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Ecological site QX191X01X507

Very Poorly Drained Mucky Clay

Last updated: 6/12/2025
Accessed: 10/19/2025

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General information

Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.

MLRA notes

Major Land Resource Area (MLRA): 191X–High Limestone Plateaus of the Mariana Islands

This MLRA consists of the northern half of Guam and the islands of Saipan), Tinian, Rota, and Aguijan. Topography consists mostly of limestone plateaus. The highest elevations are 1,700 feet (520 meters) on Rota, 1,485 feet (450 meters) on Saipan, 655 feet (200 meters) on Tinian, and 860 feet (260 meters) in the northern part of Guam. The limestone plateaus were uplifted by tectonic activity. Deeply weathered volcanic rock is exposed on some ridges and slopes. Average annual rainfall is 100 inches (2,540 millimeters) on northern Guam and 80 inches (2,030 millimeters) on Saipan, Tinian, Aguijan, and Rota. The rainy season occurs from July through November; the dry season occurs from December through June. Trade winds blow from the northeast. Average annual temperature is 79 degrees F (26 degrees C). Typhoons are frequent. Soils are Alfisols, Andisols, Entisols, Mollisols, or Oxisols. The dominant soil moisture regime is ustic. The soil temperature regime is isohyperthermic. Native vegetation consists of mixed tropical hardwoods; introduced white leadtree or tangantangan trees (Leucaena leucocephala) are abundant. Introduced deer, pigs, goats, and water buffalo are common (USDA-NRCS, 2006). The main human disturbance is clearing land for cultivation. Feral pigs, feral cattle, brown tree snakes, stray dogs (Boonie dogs), and introduced deer are destructive to the native forest (Amand, 2000; CNMI SWARS Council, 2010; Donnegan et al., 2011; Liske-Clark, 2015; Willsey et al., 2019).

Classification relationships

This ecological site occurs within Major Land Resource Area (MLRA) 191 – High Limestone Plateaus of the Mariana Islands.

Ecological site concept

This ecological site occurs on the island of Guam in the Mariana Islands. It occurs on nearly level (0 to 3 percent slopes) coastal valley bottoms and plains at elevations ranging from 0 to 20 feet (0 to 6 meters). Note: all the Inarajan Variant delineations are right at the coast and mostly 0 to 10 feet elevation, some 0 to 20 feet, and to 40 feet in extremes of minor importance, according to soil map unit extents and the elevation isohyets.

Soils are very deep, very poorly drained Inceptisols (Vertic Endoaquepts) that formed in alluvium from mixed sources. Soil temperature regimes are isohyperthermic; soil moisture regimes are aquic. Saline groundwater occurs in large areas (EC is 2 to 8 mmhos/centimeters). Mean annual precipitation is about 90 inches (2,285 millimeters). Water runoff is very high, permeability slow. Available water-holding capacity is moderate (6 inches or 15 centimeters). The surface soil (2 inches or 5 centimeters deep) is mucky clay; beneath this is clay. The water table fluctuates between the soil surface and 18 inches (45 centimeters) below the soil surface. Flooding is frequent and brief during the rainy season. Most of the area is vegetated by wetland grasses and sedges and, in some locations, mangrove forests. The soils likely are inundated by ocean tides twice daily, as suggested by the Guam Soil Survey descriptions of flooding and ponding for this soil; however, the Soil Survey is not clear on this point (USDA-SCS, 1988).

