Loamy-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 R2 More details
- Restoration pathway R2 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
This state represents the natural range of variability that dominates the dynamics of this ecological site. This state was dominated by cool-season grasses with warm-season grasses being subdominant. In pre-European times, the primary disturbance mechanisms for this site in the reference condition included frequent fire and grazing by large herding ungulates. 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/or prescribed burning, and sometimes on areas receiving occasional short periods of rest.
Submodel
Description
This state typically occurs as a result on continuous season-long grazing at moderate to heavy stocking levels over extended periods of time. Gradually short-statured species such as blue grama and threadleaf sedge become dominant. This change in plant composition alters the hydrologic cyle increasing runoff and reducing infiltration. This is due to the compact, short depth of the rooting structure of the dominant species, and in the advanced stages, to the increased bare ground.
Submodel
Description
This state is the result of very heavy, concentrated disturbance such as cropping, concentrated rodent activity, or concentrated livestock areas. This State can also result from invasion by highly competitive weed species such as Canada thistle, hound’s tongue, leafy spurge, or knapweeds. In most cases, this phase is dominated by annual and/or pioneer perennial species. Bare ground is also typically much higher than on any other plant community phase.
Submodel
Mechanism
Continuous season-long grazing over extended periods of time or the beginnings of frequent and severe defoliation (as occurs adjacent to prairie dog colonies) will tend to shift this plant community over a threshold leading to the Shortgrass Sod State (State 2).
Mechanism
Heavy continuous grazing (typically very heavy grazing for extended periods of time) or frequent and severe defoliation (as occurs with occupation by prairie dogs) will shift this plant community over a threshold leading to the 3.1 Annual/Pioneer Perennial Plant Community Phase within the Early Seral State (State 3).
Mechanism
Long-term prescribed grazing (alternating season of use and providing adequate recovery periods) or periodic light to moderate grazing possibly including periodic rest may eventually shift this plant community over a threshold to the Reference State (State 1).
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Prescribed Grazing |
Mechanism
Long-term prescribed grazing (alternating season of use and providing adequate recovery periods) or periodic light to moderate grazing possibly including periodic rest may eventually shift this plant community over a threshold to the Reference State (State 1).
Model keys
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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.