Sandy 14-17" PZ
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
- Transition T1A More details
- Transition T1C More details
- Transition T1B More details
- Transition T6A More details
- Restoration pathway R2A More details
- Transition T2A More details
- Transition T2B More details
- Transition T6A More details
- Restoration pathway R3A More details
- Transition T3A More details
- Transition T6A More details
- Transition T4A More details
- Transition T4B More details
- Transition T6A More details
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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 represents the best estimate of the natural range of variability that dominated the dynamics in this ecological site prior to European settlement. This Sandy 14-17” PZ ecological site in the Reference State (1.0), will be dominated by warm- and cool-season grasses. Grazing or the lack of grazing, fire, and drought are the major drivers between plant communities. Continuous season-long grazing can push this State to a warm-season shortgrass- dominated State (2.0). Invasion of non-native cool-season perennial or annual grasses will result in a transition to the Native/Invaded State (4.0).
In the western portion of the 14-17” PZ, the plant community pathways within the Reference State will more likely go from 1.1 to 1.3. In the eastern portion, it will more likely go from 1.1 to 1.2.
Even though the average mean annual precipitation in the 14-17” PZ ranges between 16.0 and 16.5 inches, the timing and amount of precipitation is expressed in subtle differences in plant communities on this site. The western portion of the PZ receives approximately 1.4 inches less moisture in May and June than does eastern portion of the PZ. As a result, this site in western-side will express more cool-season mid-grasses and drought-tolerant warm-season shortgrasses. In eastern-side the same site, with slightly more precipitation in May and June, will express more tall- and mid-statured warm- season grasses and less production from cool-season grasses.
Submodel
Description
The Shortgrass State is dominated by shortgrass species and upland sedges. The Shortgrass State is the result of grazing management that did not provide adequate recovery time for mid- and tall-statured warm-season grasses and mid-statured cool-season grasses. The hydrologic function of this state is altered. Runoff is higher and infiltration is lower than the Reference State. This State is very resistant to change through grazing management alone.
Submodel
Description
The Early Successional State is dominated by weedy annuals and biennials, sand dropseed, threeawn, and field sagewort (green sagewort). This State is the result of heavy disturbance such as frequent and severe defoliation or heavy livestock concentrations coupled with grazing management that does not provide adequate time for recovery. The hydrologic function is also likely to be dramatically altered. Runoff is high and infiltration is low. This State is very resistant to change through grazing management alone.
Submodel
Description
The Native/Invaded State has been invaded by cheatgrass, field brome, smooth brome, Kentucky bluegrass, or crested wheatgrass, but not at the levels to which the plant community is dominated by these species. The majority of species are native to this site, including cool-season mid-grasses, warm-season mid- and tallgrasses, and warm-season shortgrasses. Forbs will be common and diverse, and shrubs will be present in varying amounts. The Native/Invaded State is the result of long-term non-use in combination with above-average precipitation, or through continuous seasonal grazing or continuous season-long grazing. Because of the invasion and persistence of non-native cool-season grasses, this State is unlikely to return to the Reference State (1.0).
Submodel
Description
Any plant community can transition to the Disturbed State. The two separate vegetative plant communities found in this State are highly variable in nature. They are derived through different management scenarios, and are not related successionally. Infiltration, runoff, and soil erosion vary depending upon the vegetation present on the site.
Submodel
Mechanism
Continuous seasonal grazing will move the Sandy 14-17” PZ ecological site toward the Shortgrass State (2.0). This would be typical of calving/lambing pastures where the unit is continuously utilized during the late winter through spring. This transition will result in decreases in both forage production and plant species diversity. Continuous season-long grazing will also move this plant community toward the Shortgrass State (2.0), as will heavy grazing in combination with extended periods of drought. During this transition, the plant community can have the appearance of a mosaic, with sod and mixed grass communities intermingled. As the plant community becomes dominated by shortgrasses, runoff will increase, and infiltration will decrease.
Mechanism
Frequent and severe defoliation or heavy disturbance including livestock feeding areas, prairie dog towns, and calving pastures will transition the Reference State (1.0) to the Early Successional State (3.0).
Mechanism
Invasion of non-native cool-season grasses, continuous seasonal grazing, or continuous season- long grazing will result in a transition from the Reference State (1.0) to the Native/Invaded State (4.0).
Mechanism
Heavy disturbance including soil erosion, tillage, abandonment of cropland, or seeding to improved pasture species will result in a transition to the Disturbed State (5.0).
Mechanism
Long-term prescribed grazing in combination with adequate precipitation and time for recovery from grazing occurrences will move this plant community toward the Reference State (1.0). This transition will not be fast and, in the end, may not meet management objectives.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Prescribed Grazing |
Mechanism
Frequent and severe defoliation or heavy disturbance including livestock feeding areas, prairie dog towns, and calving pastures will cause a transition to the Early Successional State (3.0).
Mechanism
Long-term prescribed grazing in combination with adequate precipitation and time for recovery from grazing occurrences will move this plant community toward the Native/Invaded State (4.0). Management follows invasion of non-native cool-season grasses, including one or more of the following species: cheatgrass, field brome, smooth brome, Kentucky bluegrass, and crested wheatgrass.
Mechanism
Heavy disturbance including soil erosion, tillage, abandonment of cropland, or seeding to improved pasture species will result in a transition to the Disturbed State (5.0).
Mechanism
Removal of management-induced disturbance followed by long-term prescribed grazing in combination with adequate precipitation and time for recovery from grazing occurrences will move this plant community toward the Shortgrass State (2.0).
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Prescribed Grazing |
Mechanism
Removal of management-induced disturbance followed by long-term prescribed grazing in combination with adequate precipitation and time for recovery from grazing occurrences will move this plant community toward the Native/Invaded State (4.0). Management follows invasion of non- native cool-season grasses, including one or more of the following species: cheatgrass, field brome, smooth brome, Kentucky bluegrass, and crested wheatgrass. Changes due to management may take an extended period of time and may not meet management objectives.
Mechanism
Heavy disturbance including soil erosion, tillage, abandonment of cropland, or seeding to improved pasture species will result in a transition to the Disturbed State (5.0).
Mechanism
Continuous season-long grazing will also move this plant community toward the Shortgrass State 2.0, as will heavy grazing in combination with expended periods of drought. During this transition, the plant community can have the appearance of a mosaic, with sod and mixed grass communities intermingled. As the plant community becomes dominated by shortgrasses, runoff will increase, and infiltration will decrease.
Mechanism
Frequent and severe defoliation or heavy disturbance including livestock feeding areas, prairie dog towns, and calving pastures will result in a transition to the Early Successional State (3.0).
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.