Shrink-Swell Clay
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
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Transition T1A
Reference State (1) transitions to Kiawe-Invaded State (2) with lack of disturbance (brush management practices or absence of fire).
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Restoration pathway R1A
Reference State (1) can be restored to a facsimile of Native Savanna State (3). The site must be fenced to exclude all domestic and feral ungulates. Perimeter protection from fire must be created and maintained around the fence line. Non-native vegetation must be removed, followed by plantings of native trees, shrubs, and vines. Supplemental irrigation may be necessary in the early stages of restoration.
More details -
Transition T1B
Reference State (1) transitions to Weed-Invaded State (4) with long-term and heavy continuous grazing. Species composition changes to dominance by shortgrasses, weedy forbs, and shrubs. Bare ground increases markedly.
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Restoration pathway R2A
Kiawe-Invaded State (2) can be restored to Reference State (1) by applying brush management. Fire will kill kiawe, but there may not be enough understory fuels to carry an intense fire.
More details -
Transition T3A
Native Forest State (3) transitions to Reference State (1) when cleared by fire, long-term ungulate disturbance, or mechanical means. Desired forage species are then established.
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Restoration pathway R4A
Weed Invaded State (4) can be restored to Reference State (1) by application of a prescribed grazing program that allows buffelgrass to reassume dominance. Weed control and brush management are likely to be necessary.
More details -
Transition T4A
Weed Invaded State (4) transitions to Kiawe-Invaded State (2) with lack of brush management practices or absence of fire along with a nearby source of kiawe seeds.
More details -
Restoration pathway R4B
Weed Invaded State (4) can be restored to a facsimile of Native Savanna State (3). The site must be fenced to exclude all domestic and feral ungulates. Perimeter protection from fire must be created and maintained around the fence line. Non-native vegetation must be removed, followed by plantings of native trees, shrubs, and vines. Supplemental irrigation may be necessary in the early stages of restoration.
More details -
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
Description
The Reference State (1) consists of two community phases dominated by introduced grasses and less than 25 percent canopy cover of introduced trees. With lack of brush control or absence of wildfire, this state will transition to Kiawe-Invaded State (2), in which production and cover of buffelgrass (Pennisetum ciliare), white leadtree or koa haole (Leucaena leucocephala), and other forages is reduced. Accumulation of fine fuels under light or no grazing pressure increases the risk of fire. This can produce an open grassland with little tree overstory but presents a fire threat to developed areas nearby and likelihood of eroded soil entering the nearby ocean.
Submodel
Description
The Kiawe-Invaded State (2) consists of one community phase. It occurs when brush management has not been practiced or if fire has not occurred for a long time, allowing kiawe (Prosopis pallida) to increase in density and stature to a level at which understory production is significantly reduced.
Submodel
Description
The Native Savanna State (3) consists of one community phase. Intact examples of this community no longer exist. This historical description is compiled from field observations of remnant vegetation, isolated plants on disturbed sites, and similar ecological sites.
Submodel
Description
The Weed-Invaded State (4) consists mostly of grass species that are highly tolerant of grazing along with increased amounts of unpalatable shrubs, forbs, and subshrubs. White leadtree or koa haole (Leucaena leucocephala) is gone or is browsed down to stumps. Bare ground is extensive, so soil erosion by wind and water can be excessive.
Submodel
Mechanism
Reference State (1) transitions to Kiawe-Invaded State (2) with lack of disturbance (brush management practices or absence of fire).
Mechanism
Reference State (1) can be restored to a facsimile of Native Savanna State (3). The site must be fenced to exclude all domestic and feral ungulates. Perimeter protection from fire must be created and maintained around the fence line. Non-native vegetation must be removed, followed by plantings of native trees, shrubs, and vines. Supplemental irrigation may be necessary in the early stages of restoration.
Mechanism
Reference State (1) transitions to Weed-Invaded State (4) with long-term and heavy continuous grazing. Species composition changes to dominance by shortgrasses, weedy forbs, and shrubs. Bare ground increases markedly.
Mechanism
Kiawe-Invaded State (2) can be restored to Reference State (1) by applying brush management. Fire will kill kiawe, but there may not be enough understory fuels to carry an intense fire.
Mechanism
Native Forest State (3) transitions to Reference State (1) when cleared by fire, long-term ungulate disturbance, or mechanical means. Desired forage species are then established.
Mechanism
Weed Invaded State (4) can be restored to Reference State (1) by application of a prescribed grazing program that allows buffelgrass to reassume dominance. Weed control and brush management are likely to be necessary.
Mechanism
Weed Invaded State (4) transitions to Kiawe-Invaded State (2) with lack of brush management practices or absence of fire along with a nearby source of kiawe seeds.
Mechanism
Weed Invaded State (4) can be restored to a facsimile of Native Savanna State (3). The site must be fenced to exclude all domestic and feral ungulates. Perimeter protection from fire must be created and maintained around the fence line. Non-native vegetation must be removed, followed by plantings of native trees, shrubs, and vines. Supplemental irrigation may be necessary in the early stages of restoration.
Model keys
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