Mountain Stony Clay (slender wheatgrass)
Scenario model
Current ecosystem state
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Management practices/drivers
Select a transition or restoration pathway
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Transition T1A
introduction of exotic species
More details -
Transition T2A
Sustained heavy grazing and fire exclusion
More details -
Transition T3A
Brush management with the use of chemicals (e.g. 2, 4-D) followed by tillage and re-seeding
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 a description of this ecological site just prior to Euro-American settlement but long after the arrival of Native Americans. The description of the Reference State was determined by NRCS Soil Survey Type Site Location information and familiarity with rangeland relict areas where they exist. The least modified plant community would have been dominated primarily by grasses including slender wheatgrass (Elymus trachycaulus), bluebunch wheatgrass (Pseudoroegneria spicata), and basin wildrye (Leymus cinereus) (1.1). An abundance of forbs would have included mule-ears (Wyethia amplexicaulis), common yarrow (Achillea millefolium), western mountain aster (Symphyotrichum spathulatum var. spathulatum). A scattering of mountain big sagebrush (Artemisia tridentata ssp. vaseyana), antelope bitterbrush (Purshia tridentata), and other mountain browse species would have been present as well. A more complete list of species by lifeform for the Reference State is available in accompanying tables in the “Plant Community Composition by Weight and Percentage” section of this document.
Submodel
Description
State 2 is a description of the ecological site following Euro-American settlement, which has been influenced by the introduction of several non-native plants and animals, possible extinctions of native species, and a different climate.
Submodel
Description
In the absence of fire, but with continued heavy impacts from livestock grazing, the native grasses will markedly decrease, allowing the shrubs mainly, mountain big sagebrush, and the unpalatable species like mule-ears, to take over the site.
Submodel
Mechanism
The simultaneous introduction of exotic species, both plants and animals, possible extinctions of native flora and fauna, and climate change caused State 1 to transition to State 2. Reversal of such historic changes (i.e. a return pathway) back to State 1 is not practical.
Mechanism
During the period between 1860 and 1950, these sites experienced heavy continuous livestock use throughout the growing season of grasses. Additionally, periodic outbreaks of pocket gophers and a suspended fire regime, combined with the grazing impacts, together caused a transition into the Unpalatable Forbs & Increased Shrub State. Key indicators of the approach to this transition include a loss of perennial grass understory, an increase in the shrub component relative to grasses, and an increase in Wyethia and introduced forbs. Sustained heavy grazing and fire exclusion will trigger this transition. A restoration pathway is impracticable due to the lack of native perennial grass seed source and soil loss.
Mechanism
Brush management with the use of chemicals (e.g. 2, 4-D) followed by tillage and re-seeding can be carried out to create a monoculture of the introduced species, such as intermediate wheatgrass, smooth brome, and orchard grass. The key indicator of the approach to this transition is the loss of forage, and it is triggered by a management decision.
Model keys
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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.