Loamy 18-22 P.Z.
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
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Transition T1A
Repeated continuous seasonal grazing, rotational summer grazing with inadequate recovery periods, or prolonged (> 10 years) nonuse with no fire with invasion of non-native cool-season grasses.
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Transition T1B
Long term (> 10 years) continuous season long grazing or rotational grazing with inadequate growing season recovery periods.
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Transition T1C
Long term (> 10 years) heavy grazing or other heavy disturbance.
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Transition T1D
Woody encroachment with no prescribed burning or woody species management.
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Transition T1E
Tillage to facilitate production agriculture.
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Restoration pathway R2A
Long-term (> 15 years) prescribed grazing during spring or spring and fall.
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Transition T2A
Continued invasion of non-native cool-season grasses facilitated by seasonal grazing in summer, continuous season long grazing, rotational grazing with inadequate growing season recovery periods or non-use with no fire.
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Transition T2B
Long term (> 10 years) continuous seasonal grazing in the spring months.
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Transition T2C
Long term (> 10 years) heavy grazing or other heavy disturbance.
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Transition T2D
Woody encroachment with no prescribed burning or woody species management.
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Transition T2E
Tillage to facilitate production agriculture.
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Restoration pathway R3A
Long-term (> 15 years) prescribed grazing during spring or spring and fall.
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Transition T3A
Long term (> 10 years) heavy grazing or other heavy disturbance.
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Transition T3B
Woody encroachment with no prescribed burning or woody species management.
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Transition T3D
Tillage to facilitate production agriculture.
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Restoration pathway R4A
Long-term (> 15 years) prescribed grazing. This restoration may not be feasible.
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Restoration pathway R4B
Long-term (> 15 years) prescribed grazing. This restoration may not be feasible.
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Transition T4A
Long term (> 10 years) heavy grazing or other heavy disturbance.
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Transition T4B
Woody encroachment with no prescribed burning or woody species management.
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Transition T4C
Tillage to facilitate production agriculture.
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Transition T5A
Woody encroachment with no prescribed burning or woody species management.
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Transition T5B
Tillage to facilitate production agriculture.
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Restoration pathway R6A
Prescribed burning, wildfire, timber harvest, brush management.
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Restoration pathway R6B
Prescribed burning, wildfire, timber harvest, brush management.
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Restoration pathway R6C
Prescribed burning, wildfire, timber harvest, brush management.
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Restoration pathway R6D
Prescribed burning, wildfire, timber harvest, brush management.
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Restoration pathway R6E
Prescribed burning, wildfire, timber harvest, brush management.
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Transition R6F
Prescribed burning, wildfire, timber harvest, brush management.
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Restoration pathway T7A
Woody encroachment with no prescribed burning or woody species management.
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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 Loamy 18-22" PZ 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 the Reference Community (1.1) and the At-Risk Community (1.2). 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 At-Risk Community results from management actions that are unfavorable for a healthy Reference Community. All community phases are susceptible to eastern redcedar invasion and subject to crossing a threshold into the Invaded Woody State (4).
Submodel
Description
The Native/Invaded Grass State (2) has been degraded from the Reference State (1) and much of the native warm-season grass community has been replaced by native cool-season grasses and non-native cool-season grasses. Non-native species are typically 15 percent or more of the plant community composition by weight. The Native/Invaded Grass State developed under repeated seasonal grazing during the summer or under extended periods (more than 10 years) of non-use with no fire. With extended periods of non-use, a thick litter layer develops This thatch layer favors cool-season species and the invasion of non-native cool-season grasses, especially Kentucky bluegrass.
The loss of warm-season, tall- and midgrasses has negatively impacted energy flow and nutrient cycling. Water infiltration is reduced due to the shallow root system and rapid runoff characteristics of the current plant communities. As the management continues, the plant community will become dominated by non-native cool-season grasses and sedges causing the Native/Invaded Grass State to transition to the Invaded Grass State (3).
