Very Shallow 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 -
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
State 1
Grassland State
Description
The Reference Plant Community was a Shortgrass/Midgrass Community (1.1). Few if any tallgrass species will be found. Grass species account for 85 percent of the total site production. A wide variety of forbs are produced on this site producing 15 percent of the total annual production and only trace amounts of woody shrubs will be found.
With continuous heavy grazing, no fire, no brush management and/or pest management this site will transition to the Shortgrass/Shrub Community (1.2). As livestock and wildlife numbers increase and grazing use exceeds a plants ability to sustain defoliation, the more palatable and generally more productive species decline in stature, productivity and density. The tendency of this site is to become a shortgrass dominant site if long-term grazing abuse occurs. This will lead to a decline in sideoats grama, blue grama and other palatable grass species.
Submodel
Description
A major threshold will be crossed from the Grassland State (1.0) to the Shrubland State (2.0). In this state, mesquite, shrubs such as broom snakeweed and catclaw acacia will dominate the site. The typical shortgrass species will be perennial threeawns, hairy tridens and other invading low quality short grasses. Bare areas will increase with annuals filling the voids. The loss of herbaceous cover and increased bare soil encourages accelerated erosion, especially on sites with steeper slopes.
Submodel
Mechanism
If long-term, heavy grazing continues with no fire or any form of brush and pest management, a major threshold will be crossed to the Shrub/Shortgrass Community (2.1). In this state, mesquite, broom snakeweed and catclaw acacia will dominate the site. Bare areas will increase with annuals filling the voids.
Mechanism
Prescribed grazing with rest periods during the growing season, re-seeding with adapted native grass species, chemical and/or mechanical brush management, and some form of pest management will be required to return this state back the reference. With the reduced amounts of grass fuel, poor continuity and increased bare soil, prescribed burning will not be an option in this state.
Relevant conservation practices
| Practice | External resources |
|---|---|
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Brush Management |
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Range Planting |
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Integrated Pest Management (IPM) |
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Prescribed Grazing |
Model keys
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Major Land Resource Areas
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.