Natural Resources
Conservation Service
Mountain Shallow Loam (Mixed Conifer)
Scenario model
Current ecosystem state
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Management practices/drivers
Select a transition or restoration pathway
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Transition T1A
This transitional pathway occurs when non-native, invasive species invade the site, the perennial herbaceous community is often reduced allowing species such as cheatgrass, and other weeds to become established.
More details -
No transition or restoration pathway between the selected states has been described
Target ecosystem state
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Description
This state describes the biotic communities that may become established on this ecological site if all successional sequences are completed under natural disturbance conditions. Species composition is generally dominated by a mixed conifer overstory canopy with bristlecone pine, limber pine, two-needle pinyon and Douglas fir occurring most often. Alderleaf mountain mahogany dominates the shrub layer with lesser amounts rockspirea, Utah serviceberry and mountian snowberry commonly present. Perennial herbaceous species occurrence is directly related to canopy density with bluebunch wheatgrass, Salina wildyre and geyer sedge found most often.
The primary disturbance mechanisms are overstory canopy density, weather fluctuations, and fire or lack of fire. The reference state is self sustaining and resistant to change due to a high resistance to natural disturbances and a high resilience following those disturbances. When natural disturbances occur, the rate of recovery can be quite variable. Typically, in the reference state, this ecological site will naturally fluctuate between community phases 1.1 and 1.2.
Reference State: Plant communities influenced by canopy density, long term weather fluctuations, and periodic fire.
Indicators: A community dominated by bristlecone pine, Douglas fir, two-needle pinyon, and alderleaf mountain mahogany. The density of the overstory canopy determines the amount and composition of the other native perennial grasses, grasslikes and forbs that may be present.
Feedbacks: Natural fluctuations in weather patterns that allow for a self sustaining bristlecone pine, Douglas fir, two-needle pinyon, alderleaf mountain mahogany and native grass and grasslike community. Insect herbivory, more frequent fires, or other disturbances that may allow for the establishment of invasive species.
At-risk Community Phase: All communities are at risk when native plants are stressed and nutrients become available for invasive plants to establish.
Trigger: The establishment of invasive plant species
Submodel
Description
The current potential state is similar to the reference state, however minor amounts of invasive species are now present in all community phases. This state describes the biotic communities that may become established on this ecological site if all successional sequences are completed under natural disturbance conditions.
The current potential state is generally dominated by a mixed conifer overstory canopy with bristlecone pine, limber pine, two-needle pinyon and Douglas fir occurring most often. Alderleaf mountain mahogany dominates the shrub layer with lesser amounts Utah serviceberry, rockspirea and mountian snowberry commonly present. Perennial herbaceous species occurrence is directly related to canopy density with cheatgrass, bluebunch wheatgrass, Salina wildyre and geyer sedge found most often.
All age classes of coniferous trees are present in the current potential state. Other introduced and native grasses, forbs, and shrubs may be present in the plant community.
The primary disturbance mechanisms are overstory canopy density, weather fluctuations and fire or lack of fire. The current potential state is still self sustaining but has a lower resistant to change due to a reduced resistance to disturbances. When disturbances do occur, the rate of recovery can be highly variable.
Current Potential State: Plant communities influenced by wildlife browsing, insect herbivory, weather fluctuations, fire periods and surface disturbances.
Indicators: A community dominated by bristlecone pine, Douglas fir, two-needle pinyon and alderleaf mountain mahogany. The density of the overstory canopy determines the amount and composition of the other introduced and native grasses, grasslikes and forbs that may be present.
Feedbacks: Natural fluctuations in weather patterns that allow for a self sustaining Douglas fir, two-needle pinyon, Utah juniper, alderleaf mountain mahogany and native grass and grasslike community. Insect herbivory, more frequent fires, or other disturbances that may allow for the increase of invasive species.
At-risk Community Phase: All communities are at risk when native plants are stressed and nutrients become available for invasive plants to flourish.
Submodel
Transition T1A
This transitional pathway occurs when non-native, invasive species invade the site, the perennial herbaceous community is often reduced allowing species such as cheatgrass, and other weeds to become established.
Mechanism
This transitional pathway occurs when non-native, invasive species invade the site, the perennial herbaceous community is often reduced allowing species such as cheatgrass, and other weeds to become established. Once invasive species occupy the site, a threshold has been crossed. Cheatgrass, however, has been known to become established in healthy communities on this site.
Model keys
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Ecological sites
Major Land Resource Areas
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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