Shallow Loamy (SwLy) Absaroka Upper Foothills
Scenario model
Current ecosystem state
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Management practices/drivers
Select a transition or restoration pathway
- Transition T 1-2 More details
- Transition T 1-3 More details
- Restoration pathway R 2-1 More details
- Transition T 2-3 More details
- Transition T 2-4 More details
- Restoration pathway R 3-1 More details
- Transition T 3-4 More details
- Restoration pathway R 4-3 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 (State 1) for the Shallow Loamy Ecological Site is dominated by mid-stature, cool-season bunchgrasses and fescues. This state persisted under grazing by large ungulates and was a resource for forage and habitat for a variety of wildlife.
The Reference State (State 1) has been determined by study of rangeland relic areas, or areas protected from excessive disturbance. Trends in plant communities going from heavily grazed areas to lightly grazed areas, seasonal use pastures, and historical accounts have also been used.
Characteristics and indicators
The Reference State (State 1) is characterized by the prominent cover of bluebunch wheatgrass and Idaho fescue (20-50 percent composition). Columbia needlegrass (10-25 percent composition) and spike fescue (10-25 percent composition) also make up a significant portion of foliar cover. Shrubs such as mountain big sagebrush is primarily a minor component (5-20 percent composition) but will increase as the plant community moves away from Reference State conditions.
Resilience management
The state is stable and well adapted to the Central Rocky Mountains climate. The diversity in plant species provides resistance to influence from drought, non-native species, etc. This is a sustainable plant community (site/soil stability, watershed function, and biologic integrity).
Submodel
Description
The Perennial Grasses/Mixed Shrub State of the Shallow Loamy Ecological Site is dominated by shrubs as a result of extensive grazing and lack of fire. Preferred cool season grasses have been reduced. A mixed of shrubs account for >20 percent of plant composition.
Characteristics and indicators
The Perennial Grasses/Mixed Shrub State is characterized by the prominent cover of perennial grasses (40-80 percent composition) and greater than 20 percent composition by a variety of shrubs.
Resilience management
The state is resistant to change and may become more fire resistant as fine fuels are reduced by continued frequent and severe grazing.
Submodel
Description
The Threetip Sagebrush of the Shallow Loamy Ecological Site is dominated by Wyoming threetip sagebrush as a result of prescribed grazing and perpetuated by a fire cycle which maintains the removal of mountian big sagebrush. Bunchgrasses have been highly reduced and rhizomatous wheatgrasses have increased.
Characteristics and indicators
The Threetip Sagebrush State is characterized by the prominent cover of Wyoming threetip sagebrush up to 25 percent composition. The herbaceous component compared to the Reference State is mostly intact. Other shrubs cannot easily establish in this state when threetip becomes dominant.
Resilience management
This plant community is resistant to change as once three-tip becomes the dominant shrubs it is difficult for other shrubs to become established. The herbaceous species present are well adapted to grazing; however, species composition can be altered through long-term overgrazing. The herbaceous component is mostly intact and plant vigor and replacement capabilities are sufficient. Water flow patterns and litter movement may be occurring but only on steeper slopes. Incidence of pedestalling is minimal. Soils are mostly stable and the surface shows minimum soil loss. The watershed is functioning
and the biotic community is intact.
Submodel
Description
The Bluegrass/Invasive State is the defined by the prominent cover of bluegrasses and invasive species with the severely decreased or absence of preferred cool season mid-grasses. The state is a result of frequent and severe grazing, the removal of mountain big sagebrush, and proximity of seed source of invasive species.
Characteristics and indicators
Invasive and bluegrass species are the dominant plants in this state. Wyoming threetip sagebrush may be present as it is a strong resprouter and quickly re-establishes on sites after disturbance.
Resilience management
Soils in this state are susceptible to excessive erosion. Rill channels and gullies may be present on site or adjacent sites that are impacted due to proximity. Pedestalling around the base of plants is common.
Submodel
Mechanism
Heavy, Continuous Season-long Grazing and No Fire
• Heavy, continuous, season-long grazing plus no fire will convert the plant community to the Rhizomatous Wheatgrass/ Mixed Shrub Plant Community. The probability of this occurring is high. This is especially evident on areas where drought or heavy browsing does not adversely impact the shrub stand.
Mechanism
Repeated Wild Fire or Brush Management + Prescribed Grazing
• Repeated Wild Fire or Brush Management + Prescribed Grazing will convert the Reference State (State 1) to the Montana Wheatgrass/Threetip Sagebrush/ Plant Community.
Mechanism
Brush Management and Prescribed Grazing
Prescribed grazing plus brush management will convert this plant community to near Reference Plant Community (1.1). If prescribed fire is used as a means to reduce or remove the shrubs, sufficient fine fuels will need to be present. This may require deferment from grazing prior to treatment. Post management is critical to ensure success. This can range from two or more years of rest to partial growing season deferment, depending on the condition of the understory at the time of treatment and the growing conditions following treatment. Seeding will be required regardless of the brush treatment to reestablish the major cool-season grasses.
Mechanism
Wild Fire or Brush Management and No Change in Grazing
• Brush management or Wildfire with no change in grazing management will convert this
plant community to the Rhizomatous Wheatgrass/Lettermans Needlegrass Plant
Community.
Mechanism
Wild Fire or Brush Management and No Change in Grazing
• Brush management or Wildfire with no change in grazing management will convert this
plant community to the Bluegrass/Invasive Plant Community.
Mechanism
Prescribed Grazing and Brush Management
• Prescribed grazing and brush management will convert this plant community to the Reference State (State 1). Controlling Wyoming threetip sagebrush is difficult as it is a strong resprouter. Reestablishing the black sagebrush or mountain mahogany and the antelope bitterbrush may be difficult and may take many years.
Mechanism
Frequent and Severe Grazing
• Frequent and Severe Grazing will convert this plant community to a Bluegrass/Invasive Plant Community. If three-tip sage is present more than likely it will persist in varying degrees as it is difficult to control.
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.