Sandy 12-17" PZ
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
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Transition T1A
Absence of disturbance and natural regeneration over time, may be coupled with excessive grazing pressure
More details -
Restoration pathway R2A
Adequate rest from defoliation and removal of woody canopy, followed by reintroduction of historic disturbance regimes
More details -
Transition T2A
Absence of disturbance and natural regeneration over time, may be coupled with excessive grazing pressure
More details -
Restoration pathway R3A
Adequate rest from defoliation and removal of woody canopy
More details -
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
Description
The Tallgrass/Midgrass Grassland State is composed of tall and midgrass dominant with few perennial forbs and scattered woody shrubs. Dominant grasses include sand and little bluestem. Shrubs include sand sagebrush, skunkbush and occasional sand plum.
Submodel
Description
The decrease in density and stature of the tallgrass vegetation and increase in density of the woody vegetation brings about a new plant community, a Midgrass/Shrub Community phase (2.1). As retrogression proceeds, the tallgrasses give way to an increase in midgrasses such as sideoats grama, dropseed species and perennial threeawns. The better quality forbs are replaced with less palatable species such as gaura, western ragweed, annual wild buckwheat and camphorweed and there will be an increase in annual forbs. Sand sagebrush and skunkbush can increase to >20% of the total plant community.
Submodel
Description
If long-term heavy grazing continues, a threshold will be crossed to a Shrub Dominant Community (3.1). In this degraded state, typical vegetation will be annuals and western ragweed with an increase in perennial threeawns, red lovegrass, gummy lovegrass, sandbur and a significant canopy of sand sagebrush and possibly skunkbush. The loss of herbaceous cover and increased bare ground encourages accelerated erosion. Nutrient cycling, the water cycle, watershed protection and biological functions have been severely reduced. The plant community is so degraded that it cannot reverse retrogression without extensive energy and management inputs.
Submodel
Mechanism
With heavy continuous grazing, no fires, and brush invasion. The Tallgrass/Midgrass/Grassland State will transition to the Midgrass/Shrub State.
Mechanism
With the application of conservation practices such as Prescribed Grazing, Prescribed Burning, and Brush Management, the Midgrass/Shrub State can revert back to the Tallgrass/Midgrass Community.
Relevant conservation practices
| Practice | External resources |
|---|---|
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Brush Management |
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Prescribed Burning |
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Prescribed Grazing |
Mechanism
With heavy continuous grazing, no fire, and no brush management, the Midgrass/Shrub State will transition to the Shrubland State.
Mechanism
With the implementation of various conservation practices such as Prescribed Grazing (one to three year deferment), Brush Management, and Prescribed Burning, the Shrub Dominant Community can be restored to the Midgrass/Shrub Community.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
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Prescribed Burning |
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Prescribed Grazing |
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.