Ecological site VX166X01X002

4. Shrub Invaded Grassland State

3. Native Forest State

States 1, 5 and 2 (additional transitions)

1.1. Dallisgrass – Rose Natal Grass

R1A	-	It may be possible to restore the Reference State (1) to a plant community resembling the Native Forest State (3). 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. Fire and domestic and feral ungulates must be excluded. Extensive planting of native species would follow. If severe soil erosion has occurred, more intensive restoration measures are needed.
T1A	-	The Reference State (1) transitions to the Shrub Invaded Grassland State (4) after abandonment and, if wildfires do not occur, gradual invasion of weedy shrubs and small trees. If the site contained abundant white leadtree (koa haole) before abandonment, these small trees would overtop the grasses and greatly increase in abundance unless heavily browsed.
T2A	-	The Invaded Understory State (2) transitions to the Reference State (1) by land clearing with heavy machinery or fire followed by weed control. Land clearing would probably promote germination of the weed seed bank in the soil, requiring herbicidal control. After clearing and weed control, the site would be planted to forage species.
R2A	-	The Invaded Understory State (2) may be restored to the Native Forest State (3) by removal of the introduced understory through intensive weed control. Reintroduction of native understory species is required. The site must be fenced securely to exclude ungulates. If severe soil erosion has occurred, more intensive restoration measures are needed.
T2B	-	The Invaded Understory State (2) transitions to the Exotic Tree Invaded State (5) by growth of introduced tree species through and above the native canopy. Lack of reproduction leads to gradual loss of most native tree species.
T3B	-	The Native Forest State (3) transitions to the Reference State (1) by clearing the forest and planting desirable forage species.
T3A	-	The Native Forest State (3) transitions to the Invaded Understory State (2) through grazing, browsing, rooting, and trampling by domestic or feral ungulates (cattle, 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 fires that destroy the native tree canopy.
R4A	-	The Shrub Invaded Grassland State (4) can be restored to the Reference State (1) by brush management with follow-up control of resprouting shrubs and emerging weedy forbs. Forage species may then be replanted and maintained by prescribed grazing. If severe soil erosion has occurred, more intensive restoration measures are needed.
T4A	-	The Shrub Invaded Grassland State (4) transitions to the Exotic Tree Invaded State (5) with lack of fire. Fast-growing introduced tree species invade Shrub Invaded Grassland and quickly overtop shrubs.
R5B	-	The Exotic Tree Invaded State (5) may be restored the Reference State (1). 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. Weed 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. Ungulates must be excluded until forages are well established; prescribed grazing must then be applied.
R5A	-	It may be possible to restore the Tree Invaded State (5) to a community resembling the Native Forest State (3). Total clearing of the site would be necessary. Alternatively, it may be worthwhile to kill taller weed species in place to provide some shelter from the sun. If clearing is done by heavy machinery, soil disturbance would occur. This could induce germination of the weed seed bank and increase the potential for soil erosion. Weed control and brush management would be long-term. Fire and ungulates must be excluded. If severe soil erosion has occurred, more intensive restoration measures are needed.

State 1 submodel, plant communities

1.2. Molassesgrass – Rose Natal Grass

1.1A	-	Community phase 1.1 converts to phase 1.2 by frequent fire that reduces competitiveness of the dominant grasses and allows invasion of weeds, particularly undesirable grasses. Continuous grazing without adequate rest for preferred forages will have the same result. This conversion by either factor can be avoided if timely application of deferred and/or prescribed grazing is carried out to allow recovery of desirable species before weeds become dominant.
1.2A	-	Community phase 1.2 can be converted to phase 1.1 by removing undesirable species and favoring and reestablishing desirable forage species. Prescribed grazing will eventually bring about the conversion.

State 1
Reference State

The Reference State (1) consists of two community phases. It is naturalized grassland with introduced grasses, forbs, and scattered shrubs and trees. With continuous heavy grazing, preferred forage grasses decrease. Less preferred grass, forb, and shrub species increase under such circumstances. With severe deterioration, shrubby species can increase to eventually dominate, causing a transition to the Shrub Invaded Grassland State (4).

