transition does not occur without a significant commitment of time & resource inputs to restore ecological processes, native bunchgrasses, Wyoming sagebrush and native forb species. Shifting from State 3 to State 4: If the goal is to restore back to a native plant community, State 3 must first be shifted to State 4. It will take two years or longer to kill annual species and to exhaust the seedbank of invasive species. Site will then need to be seeded to perennial species such as crested wheatgrass to restore soil properties before native species can survive and thrive on site. The seeded species rebuild some of the basic soil properties including increased soil organic matter, increased soil moisture, and likely would also require the soil’s pore spaces, bulk density and soil microorganisms to return before the native species that used to survive in this ecological site can return. The site would also need several years of no significant fires and proper grazing management as well. See narrative for R1 transition above. Shifting from State 4 to State 2: This assumes that the shift from State 3 to State 4 has been successful. Introduced grasses must be killed before the seeding of native species. The seeding of native species should occur in two steps: (1) a seeding of native bunchgrasses so that broadleaf weeds may be controlled, (2) a re-introduction of sagebrush and native forbs. The site would also need several years of no significant fires and proper grazing management as well to ensure plant establishment and vigor. See narrative for R1 transition above.

Transition T4A
State 4 to 3

Result: Shift from seeded grass State 4 to State 3 which is dominated by invasive annual species. Primary Trigger: This transition occurs when chronic heavy grazing has removed too much of the perennial bunchgrass cover allowing invasive annual species to colonize the site. As this continues the competitive advantage goes to the exotic species which are opportunistic and take most of the site’s resources. Little of the resources remain for the desirable species. Secondary Trigger: Frequent fires or a severe fire that removes too much of the perennial bunchgrass cover and gives the competitive advantage to the invasive species. Ecological Process: Consistent defoliation pressure to seeded grasses cause poor vigor, shrinking crowns and plant mortality. With more and more of the soil surface and upper soil rooting surface open, opportunistic, exotic weeds that take advantage of the available niche space to colonize and expand until the dominate the community. Indicators: shrinking crowns and mortality of desirable species, increasing caps gaps between seeded plants, increasing cover by annual grasses.