Desert Loam (Shadscale)
Scenario model
Current ecosystem state
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Management practices/drivers
Select a transition or restoration pathway
- Transition T1a More details
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No transition or restoration pathway between the selected states has been described
Target ecosystem state
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Description
The reference state was determined by study of rangeland relic areas, areas protected from excessive disturbance and outside influences, such as grazing and recreation. Literature reviews, trends in plant community dynamics, and historical accounts are also considered.
The reference state represents the historic plant communities and ecological dynamics of the desert loam, shadscale site. This state includes the biotic communities that become established on the ecological site if all successional sequences are completed under current climatic conditions; natural disturbances are inherent in its development. This state is dominated by warm season perennial grasses and shadscale. The primary disturbance mechanism is climate fluctuations. The reference state is self sustaining and resistant to change due to high resistance to natural disturbances and high resilience following natural disturbances. When natural disturbances occur, the rate of recovery is relatively rapid due to niches being filled with highly adapted native vegetation.
Reference State: Community phases disturbed by climate fluctuations and insect herbivory.
Indicators: A site dominated by shadscale with galleta. Indian ricegrass and sand dropseed may or may not be present.
Feedbacks: Extended periods of above average precipitation resulting in an increase in the native perennial plant vigor. Insect herbivory that reduces shrub vigor and allows grass production to increase.
At-risk Community Phase: All communities are at risk when nutrients are available for invasive plants to establish. Plant community 1.2 is especially at risk due to limited production and cover of understory grasses.
Trigger: Introduction of invasive plants to fill available niches.
Submodel
Description
This state is similar to state one, however there are invasive species established in the understory—cheatgrass and halogeton being the most common. The primary disturbance mechanism is climate fluctuations; however livestock grazing may influence the ecological dynamics of the site.
Current Potential State: Plant communities disturbed by fluctuating climatic conditions insect herbivory, and livestock grazing.
Indicators: A site dominated by shadscale and galleta, where Indian ricegrass and sand dropseed may or may not be present. Invasive species are present.
Feedbacks: Fluctuations in climate allow for the maintenance of both shrubs and perennial grasses.
Submodel
Mechanism
This transition occurs as invasive species become established in the plant community. Common invasive species include cheatgrass, halogeton, and Russian thistle. Disturbances that may accelerate this transition include improper livestock grazing and extended drought. Invasive species such as cheatgrass have also been known to invade intact perennial plant community where no disturbance has occurred.
Model keys
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Ecological sites
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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.