Loamy Terrace
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
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Transition T1A
Invasion of non-native cool-season grasses, long term (>10 years) 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 T2A
Long term (> 15 years) severe disturbance or heavy, concentrated, continuous season long grazing or seasonal grazing.
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Transition T1C
Woody encroachment with no prescribed burning or woody species management.
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Transition T1D
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 (> 15 years) severe disturbance or heavy, concentrated, continuous season long grazing or seasonal grazing.
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Transition T2C
Woody encroachment with no prescribed burning or woody species management.
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Transition T2D
Tillage to facilitate production agriculture.
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Transition T3A
Long term (> 15 years) severe disturbance or heavy, concentrated, continuous season long grazing or seasonal grazing.
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Transition T3B
Woody encroachment with no prescribed burning or woody species management.
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Transition T3C
Tillage to facilitate production agriculture.
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Transition T4A
Woody encroachment with no prescribed burning or woody species management.
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Transition T4B
Tillage to facilitate production agriculture.
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Restoration pathway R5A
Prescribed burning, wildfire, timber harvest, brush management.
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Restoration pathway R5B
Prescribed burning, wildfire, timber harvest, brush management.
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Restoration pathway R5C
Prescribed burning, wildfire, timber harvest, brush management.
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Restoration pathway R5D
Prescribed burning, wildfire, timber harvest, brush management.
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Restoration pathway R5E
Prescribed burning, wildfire, timber harvest, brush management.
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Transition T6A
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 Terrace 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 three plant community phases which are the Reference Community (1.1) and the At-Risk Community (1.2). The Reference Community serves as a description of the native plant community that occurs on the site when the natural disturbance regimes are intact or closely mimicked by management practices. The At-Risk Community results from management decisions that are unfavorable for a healthy Reference Community.
Submodel
Description
The Native/Invaded Grass State (2) has been degraded from the Reference State (1) and much of the vegetation present in the Reference State has been replaced by less productive and less palatable plants. Plant species diversity has been significantly reduced both in terms of functional and structural groups and in terms of number of individual species in those groups. Non-native species are typically 15 percent or more of composition in terms the annual production by weight. This plant community developed under repeated seasonal grazing during the summer or under extended periods (more than ten years) of non-use with no fire. Extended periods of non-use cause a thick litter layer to develop. This thatch layer favors cool-season species and invasion of non-native, cool-season grasses, especially Kentucky bluegrass.
The loss of 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 invaded plant communities. As the management continues, the plant community will become dominated by non-native cool-season grasses, sedges, and annuals causing the transition to the Invaded Grass State (3).
The Native/Invaded Grass State includes the Native/Invasive Grass Community (2.1).
Submodel
Description
The Invaded Grass State (3) occurs when non-native cool-season grasses have invaded and dominate the site. In this state, non-native cool-season grasses are more than 30 percent of the plant community. The loss of native, warm-season, tall- and midgrasses and cool-season bunchgrasses and accompanying increase of nonnative 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.
Significant inputs and time are required to move this plant community towards another community and will likely not be possible through grazing management alone due to the loss of plant diversity with the corresponding loss of the seed bank and decreased hydrologic function. Seeding or renovation will likely be needed to improve vegetative production and will move the plant community to the Sodbusted State (6). If management changes are not made following this renovation, the plant community will likely return to the Invaded Grass State.
The Invaded Grass State includes the Invaded Grass Community (3.1).
Submodel
Description
The Early Seral State (4) will develop from the Reference State (1), the Native/Invaded Grass State (2), or the Invaded Grass State (3) with severe disturbance and excessive defoliation. This typically arises from heavy concentration of livestock or wildlife. The dominant vegetation includes annual grasses and forbs, and early successional biennial and perennial species.
Soil erosion is potentially high. The excessive defoliation causes an extreme reduction in canopy and litter cover, plant density, plant vigor, and root biomass. Soil compaction contributes to decreased water infiltration, increased runoff, and accelerated erosion rates.
Significant inputs and time are required to move this plant community towards another community and will not be possible through grazing management alone due to the loss of plant diversity with the corresponding loss of the seed bank, decreased hydrologic function, soil compaction and erosion. Seeding or renovation will be needed to improve vegetative production and will move the plant community to the Sodbusted State (5). If management changes are not made following this renovation, the plant community will likely return to the Invaded Grass State.
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), Early Seral State (4), or Sodbusted State (6) 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 the Invaded Woody Community (5.1).
