This state represents the natural range of variability that dominates the dynamics of this ecological site. This state is dominated by cool-season grasses, while warm-season grasses are subdominant. Pre-European settlement, the primary disturbance mechanisms for this site in the reference condition included occasional 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. Today the primary disturbance is from a lack of fire and concentrated livestock grazing. Grasses that are desirable for livestock and wildlife can decline and a corresponding increase in less desirable grasses will occur.
This State is characterized by the dominance of the shorter-statured, more saline tolerant species such as foxtail barley and inland saltgrass, the increase in bare ground, and the increased presence of salt accumulations on the soil surface. Infiltration is reduced, which allows the moisture and the salts carried by the moisture to be wicked up to the soil surface. The short-statured and shallow rooted species are more capable of withstanding the higher concentrations of salts in the soil surface. As the disturbance level increases, plant density decreases even more, giving way to annual species and invasive perennial species, as well as a further increase in bare ground.
Submodel
2.1. Foxtail Barley/Inland Saltgrass, Bare Ground
2.2. Annual/Pioneer, Non-Native Perennial, Bare Ground
This transition is a result of heavy, continuous season-long grazing (stocking levels well above recommended rates, for the entire growing season). Grazing pressure and physical impacts of livestock on the soil surface alter the plant community. The less grazing tolerant/more palatable plant species are reduced, while the grazing tolerant species increase. Physical impacts result in increased bare ground which increases surface salinity and further enhances the salt tolerant species. The physical impacts (i.e., compaction) are greater when the soil surface is wet from short-term flooding or ponding events.
Severe disturbance such as concentrated livestock areas (e.g., watering sources, calving or feeding areas) or cropping abandonment. Attempts to crop these areas often fail, resulting in bare ground and weedy species such as kochia.
Severe disturbance such as concentrated livestock areas (e.g., watering sources, calving or feeding areas) or cropping abandonment. Attempts to crop these areas often fail, resulting in bare ground and weedy species such as kochia.
Severe disturbance such as concentrated livestock areas (e.g., watering sources, calving or feeding areas) or cropping abandonment. Attempts to crop these areas often fail, resulting in bare ground and weedy species such as kochia.
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.