Community 1.1
Dallisgrass – Rose Natal Grass

Dallisgrass (Paspalum dilatatum) and rose Natal grass (Melinis repens) are the dominant forage grass species; guineagrass (Urochloa maxima) may be common in some areas. Some white leadtree or koa haole (Leucaena leucocephala) may be present (Egler, 1947; Wagner, 1999).

Dominant plant species

dallisgrass (Paspalum dilatatum), grass
rose Natal grass (Melinis repens), grass

Community 1.2
Molassesgrass – Rose Natal Grass

Molassesgrass (Melinis minutiflora) is an increaser species that will dominate this community under heavy grazing. Rose Natal grass (Melinis repens) is still present but not dominant in cover or biomass.

Dominant plant species

molassesgrass (Melinis minutiflora), grass
rose Natal grass (Melinis repens), grass

Pathway 1.1A
Community 1.1 to 1.2

Community phase 1.1 converts to phase 1.2 by frequent fire that reduces competitiveness of the dominant grasses and allows invasion of weeds, particularly undesirable grasses. Continuous grazing without adequate rest for preferred forages will have the same result. This conversion by either factor can be avoided if timely application of deferred, prescribed grazing, or both are carried out to allow recovery of desirable species before weeds become dominant.

Pathway 1.2A
Community 1.2 to 1.1

Community phase 1.2 can be converted to phase 1.1 by removing undesirable species and favoring and reestablishing desirable forage species. Prescribed grazing will eventually bring about the conversion.

State 2
Invaded Understory State

The Invaded Understory State (2) 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 fire.

Community 2.1
Lama – Devil’s-Pepper (Hao)/Lantana/Molassesgrass

Native tree species dominate the overstory. The understory consists of a variable array of introduced plant species along with remnant native species. The overstory is dominated by lama (Diospyros sandwicensis), devil's-pepper or hao (Rauvolfia sandwicensis), and other typical dry forest species. Tree species diversity varies from widely among locations and between islands; please consult the accompanying native species list. Among native shrubs, Florida hopbush or aalii (Dodonaea viscosa) and pukiawe (Styphelia tameiameiae) may still be present. The introduced shrub lantana (Lantana camara) can be very abundant, producing stands that make foot transit difficult. The introduced vine corkystem passionflower or huehue haole (Passiflora suberosa) can become very abundant, covering the canopies of remnant native understory plants. Introduced grasses are abundant where sufficient light penetrates the canopy. Brazilian pepper tree or christmasberry (Schinus terebinthifolius), an introduced small tree that produces a dense, shady canopy, may be abundant. Introduced grasses such as molassesgrass (Melinis minutiflora) grow where there is adequate sunlight (Egler, 1947; Wagner, 1999). .

Dominant plant species

lama (Diospyros sandwicensis), tree
devil's-pepper (Rauvolfia sandwicensis), tree
lantana (Lantana camara), shrub
molassesgrass (Melinis minutiflora), grass

State 3
Native Forest State

The Native Forest State (3) consists of one community phase. Very little native vegetation remains in this ecological site. The following description is historical, based on literature and historical accounts of the islands before human influences disturbed these native plant communities and on similar ecological sites on the Island of Hawaii. The general appearance of this ecological site is an open to nearly closed canopy up to 40 feet (12 meters) tall, an understory of shrubs and small trees, and a sparse ground layer of vines, forbs, and grasses. The canopy becomes shorter and sparser where the forest grades into drier or windier areas.

Community 3.1
Lama – Devil’s-Pepper (Hao)/Smooth Pricklypoppy (Pua Kala)

In this historical community phase, the tree canopy would have been dominated by lama (Diospyros sandwicensis), devil’s-pepper or hao (Rauvolfia sandwicensis), and other typical Hawaiian dry forest species. ‘Ohi’a lehua (Metrosideros polymorpha), Koaoha or Koaia (Acacia koaia), and Hawai’i olive or olopua (Nestegis sandwicensis) would have been common in some areas. Alahe’e (Psydrax odorata), a small tree, would have been the most abundant species in the understory. Common shrubs would have been Florida hopbush or aalii (Dodonaea viscosa), yellow ‘ilima (Sida fallax), Hawai’i hawthorn or ulei (Osteomeles anthyllidifolia), and alaweo (Chenopodium oahuense). Queen coralbead or huehue (Cocculus orbiculatus) would have been the most common vine. Native forbs including smooth pricklypoppy or pua kala (Argemone glauca), grasses, and ferns would have been present but not abundant (Egler, 1947; Wagner, 1999).

