Sandy - North
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
- Transition T1B More details
- Transition T1C More details
- Transition T1A More details
- Restoration pathway R2A More details
- Transition T2A More details
- Transition T2B More details
- Restoration pathway T3A More details
- Transition T3B More details
- Transition T4A More details
-
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
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 bunchgrasses and subdominant short warm-season grasses. Grazing or the lack of grazing, insects and disease, and changing fire return intervals are the major drivers between plant communities. Heavy, continuous season-long grazing (grazing at stocking levels well above sustainable carrying capacity for extended portions of the growing season, and at the same time of year each year, without adequate recovery periods following each grazing occurrence) or high-intensity fire 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 and expansion 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 the expansion of ponderosa pine due to long-term fire suppression. This state is reached when mature ponderosa pine canopy reaches approximately 25 percent or more. Bur oak and aspen 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 canopies, the expected effective precipitation can be reduced by 30 percent (Wrage, 1994).
Submodel
Description
The Native/Invaded State (3.0) is dominated by native cool-season bunchgrasses and subdominant non-native cool-season grasses (< 15 percent composition by weight). With the prevalence of non-native cool-season grasses (Kentucky bluegrass, smooth brome, and timothy) in MLRA 62, the plant communities in the Native/Invaded State (3.0) may be the most similar to those plant communities in Reference State (1.0). A restoration pathway to the Reference State (1.0) is unlikely. Extended periods of non-use and no fire, or long-term continuous seasonal grazing can result in the expansion 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 Native/Invaded State (3.0) can be found on areas that are properly managed with grazing and possibly prescribed burning. Heavy, continuous seasonal grazing or high-intensity fire can push the Native/Invaded State (3.0) to an annual and pioneer perennial State (4.0). Long-term fire suppression and conifer encroachment and/or expansion can transition this state to the Conifer State (2.0).
The Native/Invaded State (3.0) is sustainable in regard to site and soil stability, and watershed function.
Submodel
Description
The Early Successional State (4.0) occurs as a result of extreme disturbance that typically removes many or 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 seasonal grazing; frequent and severe defoliation; or heavy disturbance areas (e.g., livestock or wildlife concentration areas); will transition the Reference State (1.0) to the Early Successional State (4.0). With high-intensity fire, the Ponderosa Pine-Bur Oak/Shrubs/Roughleaf Ricegrass Plant Community (1.2) can also transition 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.
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). Insect and disease in the ponderosa pine stand can create the situation where fire is more likely and potentially more destructive.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
|
|
Prescribed Burning |
Mechanism
High-intensity fire or prescribed burning that remove 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). Insect and disease in the ponderosa pine stand can create the situation where fire is more likely and potentially more destructive.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Prescribed Burning |
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 seasonal grazing; frequent and severe defoliation; or heavy disturbance areas (e.g., livestock or wildlife concentration areas); will transition the Native/Invaded State (3.0) to the Early Successional State (4.0). With high-intensity fire, the Ponderosa Pine-Bur Oak/Shrubs/Roughleaf Ricegrass-Non-Native Cool-Season Grasses Plant Community (3.2) can also transition to the Early Successional State (4.0).
Mechanism
The invasion of non-native cool-season perennial grasses; possibly herbaceous weed control; seeding to native herbaceous species; 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 |
|
|
Range Planting |
|
|
Herbaceous Weed Control |
Model keys
Briefcase
Add ecological sites and Major Land Resource Areas to your briefcase by clicking on the briefcase (
) icon wherever it occurs. Drag and drop items to reorder. Cookies are used to store briefcase items between browsing sessions. Because of this, the number of items that can be added to your briefcase is limited, and briefcase items added on one device and browser cannot be accessed from another device or browser. Users who do not wish to place cookies on their devices should not use the briefcase tool. Briefcase cookies serve no other purpose than described here and are deleted whenever browsing history is cleared.
Ecological sites
Major Land Resource Areas
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.