Isohyperthermic Ustic Naturalized Grassland Koa haole/guineagrass/glycine (Leucaena leucocephala/Urochloa maxima/Neonotonia wightii)
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
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Restoration pathway R1A
It may be possible to restore State 1 to a plant community resembling State 3 Native Forest. Weed control must be applied to forage species and the many opportunistic plant species that would invade the site. Weed control would be a perpetual process to maintain the site. Wildfire must be excluded by establishment and maintenance of a firebreak; domestic and feral ungulates must be excluded by a suitably designed and maintained fence or application of animal control measures. Extensive planting of native species would follow.
More details -
Transition T1A
State 1 Reference transitions to State 4 Shrub Invaded Grassland with the gradual invasion of weedy shrubs and small trees which occur in the absence of disturbance such as fire or brush control. If the site contained abundant koa haole before abandonment, these small trees will overtop the guineagrass and greatly increase in abundance. This transition may be avoided through application of brush management and invasive plant species control.
More details -
Transition T2A
State 2 Invaded Understory transitions to State 1 Reference by land clearing with heavy machinery followed up by invasive plant species control. Land clearing would probably promote germination of the weed seed bank in the soil, requiring additional weed control. After clearing and weed control, the site would be planted to forage species.
More details -
Transition R2A
State 2 Invaded Understory may be restored to a facsimile of State 3 Native Forest, by removal of the introduced understory through application invasive plant species control. Reintroduction of native understory species is required. The site must be fenced securely or animal control measures implemented to exclude domestic and feral ungulates from the site.
More details -
Transition T2B
State 2 Invaded Understory transitions to State 5 Exotic Tree Invaded by growth of introduced tree species through and above the native canopy. Lack of reproduction leads to gradual loss of most native tree species. This transition can be avoided by applying brush management and invasive plant species control.
More details -
Transition T3B
State 3 Native Forest transitions to State 1 Reference by clearing the forest with heavy machinery and planting desirable forage species. Apply brush management and invasive plant species control as needed.
More details -
Transition T3A
State 3 Native Forest transitions to State 2 Invaded Understory through grazing, browsing, rooting, and trampling by domestic or feral ungulates (cows, sheep, deer, goats, and pigs). These activities destroy small native plant species and seedlings and saplings of large species. Regeneration of the native forest is prevented, leading to tree populations consisting almost entirely of mature plants. Lack of competition from native plants, introduction of weed seeds, and disturbance of the soil lead to an understory dominated by introduced plant species. Weeds can invade intact native forest even in the absence of ungulates and gradually bring about the transition. Invasive vines, shrubs, and small trees will grow under intact native canopies and begin to degrade the forest. Eventually, introduced grasses provide fine fuels that can carry wildfires that destroy the native tree canopy. This transition may be avoided by excluding domestic livestock and feral ungulates from the site with fencing or animal control measures and by implementing invasive plant species control.
More details -
Restoration pathway R4A
State 4 Shrub Invaded Grassland can be restored to State 1 Reference by brush management with follow-up invasive plant species control of resprouting shrubs and emerging weedy forbs. Forage species may then be replanted and maintained by prescribed grazing. For large, densely weedy sites or if fast results are not required, it is possible to eliminate invasive small trees, shrubs, and undergrowth by planting glycine (Neonotonia wightii) to overtop and smother weeds; this is done in conjunction with foraging by sheep and goats to consume smaller weeds. Eventually, the dead trees and shrubs collapse under the weight of the glycine; the glycine is then eaten by livestock. This process takes about eight years (Gordon Cran, Kapapala Ranch, personal communication, 2006).
More details -
Transition T4A
State 4 Shrub Invaded Grassland transitions to State 5 Exotic Tree Invaded in the absence of disturbances such as fire or brush control. Fast-growing introduced tree species invade Shrub Invaded Grassland and quickly overtop shrubs. This transition may be avoided with implementation of brush control and invasive plant species control.
More details -
Restoration pathway R5B
State 5 Exotic Tree Invaded may be restored to State 1 Reference. Total clearing of the site would be necessary. If clearing is done by heavy machinery, soil disturbance would occur. This would probably induce germination of the weed seed bank and increase the potential for soil erosion. Invasive plant species control and brush management must then be applied multiple times to control new weed germination and resprouting. After clearing and weed control, the site would be planted to forage species. Domestic and feral ungulates must be excluded until forages are well established; prescribed grazing must then be applied.