Associated sites

QX191X01X503	Very Shallow to Moderately Deep Soils on Limestone Plateaus Soils of QX191X01X503 (The Very Shallow to Moderately Deep Soils on Limestone Plateaus Ecological Site) formed in fine materials over porous coralline or argillaceous limestone. Effective rooting depth is 8 to 26 inches, available water holding capacity is very low to low (2 to 3 inches), base saturation is high, pH is 6.5 to 7.9, and there is no aluminum toxicity. Areas not farmed are vegetated by mostly introduced grass, forb, and tree species, with some areas of native upland forest. Tangantangan (Leucaena leucocephala) is abundant in places. Soils of QX191XO1X507 (The Very Poorly Drained Mucky Clay Ecological Site) occurs on coastal valley bottoms and plains. Soils formed in alluvium from mixed sources, have aquic moisture regimes, the water table occurs between 0 and 18 inches (45 centimeters) below the soil surface, they have slightly to moderately saline ground water (2 to 8 mmhos/centimeters) and frequent flooding. Most of the area is vegetated by wetland grasses and sedges and, in some locations, mangrove forest.
QX191X01X505	Very Low Available Water Capacity Soils on Limestone Plateaus and Escarpments Soils of QX191X01X505 (The Very Low Available Water Capacity Soils on Limestone Plateaus and Escarpments Ecological Site) formed in fine materials over porous coralline limestone. Effective rooting depth is 2 to 16 inches (5 to 40 centimeters); available water holding capacity is very low (1 inch). Most of the area is vegetated by native forest. These soils are limited to an area that is often shrouded in clouds and fog. Moisture is added to the soil by fog drip, which maintains soils in moist condition most of the time. These soils are mostly forested with native species. Soils of QX191XO1X507 (The Very Poorly Drained Mucky Clay Ecological Site) occur on coastal valley bottoms and plains. Soils formed in alluvium from mixed sources, are very poorly drained, have aquic moisture regimes, the water table occurs between 0 and 18 inches (45 centimeters) below the soil surface, they have slightly to moderately saline ground water (2 to 8 mmhos/centimeters) and frequent flooding. Most of the area is vegetated by wetland grasses and sedges and, in some locations, mangrove forest.
QX192X01X501	Somewhat Poorly Drained Alluvium Soils of QX192X01X501 (The Somewhat Poorly Drained Alluvium Ecological Site) occur in stream channels, depressions, and seeps on volcanic uplands. The soils, which formed in alluvium from volcanic tuff and tuff breccia, are somewhat poorly drained, have effective rooting depths greater than 60 inches, high available water holding capacity, shallow water tables during the rainy season, and are rarely flooded. Most of the area is vegetated by wetland forest, grasses, and sedges. Soils of QX191XO1X507 (The Very Poorly Drained Mucky Clay Ecological Site) occur on coastal valley bottoms and plains. Soils formed in alluvium from mixed sources, are very poorly drained, have aquic moisture regimes, the water table occurs between 0 and 18 inches (45 centimeters) below the soil surface, they have slightly to moderately saline ground water (2 to 8 mmhos/centimeters), and frequent flooding. Most of the area is vegetated by wetland grasses and sedges and, in some locations, mangrove forest.
QX191X01X506	Somewhat Poorly and Poorly Drained Valley Bottoms and Coastal Plains Soils of QX191X01X506 (The Somewhat Poorly and Poorly Drained Valleys and Alluvial Coastal Plains Ecological Site) are in broad river valley bottoms and narrow coastal plains. Soils formed in alluvium or beach deposits, are somewhat poorly and poorly drained, have aquic moisture regimes, moderately deep (about 30 inches) water tables, and are occasionally flooded. Most of the area is vegetated by grasses, forbs, and wetland forest. Soils of QX191XO1X507 (The Very Poorly Drained Mucky Clay Ecological Site) occur on coastal valley bottoms and plains. Soils formed in alluvium from mixed sources, are very poorly drained, have aquic moisture regimes, the water table is between 0 and 18 inches (45 centimeters) below the soil surface, they have slightly to moderately saline ground water (2 to 8 mmhos/centimeters) and frequent flooding. Most of the area is vegetated by wetland grasses and sedges and, in some locations, mangrove forest.
QX192X01X003	Shallow Soils on Volcanic Uplands Soils of QX192X01X003 (The Shallow Soils on Volcanic Upland Ecological Site) are shallow (less than 15 inches), well drained Mollisols with very low (2 inches) available water holding capacity, high base saturation, and no aluminum toxicity that support upland grasses, forbs, and forest. Soils of QX191XO1X507 (The Very Poorly Drained Mucky Clay Ecological Site) occur on coastal valley bottoms and plains. Soils formed in alluvium from mixed sources, are very poorly drained, have aquic moisture regimes, the water table is between 0 and 18 inches (45 centimeters) below the soil surface, they have slightly to moderately saline ground water (2 to 8 mmhos/centimeters) and frequent flooding. Most of the area is vegetated by wetland grasses and sedges and, in some locations, mangrove forest.

