On soils having a mesic soil temperature regime, Baltic rush and Nebraska sedge are subordinate to Western Wheatgrass and are aggregated in colonies only in wetter depressions. Orange arnica, silverweed and small bedstraw are typical forbs of more mesic sites. On the drier precipitation range of this site Nevada bluegrass, Beardless wildrye (creeping wildrye), western yarrow and rose pussytoes are subordinate to tufted hairgrass. If the condition of this site deteriorates as a result of overgrazing, Western wheatgrass decreases and becomes co-dominant with other grasses, sedges and forbs. Baltic rush, sedges or reedgrass become more dominant, with large colonies of arnica, and silverweed occurring on the more mesic sites.
With overgrazing on soils having a mesic soil temperature regime, Nebraska sedge is capable of becoming dominant. On the drier precipitation range of this site, prairie junegrass and oatgrass along with yarrow, aster, cinquefoil and buttercups increase. With lowering of the water table Kentucky bluegrass can become naturalized and become co-dominant with mat muhly. Severe stream entrenchment may change the stand composition to upland species such as big sagebrush, grey rabbitbrush and annual weeds. Foxtail barley, squirreltail, lupine, dock and thistle are likely to invade.
This site is used for livestock grazing and wildlife habitat. The historic climax vegetation is rush, sedge, western wheatgrass, bluejoint. Dynamics of the site revolve around available moisture and drainage and deposits of alluvial material and scouring when the intermittent stream moves the channel. These events add or subtract soil and nutrients from the site. They also change the hydrology either adding water, ponding longer or the site drys out resulting in species shifts. The shallow water almost year round makes this a highly productive and resilient site. Most of the communities in this site are in the reference state. A major long term shift in hydrology is needed to change states.
The current potential state is similar in structure and function to the reference state, however invasive and non-natives species are present in all community phases. The current potential state is generally dominated by perennial grasses. Kentucky bluegrass can become a dominant in this plant community. The current potential state is less resilient than the reference state due to the presence of non-native/invasive species in the plant community. Annual herbaceous weedy plants have increased, but occur in small patches. Invasive species present can include knapweeds, Canada thistle, and curly dock.
Submodel
2.1. Mixed Grass Meadow
2.2. Western Wheatgrass and Kentucky Bluegrass Dominant
This state results from seeding introduced perennial grasses. Some of the potential grass found may include the following: meadow foxtail, orchardgrass, meadow barley, timothy and smooth brome. Native perennial grasses, forbs and shrubs may be included in the seed mix. This state behave similar community dynamics to the current potential state community. Other vegetation treatments may be necessary to get to this state, they include mowing, disking, prescribed burning and other techniques which manipulate the plant community. The seeded state could persist for long periods of time with proper management. Native grasses and forbs may reestablish over time from nearby seed sources.
This transition is triggered by management decisions and actions. This transition, to a state that has been seeded with introduced perennial grasses. High energy inputs are needed for this transition. Brush will need to be removed with vegetation treatment techniques (I.e. chemical, mechanical, or fire) and introduced species that are adapted to the area and adapted to management needs have been seeded and become established. Water diversion maybe used to enhance or alter this site hydrological regime.
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.