More details -
Restoration pathway R5A
It may be possible to restore State 5 Exotic Tree Invaded to a community resembling State 3 Native Forest. Total clearing of the site would be necessary. Alternatively, it may be worthwhile to kill taller weed species in place by herbicide applications in order to provide some shelter from the sun. If clearing is done by heavy machinery, soil disturbance would occur. This would induce germination of the weed seed bank and increase the potential for soil erosion. Invasive plant species control and brush management would be long-term. A firebreak must be created and maintained, and ungulates would have to be excluded by a suitable fence or by invasive species pest management.
More details -
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
State 1
Reference
Description
This state consists of two community phases. It is naturalized grassland with introduced grasses, forbs, and trees. Scattered, large trees are often present. Some grasslands are on moderately deep and deep ash soils on former sugarcane plantations.
Submodel
Description
This state consists of one community phase having an open canopy of common native trees with an understory of introduced grasses, ferns, vines, small trees, and shrubs. Foraging by feral or domestic ungulates removes native understory plants and prevents regeneration of overstory species, resulting in a mature and diminishing canopy of native trees. This may occur more gradually by weed invasion into intact native forest. The understory of this plant community contains fine fuels that are susceptible to wildfire.
Submodel
Description
This state consists of one community phase. This description is hypothetical, because very little native vegetation remains in this ecological site. The following description is based on similar ecological sites on the Island of Hawaii. The general appearance of this ecological site is an open to nearly closed canopy of medium to tall height to 40 feet (12 meters) when dominated by lama (Diospyros sandwicensis) or to 70 feet (22 meters) when dominated by ohia lehua, an understory of shrubs and small trees, and a ground layer of vines, forbs, and grasses. The canopy becomes shorter and sparser where the forest grades into drier and/or windier areas near the coast.
Submodel
Description
This state consists of one community phase. It develops in land cleared by fire or on abandoned grazing land or abandoned farmland. Shrubs are dominant in canopy cover and stature. Typically, an array of introduced grass species is present. There is a moderate but increasing cover of small trees, some which potentially can grow to large stature. This tree cover creates the potential for a transition to State 5 Exotic Tree Invaded.
Submodel
State 5
Exotic Tree Invaded State
Description
This state is comprised of one community phase dominated by introduced trees. Density and composition of understory shrubs, forbs, and grasses varies greatly with overstory closure and height, which affects the susceptibility of this plant community to fire. The density, vigor, and biomass of introduced vegetation can be very high, making restoration to other states expensive and difficult.
Submodel
Mechanism
It may be possible to restore State 1 to a plant community resembling State 3 Native Forest. Weed control must be applied to forage species and the many opportunistic plant species that would invade the site. Weed control would be a perpetual process to maintain the site. Wildfire must be excluded by establishment and maintenance of a firebreak; domestic and feral ungulates must be excluded by a suitably designed and maintained fence or application of animal control measures. Extensive planting of native species would follow.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Fence |
|
|
Firebreak |
|
|
Native Plant Community Restoration and Management |
|
|
Invasive Plant Species Control |
|
|
Invasive Species Pest Management |
Mechanism
State 1 Reference transitions to State 4 Shrub Invaded Grassland with the gradual invasion of weedy shrubs and small trees which occur in the absence of disturbance such as fire or brush control. If the site contained abundant koa haole before abandonment, these small trees will overtop the guineagrass and greatly increase in abundance. This transition may be avoided through application of brush management and invasive plant species control.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
|
|
Invasive Plant Species Control |
Mechanism
State 2 Invaded Understory transitions to State 1 Reference by land clearing with heavy machinery followed up by invasive plant species control. Land clearing would probably promote germination of the weed seed bank in the soil, requiring additional weed control. After clearing and weed control, the site would be planted to forage species.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Land Clearing |
|
|
Range Planting |
|
|
Invasive Plant Species Control |
Mechanism
State 2 Invaded Understory may be restored to a facsimile of State 3 Native Forest, by removal of the introduced understory through application invasive plant species control. Reintroduction of native understory species is required. The site must be fenced securely or animal control measures implemented to exclude domestic and feral ungulates from the site.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Fence |
|
|
