This state represents the natural range of variability under pristine conditions and is dominated by drought tolerant native shrubs. Primary natural disturbance mechanisms affecting this ecological site are long-term drought and insect attack. Historically, wildfire was infrequent and patchy due to low fuel loading, resulting in long-lived stable plant communities. Timing of disturbance combined with weather events determines plant community dynamics.
Introduced annuals such as red brome, schismus and redstem stork's bill have invaded the reference plant community and have become a dominant component of the herbaceous cover. This invasion of non-natives is attributed to a combination of factors including: 1) surface disturbances, 2) changes in the kinds of animals and their grazing patterns, 3) drought, and 4) changes in fire history. These non-natives annuals are highly flammable and promote wildfires where fires historically have been infrequent.
ATHY and AMDU would persist after invasion by non-native annuals, but other species may be unsuccessful in competing with the non-natives and could be removed from the system.A biotic threshold has been crossed, with the introduction of non-natives that cannot be removed from the system. The presence of non-natives has reduced the ecological resilience of the site. Following a disturbance this state relies on the availability of an offsite seed source. These non-natives have the potential to significantly alter disturbance regimes from their historic range or variability.
The Eroded State is characterized by severely decreased soil stabilization and increased rills and gullies. A biotic threshold has been crossed, with the loss of long-lived native vegetation and microbiotic soil crust leading to active soil erosion. This state is characterized by a new ecological equilibrium, one that includes reduced nutrient cycling and infiltration.
Introduction of non-native species through anthropogenic disturbances, including OHV use, dry land farming, grazing, linear corridors, mining, military training operations, and settlements.
Continued disturbance removes existing vegetation and remaining soil crust, leading to severe erosion.
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.