Similar sites

QX191X01X005	Very Poorly Drained Muck Soils of QX191X01X005 (The Very Poorly Drained Muck Ecological Site) occur in depressions near sea level. They are very deep (greater than 72 inches) organic soils with fresh to saline groundwater (EC is 8 to 16 mmhos/centimeters) with a water table that occurs at soil surface (about 0 inches). Flooding is frequent, ponding is rare. Most of the area is vegetated by marsh grasses and, in a few locations, small stands of sea hibiscus (Hibiscus tiliaceus) or mangrove (Rhizophora spp.) forest. Soils of QX191XO1X507 (The Very Poorly Drained Mucky Clay Ecological Site) occur on coastal valley bottoms and plains. They formed in alluvium from mixed sources, are very poorly drained, have aquic moisture regimes, the water table is between 0 and 18 inches (45 centimeters) below the soil surface, they have slightly to moderately saline ground water (2 to 8 mmhos/centimeters) and frequent flooding. Most of the area is vegetated by wetland grasses and sedges and, in some locations, mangrove forest.

QX191X01X005

Very Poorly Drained Muck

Soils of QX191X01X005 (The Very Poorly Drained Muck Ecological Site) occur in depressions near sea level. They are very deep (greater than 72 inches) organic soils with fresh to saline groundwater (EC is 8 to 16 mmhos/centimeters) with a water table that occurs at soil surface (about 0 inches). Flooding is frequent, ponding is rare. Most of the area is vegetated by marsh grasses and, in a few locations, small stands of sea hibiscus (Hibiscus tiliaceus) or mangrove (Rhizophora spp.) forest. Soils of QX191XO1X507 (The Very Poorly Drained Mucky Clay Ecological Site) occur on coastal valley bottoms and plains. They formed in alluvium from mixed sources, are very poorly drained, have aquic moisture regimes, the water table is between 0 and 18 inches (45 centimeters) below the soil surface, they have slightly to moderately saline ground water (2 to 8 mmhos/centimeters) and frequent flooding. Most of the area is vegetated by wetland grasses and sedges and, in some locations, mangrove forest.

Table 1. Dominant plant species

Tree	(1) Rhizophora apiculata (2) Rhizophora mucronata
Shrub	Not specified
Herbaceous	(1) Acrostichum aureum

Legacy ID

F191XY507MP

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Physiographic features

This ecological site occurs in coastal mangrove swamps or what may have been mangrove swamps before human disturbance (USDA-SCS, 1988). According to the Guam Soil Survey, the soils are flooded frequently to a depth of about 18 inches (45 centimeters).

Table 2. Representative physiographic features

Landforms	(1) Coastal plain > Mangrove swamp
Runoff class	Very high
Flooding frequency	Frequent
Ponding frequency	None
Elevation	20 ft
Slope	3%
Water table depth	18 in
Aspect	Aspect is not a significant factor

Climatic features

Summary for this Ecological Site

Rainfall statistics were determined from PRISM rainfall raster data (PRISM, 2006). Representative (20th and 80th percentiles) values for mean annual precipitation range from 88 to 91 inches (2,235 to 2,310 millimeters) while actual (10th and 90th percentiles) values for mean annual precipitation range from 87 to 95 inches (2,210 to 2,415 millimeters). Extreme values range from 87 to 95 inches (2,210 to 2,415 millimeters). The mean annual precipitation is 90 inches (2,285 millimeters) and the median annual average precipitation is also 90 inches (2,285 millimeters).

Temperature statistics were determined from PRISM temperature raster data (PRISM, 2006) Representative (20th and 80th percentiles) values for mean annual temperatures range from 81 to 81 degrees F (27 to 27 degrees C) while actual (10th and 90th percentiles) values for mean annual temperatures also range from 81 to 81 degrees F (27 to 27 degrees C). Extreme values also range from 81 to 81 degrees F (27 to 27 degrees C). The average annual temperature is 81 degrees F (27 degrees C), and the median annual temperature is also 81 degrees F (27 degrees C).

