Sandy Lowland
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
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Transition T1A
Long-term (> 10 years) heavy grazing, or repetitive haying, with inadequate growing season recovery periods.
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Transition T1B
Tillage to facilitate production agriculture.
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Transition T1C
Woody encroachment with no fire or brush management.
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Transition T2A
Tillage to facilitate production agriculture.
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Transition T2B
Woody encroachment with no fire or brush management.
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Transition T3A
Woody encroachment with no fire or brush management.
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Restoration pathway R4A
Prescribed burning, wildfire, mechanical harvest, and brush management.
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Restoration pathway R4B
Prescribed burning, wildfire, mechanical harvest, and brush management.
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Restoration pathway R4C
Prescribed burning, wildfire, mechanical harvest, and brush 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 Sandy Lowland 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), the At-Risk Community (1.2), and the Excessive Litter Community (1.3). 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. The Excessive Litter Community results when herbivory and fire are removed 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 component has been replaced by warm-season shortgrasses and non-native, cool-season grasses. 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 shortgrass and invaded grass plant communities. Due to the changes in the plant community, soil stability, and hydrologic function, restoration to the Reference State is not feasible. However, renovation with seeding, herbicide treatment, and management can produce a plant community that is similar to the Reference Community (1.1). The Native/Invaded Grass State includes the Native Shortgrass-Invasive Grass (2.1) Community.
Submodel
Description
The threshold to the Sodbusted State (3) 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 (3.1), be seeded to a tame pasture forage mixture resulting in the Seeded Pasture Community (3.2) or be abandoned with no seeding which will result in the Natural Reclamation Community (3.3). Permanent alterations of the soil, plant community, and hydrologic cycle make restoration to the Reference State (1) extremely difficult, if not impossible.
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) or the Sodbusted State (3), 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
Long-term (more than 10 years) heavy, continuous grazing or repetitive haying without adequate 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, biotic integrity, and hydrologic function are degraded to the point that a return to the Reference State may not be feasible.
Mechanism
The Reference State (1) is significantly altered by tillage to facilitate production agriculture. The disruption to the plant community, the soil and the hydrology of the system make restoration to the Reference State unlikely.
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 (4).
Mechanism
The Native/Invaded Grass State (2) is significantly altered by tillage to facilitate production agriculture. The disruption to the plant community, the soil and the hydrology of the system make restoration to the Native/Invaded Grass State unlikely.
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 (4).
Mechanism
Disruption of the natural fire regime and the encroachment of invasive exotic and native woody species can cause the Sodbusted State (3) to shift to the Invaded Woody State (4).
Mechanism
Prescribed burning, wildfire, harvest, and brush management will move the Invaded Woody State (4) toward 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. 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 Woody Invaded State from the Native/Invaded Grass State (2) or the Sodbusted State (3), 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 (4) toward 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. 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 Woody Invaded State from the Native/Invaded Grass State or the Sodbusted State (3), 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 (4) toward the Sodbusted 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. 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 Woody Invaded State from the Native/Invaded Grass State (2) 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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