Shallow Clayey - North
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
- Transition T1B More details
- Transition T1A More details
- Transition T1C More details
- Restoration pathway R2A More details
- Transition T2A More details
- Transition T2B More details
- Transition T3A More details
- Transition T3B More details
- Transition T4A More details
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No transition or restoration pathway between the selected states has been described
Target ecosystem state
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Description
The Reference State represents what is believed to show the natural range of variability that dominated the dynamics of the ecological site prior to European settlement. This site in the Reference State (1.0) is dominated by cool-season grasses and subdominant warm-season grasses. Grazing or the lack of grazing, and occasional fire are the major drivers between plant communities. Heavy, continuous season-long grazing can push this state to an annual and pioneer perennial State (4.0). Non-use, no fire, and invasion of non-native cool-season grasses will result in a transition to a Native/Invaded State (3.0). Long-term fire suppression and conifer encroachment can transition the Reference State (1.0) to the Conifer State (2.0).
Submodel
Description
This Conifer State consists of areas where tree canopy increases to a level that impedes the reproductive capability of the major native perennial grass species. The increase in conifer canopy is a result of encroachment from forest sites, or from rangeland sites that have been invaded, and the disruption of the natural historic fire regime that maintained conifer trees in an immature stage. This state is reached when mature conifer canopy reaches approximately 25 percent or more. The canopy typically is dominated by ponderosa pine, but bur oak and Rocky Mountain juniper may also be present in varying amounts.
With continued long-term fire suppression and no brush management, the conifer canopy can eventually become closed with much of the herbaceous understory lost. This loss is partly driven by the interception of precipitation. Ponderosa pine canopy can significantly reduce precipitation reaching the ground due to canopy interception. In areas with intermediate and dense canopy’s, the expected reduction can reach 30 percent (Wrage, 1994).
Submodel
Description
The Native/Invaded State is dominated by native cool- and warm-season grasses, and subdominant non-native cool-season grasses (< 15 percent composition by weight). It can be found on areas that would appear to be properly managed with grazing and possibly prescribed burning. Extended periods of non-use and no fire, or long-term light grazing can result in the invasion and establishment of non-native cool-season grasses on this site. As native cool-season grasses decline a corresponding increase of non-native cool-season grasses will occur. The non-native cool-season grasses will include, smooth brome, Kentucky bluegrass, cheatgrass, and field brome. Forbs will be common and diverse. Shrubs will include fringed sagewort, rose, silver sagebrush, and western snowberry. Scattered ponderosa pine and bur oak will be found across this site.
This a sustainable state in regard to site and soil stability, and watershed function.
Submodel
Description
This state occurs as a result of extreme disturbance that typically removes most of the native species normally present on this site. Disturbance in the form of high-intensity fire; and heavy to severe grazing over several years are the most typical disturbances. The dominant species present is highly variable, but the common characteristics include high amounts of bare ground, reduced soil aggregate stability, increased runoff and increased erosion (including increased sediment loads in the runoff). Restoration of the ecological processes will be very difficult.
Submodel
Mechanism
Long-term no fire and the encroachment and establishment of conifers will transition the Reference State (1.0) to the Conifer State (2.0).
Mechanism
The invasion of non-native cool-season grasses; continuous seasonal grazing (stocking levels above carrying capacity for extended portions of the growing season, and at the same time of year each year, typically beginning early in the growing season); or no use and no fire will transition the Reference State (1.0) to the Native/Invaded State (3.0).
Mechanism
Heavy, continuous season-long grazing; frequent and severe defoliation; or heavy disturbance areas such as livestock or wildlife concentration areas will transition the Reference State (1.0) to the Early Successional State (4.0).
Mechanism
Fire; prescribed burning; or mechanical brush management in conjunction with long-term prescribed grazing may lead the Conifer State (2.0) across a threshold back to the Reference State (1.0). This transition will need to take place before the trees reach maturity and are still susceptible to fire, and reproductive propagules of the perennial grasses are still present. This transition is most likely to originate from Plant Community 2.1.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
|
|
Prescribed Burning |
|
|
Prescribed Grazing |
Mechanism
Invasion of non-native cool-season grasses; low-intensity fire, prescribed burning, or mechanical brush management to treat conifer encroachment on this site will transition the Conifer State (2.0) to the Native/Invaded State (3.0). This transition is most likely to originate from Plant Community 2.1.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
|
|
Prescribed Burning |
Mechanism
High-intensity fire or prescribed burning that removes all or most of the conifer encroachment, and adversely affects the herbaceous understory will likely transition the Conifer State (2.0) to the Early Successional State (4.0).
Mechanism
Long-term no fire and the encroachment and establishment of conifers will transition the Native/Invaded State (3.0) to the Conifer State (2.0).
Mechanism
Heavy, continuous season-long grazing; frequent and severe defoliation; or heavy disturbance will transition the Native/Invaded State (3.0) to the Early Successional State (4.0).
Mechanism
The invasion of non-native cool-season perennial grasses; possibly herbaceous weed control; and long-term prescribed grazing with proper stocking rates, change in season of use, and adequate time for plant recovery will transition the Early Successional State (4.0) towards the Native/Invaded State (3.0). This transition could require significant time and inputs to achieve and, in the end, may not meet management objectives.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Prescribed Grazing |
|
|
Herbaceous Weed Control |
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.