This state represents the natural range of variability under pristine conditions. Plant community phase changes are maintained by occasional flooding in response to heavy rainfall events, periodic drought and insect attack. Fire is rare in this system, but can have long term impacts on plant community composition. Timing of disturbances 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.
Dominant shrubs persist after invasion by non-native annuals, but the other shrubs and desirable grasses may be unsuccessful in competing with the non-natives. A biotic threshold has been crossed with the introduction of non-native annuals that cannot be removed from the system. Ecological resiliency has been reduced by the presence of non-native species that have the potential to alter disturbance regimes significantly from their natural or historic range of disturbances. In addition to non-native annual grasses like Mediterranean grass and red brome, this site is also susceptible to invasion by saltcedar.
The Eroded State is characterized by increased channel erosion. An abiotic threshold has been crossed, triggered by chronic disturbance or even a discrete event such as an intense rainfall event, leading to sediment transport and the loss of perennial vegetation.
Introduction of non-native species due to anthropogenic impacts including OHV use, dry land farming, grazing, linear corridors, mining, military operations, and settlements.
Restoration pathway. Ecological processes can be restored to the site, but non-natives remain. Possible restoration techniques include stabilizing the site by reestablishing native perennials and the use of artificial rip-rap to dissipate energy and reestablish the flood plain.
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.
