The reference state is representative of the natural range for variability under pristine conditions. Primary natural disturbance mechanisms affecting this ecological site are infrequent wildfire, prolonged drought and insect attack. Historically, infrequent wildfire occured due to the natural build up of woody fuels and lightning strikes. Plant communities of this site are stable, long-lived and dynamic in response to changes in disturbance regimes and weather patterns.
The invaded state is characterized by the presence of non-natives in the understory. Ecological function has not been compromised at this time, however the presence of non-natives has reduced ecological resilience of the site. A biotic threshold has been crossed with the introduction of non-natives that are very difficult to remove from the system and have the potential to significantly alter disturbance regimes from their historic range of variation. These non-natives annuals are highly flammable and can promote wildfires where fires historically have been infrequent.
Introduction of non-native species due to a combination of factors including: 1) surface disturbance, 2) changes in the kinds of animals and their grazing patterns, 3) drought and/or 4) changes in fire history.
Model keys
Briefcase
Add ecological sites and Major Land Resource Areas to your briefcase by clicking on the briefcase () 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.
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.