The Native/Invaded Grass State includes the Native Cool-Season-Invasive Cool-Season Grass Community (2.1).
Submodel
Description
The Invaded Grass State (3) occurs when non-native cool-season grasses dominate the site and are than 30 percent of the plant community composition by weight. Smooth brome tends to dominate the site with long term heavy grazing while Kentucky bluegrass tends to dominate the site with non-use and no fire due to thatch buildup.
The loss of warm-season, tall- and midgrasses and increase of non-native cool-season grasses has negatively impacted energy flow and nutrient cycling. Water infiltration is reduced due to the shallow root system and rapid runoff characteristics of the current plant community.
Long term (more than 15 years) prescribed grazing which includes concentrated grazing in the spring and fall and no grazing during the summer months may restore the plant community to the Native/Invaded State (2). The feasibility of this restoration depends upon the amount of native grasses remaining in the plant community. The fewer the native grasses present, the less likely that restoration is possible.
The Invaded Grass State includes the Invaded Grass Community (3.1).
Submodel
Description
The Shortgrass Sod State (4) most of the native warm-season tall- and midgrasses and cool-season bunchgrasses have been replaced by warm-season shortgrasses and sedges. The loss of warm-season tall- and midgrass and cool-season bunchgrass functional groups has negatively impacted energy flow and nutrient cycling. Water infiltration has been reduced while runoff has been increased due to the relatively shallow root systems of existing plant community. The Shortgrass Sod State includes the Shortgrass Sod Community (4.1).
Submodel
Description
The Early Seral State (5) occurs with long term, heavy, concentrated grazing (continuous, season long, seasonal, or rotational with inadequate growing season recovery periods). Palatable warm-season grasses have been eliminated from plant community and have been replaced by less palatable warm-season grasses such as Fendler's threeawn and annual grasses such as cheatgrass. In some cases, remnant native grasses are present where protected from grazing, such as within shrub canopy. Litter levels are low and there is a significant amount of bare ground. Runoff is high and water infiltration is low. Soil erosion through both wind and water has increased significantly when compared to the other herbaceous states. Biotic integrity, hydrologic function, and site stability have been severely degraded. The Early Seral State includes the Shortgrass/Annuals Community (5.1).
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 this state toward a grass dominated state. Land that transitioned to the Invaded Woody State from the Native/Invaded Grass State (2), Invaded Grass State (3), Shortgrass Sod State (4), Early Seral State (5), or Sodbusted State (7) 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. The Invaded Woody State includes one community, the Invaded Woody Community (6.1).
Submodel
Description
The threshold to the Sodbusted State (7) is crossed as a result of mechanical disturbance to facilitate production agriculture. If farming operations are suspended, the site can be abandoned, which will result in the Natural Reclamation Community (7.3), or be seeded to a tame pasture forage mixture, the Seeded Pasture Community (7.2) or to a mixture of native grasses and forbs, the Reseeded Native Grass Community (7.1). Permanent alterations of the soil community and the hydrologic cycle make restoration to the Reference State (1) extremely difficult, if not impossible. Formation of a compacted plowpan in the soil profile is likely.
Submodel
Mechanism
Repeated continuous seasonal grazing or rotational summer grazing with inadequate recovery periods will cause the Reference State (1) to lose a significant portion of warm-season tall- and midgrass species and cross a threshold to the Native/Invaded Grass State (2). Extended periods (greater than ten years) of non-use with no fire favors cool-season species and the invasion of Kentucky bluegrass and also facilitates this transition. Annual haying conducted during the same time-frame each summer will also cause this transition.
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 may be 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
The Reference State (1) can transition to the Shortgrass Sod State (4) with long term (more than ten years), heavy, continuous, season long grazing or heavy, rotational grazing with inadequate growing season recovery periods. Continuous, heavy seasonal grazing (grazing during the same time frame each year) in the spring and early summer will also case this transition.