The data presented in the climate normals tables below are from climate stations in Guam. I used the data from these stations because they are representative of the spatial distribution of this ecological site and because the values for mean annual precipitation (95 inches or 2,415 millimeters) and the mean annual temperature (81 degrees F or 27 degrees C) are reasonably comparable (e.g. mean annual precipitation is within 8 inches or 205 millimeters) to the PRISM values presented above.

General Principles

The climate is uniformly warm and humid throughout the year. Afternoon temperatures typically are about 86 degrees F (30 degrees C); nighttime temperatures are about 68 degrees F (20 degrees C). Relative humidity is 65 to 75 percent in the afternoon to 85 to 100 percent at night. Though temperature and humidity vary only slightly throughout the year, rainfall and wind conditions vary markedly. There are two main seasons, the dry season from December through June and the rainy season from mid-July to mid-November. Moisture deficit occurs between January and June. Mean annual rainfall ranges from about 98 inches (2,490 millimeters) on the windward (eastern) side of the higher mountains to about 79 inches (2,005 millimeters) along the coast of the western side of the islands. On average, about 15 percent of the annual rainfall occurs during the dry season and 55 percent during the rainy season (Fosberg, 1960; USDA-SCS, 1988; USDA-SCS, 1989).

Throughout the year, the dominant winds are the trade winds that blow from the east or northeast. The trade winds are strongest and most constant during the dry season, when windspeeds of 15 to 25 mph (25 to 40 kph) are common. Coastal areas that have east, and northeast exposures are subject to salt spray and buffeting winds (Fosberg, 1960; USDA-SCS, 1988; USDA-SCS, 1989).

During the rainy season the trade winds may break down and be replaced by a weak, westerly monsoon influence that brings heavy showers or steady and sometimes torrential rains. The islands lie in the path of typhoons from the southeast and east. They bring heavy rains and violent winds that may result in a surge of water onto low-lying coastal areas. They occur most frequently during the latter half of the year. The chance of having one or more typhoons pass close to the islands in any particular year is about once in three years. The chance of having a typhoon move directly across an island is about once in eight years (Fosberg, 1960; USDA-SCS, 1988; USDA-SCS, 1989).

Table 3. Representative climatic features

Frost-free period (characteristic range)	365 days
Freeze-free period (characteristic range)	365 days
Precipitation total (characteristic range)	88-91 in
Frost-free period (actual range)	365 days
Freeze-free period (actual range)	365 days
Precipitation total (actual range)	87-95 in
Frost-free period (average)	365 days
Freeze-free period (average)	365 days
Precipitation total (average)	90 in

Characteristic range

Actual range

Bar

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Figure 1. Monthly precipitation range

Characteristic range

Actual range

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Figure 2. Monthly minimum temperature range

Characteristic range

Actual range

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Figure 3. Monthly maximum temperature range

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Figure 4. Monthly average minimum and maximum temperature

Figure 5. Annual precipitation pattern

Figure 6. Annual average temperature pattern

Climate stations used

(1) GUAM INTL AP [GQW00041415], GU
(2) ANDERSEN AFB GUAM [GQC00914025], GU

Soil features

One soil is associated with this ecological site, Inarajan Variant (Inceptisols).

It is a poorly drained Vertic Endoaquepts. There is a 2 inch (5 centimeter) thick surface horizon of mucky clay overlying very deep clay derived from alluvium from mixed sources. The soil temperature regime is isohypothermic (very warm) with a mean temperature of 80 degrees F (27 degrees C). The soil moisture regime is aquic. There are many areas with saline ground water (EC is 2 to 8 mmhos/centimeter) (USDA-SCS, 1988).