Dominant plant species

lama (Diospyros sandwicensis), tree
devil's-pepper (Rauvolfia sandwicensis), tree
smooth pricklypoppy (Argemone glauca), other herbaceous

State 4
Shrub Invaded Grassland State

The Shrub Invaded Grassland State (4) consists of one community phase. It may have developed on abandoned grazing land, land cleared by fire, 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 the Exotic Tree Invaded State (5).

Community 4.1
Lantana - Brazilian Peppertree (Christmasberry)/Molassesgrass

The shrub community usually is dominated by introduced species but can be a mix of native and introduced species. The most common introduced species present are Brazilian peppertree or christmasberry (Schinus terebinthifolius), white leadtree or koa haole (Leucaena leucocephala), both of which are of small stature in this community phase, and lantana (Lantana camara). Guava (Psidium guajava) is common in areas with higher rainfall or cooler temperatures. Pukiawe (Styphelia tameiameiae), Florida hopbush or aalii (Dodonaea viscosa), and yellow ‘ilima (Sida fallax) are native shrubs that may be common in some locations. Introduced grasses such as molassesgrass (Melinis minutiflora) grow where there is adequate sunlight (Egler, 1947; Wagner, 1999).

Dominant plant species

lantana (Lantana camara), shrub
Brazilian peppertree (Schinus terebinthifolius), shrub
molassesgrass (Melinis minutiflora), grass

State 5
Exotic Tree Invaded State

The Exotic Tree Invaded State (5) 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.

Community 5.1
Christmasberry (Brazilian Peppertree)/Lantana/Molassesgrass

In many cases, the overstory consists of very dense Brazilian peppertree or christmasberry (Schinus terebinthifolius) that is 15 to 25 feet (4.6 to 8 meters) tall with very little understory. Introduced tree species such as silkoak (Grevillea robusta), Scotch attorney or autograph tree (Clusia rosea), Indian walnut or kukui (Aleurites moluccanus), and octopus tree (Schefflera actinophylla) that have greater height potentials than christmasberry are often able to grow up through the christmasberry canopy and eventually dominate the site. Remnant, mature ‘ohi’a lehua (Metrosideros polymorpha) trees may be present but are not able to regenerate. Native alahe’e (Psydrax odorata) trees sometimes can reproduce and maintain a sparse population in the understory (Egler, 1947; Wagner, 1999). The overstory composition can be highly variable from site to site, but christmasberry is typically the most abundant species. Christmasberry often dominates any remaining understory (greater than 13 feet or 4 meters tall) and can be so dense as to exclude most other species. Where more light is available, guava (Psidium guajava) and white leadtree or koa haole (Leucaena leucocephala) are common, and guava may dominate wetter or cooler sites. Lantana (Lantana camara) is the most common shrub to be found. Introduced grasses such as molassesgrass (Melinis minutiflora) grow where there is adequate sunlight (Egler, 1947; Wagner, 1999).

Dominant plant species

Brazilian peppertree (Schinus terebinthifolius), tree
lantana (Lantana camara), shrub
molassesgrass (Melinis minutiflora), grass

Restoration pathway R1A
State 1 to 3

It may be possible to restore the Reference State (1) to a plant community resembling the Native Forest State (3). 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. Fire and domestic and feral ungulates must be excluded. Extensive planting of native species would follow. If severe soil erosion has occurred, more intensive restoration measures are needed.

