Long-term excessive grazing or frequent and severe defoliation, without adequate recovery between grazing events, or heavy, excessive grazing with overstocking
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
1.1. Skunkbush Sumac, Yucca, Prairie Sandreed, and Needle and Thread
1.2. Skunkbush Sumac, Yucca, Prairie Sandreed, and Blue Grama
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
2.1. Skunkbush Sumac, Yucca, Threadleaf Sedge, Blue Grama, Hairy False Goldenaster, and Cuman Ragweed
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.
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.
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
Briefcase
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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.
) 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.