Table 4. Representative soil features

Parent material	(1) Alluvium
Surface texture	(1) Mucky clay
Family particle size	(1) Very-fine
Drainage class	Very poorly drained
Permeability class	Slow
Depth to restrictive layer	72 in
Soil depth	72 in
Surface fragment cover <=3"	Not specified
Surface fragment cover >3"	Not specified
Available water capacity (0-40in)	4.8 – 6 in
Calcium carbonate equivalent (0-40in)	Not specified
Electrical conductivity (0-40in)	2 – 8 mmhos/cm
Sodium adsorption ratio (0-40in)	Not specified
Soil reaction (1:1 water) (0-10in)	5.3 – 5.9
Subsurface fragment volume <=3" (0-40in)	Not specified
Subsurface fragment volume >3" (0-40in)	Not specified

Ecological dynamics

Mangrove swamps occur primarily on coastal areas protected by reefs, headlands, or offshore islands; they may occur in river mouths where fresh water enters ocean. They establish on mudflats, estuaries, and sheltered lagoons where sedimentation is occurring in places to which their seeds or sprouted seedlings can reach by floating in the water (Fosberg, 1960; Marshall et al., 2020; Plentovich et al., 2020; Stemmermann, 1981; Stone, 1970; Wagner and Grether, 1948; Willsey et al., 2019).

The main natural disturbance is strong storms that can damage and kill mangrove trees. The main human disturbances are wood harvesting and filling to claim areas for building construction (Fosberg, 1960; Marshall et al., 2020; Plentovich et al., 2020; Stemmermann, 1981; Stone, 1970; Wagner and Grether, 1948; Willsey et al., 2019).

Only small areas of mangrove forest remain in the Mariana Islands, mostly on Guam. It is likely that the extent of mangrove forests has been greatly reduced since the arrival of humans in the islands, having been replaced by vegetation composed largely of introduced species or filled to create urban land (Fosberg, 1960; Marshall et al., 2020; Plentovich et al., 2020; Stemmermann, 1981; Stone, 1970; Wagner and Grether, 1948; Willsey et al., 2019).

State and transition model

Custom diagram

Standard diagram

Figure 7. State-and-Transition Model for F191XY507MP (Very Poorly Drained Mucky Clay).

More interactive model formats are also available. View Interactive Models

More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective text

Ecosystem states

1. Reference State

2. Landfilled State

3. Invaded State

T1A	-	The Reference State (1) transitions to the Landfilled State (2) by intentional filling of the swamp to produce construction sites.
T1B	-	The Reference State (1) transitions to the Invaded State (3) with long-term, severe human disturbance such as land clearing or removal of large amounts of wood. Introduced plant species can invade these sites and maintain themselves for long periods of time.
R3A	-	The Invaded State (3) can be resotred back to the Reference State (1). Mangrove forests have been restored to suitable habitats in many places in the world. Replanting of mangrove trees and control of weedy species are necessary.
T3A	-	The Invaded State (3) transitions to the Landfilled State (2) by intentional filling of the swamp to produce construction sites.

State 1 submodel, plant communities

1.1. Mangrove – Asiatic Mangrove/Golden Leatherfern

1.2. Embrert/Golden Leatherfern

1.1A	-	Community phase 1.1 shifts to phase 1.2 due to heavy damage and tree mortality from storms or overharvesting of wood.
1.2A	-	Community phase 1.2 reverts to phase 1.1 with gradual regrowth of mangroves when given adequate time to recover after disturbance.

State 2 submodel, plant communities

2.1. Urban Development

State 3 submodel, plant communities

3.1. Nipa Palm/Golden Leatherfern/Knotgrass

State 1
Reference State

The Reference State (1) consists of two community phases occurring in brackish to saline water at the coast. One phase is dominated by dense stands of mangrove trees (Fosberg, 1960; Marshall et al., 2020; Plentovich et al., 2020; Stemmermann, 1981; Stone, 1970; Wagner and Grether, 1948; Willsey et al., 2019). Storms or intensive wood harvest that destroy small to large patches of the forest may be recolonized initially by the shrub embrert (Clerodendrum inerme) and golden leatherfern (Acrostichum aureum) before transitioning back to mangrove forest (Fosberg, 1960; Marshall et al., 2020; Plentovich et al., 2020; Stemmermann, 1981; Stone, 1970; Wagner and Grether, 1948; Willsey et al., 2019).

Community 1.1
Mangrove – Asiatic Mangrove/Golden Leatherfern

Common trees in the community phase are mangrove or tall-stilt mangrove (Rhizophora apiculata), Asiatic mangrove (Rhizophora mucronata), Oriental mangrove (Bruguiera gymnorhiza), Xylocarpus moluccensis, Heritiera littoralis, and Lumnitzera littorea. Where enough light reaches the surface there may be golden leatherferns (Fosberg, 1960; Marshall et al., 2020; Plentovich et al., 2020; Stemmermann, 1981; Stone, 1970; Wagner and Grether, 1948; Willsey et al., 2019).

