Rocky Hills-South (16-18" PZ)
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
- Transition T1A More details
- Transition T1B More details
- Restoration pathway R2A More details
- Transition T2A More details
- Restoration pathway R3A More details
- Transition T3A 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 the best estimate of the natural range of variability that dominated the dynamics of the Rocky Hills 16-18” PZ ecological site prior to European settlement. This state is dominated by cool- and warm-season grasses. In pre-European times, the primary disturbance mechanisms included occasional fire and grazing by large herding ungulates and browsers. Timing of fires and grazing coupled with weather events dictated the dynamics that occurred within the natural range of variability. Taller cool- and warm-season grasses would have declined and a corresponding increase in short statured grass and grass-like species would have occurred. Today, a similar state can be found on areas that are properly managed with grazing and prescribed burning and sometimes on areas receiving occasional short periods of rest.
The Reference State (1.0) is susceptible to invasion of non-native cool-season grasses and the encroachment of conifers.
Submodel
Description
The Native/Invaded State is dominated by native cool-season grasses and grass-likes and, and subdominant non-native cool-season grasses. If the native cool-season grasses decline rapidly, exposing bare ground, a corresponding increase of non-native cool-season grasses can occur. The non-native cool-season grasses will include cheatgrass, field brome, and possible Kentucky bluegrass.
Submodel
Description
This 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 tree canopy is a result of a disruption of the natural historic fire regime that kept the trees at an immature stage. This state is reached when mature tree canopy reaches approximately 25 percent or more. Tree canopy typically is dominated by Rocky Mountain juniper, but ponderosa pine may also be present in varying amounts.
Submodel
Mechanism
Extended periods of drought; fire; heavy wildlife browse; and the invasion of non-native cool-season grasses and will cause a transition from the Reference State (1.0) to the Native/Invaded State (2.0).
Mechanism
The encroachment of conifers, primarily Rocky Mountain juniper, and no fire will transition the Reference State (1.0) to the Conifer State (3.0).
Mechanism
Long-term prescribed grazing (moderate stocking levels coupled with adequate recovery periods; grazing systems intended to treat specific species dominance; or periodic light to moderate stocking levels possibly including periodic rest), coupled with a return to more normal precipitation cycles may lead the Native/Invaded State (2.0) over a threshold to the Reference State (1.0). This will likely take a long period of time, possibly up to 10 years or more, and recovery may not be attainable.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Prescribed Grazing |
Mechanism
The encroachment of conifers, primarily Rocky Mountain juniper, and no fire will transition the Native/Invaded State (2.0) to the Conifer State (3.0).
Mechanism
Fire, prescribed burning, or mechanical brush management to remove conifer encroachment, and prescribed grazing, may lead this plant community across a threshold back to the Reference State (1.0). This would have to take place before the conifers reach maturity and are still susceptible to fire, and reproductive propagules of the perennial grasses and shrubs are still present. After trees reach maturity, a stand replacing fire or brush management would be needed to move this plant community over the threshold back to the Reference State (1.0). This recovery may take a long period of time, possibly up to 10 years or more, and may not meet management objectives.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
|
|
Prescribed Burning |
|
|
Prescribed Grazing |
Mechanism
Invasion of non-native cool-season grasses; fire, mechanical brush management, or prescribed burning to remove conifers; will transition the Conifer State (3.0) to the Native/Invaded State (2.0).
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
|
|
Prescribed Burning |
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.