Very Shallow
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
- Transition 1A More details
- Restoration pathway 2A More details
-
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
Description
This state represents what is believed to represent the natural range of variability and plant community dynamics of this ecological site prior to European settlement. This site is dominated by warm-season grasses, a diverse forb component, and various low-growing shrubs. In pre- European times, the primary disturbances included fire and grazing by large ungulates and small mammals. Favorable growing conditions occurred during the spring, and the warm months of June and July. Routine and/or occasional fires and reduced tree cover contributed to the ecological processes that maintained the reference plant community.
Submodel
Description
This state is dominated by ponderosa pine and ground juniper. This transition is a result of heavy, continuous grazing and lack of frequent fire or no use and no fire, resulting in encroachment of ponderosa pine. Areas of intermediate and dense ponderosa pine canopy were found to reduce precipitation reaching the forest floor by an average of 30 percent (Wrage, 1994). If pine encroachment is moderate to severe, the soil surface may be covered with up to 1 inch of pine needles and duff. Native warm-season grasses such as bluestems, sideoats grama and blue grama, and cool-season grasses such as wheatgrass and needlegrass decline as overstory canopy cover increases. Shade-tolerant grasses, such as slender wheatgrass, poverty oatgrass, bluegrasses, and rough-leaved ricegrass will increase, as well as common and creeping juniper. In the absence of fire, this plant community phase will be resistant to change. Ponderosa pine canopy can continue to increase over time, reducing herbaceous production and increasing bare ground. This state will have lower water infiltration rates, increased runoff, and a higher potential for soil erosion.
Submodel
Mechanism
Continuous season-long grazing with stocking rates above the carrying capacity for the entire growing season, combined with the absence of fire to control conifer seedling establishment, or no use, no fire and pine encroachment will lead toward a pine-juniper-dominated state, State 2. More shade-tolerant grasses will become dominant in this state.
Mechanism
Prescribed burning or mechanical brush management plus long-term prescribed grazing may move the Pine-Juniper State back to the Reference State depending upon the plant community and climatic conditions. This could be a long-term process, and the results may not achieved or meet management goals.
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.