Dominant plant species

mangrove (Rhizophora apiculata), tree
Asiatic mangrove (Rhizophora mucronata), tree
golden leatherfern (Acrostichum aureum), other herbaceous

Community 1.2
Embrert/Golden Leatherfern

Community phase 1.2 may be dominated by the native shrub embrert (Clerodendrum inerme) and stands of golden leatherfern (Acrostichum aureum) (Fosberg, 1960; Marshall et al., 2020; Plentovich et al., 2020; Stemmermann, 1981; Stone, 1970; Wagner and Grether, 1948; Willsey et al., 2019).

Dominant plant species

embrert (Clerodendrum inerme), shrub
golden leatherfern (Acrostichum aureum), other herbaceous

Pathway 1.1A
Community 1.1 to 1.2

Community phase 1.1 shifts to phase 1.2 due to heavy damage and tree mortality from storms or overharvesting of wood.

Pathway 1.2A
Community 1.2 to 1.1

Community phase 1.2 reverts to phase 1.1 with gradual regrowth of mangroves when given adequate time to recover after disturbance.

State 2
Landfilled State

The Landfilled State (2) consists of filled land occupied by buildings (Fosberg, 1960; Marshall et al., 2020; Plentovich et al., 2020; Stemmermann, 1981; Stone, 1970; Wagner and Grether, 1948; Willsey et al., 2019).

Community 2.1
Urban Development

The hydrologic conditions of mangrove swamp have been obliterated. Vegetation consists of weedy or intentionally planted species (Fosberg, 1960; Marshall et al., 2020; Plentovich et al., 2020; Stemmermann, 1981; Stone, 1970; Wagner and Grether, 1948; Willsey et al., 2019).

State 3
Invaded State

The Invaded State (3) was probably mangrove forest in the past, but extreme disturbance by humans, invasion by introduced species, and minimal availability of mangrove propagules has resulted in vegetation lacking or largely lacking mangroves. Competitive introduced species have established and now dominate (Fosberg, 1960; Marshall et al., 2020; Plentovich et al., 2020; Stemmermann, 1981; Stone, 1970; Wagner and Grether, 1948; Willsey et al., 2019).

Community 3.1
Nipa Palm/Golden Leatherfern/Knotgrass

Community phase 3.1 is often dominated by nipa palm (Nypa fruticans), generally considered to be an introduced species. Stands of golden leatherfern (Acrostichum aureum) may persist. Introduced grasses such as knotgrass (Paspalum distichum) can cover large areas. Areas with very low salinity may also support dense stands of tall reed (Phragmites karka), a native species, and common bamboo (Bambusa vulgaris), an introduced species (Fosberg, 1960; Marshall et al., 2020; Plentovich et al., 2020; Stemmermann, 1981; Stone, 1970; Wagner and Grether, 1948; Willsey et al., 2019).

Dominant plant species

nipa palm (Nypa fruticans), tree
knotgrass (Paspalum distichum), grass
golden leatherfern (Acrostichum aureum), other herbaceous

Transition T1A
State 1 to 2

The Reference State (1) transitions to the Landfilled State (2) by intentional filling and altering the hydrology of the sites.

Transition T1B
State 1 to 3

The Reference State (1) transitions to the Invaded State (3) with long-term, severe human disturbance such as land clearing or removal of large amounts of wood. Introduced plant species can invade these sites and maintain themselves for long periods of time.

Restoration pathway R3A
State 3 to 1

The Invaded State (3) can be restored back to the Reference State (1). Mangrove forests have been restored to suitable habitats in many places in the world. Replanting mangrove trees and controlling weedy species are necessary.

Transition T3A
State 3 to 2

The Invaded State (3) transitions to the Landfilled State (2) by intentional filling and altering the hydrology of the sites.

Additional community tables

Supporting information

Other references

References for QX191X01X507 (The Very Poorly Drained Mucky Clay Ecological Site)

Amand, A. (2000). Boiga irregularis (Brown Tree Snake) on Guam and Its Effect on Fauna. Restoration and Reclamation Review, 6 1-6.

