Moderately Deep Oxic Soils on Volcanic Uplands
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
-
Restoration pathway R1A
The Reference State (1) can be restored to the Native Forest State (2) by fire protection, weed control, erosion control (vetiver-grass (Vetiveria sp) is useful), mulching, fertilizing, liming, and replanting of native plant species.
More details -
Transition T1B
The Reference State (1) transitions to the Tree-Invaded State (3) when fire is infrequent, allowing the growth of trees and shrubs.
More details -
Transition T1A
The Reference State (1) transitions to the Badlands State (4) by loss of upper soil horizons to erosion due to human caused grassland fires on soils which developed over volcanic bedrock resulting in vegetation and litter cover which are inadequate to protect soils from run off caused by strong storms and typhoons (Guampedia, 2025).
More details -
Transition T2A
The Native Forest State (2) transitions to the Reference State (1) by destruction of the forest by human-caused fire. Moreover, areas with low can result in aluminum toxicity which favors swordgrass monocultures over diverse grass, forb, shrub plant communities.
More details -
Restoration pathway R3B
The Tree-Invaded State (3) is restored to the Reference State (1) by fire.
More details -
Restoration pathway R3A
The Tree-Invaded State (3) may be restored to the Native Forest State (2). The intensity of active restoration measures will be determined by the presence or lack of native trees already on the site as well as the density and species mix of grasses, vines, shrubs, and introduced trees present on the site, especially if many competitive introduced species are present.
More details -
Transition T3A
The Tree-Invaded State (3) transitions to the Badlands State (4) through destruction of trees and surface litter by fire, leading to loss of surface soil horizons by erosion and slumping. Soil slumping is considered rare in forested sites in the Marianas Islands.
More details -
Restoration pathway R4A
The Badlands State (4) can be restored to the Reference State (1) by instituting erosion control measures and temporarily excluding fire.
More details -
Restoration pathway R4B
The Badlands State (4) can be restored to the Tree-Invaded State (3) by instituting erosion control measures and excluding fire. Replanting trees, either native, introduced, or both, can then be successful with mulching, fertilization, and reducing acidity and aluminum toxicity by lime application and maintenance of soil organic matter.
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) is tall (to 6.5 feet or 2 meters) grassland. The near-consensus of authors indicates that this Miscanthus-dominated grassland did not exist in the southern Marianas Islands until humans arrived and started burning the ubiquitous forests of these islands. However, naturally occurring Miscanthus grassland is considered to occur on certain locations on the young stratovolcano islands of the northern end of the island chain (Amidon et al., 2019; Amidon et al., 2017; Athens and Ward, 2004; Fosberg, 1960; Stone, 1970; Wagner and Grether, 1948; Willsey et al., 2019).
Submodel
Description
The Native Forest State (2) consists of two community phases consisting of native forest species. No intact examples of the original native forest remain, so the species list is historical and based on remnant plants and species persisting in ravines. The consensus of authors suggests that fire was probably not an important disturbance in these forests before humans arrived. The main disturbance was storm damage due to typhoons (Amidon et al., 2019; Amidon et al., 2017; Athens and Ward, 2004; Fosberg, 1960; Stone, 1970; Wagner and Grether, 1948; Willsey et al., 2019).
Measurements of soil pH on forested sites and grassland sites indicate lower acidity and aluminum toxicity on the forested sites (Amidon et al., 2019).
Submodel
Description
The Tree-Invaded State (3) consists of one community phase dominated by a variable mixture of small trees, shrubs, vines, forbs, and grasses that thrive in the absence of fire.
Submodel
Description
The Badlands State (4) consists of one community phase. It is sparsely vegetated with much bare ground. Most of the upper soil horizons has been eroded away, leaving highly acidic and infertile subsoil that supports few plant species (USDA-SCS, 1988).
Submodel
Mechanism
The Reference State (1) can be restored to the Native Forest State (2) by fire protection, weed control, erosion control (vetivergrass (Vetiveria sp) is useful), mulching, fertilizing, liming, and replanting of native plant species.
Mechanism
The Reference State (1) transitions to the Tree-Invaded State (3) when fire is infrequent, allowing the growth of trees and shrubs.
Mechanism
The Reference State (1) transitions to the Badlands State (4) by loss of upper soil horizons to erosion due to human caused grassland fires on soils which developed over volcanic bedrock resulting in vegetation and litter cover which are inadequate to protect soils from run off caused by strong storms and typhoons (Guampedia, 2025).
Mechanism
The Native Forest State (2) transitions to the Reference State (1) by destruction of the forest by human-caused fire. Moreover, areas with low can result in aluminum toxicity which favors swordgrass monocultures over diverse grass, forb, shrub plant communities.
Mechanism
The Tree-Invaded State (3) is restored to the Reference State (1) by fire.
Mechanism
The Tree-Invaded State (3) may be restored to the Native Forest State (2). The intensity of active restoration measures will be determined by the presence or lack of native trees already on the site as well as the density and species mix of grasses, vines, shrubs, and introduced trees present on the site, especially if many competitive introduced species are present.
Mechanism
The Tree-Invaded State (3) transitions to the Badlands State (4) through destruction of trees and surface litter by fire, leading to loss of surface soil horizons by erosion and slumping. Soil slumping is considered rare in forested sites in the Marianas Islands.
Mechanism
The Badlands State (4) can be restored to the Reference State (1) by instituting erosion control measures and temporarily excluding fire.
Mechanism
The Badlands State (4) can be restored to the Tree-Invaded State (3) by instituting erosion control measures and excluding fire. Replanting trees, either native, introduced, or both, can then be successful with mulching, fertilization, and reducing acidity and aluminum toxicity by lime application and maintenance of soil organic matter.
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.