Transition T1A
State 1 to 4

The Reference State (1) transitions to the Shrub Invaded Grassland State (4) after abandonment and, if wildfires do not occur, gradual invasion of weedy shrubs and small trees. If the site contained abundant white leadtree (koa haole) before abandonment, these small trees would overtop the grasses and greatly increase in abundance unless heavily browsed.

Transition T2A
State 2 to 1

The Invaded Understory State (2) transitions to the Reference State (1) by land clearing with heavy machinery or fire followed by weed control. Land clearing would probably promote germination of the weed seed bank in the soil, requiring herbicidal control. After clearing and weed control, the site would be planted to forage species.

Restoration pathway R2A
State 2 to 3

The Invaded Understory State (2) may be restored to the Native Forest State (3) by removal of the introduced understory through intensive weed control. Reintroduction of native understory species is required. The site must be fenced securely to exclude ungulates. If severe soil erosion has occurred, more intensive restoration measures are needed.

Transition T2B
State 2 to 5

The Invaded Understory State (2) transitions to the Exotic Tree Invaded State (5) by growth of introduced tree species through and above the native canopy. Lack of reproduction leads to gradual loss of most native tree species.

Transition T3B
State 3 to 1

The Native Forest State (3) transitions to the Reference State (1) by clearing the forest and planting desirable forage species.

Transition T3A
State 3 to 2

The Native Forest State (3) transitions to the Invaded Understory State (2) through grazing, browsing, rooting, and trampling by domestic or feral ungulates (cattle, 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 fires that destroy the native tree canopy.

Restoration pathway R4A
State 4 to 1

The Shrub Invaded Grassland State (4) can be restored to the Reference State (1) by brush management with follow-up control of resprouting shrubs and emerging weedy forbs. Forage species may then be replanted and maintained by prescribed grazing. If severe soil erosion has occurred, more intensive restoration measures are needed.

Transition T4A
State 4 to 5

The Shrub Invaded Grassland State (4) transitions to the Exotic Tree Invaded State (5) with lack of fire. Fast-growing introduced tree species invade Shrub Invaded Grassland and quickly overtop shrubs.

Restoration pathway R5B
State 5 to 1

The Exotic Tree Invaded State (5) may be restored the Reference State (1). 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. Weed 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. Ungulates must be excluded until forages are well established; prescribed grazing must then be applied.

Restoration pathway R5A
State 5 to 3

It may be possible to restore the Tree Invaded State (5) to a community resembling the Native Forest State (3). Total clearing of the site would be necessary. Alternatively, it may be worthwhile to kill taller weed species in place to provide some shelter from the sun. If clearing is done by heavy machinery, soil disturbance would occur. This could induce germination of the weed seed bank and increase the potential for soil erosion. Weed control and brush management would be long-term. Fire and ungulates must be excluded. If severe soil erosion has occurred, more intensive restoration measures are needed.

Additional community tables

Supporting information

Other references

REFERENCES for R166XY002HI Isothermic Ustic Naturalized Grassland

Abrahamson, I.L. (2013). Fire regimes in Hawai’ian plant communities. Fire Effects
Information System [https://www.fs.usda.gov/database/feis/fire_regimes/Hawaii/all.html].

Athens, J.S. (1997). Prehistoric environmental and landscape change. In Kirch, P.V. & T.L. Hunt (Eds.), Hawai’ian native lowland vegetation in the Pacific Islands (Pgs. 248 -270). Yale University Press. [https://www.pelagicos.net/BIOL3010/readings/Athens_1997.pdf].

Cuddihy, L.W., & C.P. Stone. (1990). Alteration of native Hawai’ian vegetation: Effects of humans, their activities and introductions. University of Hawaii Cooperative National Park Resources Study Unit.

Department of Land and Natural Resources (2024). Hawai’i State Aha Moku. [https://dlnr.hawaii.gov/ahamoku/councils/].

Egler F.E. (1947). Arid Southeast Oahu Vegetation. Ecological Monographs 17:4.

Giambelluca, T.W., Q. Chen, A.G. Frazier, J.P. Price, Y.L. Chen, P.-S. Chu, J.K. Eischeid, & D.M. Delparte. (2013): Online rainfall atlas of Hawai’i. Bull. Amer. Meteor. Soc. 94, 313-316, DOI: [https://doi.org/10.1175/BAMS-D-11-00228.1].

