State and transition model
State 1
1 Reference State
The dominate aspect is a shrub canopy of blackbrush with lesser amounts of Mormon tea, fourwing saltbush, Stansbury cliffrose and Bigelow sagebrush. Common grasses include blue grama, sand dropseed, James' galleta and Indian ricegrass. Blackbrush appears to act as a paleo-endemic species in this MLRA and may not be able to or be very slow to reestablish itself after significient disturbance. Plants likely to increase are annual grasses and forbs, perennial forbs and broom snakweed. Plants likely to invade and become established are cheatgrass, Russian thistle and red brome.
Community 1.1
1.1 Shrubland with Native Perennial Grasses
This plant community is dominated by blackbrush with scattered perennial grasses and half-shrubs. Common grasses include blue grama, sand dropseed, Indian ricegrass, James' galleta, black grama, squirreltail and sixweeks fescue. Other shrubs commonly found include Mormon tea, Stansbury cliffrose, Bigelow sagebrush, narrowleaf yucca, fourwing saltbush, broom snakeweed and pricklypear.
Community 1.2
1.2 Blackbrush Shrubland
This plant community is dominated by blackbrush with scattered perennial warm season grasses and half-shrubs. Common grasses include blue grama, sand dropseed, James' galleta, Indian ricegrass. Other shrubs commonly found include Mormon tea, narrowleaf yucca, and broom snakeweed. There is a decline in perennial grasses and shrubs, such as fourwing saltbush and Bigelow sagebrush. Plant community composition by weight are about 75-95 percent for shrubs, 1-10 percent for grasses, 1-15 percent for forbs, and less than 5 percent for trees. There is an increase in bare ground as herbaceous cover decreases in shrub interspaces.
Pathway 1.1A
Community 1.1 to 1.2
Continous livestock grazing, prolonged drought, surface disturbance reduces herbaceous cover.
Pathway 1.2A
Community 1.2 to 1.1
Prescribed grazing or Rest, favorable climate or time for recovery allows for increase cover of perennial herbaceous species.
State 2
2 Introduced Non-Natives State
This state is similar to the Reference State, but non-native annual grasses and forbs have been introduced into the plant community. In the plant communities phases of the Introduced Non-Native State is the amount of annual grasses and forbs is only a small amount (1-3%), but will fluctuate slightly from year to year due to fluctuations in the amount and timing of precipitation. Normal soil surface disturbance expected from moderate levels of livestock grazing may cause the amount of non-native annual grasses and forbs to increase slightly.
Community 2.1
2.2 Blackbrush Shrubland with Introduced Annuals
Introduced non-native annual grasses and forbs are present in minor amounts (1-3%) in the plant community, but the amount of native plants is similar to that of 1.2, Blackbrush Shrubland.
Community 2.2
2.2 Blackbrush Shrubland with Introduced Annuals
Introduced non-native annual grasses and forbs are present in minor amounts (1-3%) in the plant community, but the amount of native plants is similar to that of 1.2, Blackbrush Shrubland.
Pathway 2.1A
Community 2.1 to 2.2
Continous livestock grazing, prolonged drought, surface disturbance reduces herbaceous cover.
Pathway 2.2A
Community 2.2 to 2.1
Prescribed grazing or Rest, favorable climate or time for recovery allows for increase cover of perennial herbaceous species.
Transition T1A
State 1 to 2
The introduction of non-native annual grasses and forbs creates an irreversible change in the plant community.