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
Heavy, continuous grazing or rotational grazing or haying with inadequate growing season recovery periods.
More details -
Transition T1B
Tillage to facilitate production agriculture.
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Transition T1C
Woody encroachment and no fire or woody species management.
More details -
Transition T2A
Tillage to facilitate production agriculture.
More details -
Transition T2B
Woody encroachment and no fire or woody species management.
More details -
Transition T3A
Woody encroachment and no fire or woody species management.
More details -
Restoration pathway R4A
Prescribed burning, wildfire, harvest, and brush management.
More details -
Restoration pathway R4B
Prescribed burning, wildfire, harvest, and brush management
More details -
Restoration pathway R4C
Prescribed burning, wildfire, harvest, and brush management.
More details -
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
State 1
Reference State
Description
The Reference State describes the range of vegetative community phases that occur on the Loamy Terrace ecological site where the natural processes are mostly intact. The Reference Community (1.1) is a representation of the native plant community phase that occupies a site that has been minimally altered by management. The Degraded Native Grass (1.2), the At-Risk (1.3), and the Excessive Litter (1.4) Communities are the phases that result from management decisions that are unfavorable for a healthy Reference Community. High perennial grass cover and production allows for increased soil moisture retention, vegetative production, and overall soil quality.
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Grass State (2) has been degraded from the Reference State (1) and much of the native warm-season grass community has been replaced by less desirable plants. The loss of warm-season, tall and mid 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 grazing tolerant plant communities. Alterations to the soil and the hydrological processes make return to reference state unlikely. This state includes two communities, the Shortgrass Sod/Invaded Grass (2.1) and the Invaded Cool-Season Grass (2.2) Communities.
Submodel
Description
The threshold to the Sod-busted State (3) is crossed as a result of mechanical disturbance to facilitate production agriculture. Extensive areas of this ecological site were plowed and converted to crop production by early European settlers and their subsequent generations. In addition to permanently altering the existing vegetative community, repeated tillage negatively impacted soil properties. Reductions in organic matter, mineral levels, soil structure, oxygen levels, and water holding capacity along with increased runoff and erosion as well as shifts in the populations of soil dwelling organisms were common on these sites. The extent of these changes depended upon the duration of cropping as well as crops grown and other management practices.
If farming operations are suspended, the site can be abandoned or seeded to permanent vegetation. Seedings are either a tame pasture forage mixture, the Seeded Pasture Community (3.2), or a mixture of native grasses and forbs, the Reseeded Native Grass Community (3.1). Abandonment results in the Natural Reclamation Community (3.3). Permanent alterations of the soil, plant community, and the hydrologic cycle make restoration to the Reference State (1) extremely difficult, if not impossible.
Submodel
Description
The Invaded Woody State (4) is the result of woody encroachment. Once the tree canopy cover reaches 15 percent with an average tree height exceeding five feet, the threshold is crossed. Woody species are encroaching due to lack of prescribed fire and other brush management practices. Typical ecological impacts are a loss of native grasses, degraded forage productivity, and reduced soil quality. This state consists of the Invaded Woody Community (4.1)
Prescribed burning, wildfire, timber harvest and brush management will move this state toward a grass dominated state. If the Invaded Woody State (4) transitioned from the Native/Invaded Grass State (2) or the Sod-busted State (3), the land cannot be restored to the Reference State (1) as the native plant community, soils, and hydrologic function have been too severely impacted prior to the woody encroachment to allow restoration to the Reference State (1).
Submodel
Mechanism
Heavy, continuous grazing or rotational grazing or haying with inadequate growing season recovery periods (deferment) will cause the Reference State (1) to lose a significant proportion of tall and mid warm-season grass 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 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 (1).
Mechanism
The Reference State (1) is significantly altered by mechanical tillage converting site to the Sod-busted State (3) to facilitate production agriculture. The disruption to the plant community, the soil and the hydrology of the system make restoration to a true 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 state is significantly altered by mechanical tillage converting site to the Sod-busted State (3) 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 (2) 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 Sod-busted 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 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 (4).
Land that transitioned to the Invaded Woody State (4) from the Native/Invaded Grass State (2) or the Sod-busted State (3) cannot be restored to the Reference State (1) through removal of woody species.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
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Prescribed Burning |
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Prescribed Grazing |
Mechanism
Prescribed burning, wildfire, harvest, and brush management will move Invaded Woody State (4) toward the Native/Invaded State (2). 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 (4).
Land that transitioned to the Invaded Woody State (4) from the Native/Invaded Grass State (2) or the Sod-busted State (3) cannot be restored to the Reference State (1) through removal of woody species.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
|
|
Prescribed Burning |
|
|
Prescribed Grazing |
Mechanism
Prescribed burning, wildfire, harvest, and brush management will move the Invaded Woody State (4) toward the Sod-busted State (3). 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 (4) from the Native/Invaded Grass State (2) or the Sod-busted State (3) cannot be restored to the Reference State (1) through removal of woody species.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
|
|
Prescribed Burning |
|
|
Prescribed Grazing |
Model keys
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