Natural Resources
Conservation Service
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
- Transition T1A More details
- Restoration pathway R2A More details
-
No transition or restoration pathway between the selected states has been described
Target ecosystem state
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State 1
Savannah State - Reference
Savannah State - Reference
Dominant plant species
post oak (Quercus stellata), tree
big bluestem (Andropogon gerardii), grass
Submodel
Dominant plant species
post oak (Quercus stellata), tree
Ashe's juniper (Juniperus ashei), tree
sideoats grama (Bouteloua curtipendula), grass
Texas wintergrass (Nassella leucotricha), grass
Submodel
Mechanism
The Savannah State is resistant to shrub dominance. However, shrubs and trees make up a portion of the plant community in this state, therefore propagules are present. The mean fire return interval in the Savannah State is 3-7 years. Even with proper grazing management and favorable climate conditions, lack of fire for 10-20 years will allow woody species to increase in canopy to reach the 40% threshold level. An infusion of invasive species (i.e. juniper or mesquite) will speed up the process. Improper grazing, prolonged drought, and warming climate will provide a competitive advantage to shrubs which will accelerate this process. Tallgrasses will decrease to less than 5% species composition.
Mechanism
Restoration of the Shrubland State to the Savannah State requires substantial energy input. Mechanical or herbicidal brush control treatments can be used to remove woody species. A long-term prescribed fire program may sufficiently reduce brush density to a level below the threshold of the Savannah State, particularly if the woody component is dominated by species that are not fire sprouters. Brush control in combination with prescribed fire, proper grazing management, and favorable growing conditions may be the most economical means of creating and maintaining the desired plant community. If remnant populations of tallgrasses, midgrasses, and desirable forbs are not present at sufficient levels, range planting will be necessary to restore the reference plant community.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
|
|
Prescribed Burning |
|
|
Prescribed Grazing |
Model keys
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Ecological sites
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.
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