The Reference State is represenative of the natural range of variability under pristine conditions. The plant community is shrub dominated with few perennial grasses and forbs. Historically, this state experienced an extended fire return interval, which resulted in long-lived stable saltbush plant communities. These communities were sparsely vegetated and soil stability was primarily provided by surface rock fragments and microbiotic soil crust.
The Invaded State is characterized by the presence of non-native annuals in the understory. Introduced annuals such as red brome, Mediterranean grass and redstem filaree have invaded the reference plant community. These non-natives annuals are highly flammable and promote wildfires where fires historically have been infrequent.
A biotic threshold has been crossed, with the introduction of non-natives that are difficult to remove from the system and have the potential to significantly alter disturbance regimes from their natural or historic range of variability.
The Eroded State is characterized by a reduction in soil stabilization. Prolonged soil surface disturbance has caused this site to cross an abiotic threshold. The loss of vegetation and soil crust has decreased the stability of the site. Site function is controlled by soil erosion, wind and soil temperature.
Introduction of non-natives is attributed to a combination of factors including 1) surface disturbances (anthropogenic), 2) changes in the kinds of animals and their grazing patterns, 3) drought, and 4) changes in fire history.
Continued soil surface disturbance, loss of perennial vegetation and soil crust.
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.