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 may be 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
The Reference State (1) will transition to the Early Seral State (5) when management consists of long term, heavy, concentrated grazing (continuous season long, continuous seasonal, or rotational grazing with inadequate growing season recovery periods). This transition may also occur with severe defoliation from rodents or other heavy disturbance.
Mechanism
Disruption of the natural fire regime and the encroachment of invasive exotic and native woody species can cause the Reference State (1) to shift to the Invaded Woody State (6).
Mechanism
The Reference State (1) is significantly altered by tillage to facilitate production agriculture. The disruption to the plant community, soil, and hydrology of the system makes restoration unlikely.
Mechanism
Long-term (more than fifteen years or more) prescribed grazing with adequate growing season recovery periods and appropriate stocking rates timed to coincide with the rapid growth phase of the cool-season grasses will return the Native/Invaded Grass State (2) to the Reference State (1). The length of time required depends upon the amount of native grasses remaining in the plant community. This restoration may not be feasible if there is an inadequate amount of native plants remaining in the plant community. Appropriately timed prescribed burning may accelerate this process.
Mechanism
Continued seasonal, continuous season long, or rotational summer grazing with inadequate recovery periods will cause the Native/Invaded Grass State (2) to lose most, if not all, warm-season tall- and midgrass species and cross a threshold to the Invaded Grass State (3). Continued non-use with no fire increases the invasion of Kentucky bluegrass and also facilitates this transition.
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 may be 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 Native/Invaded Grass State.
Mechanism
The Native/Invaded Grass State (2) can transition to the Shortgrass Sod State (4) with long term (more than ten years) continuous seasonal grazing in the spring. Heavy, rotational grazing with inadequate growing season recovery periods may also cause this change.
Mechanism
The Native/Invaded Grass State (2) will transition to the Early Seral State (5) when management consists of long term, heavy, concentrated grazing (continuous season long, continuous seasonal, or rotational grazing with inadequate growing season recovery periods). This transition may also occur with severe defoliation from rodents or other heavy disturbance.
Mechanism
Disruption of the natural fire regime and the encroachment of invasive exotic and native woody species can cause the Native/Invaded Grass State (2) to shift to the Invaded Woody State (6).
Mechanism
The Native/Invaded Grass State (2) is significantly altered by tillage to facilitate production agriculture. The disruption to the plant community, soil, and hydrology of the system makes restoration unlikely.
Mechanism
With long term (more than fifteen years) seasonal prescribed grazing in the spring or in the spring and fall the amount of non-native cool-season grasses can be reduced and be replaced by native grasses if an adequate amount of remnant native grasses are present in the plant community. If native grasses have been eliminated, or nearly eliminated, from the plant community, this restoration will not be possible.
Mechanism
The Invaded Grass State (3) will transition to the Early Seral State (5) when management consists of long term, heavy, concentrated grazing (continuous season long, continuous seasonal, or rotational grazing with inadequate growing season recovery periods). This transition may also occur with severe defoliation from rodents or other heavy disturbance.
Mechanism
Disruption of the natural fire regime and the encroachment of invasive exotic and native woody species can cause the Invaded Grass State (3) to shift to the Invaded Woody State (6).
Mechanism
The Invaded Grass State (3) is significantly altered by tillage to facilitate production agriculture. The disruption to the plant community, soil, and hydrology of the system makes restoration unlikely.
Mechanism
Long term (more than fifteen years) prescribed grazing may move the Shortgrass Sod State (4) to the Reference State (1) if adequate amounts of native, warm-season, tall- and midgrasses and native cool-season grasses remain in the plant community. This transition may not be feasible when the warm-season tall- and midgrasses and native cool-season grasses have been reduced to trace levels.
Mechanism
Long term (more than fifteen years) prescribed grazing may move the Shortgrass Sod State (4) to the Native/Invaded Grass State (2) if adequate amounts of native, warm-season, tall- and midgrasses and native cool-season grasses remain in the plant community. This transition may not be feasible when the warm-season tall- and midgrasses and native cool-season grasses have been reduced to trace levels.
