Eastern Clay Loam
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
-
Transition T1A
Absence of disturbance and natural regeneration over time, may be coupled with excessive grazing pressure
More details -
Transition T1B
Prolonged drought conditions coupled with excessive grazing pressure
More details -
Transition T1C
Removal of vegetation followed by extensive soil disturbance and planting with non-native species
More details -
Restoration pathway R2A
Reintroduction of historic disturbance return intervals
More details -
Transition T2A
Removal of vegetation followed by extensive soil disturbance and planting with non-native species
More details -
Restoration pathway R3A
Release from drought and reintroduction of historic disturbance return intervals
More details -
Transition T3A
Extensive soil disturbance followed by planting with non-native species
More details -
Restoration pathway R4A
Seeding native species followed by reintroduction of historic disturbance return intervals
More details -
Transition T41
Absence of disturbance and natural regeneration over time, may be coupled with excessive grazing pressure
More details -
Restoration pathway R4C
Seeding with native species followed by reintroduction of historic disturbance return intervals
More details -
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
Mechanism
Shrubs make up a portion of the community in the Savannah State (1), hence woody propagules are present. Regardless of grazing management, without some form of brush control, the Midgrass Savannah Community (1.1) will transition to the Shrubland State (2) even if the understory component does not shift to dominance by shortgrasses. Therefore, the Savannah State (1) is always at risk for shrub and tree dominance and the transition to the Shrubland State (2) in the absence of fire and brush management. The driver for Transition T1A is lack of fire and/or brush control. The mean fire return interval in the Savannah State (1) is three to seven years. Most fires will burn only the understory. Even with proper grazing and favorable climate conditions, lack of fire for 5 to 10 years will allow trees and shrubs to increase in canopy to reach the 20 percent threshold level. The introduction of aggressive woody invader species increases the risk and accelerates the rate at which this transition is likely to occur. Transition to the Shrubland State (2) can occur from any community within the Savannah State (1), it is not dependent on degradation of the herbaceous community, but on the lack of some form of brush control. Improper grazing, prolonged drought, and a warming climate will provide a competitive advantage to shrubs which will accelerate this process.
Mechanism
The Savannah State (1) transitions to the Sparsely Vegetated State (3) if soil loss continues or increases to the point that total plant canopy cover is less than 25 percent or total annual aboveground biomass production is less than 1,000 pounds per acre. This could occur due to overgrazing (failure to adjust stocking rate to declining forage production due to increased dominance of unpalatable forbs or inaccessible shrubs), long-term lack of fire, warming climate, or extensive drought. The trigger for this transition is the loss of vegetation. This creates open spots with bare soil. If the A-horizon erodes, the soil fertility decreases sharply and the site transitions to the Sparsely Vegetated State (3). Other key factors signaling approach of transition T1B are increases in soil physical crusting, decreases in cover of cryptogamic crusts, decreases in soil surface aggregate stability, and/or evidence of erosion including water flow patterns, development of plant pedestals, and litter movement. The driver for this transition is improper grazing management in combination with long-term drought.
Mechanism
The transition to the Converted State from the Savannah State occurs when the savannah is plowed for planting to cropland or hayland. The threshold for this transition is the plowing of the savannah soil and removal of the woody plant community. The Converted State (4) includes cropland, tame pasture, and go-back land. The site is considered “go-back land” during the period between cessation of active cropping, fertilization, and weed control and the return to the “native” states. Agronomic practices are used to convert rangeland to the Converted State (4) and to make changes between the communities in the Converted State (4). The driver for these transitions is management’s decision to farm the site.
Mechanism
Restoration of the Shrubland State (2) to the Savannah State (1) requires substantial energy input. The driver for this restoration pathway is removal of woody species, restoration of native herbaceous species, and ongoing management of woody species. Without maintenance, woody species are likely to increase again.
