Subirrigated Bottomland
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
-
Transition T1A
No fire, No brush management
More details -
Transition T1B
Tillage, Seeding
More details -
Restoration pathway R2A
Selective thinning, Prescribed burning, Prescribed grazing
More details -
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
State 1
Savannah
Description
This is the reference state for this ecological site. It represents the historical variability of plant communities for the site.
Characteristics and indicators
Tallgrasses dominate the plant communities within this state. Other vegetative components include numerous forbs, midgrasses, and bottomland hardwood tree species. Woody canoy averages 30-50 percent.This canopy may vary substantially as areas adjacent to creeks and streams are more protected from fire. This often leads to a feathered effect of low canopy further from the the water course and higher canopy adjacent to it.
Resilience management
The plant communities within this state evolved under disturbance from periodic fire and grazing. Woody species vigor and reproduction is restricted by periodic fires. As grazing pressure increases, more palatable tallgrass species and forbs will decline in vigor and may be replaced by less desirable midgrass species.
Submodel
State 2
Woodland
Description
This ecological state is the result of long term exclusion of fire from the ecosystem.
Characteristics and indicators
Woody species that were historically controlled by periodic fire have been allowed to reproduce and have encroached in the savannah ecosystem of the reference state (1).
Resilience management
The ecological function of the site has been altered and is now dominated by woody species. While sites in this state may be grazed by cattle, the production of palatable herbaceous species is diminished. Thus, the production value of grazing is greatly reduced. Some species of wildlife will find use of the site in this state; however, other species will not persist as the site becomes dominated by woody plants.
Submodel
State 3
Converted
Description
This ecological state is the result of reseeding herbaceous plant species or abandonment following a period of cultivation. The plant communities within this state are highly variable in both species composition and production. The species composition, ecological function, and soil health may never be restored to reference conditions. Therefore, careful consideration should be taken when evaluating a bottomland site that may have been broken out for cultivation in the past.
Submodel
Mechanism
In the absence of fire, many woody species are allowed to encroach across the landscape. Once these woodies are abundant enough, they begin to drive the ecological functions of the site.
Constraints to recovery
Shading negatively affects the herbaceous plants and hydrologic changes may lower the water table, limiting available water for these species. As the woody species begin to dominate the site, it will transition to a woodland ecological state (2).
Mechanism
Many of these sites have been plowed for farming purposes over the last century, although typically for short durations. Once the site is cultivated, it transitions to an alternative state (3).
Constraints to recovery
The soils structure, organic matter, and biota have been altered and will no longer function the same as the soils in the reference state. A majority of the sites that were once cultivated have been abandoned or reseeded to non-native perennial grasses.
Mechanism
Through an integrated program of Brush Management (selective thinning), Grazing Management (deferment), and Prescribed Fire, the Woodland State may be restored to the Reference Savannah State (1). Selective thinning will be required to remove undesirable woody species while leaving the large bottomland trees that occur in the Reference State. Prescribed grazing will be required in order to allow the tallgrasses, forbs, and legumes recover and re-establish once the canopy is thinned. This will also be required in order to establish proper fuel loads in order to successfully implement a prescribed fire program. Prescribed fire will be necessary in order to clean up remaining understory species and can be used as a management tool to prevent future woody encroachment.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
|
|
Prescribed Burning |
|
|
Prescribed Grazing |
Model keys
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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.