Submodel
Description
The threshold to the Sodbusted State (6) is crossed as a result of mechanical disturbance to facilitate production agriculture. If farming operations are suspended, the site can seeded to native grasses and forms resulting in the Reseeded Native Grass Community (6.1), be seeded to a tame pasture forage mixture resulting in the Seeded Pasture Community (6.2) or be abandoned with no seeding which will result in the Natural Reclamation Community (6.3). Permanent alterations of the soil, plant community, and hydrologic cycle make restoration to the Reference State (1) extremely difficult, if not impossible.
Submodel
Mechanism
The Reference State (1) will transition to the Native/Invaded Grass State (2) with the invasion of non-native cool-season grasses caused by long term (more than 10 years) seasonal grazing in summer, continuous season long grazing, or rotational grazing with inadequate growing season recovery periods. This change will also occur with long-term absence of herbivory and fire or annual haying during the same plant growth stage.
A significant proportion of the native, cool-season grass species as well as the native, warm-season tall- and midgrasses have been removed from the plant community. Water infiltration and other hydrologic functions are 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 degraded. Once this transition occurs, the return to the Reference State may not be feasible.
Mechanism
The Reference State (1) will transition to the Early Seral State (4) with long-term (more than 15 years) severe disturbance with heavy, continuous seasonal or heavy, season long grazing and excessive defoliation. Due to the severe soil disturbance and extreme loss of plant species diversity, return to the Reference State is not feasible.
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 (5).
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 15 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 for this restoration depends upon the amount of native grasses remaining in the plant community and will only be feasible if adequate native grasses remain in the plant community. Appropriately timed prescribed burning may accelerate this process.
Mechanism
The Native/Invaded Grass State (2) transitions to the Invaded Grass State (3) when the management that caused the transition to the Native/Invaded Grass State from the Reference State (1) continues. Non-native cool-season grasses continue to increase in abundance, facilitated by seasonal grazing in summer, continuous season long grazing, or rotational grazing with inadequate growing season recovery periods. This transition will also occur with continued non-use with no fire or with continued annual summer haying.
Very few, if any, native grasses remain in the plant community resulting in extreme reduction in diversity of functional and structural groups as well as individual species diversity. Water infiltration and other hydrologic functions are reduced due to the root-matting presence of sod-forming grasses. With the decline and loss of deeper-penetrating root systems, soil structure and biotic integrity are degraded. Once this transition occurs, the return to the Native/Invaded State may not be feasible.
Mechanism
The Native/Invaded Grass State (2) will transition to the Early Seral State (4) with long-term (more than 15 years), under severe disturbance with heavy, continuous seasonal or heavy, season long grazing and excessive defoliation. Due to the severe soil disturbance and extreme loss of species diversity return to the Reference State or the Native/Invaded State is not is not feasible.
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 (5).
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
The Invaded Grass State (3) will transition to the Early Seral State (4) with long-term (more than 15 years) severe disturbance with heavy, continuous seasonal or heavy, season long grazing and excessive defoliation. Due to the severe soil disturbance and extreme loss of species diversity return to the Reference State is not feasible.
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 (5).
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
Disruption of the natural fire regime and the encroachment of invasive exotic and native woody species can cause the Early Seral State (4) to shift to the Invaded Woody State (5).
Mechanism
The Early Seral State (3) is significantly altered by tillage to facilitate production agriculture.
Mechanism
Prescribed burning, wildfire, harvest, and brush management will move the Invaded Woody State (5) to the Reference State (1). The forb component may 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.
Land that transitioned to the Invaded Woody State from the Native/Invaded Grass State (2), Invaded Grass State (3), Early Seral State (4), or the Sodbusted State 6), 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 (5) to the Native/Invaded Grass State (2). The forb component may 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.
Land that transitioned to the Invaded Woody State from the Native/Invaded Grass State, Invaded Grass State (3), Early Seral State (4), or the Sodbusted State 6), 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 (5) to the Invaded Grass State (3). The forb component may 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.
Land that transitioned to the Invaded Woody State from the Native/Invaded Grass State (2), Invaded Grass State (3), Early Seral State (4), or the Sodbusted State 6), 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 (5) to the Early Seral State (4). The forb component may 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.
Land that transitioned to the Invaded Woody State from the Native/Invaded Grass State (2), Invaded Grass State (3), Early Seral State, or the Sodbusted State 6), 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 (5) to the Sodbusted State (6). The forb component may 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.
Land that transitioned to the Invaded Woody State from the Native/Invaded Grass State (2), Invaded Grass State (3), Early Seral State (4), 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.
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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.