Giambelluca, T.W., X. Shuai, M.L. Barnes, R.J. Alliss, R.J. Longman, T. Miura, Q. Chen, A.G. Frazier, R.G. Mudd, L. Cuo, & A.D. Businger. (2014). Evapotranspiration of Hawai’i. Final report submitted to the U.S. Army Corps of Engineers - Honolulu District, and the Commission on Water Resource Management, State of Hawai’i. [https://www.hawaii.edu/climate-data-portal/evapotranspiration-atlas/].

Handy, E.S.C., E.G. Handy, & Pukui, M.K. (First Edition 1972, Revised Edition 1991). Native planters in old Hawai’i: Their life, lore, and environment. Bishop Museum Press.

Henke, L.A. (1929). A survey of livestock in Hawai’i. Research Publication No. 5. University of Hawai’i, Honolulu. [https://www.ctahr.hawaii.edu/oc/freepubs/pdf/RP-5.pdf].

Juvik, J.O., & Nullett, D. (1993). A climate transect through tropical montane rain forests in Hawai’i. Department of Geography, University of Hawai’i at Hilo, Hilo Hawai’i. Journal of Applied Meteorology. Volume 33.

Kirch, P.V. (1982). The impact of the prehistoric Polynesians in the Hawai’ian ecosystem. Pacific Science 36 (1):1-14.

Kirch, P.V. (1983). Introduction. In Archaeological investigations of the Mudlane-Waimea-Kawaihae Road Corridor, Island of Hawai’i: An Interdisciplinary Study of an Environmental Transect. Clark, J.T. and Kirch, P.V., eds. Dept. of Anthropology, Bernice Pauahi Bishop Museum, Report 83-1, Honolulu, HI.

Leopold, L.B. (1949). The interaction of trade wind and sea breeze, Hawai’i. Journal of Meteorology 6: 312-320.

Malo, D. (1903). Hawaiian antiquities. N.B. Emerson (trans.). Bishop Museum Special Publication 2. Honolulu.

Sanderson, M. (ed.). (1993). Prevailing trade winds, weather and climate in Hawai’i. University of Hawai’i Press. Honolulu.

U.S. Department of Agriculture, Natural Resources Conservation Service. (2006). Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. United States Department of Agriculture, Agriculture Handbook 296. [https://www.nrcs.usda.gov/sites/default/files/2022-10/AgHandbook296_text_low-res.pdf].

U.S. Department of Agriculture, Soil Survey Conservation Service. (1972). Soil survey of Islands of Kauai, Oahu, Maui, Molokai, and Lanai, State of Hawai’i. Foote D.E., Hill E.L., Nakamura S., & F. Stephens, in cooperation with The University of Hawai’i Agricultural Experiment Station.

U. S. Department of Interior, Fish & Wildlife Service. (2023). Download seamless wetlands data by state. National Wetlands Inventory website. U.S. Department of the Interior, Fish and Wildlife Service, Washington, D.C. Accessed April 24, 2024. [https://www.fws.gov/program/national-wetlands-inventory/download-state-wetlands-data].

U.S. Department of Interior, Geological Survey. (2006). A Gap analysis of Hawai’i: February 2006 final report. National gap analysis program. [https://catalog.lib.uchicago.edu/vufind/Record/6329681/Details].

U.S. Department of Interior, Geological Survey. (2019). National Hydrography Dataset (NHD) – USGS national map downloadable data collection: USGS – National Geospatial Technical Operations Center (NGTOC). [https://www.usgs.gov/national-hydrography/access-national-hydrography-products].

Wagner, W.L., D.R. Herbst, & S.H. Sohmer. (1999). Manual of the flowering plants of Hawai’i, Revised Edition. Bishop Museum Press, Honolulu.

Western Regional Climate Center, (2020). Climate of Hawai’i. Available: [https://wrcc.dri.edu/Climate/narrative_hi.php].