Mechanism
The Shortgrass Sod State (4) will transition to the Early Seral State (5) when management consists of long term, heavy, concentrated grazing (continuous season long, continuous seasonal, or rotational grazing with inadequate growing season recovery periods). This transition may also occur with severe defoliation from rodents or other heavy disturbance.
Mechanism
Disruption of the natural fire regime and the encroachment of invasive exotic and native woody species can cause the Shortgrass Sod State (4) to shift to the Invaded Woody State (6).
Mechanism
The Shortgrass Sod State (4) is significantly altered by tillage to facilitate production agriculture. The disruption to the plant community, soil, and hydrology of the system makes restoration unlikely.
Mechanism
Disruption of the natural fire regime and the encroachment of invasive exotic and native woody species can cause the Early Seral State (5) to shift to the Invaded Woody State (6).
Mechanism
The Early Seral State (5) is significantly altered by tillage to facilitate production agriculture.
Mechanism
Prescribed burning, wildfire, harvest, and brush management will move the Invaded Woody State (6) to the Reference State (1). The forb component ma initially increase following tree 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. The heavier the existing canopy cover, the greater the energy input required to return to the Reference State by management practices. The amount of time required for this restoration to occur depends on the severity and duration of the encroachment.
Land that transitioned to the Invaded Woody State from the Native/Invaded Grass State (2), Invaded Grass State (3), Shortgrass Sod State (4), Early Seral State (5), or the Sodbusted State (7), cannot be restored to the Reference State 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 (6) to the Native/Invaded Grass State (2). The forb component ma initially increase following tree 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. The heavier the existing canopy cover, the greater the energy input required to return to the Reference State by management practices. The amount of time required for this restoration to occur depends on the severity and duration of the encroachment.
Land that transitioned to the Invaded Woody State from the Native/Invaded Grass State, Invaded Grass State (3), Shortgrass Sod State (4), Early Seral State (5), or the Sodbusted State (7), cannot be restored 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 (6) to the Invaded Grass State (3). The forb component ma initially increase following tree 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. The heavier the existing canopy cover, the greater the energy input required to return to the Reference State by management practices. The amount of time required for this restoration to occur depends on the severity and duration of the encroachment.
Land that transitioned to the Invaded Woody State from the Native/Invaded Grass State (2), Invaded Grass State, Shortgrass Sod State (4), Early Seral State (5), or the Sodbusted State (7), cannot be restored 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 (6) to the Shortgrass Sod State (4). The forb component ma initially increase following tree 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. The heavier the existing canopy cover, the greater the energy input required to return to the Reference State by management practices. The amount of time required for this restoration to occur depends on the severity and duration of the encroachment.
Land that transitioned to the Invaded Woody State from the Native/Invaded Grass State (2), Invaded Grass State (3), Shortgrass Sod State, Early Seral State (5), or the Sodbusted State (7), cannot be restored 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 (6) to the Early Seral State (5). The forb component ma initially increase following tree 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. The heavier the existing canopy cover, the greater the energy input required to return to the Reference State by management practices. The amount of time required for this restoration to occur depends on the severity and duration of the encroachment.
Land that transitioned to the Invaded Woody State from the Native/Invaded Grass State (2), Invaded Grass State (3), Shortgrass Sod State (4), Early Seral State, or the Sodbusted State (7), cannot be restored 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 (6) to the Sodbusted State (7). The forb component ma initially increase following tree 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. The heavier the existing canopy cover, the greater the energy input required to return to the Reference State by management practices. The amount of time required for this restoration to occur depends on the severity and duration of the encroachment.
Land that transitioned to the Invaded Woody State from the Native/Invaded Grass State 2), Invaded Grass State (3), Shortgrass Sod State (4), Early Seral State (5), or the Sodbusted State, cannot be restored 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.