Loamy Lowland (LyL)
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
-
Transition T1A
Excessive grazing.
More details
Lack of fire. -
Transition T1B
Excessive grazing.
More details
Lack of fire. -
Restoration pathway R2A
Natural flooding.
More details
Prescribed grazing.
Native seeding. -
Transition T2A
Excessive grazing.
More details
Lack of fire. -
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
Description
The Reference State is characterized by three distinct plant community phases. The plant communities and various successional stages between them represent the natural range of variability within the Reference State.
Submodel
Description
An ecological threshold has been crossed and a significant amount of production and diversity has been lost when compared to the Reference State. Significant biotic and soil changes have negatively impacted energy flow and nutrient and hydrologic cycles.
This is a very stable state, resistant to change due to the high tolerance of blue grama and buffalograss to grazing, the development of a shallow root system (root pan), and subsequent changes in hydrology and nutrient cycling. The loss of other functional/structural groups such as cool-season bunch and rhizomatous grasses, forbs, and shrubs, and the loss of cottonwood seedling recruitment reduces the biodiversity and productivity of this site.
Submodel
Description
Litter levels are extremely low due to reduced production. The changes in water movement and the plant community affect changes in hydrologic functionality, biotic integrity, and soil and site stability. Infiltration, runoff, and soil erosion vary depending on the vegetation present. An ecological threshold has been crossed and erosion and loss of organic matter and carbon reserves are resource concerns.
Submodel
Mechanism
Frequent and severe defoliation without adequate recovery periods between grazing events and lack of fire shift this plant community across an ecological threshold toward the Sod-bound State. Biotic integrity and hydrologic function are impaired as a result of this transition.
Mechanism
Long-term heavy, continuous, grazing without adequate recovery periods and lack of fire shift this plant community across an ecological threshold to the Increased Bare Ground State. Erosion and loss of organic matter and carbon reserves are resource concerns. Non-native exotic plants are likely to invade.
Mechanism
Flooding followed by very long-term prescribed grazing moves this state to the Reference State. A timely flood event can result in germination of cottonwood seeds. Cottonwood regeneration is feasible if grazing and degree of browsing is closely monitored and controlled. It could take generations to reestablish the mid and tallgrasses, forbs, and shrubs, depending on the availability of a seed source. Pasture planting may be an option to return this site to a productive condition in a shorter management timeframe.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Prescribed Grazing |
Mechanism
Long-term frequent and severe defoliation without adequate recovery between grazing events and lack of fire cause a shift across an ecological threshold to the Increased Bare Ground State.
Erosion and loss of organic matter along with invasion of introduced plants and noxious weeds are resource concerns.
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.