Shallow Limestone
Scenario model
Current ecosystem state
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Management practices/drivers
Select a transition or restoration pathway
- Transition T1A More details
- Restoration pathway R1A 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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State 1
Reference State
Description
1.1 Warm season grasses/shrubs/succulents (diagnostic plant community)
A mix of grasses, shrubs and succulents is present. Total foliar cover is > 65%, depending on the amount of rock outcrop.
1.1A Community Pathway: This pathway represents intervals between fires, during which natural processes increase shrub and succulent vigor and suppress grass production and percent composition.
1.1B Community Pathway: This pathway represents fire. Fire sets back succulents and many shrubs, giving grasses a competitive advantage.
1.1C Community Pathway: This pathway represents intensive, season long browsing and grazing, decreasing rangeland health.
1.2 Shrubs/warm season grasses/succulents: Over time, foliar cover of shrubs and succulents increases and that of warm season grasses decreases.
1.2A This pathway represents an interval between fires which is longer than the historic range of variability. Fire suppression, whether through loss of fuel load due to herbivory or from fighting natural wildfires, has increased shrub and succulent vigor and decreased grass production and percent composition.
1.2B Community Pathway: This pathway represents fire. Fire suppresses succulents and some shrubs, giving grasses a competitive advantage.
1.3 Warm season grasses/scattered shrubs: This plant phase exists after fire. Grasses respond well to fire, while many shrubs and succulents are suppressed.
1.3A Community Pathway: This pathway represents intervals between fires where natural processes increases shrub and succulent vigor and decreases grass production and composition.
1.4 At risk: shrubs/succulents/warm season grasses: Due to gradual changes in hydrologic function and soil chemistry, shrubs and succulents increase over time. Fire suppression has pushed this community beyond the historic range of variability.
1.4B Community Pathway: This pathway represents a decrease in shrubs and an increase in grasses, through either anthropogenic or natural processes.
T1A Transition one: Slow variables: Continued increase of shrubs due to fire suppression, coupled with the loss of grasses due to a decrease in soil organic matter, leading to a decrease in plant available water. Trigger events: A severe drought, or a severe wildfire causing a loss of organic carbon. Threshold: A hydrologic function threshold is crossed.
1.5 At risk: reduced warm season grasses/succulents/ scattered shrubs: This plant community is a departure from the historic range of variability because of excessive browsing and grazing. Foliar cover is less than 50 percent.
1.5A Community Pathway: This pathway represents a long, slow passage of time coupled with the end of excessive defoliation of shrubs and grasses. Slowly, range health improves and the plant community moves back into the historic range of variability.
2.0 Shrub State
2.1 Shrubs: Very few grasses exist as the bulk of the foliar cover is made of shrubs.
R1A Restoration Process: An increase in the competitive advantage of grasses through physical, chemical, and biological management practices.
Submodel
States 1 and 5 (additional transitions)
1.1. Warm season grasses/shrubs/succulents (diagnostic plant community)
1.5. At risk: reduced warm season grasses/succulents/ scattered shrubs
Mechanism
Slow variables: Continued increase of shrubs due to fire suppression, coupled with the loss of grasses due to a decrease in soil organic matter, leading to diminished plant available water. Trigger events: A severe drought, or a severe wildfire causing a loss of grasses and organic carbon. Threshold: A hydrologic function threshold is crossed.
Mechanism
An increase in the competitive advantage of grass species through physical, chemical, and biological management practices.
Various facilitating and management practices can be used to restore this ecological site back to reference. Chemical, mechanical, and biological practices can all be used to reduce shrubs. Also, range seeding, winter feeding, and high intensity-short duration livestock grazing can help bring grass and organic matter back into the system while restoring soil carbon and microbial levels. Eventually, once fuel loads are adequate, prescribed burning will help reduce shrub competition and improve grass vigor.
Monitoring foliar cover by species will help inform the land manager if plant species composition is responding to management.
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.