The Reference state is characterized by two plant community phases that represent the natural range of variability and disturbance regimes within the site. These plant community phases are maintained by a historic fire frequency estimated to be on 15 to 20 year intervals, and herbivory by large ungulates with adequate recovery periods.
The Blue Grama Dominant state is represented by one plant community phase. Species diversity and production have been severely reduced. Litter levels are very low. Mineral and water cycles are impaired due to the loss of deeper-rooted grasses, forbs, and shrubs. Rills are evident and soil loss is obvious, especially on steeper slopes. Pedestalled plants with exposed roots are common. The loss of dominant and subdominant structural/functional groups reduces the biodiversity and productivity.
This state has one community. It is characterized by an impairment of all ecological functions. Bare ground, cushion plants, and cryptogamic crusts have significantly increased.
Water erosion can be severe on steeper slopes as evidenced by pedestaled plants and connected water flow paths.
Submodel
3.1. Cheatgrass and Spiny Phlox Bare Ground, Cryptogams
Heavy, continuous grazing without adequate recovery periods and lack of fire shifts this state across an ecological threshold to the Blue Grama Dominant State.
Long-term prescribed grazing with adequate recovery opportunity between grazing events and prescribed fire move this plant community to the Reference State. This transition may take upwards of 40 years or more to achieve.
Heavy, continuous grazing without adequate recovery periods and lack of fire shift this state across an ecological threshold to the Bare Ground State.
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.
