State 1
Reference State

The reference state is generally dominated by blackbrush, however depending on disturbance history, native grasses, forbs, or other shrubs may occupy significant composition in the plant community. Primary disturbance mechanisms include climate fluctuations and both native and domestic herbivore grazing. Timing of these disturbances dictates the ecological dynamics that occur. The reference state is self sustaining and resistant to change due to high resistance to natural disturbances and high resilience following natural disturbances. Once invasive plants establish, return to the reference state may not be possible.

Characteristics and indicators. A community dominated by blackbrush where native perennial grasses and forbs may or may not be present.

Community 1.1
Blackbrush Shrubland with Perennial Grasses

This community phase is characterized by a blackbrush dominated shrub layer with Cutler's jointfir is also commonly present. Perennial grasses are also be present. Commonly occurring grasses include Indian ricegrass, needle-and-thread, Jamres galleta, six weeks fescue, and several dropseed species. These species are often concentrated near or within the shrub canopy. As grass cover increases, shrub interspaces are filled. Other perennial grasses, shrubs, and forbs may also be present and cover is variable.

Community 1.2
Blackbrush Shrubland

This community phase is characterized by a shrub canopy dominated by blackbrush and Cutler's jointfir, a few perennial grasses may also be present. Where perennial grasses are present, Indian ricegrass, needle-and-thread, James galleta, six weeks fescue, and dropseed species are most common with many occurring solely in the shrub canopy. There is little herbaceous cover in the shrub interspaces.

Pathway 1.1a
Community 1.1 to 1.2

This community pathway occurs when any combination of season long grazing providing little rest and recovery for preferred grazed plants during critical growing periods coupled with high utilization, drought or surface disturbance reduces the amount of herbaceous vegetation.

Pathway 1.2a
Community 1.2 to 1.1

This community pathway occurs when proper livestock grazing, wet weather periods and time allow for the recovery of surface disturbance which increases the amount of perennial herbaceous vegetation on the site.

State 2
Current Potential State

The current potential state is similar to the reference state, however invasive species are now present. This state is generally dominated by blackbrush. Disturbance mechanisms that may occur include climate fluctuations, native herbivore grazing, domestic livestock grazing, and surface disturbances such as road and pipeline development and off road vehicle (OHV) use. The current potential state is still self sustaining but is losing resistance to change due to a lower resistance to disturbances and lower a resilience following disturbances. New disturbances such as fire are now more likely to occur.

Characteristics and indicators. A community dominated by blackbrush where native perennial grasses and forbs may also be present. Invasive grasses and forbs are present.

Community 2.1
Blackbrush Shrubland with Perennial Grasses & Invasive Species.

This community phase is characterized by a blackbrush dominated shrub layer with Cutler's jointfir is also commonly present. Perennial and invasive grasses are also be present. Commonly occurring native grasses include Indian ricegrass, needle-and-thread, James galleta, six weeks fescue, and several dropseed species. Commonly occurring invasive species include cheatgrass, red brome and Russian thistle. These species are often concentrated near or within the shrub canopy. As both perennial and annual herbaceous cover increases, shrub interspaces are filled. Other perennial grasses, shrubs, and forbs may also be present and cover is variable.

Community 2.2
Blackbrush Shrubland with Invasive Species.

This community phase is characterized by a shrub canopy dominated by blackbrush and Cutler's jointfir, a few perennial grasses may also be present. Where grasses are present, Indian ricegrass, needle-and-thread, James galleta, six weeks fescue, and dropseed species are most common with many occurring solely in the shrub canopy. There is little herbaceous cover in the shrub interspaces. Invasive annuals are now present with cheatgrass, red brome and Russian thistle being the most common. Other perennial grasses, shrubs, and forbs may also be present and cover is variable.

Pathway 2.1a
Community 2.1 to 2.2

This community pathway occurs when any combination Season long grazing providing little rest and recovery for preferred grazed plants during critical growing periods coupled with high utilization, drought or surface disturbance reduces the amount of herbaceous vegetation on the site.

Pathway 2.2a
Community 2.2 to 2.1

This community pathway occurs when proper livestock grazing, wet weather periods and time allow for the recovery of surface disturbance which increases the amount of perennial herbaceous vegetation on the site.

State 3
Disturbed State

This phase of the ecological state is characterized as highly disturbed. Blackbrush and other shrubs may or may not be present in the community. Where other shrubs are present, Cutler's and Torrey's jointfir, are common species. Perennial grasses and forbs are mostly missing. Pricklypear cactus, cheatgrass, red brome, and Russian thistle may be present. Utah juniper may be invading this site if a seed source is present. The appearance of many forbs is episodic in nature and is closely tied to precipitation events.

Community 3.1
Disturbed State

This phase of the ecological state is characterized as highly disturbed. Blackbrush and other shrubs may or may not be present in the community. Where other shrubs are present, Cutler's and Torrey's jointfir, are common species. Perennial grasses and forbs are mostly missing. Pricklypear cactus, cheatgrass, red brome, and Russian thistle may be present. Utah juniper may be invading this site if a seed source is present. The appearance of many forbs is episodic in nature and is closely tied to precipitation events.

Transition T1A
State 1 to 2

This transition is from the native perennial grass understory in the reference state to a state that contains invasive species. Events include season long continuous grazing providing little rest and recovery for perennial grasses during critical growing periods coupled with high utilization, prolonged drought, and surface disturbances, etc. However invasive species such as cheatgrass have been known to invade intact perennial plant communities with little to no disturbances. Once invasive plants are found in the plant community a threshold has been crossed.

Transition T2A
State 2 to 3

This transition is from a mix of native shrubs and grasses along with invasive annual species found in community phase 2.1 to a state that is dominated by pricklypear cactus, broom snakeweed and/or a mix other non-native, invasive species. Events include season long continuous grazing providing little rest and recovery for perennial grasses during critical growing periods coupled with high utilization, prolonged drought, surface disturbances, etc. Once invasive species dominate the plant community a threshold has been crossed.