Natural Resources
Conservation Service
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
- Transition T1a More details
- Transition T1b More details
- Transition T2 More details
-
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
Description
The reference state is representative of the natural range of variability under pristine conditions. It is dominated by an evergreen shrub community with a significant amount of perennial grass. Plant community phase changes are primarily driven by periodic wildfire, insect/disease attack and long-term drought. Plant community dynamics are driven by interactions between climatic patterns and disturbance regimes.
Submodel
Description
This state is characterized by the presence of non-native species in the understory. Introduced annuals such as cheatgrass have invaded the plant community. A biotic threshold is crossed with the introduction of non-native annuals that are difficult to remove from the system and have the potential to significantly alter disturbance regimes from their historic range of variation. These non-native annuals are highly flammable and can promote wildfire where fires historically have been infrequent. Recovery of sagebrush to pre-fire conditions is dependent on available seed source and favorable weather conditions and may take an extended period of time.
Submodel
Description
This state is characterized by the invasion of pinyon and juniper and tree cover of greater than 20 percent. Lack of fire, insect/disease attack and drought allows seedlings and saplings to infill and eventually dominate the plant community, changing the ecological dynamics of the site. Non-native annuals may or may not be present in the understory. This state experiences reduced infiltration and increased runoff during precipitation events, diminishing soil moisture. Feedbacks contributing to the stability of this state include reduced understory vegetation resulting from decreased soil moisture and overstory shading.
Submodel
Mechanism
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.
Mechanism
Continued lack of disturbance. Encroachment and establishment of pinyon and juniper. Tree canopy is greater than 20 percent and bare ground is increasing.
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.
Ecological sites
Major Land Resource Areas
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.
Accessibility statement