DEFINITIONS

Alluvial: Materials or processes associated with transportation and/or deposition by running water.

Aridic soil moisture regime: A regime in which defined parts of the soil are, in normal years, dry for more than half of the growing season and moist for less than 90 consecutive days during the growing season. In Hawaii it is associated with hot, dry areas with plants such as kiawe, wili wili, and buffelgrass. The terms aridic and torric are basically the same.

Available water capacity: The amount of soil water available to plants to the depth of the first root-restricting layer.

CaCO3 equivalent: The amount of free lime in a soil. Free lime exists as solid material and typically occurs in regions with a dry climate.

Canopy cover: The percentage of ground covered by the vertical projection downward of the outermost perimeter of the spread of plant foliage. Small openings within the canopy are included.

Community pathway: A description of the causes of shifts between community phases. A community pathway is reversible and is attributable to succession, natural disturbances, short-term climatic variation, and facilitating practices, such as grazing management.

Community phase: A unique assemblage of plants and associated dynamic soil properties within a state.

Dominant species: Plant species or species groups that exert considerable influence upon a community due to size, abundance, or cover.

Drainage class: The frequency, duration, and depth of a water table in a soil. There are seven drainage classes, ranging from “excessively drained” (soils with very rare or very deep water tables) to “well drained” (soils that provide ample water for plant growth but are not so wet as to inhibit root growth) to “very poorly drained” (soils with a water table at or near the surface during much of the growing season that inhibits growth of most plants).

Electrical conductivity (EC): A measure of the salinity of a soil. The standard unit is deciSiemens per meter (dS/m), which is numerically equivalent to millimhos per centimeter (mmhos/cm). An EC greater than about 4 dS/m indicates a salinity level that is unfavorable to growth of most plants.

Ion exchange capacity: The ability of soil materials such as clay or organic matter to retain ions (which may be plant nutrients) and to release those ions for uptake by roots.

Isohyperthermic soil temperature regime: A regime in which mean annual soil temperature is 72 degrees F (22 degrees C) or higher and mean summer and mean winter soil temperatures differ by less than 11 degrees F (6 degrees C) at a specified depth.

Isomesic soil temperature regime: A regime in which mean annual soil temperature is 47 degrees F (8 degrees C) or higher but lower than 59 degrees F (15 degrees C) and mean summer and mean winter soil temperatures differ by less than 11 degrees F (6 degrees C) at a specified depth.

Isothermic soil temperature regime: A regime in which mean annual soil temperature is 59 degrees F (15 degrees C) or higher but lower than 72 degrees F (22 degrees C) and mean summer and mean winter soil temperatures differ by less than 11 degrees F (6 degrees C) at a specified depth.

Major Land Resource Area (MLRA): A geographic area defined by NRCS that is characterized by a particular pattern of soils, climate, water resources, and land uses. The island of Hawaii contains nine MLRAs, some of which also occur on other islands in the state.

Mollisols: Soils with relatively thick, dark surface horizons, high cation-exchange capacity, high calcium content, that do not become hard or very hard when dry. Mollisols are conducive to plant growth. They characteristically form under grass in climates that are seasonally dry, but can form under forests.

Naturalized plant community: A community dominated by adapted, introduced species. It is a relatively stable community resulting from secondary succession after disturbance. Most grasslands in Hawaii are in this category.

Parent material: Unconsolidated and chemically weathered material from which a soil is developed.

pH: The numerical expression of the relative acidity or alkalinity of a soil sample. A pH of 7 is neutral; a pH below 7 is acidic and a pH above 7 is basic.

Reference community phase: The phase exhibiting the characteristics of the reference state and containing the full complement of plant species that historically occupied the site. It is the community phase used to classify an ecological site.

Reference state: A state that describes the ecological potential and natural or historical range of variability of an ecological site.

Restoration pathway: A term describing the environmental conditions and practices that are required to recover a state that has undergone a transition.

Sodium adsorption ratio (SAR): A measure of the amount of dissolved sodium relative to calcium and magnesium in the soil water. SAR values higher than 13 create soil conditions unfavorable to most plants.