CNMI SWARS Council. (2010). Commonwealth of the Northern Mariana Islands (CNMI) Statewide Assessment and Resource Strategy 2010-2015+. CNMI Forestry. Contains good information about fire, invasive species, reforestation, and badlands.

Donnegan, J. A., Butler, S. L., Kuegler, O., Hiserote, B. A. (2011). Commonwealth of the Northern Mariana Islands’ Forest resources, 2004. Resource. Bull. PNW-RB-261. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 40 p. Forest survey based on randomized plots. Contains species lists by vegetation type, some soil and disturbance information, and size and cover data.

Federal Geographic Data Committee. (2019). Wetlands and Deepwater Habitats Classification Map Code Diagram.

Fosberg, F. R. (1960). The Vegetation of Micronesia. I. General descriptions, the vegetation of the Marianas Islands, and a detailed consideration of the vegetation of Guam. Bulletin of the American Museum of Natural History 199:1.

Liske-Clark, J. (2015). Wildlife Action Plan for the Commonwealth of the Northern Mariana Islands, 2015-2025. CNMI DLRN-Division of Fish and Wildlife, Saipan, MP. Extensive review of habitat types with their plant species; discusses disturbances, invasive species.

Marshall, A. P., Willsey, T., Reeves, M., Amidon, F., Miller, S., (2020). Wetlands of the Mariana Islands. In: Goldstein, M. I., DellaSala, D. A. (Eds.), Encyclopedia of the World's Biomes, vol. 4. Elsevier, pp. 295–315.

Plentovich, S., Mizerek, T., Reeves, M. K., Amidon, F., Miller, S.E., Nanbara, M., (2020). Coastal Strand and Mangrove Swamps of the Mariana Islands. In: Goldstein, M.I., DellaSala, D.A. (Eds.), Encyclopedia of the World's Biomes, vol. 1. Elsevier, pp. 185–197.

PRISM Climate Group, Oregon State University. (2006). https://prism.oregonstate.edu, data created 4 Feb 2014, accessed 09 Oct 2024. Pacific Islands Project: Average monthly precipitation, minimum and maximum temperature, relative humidity, and mean dew point temperature for the period 1971-2000 (completed 2006). Covers Hawaii, Kosrae, Manua, Pohnpei, Tutuila, Guam, CNMI, and Palau. Project sponsored by USDA Natural Resources Conservation Service.

Stemmermann, L. (1981). A Guide to Pacific Wetland Plants. US Army Corps of Engineers, Honolulu District.

Stone, B. C. (1970). The Flora of Guam. A Manual for the Identification of the Vascular Plants of the Island. Micronesica – Journal of the University of Guam, vol. 6, July 1970.

USDA-NRCS. (2006). Major Land Resource Regions. USDA Agriculture Handbook 296. http://soils.usda.gov/MLRAExplorer

USDA-SCS. (1988). Soil Survey of Territory of Guam.

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

Wagner, W. H. and Grether, D. F. (1948). The Pteridophytes of Guam. Occasional Papers of Bernice P. Bishop Museum, volume XIX, number 2. Honolulu, Hawaii.

Willsey, T., Kwon, J. A., Reeves, M. K., Amidon, F., and Miller, S. E. (2019). Mariana Islands Forest. Encyclopedia of the World's Biomes. https://doi.org/10.1016\B978-0-12-409548-9.12012-3

Contributors

David Clausnitzer, PhD
John Proctor
Ann Tan
Daniel Bowman
Amy Koch
Kendra Mosely
Daniel Block
Jill Ficke-Beaton
Brendan Brazee

Approval

Kendra Moseley, 6/12/2025

Acknowledgments

Assistance, advice, review, and/or insights:

Michael Constantinides, NRCS-PIA
Jennifer Higashino, USFWS and NRCS
Mike Kolman, NRCS
Bart Lawrence, NRCS
Pamela Sablan, NRCS
Jay Doronila, NRCS
Carolyn Auweloa, NRCS

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	06/21/2025
Approved by	Kendra Moseley
Approval date
Composition (Indicators 10 and 12) based on	Annual Production