Natural Resources
Conservation Service
CLAYPAN 12-16 P.Z.
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
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Transition T1A
Introduction of non-native species
More details -
Transition T1B
Loss of deep-rooted perennial bunchgrass
More details -
Transition T2A
Loss of deep-rooted perennial bunchgrass
More details -
Transition T2B
Increase size and frequency of wildfire
More details -
Restoration pathway R3A
Herbicide treatment and seeding with native species
More details -
Transition T3A
Increased size and frequency of wildfire
More details -
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
State 1
Reference State
Reference State
Description
The Reference State 1.0 is a representative of the natural range of variability under pristine conditions. State dynamics are maintained by interactions between climatic patterns and disturbance regimes. Negative feedbacks enhance ecosystem resilience and contribute to the stability of the state. These include the presence of all structural and functional groups, low fine fuel loads, and retention of organic matter and nutrients. Plant community phase changes are primarily driven by fire, periodic drought and/or insect or disease attack. Due to the nature and extent of disturbance in this site, all three plant community phases would likely occur in a mosaic across the landscape.
Characteristics and indicators
Low sagebrush is killed by fire and does not sprout (Young 1983). Establishment after fire is from seed, generally blown in and not from the seed bank (Bradley et al. 1992). Fire risk is greatest following a wet, productive year when there is greater production of fine fuels (Beardall and Sylvester 1976). Fire return intervals have been estimated at 100-200 years in low sagebrush (Artemisia Arbuscula) dominated sites (Kitchen and McArthur 2007) and likely is similar in the black sagebrush ecosystem; however, historically fires were probably patchy due to the low productivity of these sites.
Dominant plant species
little sagebrush (Artemisia arbuscula), shrub
Idaho fescue (Festuca idahoensis), grass
bluebunch wheatgrass (Pseudoroegneria spicata), grass
Submodel
State 2
Current Potential State
Current Potential State
Description
This state is similar to the Reference State 1.0. Ecological function has not changed, however the resiliency of the state has been reduced by the presence of invasive weeds. This state has the same three general community phases. These non-natives can be highly flammable, and can promote fire where historically fire had been infrequent. Negative feedbacks enhance ecosystem resilience and contribute to the stability of the state. These include the presence of all structural and functional groups, low fine fuel loads and retention of organic matter and nutrients. Positive feedbacks decrease ecosystem resilience and stability of the state. These include the non-natives’ high seed output, persistent seed bank, rapid growth rate, ability to cross pollinate and adaptations for seed dispersal.
Characteristics and indicators
Management would be to maintain high diversity of native species to promote organic matter inputs and reduce dispersal and seed production of the non-native invasive species.
Dominant plant species
little sagebrush (Artemisia arbuscula), shrub
Idaho fescue (Festuca idahoensis), grass
bluebunch wheatgrass (Pseudoroegneria spicata), grass
Submodel
Description
This state is characterized by dominance of low sagebrush and rabbitbrush. The deep-rooted perennial bunchgrass component is missing and the understory is dominated by bluegrass and/or annual non-native species. Nutrient cycling and energy cycling have been truncated by the lack of deep-rooted bunchgrasses. Pedestalling and bare ground has increased and soil moisture is reduced due to the redistribution of water off site.
Dominant plant species
little sagebrush (Artemisia arbuscula), shrub
bluegrass (Poa), grass
Submodel
Description
This state is dominated by annual non-native species, such as cheatgrass, annual mustards, and medusahead. Soil moisture, soil nutrients and soil organic matter distribution and cycling are severely altered due to degraded soil surface conditions.
Dominant plant species
little sagebrush (Artemisia arbuscula), shrub
yellow rabbitbrush (Chrysothamnus viscidiflorus), shrub
cheatgrass (Bromus tectorum), grass
Submodel
Transition T1A
Introduction of non-native species
Mechanism
Trigger: This transition is caused by the introduction of non-native annual plants, such as cheatgrass and mustards. Slow variables: Over time the annual non-native species will increase within the community. Threshold: Any amount of introduced non-native species causes an immediate decrease in the resilience of the site. Annual non-native species cannot be easily removed from the system and have the potential to significantly alter disturbance regimes from their historic range of variation.
Mechanism
Trigger: Repeated, heavy, growing season grazing will decrease or eliminate deep rooted perennial bunchgrasses, increase Sandberg bluegrass and favor shrub growth and establishment. From community phase 1.3 to community phase 3.2: Severe fire will remove sagebrush overstory, decrease perennial bunchgrasses and enhance Sandberg bluegrass. Slow variables: Long term decrease in deep-rooted perennial grass density. Threshold: Loss of deep-rooted perennial bunchgrasses changes nutrient cycling, nutrient redistribution, and reduces soil organic matter.
Mechanism
Trigger: Prolonged drought coupled with excessive herbivory will decrease or eliminate deep-rooted perennial bunchgrasses. Soil disturbing practices/management actions will also reduce sagebrush and favor an increase in Sandberg bluegrass. Slow variables: Long term decrease in deep-rooted perennial grass seed production, reproduction, and density allows for an increase in Sandberg bluegrass and shrub growth and establishment. Threshold: Loss of deep-rooted perennial bunchgrasses changes nutrient cycling, reduces soil organic matter, and results in the redistribution of precipitation - increased runoff and decreased infiltration.
Transition T2B
Increase size and frequency of wildfire
Mechanism
Trigger: Multiple wildfires and/or soil disturbing treatments that remove native species. Slow variables: Increased seed production and cover of annual non-native species. Threshold: Increased, continuous fine fuels modify the fire regime by changing frequency, intensity, size and spatial variability of fires. Changes in plant community composition and spatial variability of vegetation due to the loss of perennial bunchgrasses and sagebrush truncate energy capture and impact the temporal and spatial aspects of nutrient cycling and distribution.
Mechanism
Herbicide treatment, followed seeding with native perennial bunchgrasses, and grazing management that facilitating reestablishment or an increase in perennial bunchgrasses and a decline in shrubs. Probability of success is low. Risk of increased soil erosion and establishment on non-natives is high. Frost heaving in the spring may reduce seedling establishment.
Mechanism
Trigger: Multiple wildfires and/or soil disturbing treatments that remove native species. Slow variables: Increased seed production and cover of annual non-native species. Threshold: Increased, continuous fine fuels modify the fire regime by changing frequency, intensity, size and spatial variability of fires. Changes in plant community composition and spatial variability of vegetation due to the loss of perennial bunchgrasses and sagebrush truncate energy capture and impact the temporal and spatial aspects of nutrient cycling and distribution.
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.
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