Soil moisture regime: A term referring to the presence or absence either of ground water or of water held at a tension of less than 1500 kPa (the crop wilting point) in the soil or in specific horizons during periods of the year.

Soil temperature regime: A defined class based on mean annual soil temperature and on differences between summer and winter temperatures at a specified depth.

Soil reaction: Numerical expression in pH units of the relative acidity or alkalinity or a soil.

State: One or more community phases and their soil properties that interact with the abiotic and biotic environment to produce persistent functional and structural attributes associated with a characteristic range of variability.

State-and-transition model: A method used to display information about relationships between vegetation, soil, animals, hydrology, disturbances, and management actions on an ecological site.

Transition: A term describing the biotic or abiotic variables or events that contribute to loss of state resilience and result in shifts between states.

Ustic soil moisture regime: A regime in which moisture is limited but present at a time when conditions are suitable for plant growth. In Hawaii it usually is associated with dry forests and subalpine shrublands.

Contributors

David Clausnitzer PhD
John Proctor
Carolyn Auweloa
Kendra Moseley
Amy Koch
Ann Tan
Sarah Quistberg
Jennifer Fedenko
Daniel Bowman

Approval

Kendra Moseley, 5/08/2025

Acknowledgments

Assistance, advice, review, and/or insights:

Randy Bartlett, Puu Kukui Watershed Preserve
Alison Cohan, The Nature Conservancy
Michael Constantinides, NRCS-PIA
Gordon Cran, Kapapala Ranch
Diana Crow, Ulupalakua Ranch
Lance DeSilva, Hawaii DLNR
Kerri Fay, Waikamoi Preserve, The Nature Conservancy
Alex Franco, Kaupo Ranch
Ranae Ganske-Cerizo, NRCS
Carl Hashimoto, NRCS
Bob Hobdy, consultant, Maui
Wallace Jennings, NRCS
Mike Kolman, NRCS
Jennifer Higashino, NRCS
Mel Johansen, The Nature Conservancy
Jordan Jokiel, Haleakala Ranch
David Leonard, volunteer
Penny Levin
Reese Libby, GIS - NRCS
Hannah Lutgen, Maui SWCD
Joseph May, NRCS
Scott Meidel, Haleakala Ranch
Anna Palomino, Hoolawa Farms Inc.
Jon Price, USGS
Tamara Sherrill, USFWS, Maui Nui Botanical Garden
Amber Starr, Hana Ranch
Kahana Stone, NRCS
Mark Vaught, Water Resources, Alexander & Baldwin
Jacqueline Vega, NRCS
Rich von Wellsheim, Whispering Bamboos, Kipahulu

Rangeland health reference sheet

Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.

Author(s)/participant(s)
Contact for lead author
Date	05/13/2025
Approved by	Kendra Moseley
Approval date
Composition (Indicators 10 and 12) based on	Annual Production

Indicators

Number and extent of rills:
Presence of water flow patterns:
Number and height of erosional pedestals or terracettes:
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Number of gullies and erosion associated with gullies:
Extent of wind scoured, blowouts and/or depositional areas:
Amount of litter movement (describe size and distance expected to travel):
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
Functional/Structural Groups (list in order of descending dominance by above-ground annual-production or live foliar cover using symbols: >>, >, = to indicate much greater than, greater than, and equal to):

Dominant:

Sub-dominant:

Other:

Additional:
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Average percent litter cover (%) and depth ( in):
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
Potential invasive (including noxious) species (native and non-native). List species which BOTH characterize degraded states and have the potential to become a dominant or co-dominant species on the ecological site if their future establishment and growth is not actively controlled by management interventions. Species that become dominant for only one to several years (e.g., short-term response to drought or wildfire) are not invasive plants. Note that unlike other indicators, we are describing what is NOT expected in the reference state for the ecological site:
Perennial plant reproductive capability:

Download reference sheet

Click on box and path labels to scroll to the respective text.

Ecosystem states

4. Shrub Invaded Grassland State

3. Native Forest State

States 1, 5 and 2 (additional transitions)