Steep Sandy
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
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Transition T1A
Heavy grazing with inadequate growing season recovery periods.
More details -
Transition T1B
Woody encroachment and no fire or brush management.
More details -
Transition T2A
Woody encroachment and no fire or brush management.
More details -
Restoration pathway R3A
Prescribed burning, wildfire, harvest, and recurring brush management.
More details -
Restoration pathway R3B
Prescribed burning, wildfire, harvest, and recurring brush management.
More details -
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
Description
The Reference State (1) describes the range of vegetative communities that occur on the Steep Sandy ecological site where the range of natural variability under historic conditions and disturbance regimes is mostly intact. The Reference State developed under the combined influences of climatic conditions, periodic fire activity, grazing by large herbivores, and impacts from small mammals and insects. High perennial grass cover and production allows for increased soil moisture retention, vegetative production and overall soil quality.
The Reference State includes four plant community phases which are the Reference Community (1.1), the Degraded Native Grass Community (1.2), the At-Risk Community (1.3), and the Excessive Litter Community (1.4). The Reference Community (1.1) serves as a description of the native plant community that naturally occurs on the site when the natural disturbance regimes are intact or closely mimicked by management practices. The Degraded Native Grass and At-Risk Communities result from management actions that are unfavorable for a healthy Reference Community. The Excessive Litter Community occurs when herbivory and fire are eliminated from the landscape.
Submodel
Description
The Native/Invaded Grass State (2) has transitioned from the Reference State (1) and much of the native warm-season tall- and midgrass community has been replaced by native, warm-season shortgrasses and non-native grasses. The loss of warm-season tall- and midgrasses has negatively impacted energy flow and nutrient cycling. The Native/Invaded Grass State includes the Native Shortgrass-Invasive Grass Community (2.1).
Submodel
Description
The Invaded Woody State (5) is the result of woody encroachment. Once the tree canopy cover reaches 15 percent with an average tree height exceeding five feet, the threshold to the Invaded Woody State has been crossed. Woody species are increasing due to the lack of prescribed fire, brush management, or other woody tree removal. Typical ecological impacts are a loss of native grasses, reduced diversity of functional and structural groups, reduced forage production, and reduced soil quality.
Prescribed burning, wildfire, timber harvest and brush management will move the Invaded Woody State toward a grass dominated state. If the Invaded Woody State transitioned from the Native/Invaded Grass State (2) the land cannot return to the Reference State (1) as the native plant community, soils, and hydrologic function had been too severely impacted prior to the woody encroachment to allow the return to the Reference State through woody species removal alone. The Invaded Woody State includes one community, the Invaded Woody Community (4.1).
Submodel
Mechanism
Heavy grazing with inadequate growing season recovery periods will cause the Reference State (1) to lose a significant proportion of warm-season tall- and midgrass species and cross a threshold to the Native/Invaded Grass State (2). Water infiltration and other hydrologic functions will be reduced due to the root-matting presence of sod-forming grasses. With the decline and loss of deeper-penetrating root systems, soil structure and biological integrity are catastrophically degraded to the point that recovery is unlikely. Once this occurs, it is highly unlikely that grazing management alone will return the community to the Reference State.
Mechanism
Disruption of the natural fire regime and encroachment of invasive exotic and native woody species can cause the Reference State (1) to shift to the Invaded Woody State (3).
Mechanism
Disruption of the natural fire regime and encroachment of invasive exotic and native woody species can cause the Native/Invaded Grass State (2) to shift to the Invaded Woody State (3).
Mechanism
Prescribed burning, wildfire, harvest, and brush management will move the Invaded Woody State (3) toward the Reference State (1). Using prescribed fire to control the eastern redcedar without negatively impacting the desired pine overstory may be extremely difficult on this site. Mechanical removal followed by low intensity maintenance burns is usually the most effective eastern redcedar control method. The forb component of a site with heavy tree density or canopy cover may initially increase following tree removal through mechanical brush management treatments and prescribed fire.
If re-sprouting brush is present, stumps must be chemically treated immediately after mechanical removal. Ongoing brush management such as hand cutting, chemical spot treatments, or periodic prescribed burning is required to prevent a return to the Invaded Woody State.
Land that transitioned to the Invaded Woody State (3) from the Native/Invaded Grass State (2) cannot transition to the Reference State (1) through removal of woody species as the native plant community, soils, and hydrologic function have been too severely impacted for that restoration to occur.
Mechanism
Prescribed burning, wildfire, harvest, and brush management will move the Invaded Woody State (3) toward the Native/Invaded Grass State (2). Using prescribed fire to control the eastern redcedar without negatively impacting the desired pine overstory may be extremely difficult on this site. Mechanical removal followed by low intensity maintenance burns is usually the most effective eastern redcedar control method. The forb component of a site with heavy tree density or canopy cover may initially increase following tree removal through mechanical brush management treatments and prescribed fire.
If re-sprouting brush is present, stumps must be chemically treated immediately after mechanical removal. Ongoing brush management such as hand cutting, chemical spot treatments, or periodic prescribed burning is required to prevent a return to the Invaded Woody State.
Land that transitioned to the Invaded Woody State (3) from the Native/Invaded Grass State (2) cannot transition to the Reference State (1) through removal of woody species as the native plant community, soils, and hydrologic function have been too severely impacted for that restoration to occur.
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.