Integrated Pest Management (IPM) |
|
|
Restoration and Management of Rare and Declining Habitats |
|
|
Native Plant Community Restoration and Management |
|
|
Invasive Plant Species Control |
|
|
Invasive Species Pest Management |
Mechanism
State 2 Invaded Understory transitions to State 5 Exotic Tree Invaded by growth of introduced tree species through and above the native canopy. Lack of reproduction leads to gradual loss of most native tree species. This transition can be avoided by applying brush management and invasive plant species control.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
|
|
Invasive Species Pest Management |
Mechanism
State 3 Native Forest transitions to State 1 Reference by clearing the forest with heavy machinery and planting desirable forage species. Apply brush management and invasive plant species control as needed.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
|
|
Land Clearing |
|
|
Range Planting |
|
|
Invasive Plant Species Control |
Mechanism
State 3 Native Forest transitions to State 2 Invaded Understory through grazing, browsing, rooting, and trampling by domestic or feral ungulates (cows, sheep, deer, goats, and pigs). These activities destroy small native plant species and seedlings and saplings of large species. Regeneration of the native forest is prevented, leading to tree populations consisting almost entirely of mature plants. Lack of competition from native plants, introduction of weed seeds, and disturbance of the soil lead to an understory dominated by introduced plant species. Weeds can invade intact native forest even in the absence of ungulates and gradually bring about the transition. Invasive vines, shrubs, and small trees will grow under intact native canopies and begin to degrade the forest. Eventually, introduced grasses provide fine fuels that can carry wildfires that destroy the native tree canopy. This transition may be avoided by excluding domestic livestock and feral ungulates from the site with fencing or animal control measures and by implementing invasive plant species contol.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Fence |
|
|
Firebreak |
|
|
Invasive Plant Species Control |
|
|
Invasive Species Pest Management |
Mechanism
State 4 Shrub Invaded Grassland can be restored to State 1 Reference by brush management with follow-up invasive plant species control of resprouting shrubs and emerging weedy forbs. Forage species may then be replanted and maintained by prescribed grazing. For large, densely weedy sites or if fast results are not required, it is possible to eliminate invasive small trees, shrubs, and undergrowth by planting glycine (Neonotonia wightii) to overtop and smother weeds; this is done in conjunction with foraging by sheep and goats to consume smaller weeds. Eventually, the dead trees and shrubs collapse under the weight of the glycine; the glycine is then eaten by livestock. This process takes about eight years (Gordon Cran, Kapapala Ranch, personal communication, 2006).
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
|
|
Range Planting |
|
|
Planned Grazing System |
|
|
Prescribed Grazing |
|
|
Invasive Plant Species Control |
Mechanism
State 4 Shrub Invaded Grassland transitions to State 5 Exotic Tree Invaded in the absence of disturbances such as fire or brush control. Fast-growing introduced tree species invade Shrub Invaded Grassland and quickly overtop shrubs. This transition may be avoided with implementation of brush control and invasive plant species control.
Mechanism
State 5 Exotic Tree Invaded may be restored to State 1 Reference. Total clearing of the site would be necessary. If clearing is done by heavy machinery, soil disturbance would occur. This would probably induce germination of the weed seed bank and increase the potential for soil erosion. Invasive plant species control and brush management must then be applied multiple times to control new weed germination and resprouting. After clearing and weed control, the site would be planted to forage species. Domestic and feral ungulates must be excluded until forages are well established; prescribed grazing must then be applied.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
|
|
Fence |
|
|
Prescribed Grazing |
|
|
Range Planting |
|
|
Planned Grazing System |
|
|
Invasive Plant Species Control |
|
|
Invasive Species Pest Management |
Mechanism
It may be possible to restore State 5 Exotic Tree Invaded to a community resembling State 3 Native Forest. Total clearing of the site would be necessary. Alternatively, it may be worthwhile to kill taller weed species in place by herbicide applications in order to provide some shelter from the sun. If clearing is done by heavy machinery, soil disturbance would occur. This would induce germination of the weed seed bank and increase the potential for soil erosion. Invasive plant species control and brush management would be long-term. A firebreak must be created and maintained, and ungulates would have to be excluded by a suitable fence or by invasive species pest management.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
|
|
Fence |
|
|
Firebreak |
|
|
Land Clearing |
|
|
Restoration and Management of Rare and Declining Habitats |
|
|
Native Plant Community Restoration and Management |
|
|
Invasive Plant Species Control |
|
|
Invasive Species Pest Management |
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