Shallow Sandy (SwSy) 15-17” PZ
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
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Transition T1A
Excessive grazing without adequate recovery periods, or frequent and severe defoliation
More details -
Transition T2A
Long-term excessive grazing or frequent and severe defoliation, without adequate recovery between grazing events, or heavy, excessive grazing with overstocking
More details -
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
Description
The Reference state is characterized by two distinct plant communities: Skunkbush Sumac, Yucca, Prairie Sandreed, and Needle and Thread and Skunkbush Sumac, Yucca, Prairie Sandreed, and Blue Grama communities. The plant communities, and various successional stages between them, represent the natural range of variability within the Reference state.
Submodel
Description
This state is characterized by the sod-bound shortgrass plant community. An ecological threshold has been crossed and a significant amount of production and diversity has been lost when compared to the Reference state. Significant biotic and soil changes have negatively impacted energy flow, and nutrient and hydrologic cycles.
This is a very stable state, resistant to change due to the high tolerance of blue grama and threadleaf sedge to grazing, the development of a shallow root system (root pan) and subsequent changes in hydrology and nutrient cycling. Loss of other functional/structural groups such as cool-season bunch- and rhizomatous grasses, forbs, and shrubs, reduces the biodiversity productivity of this site.
Submodel
Description
The Eroded State develops with heavy, excessive grazing with overstocking, or frequent and severe defoliation. An ecological threshold has been crossed. Soil erosion and loss of organic matter and carbon reserves are resource concerns.
Submodel
Mechanism
Excessive grazing without adequate recovery periods, or frequent and severe defoliation, will shift this plant community across an ecological threshold toward the Sod Bound state. Biotic integrity and hydrologic function will be impaired as because of this transition.
Mechanism
Long-term excessive grazing or frequent and severe defoliation, without adequate recovery between grazing events, or heavy, excessive grazing with overstocking, will cause a shift across an ecological threshold to the Eroded state. Non-native annual bromes begin to invade in this transition.
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.