State and transition model
Community 1.1
1.1 Historic Climax Plant Community
The historic climax plant community is composed of mid and short grasses with a moderate percentage of forbs and shrubs. There is a mixture of both cool and warm season grasses and half-shrubs.
Plant species most likely to invade or increase on this site when it deteriorates are sand sagebrush, big sagebrush, rabbitbrush, annuals, sandhill muhly, wooly groundsel, and snakeweed.
Community 1.2
1.2 Shrubs with Grasses Community
This plant community is characterized by a mix of shrubs and grasses. There is a slight increase of large and half shrubs, decrease in perennial grasses, especially cool season grasses. Grasses in decline include black grama, needle and thread and Indian ricegrass.
Pathway 1.1a
Community 1.1 to 1.2
Unmanaged grazing, long term winter dominated precipitation, and/or drought that reduces perennial warm and cool season grasses
Pathway 1.2a
Community 1.2 to 1.1
Managed grazing, adequate precipitation
Community 2.1
2.1 Sagebrush Dominated Community
Sagebrush species such as big sagebrush and/or sand sagebrush. Other shrubs in moderate amounts include rabbitbrush species and snakeweed. In the understory is a mix of warm and cool season grasses dominanted by blue grama, Indian ricegrass, squirreltail, and dropseeds.
Community 2.2
2.2 Sagebrush with Scattered Juniper Community
The dominant aspect of this site is a shrubland with a scattered overstory of junipers. Dominant shrubs include sagebrush, snakeweed, Bigelow rubber rabbitbrush and other native shrubs. The herbaceous understory is dominated by blue grama, needle and thread, sand dropseed, sandhill muhly and Indian ricegrass.
Pathway 2.1a
Community 2.1 to 2.2
Unmanaged grazing, summer drought, seed source for juniper
Pathway 2.2a
Community 2.2 to 2.1
Natural patchy fire, well managed grazing, and adequate precipitation
State 3
3 Juniper/Shrubs State
Juniper and occasional pinyon pine increases to dominate overstory with a shrub understory. Shrubs species include sagebrush, snakeweed, rabbitbrush, Cultler's mormon tea and antelope bitterbrush. There is also a increase of introduced annual forbs and grasses. Dominant grasses are sandhill muhly, blue grama, sand dropseed and Indian ricegrass.
Community 4.1
4.1 Tree/Shrub with Introduced Annuals Community
The dominant aspect of the site is woody overstory of shrubs and trees with a herbaceous understory dominated by forbs. This site has a high degree of bare ground with active signs of soil erosion. Bare ground can reach as high as 85%, but in wet years can be as low as 35% with high forb production. Plant understory composition by weight for forbs and annual grasses can range from 25-45%, but can be as high as 80% during high precipitation events. Dominate grasses include sandhill muhly, dropseeds and Indian ricegrass. Dominate shrubs include Bigelow rubber rabbitbrush, Greene's rabbtibrush, sand sagebrush, frosted mint, antelope bitterbrush and sand buckwheat. Tree canopy can vary, but is dominated by juniper species.
Transition T1A
State 1 to 2
Loss of biotic integrity due to loss of perennial grasses and shrub encroachment, causing some loss of soil site stability and hydrologic function with more stability and infiltration under shrubs.
Transition T1B
State 1 to 3
Loss of biotic integrity due to loss of perennial grasses and juniper and shrub encroachment, causing some loss of soil site stability and hydrologic function.
Transition T2A
State 2 to 3
Further loss of biotic integrity with increasing juniper. Soil site stability and hyrdologic function at least moderately departed from the reference state due to changes in infilration pattern.
Transition T2B
State 2 to 4
Drought, unmanaged grazing and/or fire removes the perennial herbaceous component of the plant community. Introduced annual grasses and forbs move into the plant community further reducing the biotic integrity of the site. Soil site stability is lost except around remaining trees and shrubs.
Restoration pathway R3A
State 3 to 1
Reduction of juniper and other woody shrubs that have encroached on the site. Seeding or planting where remaining seed source is inadequate. Well managed grazing before and after treatment.
Transition T3A
State 3 to 4
Drought, fire, and/or unmanaged grazing reduce the perennial herbaceous component and some of the shrubs further reducing the biotic integrity of the site. Introduced annual grasses and forbs move into the plant community. Soil site stability and hydrogic function are at least moderately departed from the reference state.
Restoration pathway R4A
State 4 to 2
Reduction of junipers and shrub species that have encroached on the site. Seeding where there is not an adequate seed source of the desired species. Control of introduced grasses and fobs may be needed if they are significant on the site. Well managed grazing is required before and after treatment.