Natural Resources
Conservation Service
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
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Transition T1A
Abandonment, no fire, and grazing management
More details -
Transition T1B
Brush management, plowed, pasture planting
More details -
Restoration pathway R2A
Prescribed grazing, fire, and/or brush management
More details -
Transition T2A
Abandonment, no fire, and "inadequate" grazing management
More details -
Transition T2B
Brush management, plowed, pasture planting
More details -
Restoration pathway R3A
Extensive brush management or herbicide applications
More details -
Transition T3A
Brush management, plowed, pasture planting
More details -
Restoration pathway R4A
Range planting, prescribed grazing, prescribed burning
More details -
Restoration pathway T4A
Heavy continuous grazing, no brush management, abandonment
More details -
Transition T4B
Heavy continuous grazing, brush management
More details -
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
Description
One community phase exists in the Reference State, the 1.1 Tallgrass/Oak Savannah Community Phase. The State is dominated by warm-season perennial grasses and the overstory canopy cover is less than 30 percent.
Submodel
Description
One community exists in the Shrubland Dominated State, the 2.1 Oak Scrub/Shrubland Community. The herbaceous production is not as great compared to the Reference State, and overstory canopy has increased to 30 and 50 percent.
Submodel
Description
One community phase exists in the Encroached State, the 3.1 Oak/Yaupon Woodland Community. The ecological site is characterized by a decrease in herbaceous species and an increase in woody species. The overstory canopy cover is greater than 50 percent with significant shrub understory.
Submodel
Mechanism
The Reference State will transition to the Shrubland Dominated State with continued heavy grazing pressure, no brush management, or abandonment occurs. The transition is evident when woody species canopy cover exceeds 30 percent and grasses shift composition to more shade-tolerant species.
Mechanism
The transition to the Pastureland State occurs when the site is plowed for planting pasture. The driver for the transition is the land manager's decision to farm the site.
Mechanism
Restoration back to the Reference State requires brush management, prescribed grazing or prescribed fire. The woody canopy cover needs to be less than 50 percent and adequate herbaceous fine fuel to carry fire. When the threshold is exceeded, mechanical or chemical brush control becomes necessary to move this transitional community back towards Reference state. Prescribed grazing may require destocking and/or deferment, depending on the condition of the herbaceous understory and seed bank. While these treatment methods may remove the woody species, re-establishment of the herbaceous component is very difficult due to the low water holding capacity and low fertility of the soils.
Mechanism
The Shrubland Dominated State will transition to the Encroached State when continued heavy grazing pressure, no brush management, or abandonment continues. The transition is evident when woody species canopy cover exceeds 50 percent and grasses shift composition to more shade-tolerant species.
Mechanism
The transition to the Pastureland State occurs when the site is cultivated and planted to pasture. The driver for the transition is the land manager's decision to cultivate the site.
Restoration pathway R3A
Extensive brush management or herbicide applications
Mechanism
Restoration back to the Reference State requires substantial energy inputs. Brush management/"prescribed fire" and prescribed grazing will be needed to shift the community back. Mechanical or chemical controls can be used to remove the woody overstory species back below 30 percent. Chemical brush control on a large scale is not a viable treatment option due to resistance of yaupon to broadcast herbicide applications. Individual plant treatment with herbicides on a small acreages may be a viable treatment option. Prescribed grazing may require destocking and deferment to manage the understory grasses back to those found in the reference community. Prescribed fire may be a viable option if enough fine fuel still exists in the understory to help carry the fire across the landscape. Increased frequency of burns may be required to initiate a burning schedule. The low water holding capacity and low fertility of these soils make re-establishment of herbaceous species difficult.
Mechanism
The transition to the Pastureland State occurs when the site is cultivated and planted for pasture. The driver for the transition is the land manager's decision to cultivate the site.
Restoration pathway R4A
Range planting, prescribed grazing, prescribed burning
Mechanism
The restoration to Reference State can occur when the land manager ceases agronomic practices. Range planting of native species found in the reference community will be required to bring back a similar community as the Reference State plant composition. Proper grazing and brush management will be required to ensure success.
Mechanism
The Converted Land State will transition to the Shrub Dominated State when continued heavy grazing pressure, no brush management, or abandonment continues. The transition is evident when woody species canopy cover exceeds 50 percent and grasses shift composition to more shade-tolerant species.
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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