Semidesert Clay Loam
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
- Transition T1A More details
- Transition T1B More details
- Transition T2A More details
- Transition T2B More details
- Restoration pathway R3A More details
- Transition T3A More details
- Restoration pathway R4A More details
- Transition T4A More details
- Transition T4B More details
- Transition T5A More details
- Restoration pathway R5A More details
- Restoration pathway R6A More details
- Transition T6B More details
- Transition T6A More details
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No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
Description
The reference state represents the expected historical plant communities and ecological dynamics of this site, without the effects of improper grazing, an altered fire regime, introduction of non-native species, or other human disturbances. The reference state is dominantly Wyoming big sagebrush and perennial grasses. It is self-sustaining, which means it is resistant to natural disturbances and exhibits high resilience following natural disturbances (Briske et al., 2008). All community phases are at risk for establishment of non-native, invasive plants if a seed source and germination sites are available.
Submodel
Description
The current potential state is similar in structure and function to the reference state; however, invasive species are in all community phases of the current potential state. It generally is dominantly big sagebrush and perennial grasses, but it has an additional phase due to juniper encroachment as a result of fire suppression. The current potential state is less resilient than the reference state due to the presence of non-native, invasive species.
Submodel
Description
This state is in areas where the native perennial grasses are removed by excessive grazing. The abundance of native forbs is also reduced. The fire return interval is increased due to a lack of fine fuels, which facilitates establishment of Utah juniper.
Submodel
Description
This state occurs due to prolonged periods without fire or other brush-controlling disturbances. Utah juniper thrives in this ecological site in the absence of disturbance, and it eventually outcompetes Wyoming big sagebrush for water and nutrients. The result is a juniper-dominant state that has little, if any, Wyoming big sagebrush, perennial grasses, and forbs in the understory.
Submodel
Description
This state is dominantly invasive annual species. These species include cheatgrass, Russian thistle, kochia, Halogeton, storksbill geranium, and annual mustards. Generally, annual forbs and grasses will invade the site as ecological conditions deteriorate and perennial vegetation decreases in abundance due to disturbances such as fire, overgrazing, drought, off-road vehicle use, and erosion. The presence of invasive annual species depends on soil properties and moisture availability; however, these invaders are highly adaptive and can flourish in many locations. Once established, complete removal is difficult but suppression may be possible.
Submodel
Description
This state results from seeding introduced perennial grasses such as crested wheatgrass and Russian wildrye. Native perennial grasses, forbs, and shrubs may be included in the seed mix. This state has community dynamics similar to those of the current potential state. Other vegetation treatments may be needed, including chaining, mowing, disking, prescribed burning, and other techniques that manipulate the plant community. Under proper management, the seeded state could persist for long periods. Over time, native grasses and forbs may re-establish from nearby seed sources. Shrubs typically will re-establish within 30 to 40 years.
Submodel
Mechanism
Invasive species are in this plant community. The current potential state is less resilient than the reference state due to the presence of non-native, invasive species.
Mechanism
Continuous grazing of perennial species and lack of disturbance for a very long period.
Mechanism
Continuous grazing of perennial species and lack of disturbance for a very long period.
Mechanism
This transition is from a state that is dominantly Wyoming big sagebrush to one that is dominantly invasive species. Events include establishment of invasive species; fire (return interval of less than 5 to 20 years); continuous, season-long grazing of perennial grasses; and long-term drought.
Mechanism
Brush management and seeding of adapted perennial grasses, forbs, and shrubs under favorable climatic conditions may result in a restoration of state 2 from the depauperate state 3.
Mechanism
This transition is expected to occur when fire or other juniper-controlling disturbances have been absent from the site at least 150 years. Sagebrush becomes decadent, and Utah juniper outcompetes all species for water and other resources.
Mechanism
Pathway drivers include brush treatment, seeding, insect herbivory or pathogen, proper grazing, drought, and fire. This pathway requires an extensive input of energy.
Mechanism
This transition is from a state that is dominantly Wyoming big sagebrush to a state that is dominantly invasive species. Drivers include establishment of invasive species; fire (return interval of less than 5 to 20 years); continuous, season-long grazing of perennial grasses; and long-term drought.
Mechanism
Seeding of introduced or native species (grasses and forbs) is the pathway to state 4. Trees commonly are removed by mechanical or chemical treatments. This transition requires an input of energy.
Mechanism
This transition requires lengthening the fire return interval. Fire suppression may be needed to interrupt the fire return interval, which has been shortened by the invasion of cheatgrass and other annuals. Juniper will encroach onto the site during periods without fire. Seeding may be needed to establish perennial plants. This transition may require a significant input of energy.
Mechanism
Treatment and suppression of invasive annuals is needed to allow desired seeded species to complete and become established. Seeding of introduced species is the pathway to state 4. This transition is difficult; it requires a substantial input of energy and management. It may not be practical on a large scale.
Mechanism
A long period without disturbance could result in this return pathway. Native plants from adjacent sites would slowly become established in the seeded state. Proper grazing by livestock and wildlife would favor the establishment of native plants. Removal of encroached Utah juniper and pinyon would be necessary.
Mechanism
This transition is from a state consisting of big sagebrush and seeded grass to a state that is dominantly two-needle pinyon and Utah juniper. Events include fire suppression; time without disturbance; insect herbivory; continuous, season-long grazing of perennial grasses, and tree invasion. As the density of the canopy increases, the amount of bare ground will increase. This will increase the fire return interval, accelerate erosion, increase runoff, and further affect the functionality of the watershed. This transition favors the establishment of invasive annual species such as cheatgrass.
Mechanism
This transition is from a seeded state to a state that is dominantly invasive species. Events include increased invasive species, a shortened fire return interval, and long-term drought. Improper continuous, season-long grazing of perennial grasses can decrease the time needed for this transition.
Model keys
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The Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.