Mechanism
The transition to the Converted State from the Shrubland State occurs when the site is plowed for planting to cropland or hayland. The size and density of brush in the Shrubland State (2) will require heavy equipment and energy-intensive practices (i.e. rootplowing, raking, rollerchopping, or heavy disking) to prepare a seedbed. The threshold for this transition is the plowing of the savannah soil and removal of the woody plant community. The Converted State (4) includes cropland, tame pasture, and go-back land. The site is considered “go-back land” during the period between cessation of active cropping, fertilization, and weed control and the return to the “native” states. Agronomic practices are used to convert rangeland to the Converted State (4) and to make changes between the communities in the Converted State (4). The driver for these transitions is management’s decision to farm the site.
Mechanism
This state has lost soil or vegetation attributes to the point that recovery to the Savannah State (1) will require reclamation efforts, such as soil rebuilding, intensive mechanical treatments, and/or reseeding in recommended areas only. The driver for this restoration pathway is reclamation efforts.
Mechanism
The transition to the Converted State from the Sparsely Vegetated State occurs when the site is plowed for planting to cropland or hayland. The threshold for this transition is the plowing of the savannah soil and removal of the woody plant community. The Converted State (4) includes cropland, tame pasture, and go-back land. The site is considered “go-back land” during the period between cessation of active cropping, fertilization, and weed control and the return to the “native” states. Agronomic practices are used to convert rangeland to the Converted State (4) and to make changes between the communities in the Converted State (4). The driver for these transitions is management’s decision to farm the site.
Mechanism
Restoration from the Converted State (4) can occur in the short term through active restoration or over the long-term due to cessation of agronomic practices. Cropland and tame pasture require repeated and continual inputs of fertilizer and weed control to maintain the Converted State (4). If the soil chemistry and structure have not been overly disturbed (which is most likely to occur with tame pasture) the site can be restored to the Savannah State (1). The level of disturbance while in the converted state determines whether the site restoration pathway is likely to be (R4A, R4B, or R4C).
Return to native savannah communities in the Savannah State (1) is more likely to be successful if soil chemistry and structure are not heavily disturbed. The presence of residual introduced forage plants may preclude a full return to native grasses. Preservation of favorable soil microbes increases the likelihood of a return to reference, or near reference, conditions as does remnant seed sources. Converted sites can be returned to the Savannah State (1) through active restoration, including seedbed preparation and seeding of native grass and forb species. Protocols and plant materials for restoring savannah communities is a developing part of restoration science. The driver for both of these restoration pathways is the cessation of agricultural disturbances.
Mechanism
Restoration from the Converted State (4) can occur in the short term through active restoration or over the long-term due to cessation of agronomic practices. Cropland and tame pasture require repeated and continual inputs of fertilizer and weed control to maintain the Converted State (4). Heavily disturbed soils are more likely to return to the Shrubland State (2) or the Sparsely Vegetated State (3). Without continued disturbance from agriculture, the site can eventually return to either the Savannah (1) or Shrubland State (2). The level of disturbance while in the converted state determines whether the site restoration pathway is likely to be (R4A, R4B, or R4C).
Mechanism
Restoration from the Converted State (4) can occur in the short term through active restoration or over the long-term due to cessation of agronomic practices. Cropland and tame pasture require repeated and continual inputs of fertilizer and weed control to maintain the Converted State (4). Heavily disturbed soils are more likely to return to the Shrubland State (2) or the Sparsely Vegetated State (3). Without continued disturbance from agriculture, the site can eventually return to either the Savannah (1) or Shrubland State (2). The level of disturbance while in the converted state determines whether the site restoration pathway is likely to be (R4A, R4B, or R4C).
Model keys
Briefcase
Add ecological sites and Major Land Resource Areas to your briefcase by clicking on the briefcase (
) icon wherever it occurs. Drag and drop items to reorder. Cookies are used to store briefcase items between browsing sessions. Because of this, the number of items that can be added to your briefcase is limited, and briefcase items added on one device and browser cannot be accessed from another device or browser. Users who do not wish to place cookies on their devices should not use the briefcase tool. Briefcase cookies serve no other purpose than described here and are deleted whenever browsing history is cleared.
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.