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Ecological site QX191X01X005

Very Poorly Drained Muck

Last updated: 8/19/2025
Accessed: 09/14/2026

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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 islands of Saipan and Tinian in the Mariana Islands. It occurs in nearly level (0 to 2 percent slopes) depressions at elevations ranging from 0 to 16 feet (0 to 5 meters) (Amidon et al., 2017; Liu and Fischer, 2008; USDA-SCS, 1989).

Soils are very deep, very poorly drained Histisols (Terric Haplosaprists) that are formed in marine deposits, alluvium, and organic material. Soil temperature regimes are isohyperthermic; soil moisture regimes are aquic. Average annual rainfall is about 74 inches (1,880 millimeters) (PRISM, 2006). Water runoff is negligible; permeability is moderate. Effective rooting depth is greater than 72 inches (180 centimeters). Available water-holding capacity is about 7 inches (18 centimeters). The surface soil (8 inches or 20 cm deep) is muck; beneath this is mucky clay loam; below this is gravelly sandy loam. Groundwater varies from fresh to saline (EC 8 to 16 dS/m) depending on location. The permanent water table is at ground level most of the year. Flooding is frequent and very brief. Ponding is rare and very brief (USDA-SCS, 1989). Most of the area is vegetated by marsh grasses and, in a few locations, small stands of hibiscus (Hibiscus tiliaceus) or mangrove (Rhizophora spp.) forest. Much of this ecological site occurs around Lake Susupe on Saipan (Fosberg, 1960; USDA-SCS, 1989).

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 high (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. White leadtree or tangantangan (Leucaena leucocephala) is abundant in places. Soils of QX191X01X005 (The Very Poorly Drained Muck Ecological Site) occurs in depressions near sea level. Soils are very deep (greater than 72 inches) organic soils with fresh to saline groundwater that is at the soil surface. Flooding is frequent; ponding is rare. Most of the area is vegetated by marsh grasses and, in a few locations, small stands of hibiscus (Hibiscus tiliaceus) or mangrove (Rhizophora spp.) forest.
QX191X01X501	Excessively and Somewhat Excessively Drained Coastal Strand Soils of QX191X01X501 (The Excessively Drained Coastal Strand Ecological Site) formed in coral sand near the sea and fine materials over limestone where it borders inland limestone plateaus and escarpments. Effective rooting depth is 6 to greater than 72 inches; available water holding capacity is very low to low (0 to 3 inches). Windborne salt spray and rare flooding by seawater affect the entire area. Vegetation is mostly native forest. Soils of QX191X01X005 (The Very Poorly Drained Muck Ecological Site) occurs in depressions near sea level. Soils are very deep (greater than 72 inches) organic soils with fresh to saline groundwater that is at the soil surface. Flooding is frequent; ponding is rare. Most of the area is vegetated by marsh grasses and, in a few locations, small stands of hibiscus (Hibiscus tiliaceus) or mangrove (Rhizophora spp.) forest.
QX191X01X502	Deep and Very Deep Soils on Limestone Plateaus Soils of F191XY502MP (Deep and Very Deep Soils on Limestone Plateaus) formed in fine materials over porous coralline or argillaceous limestone. Effective rooting depth is 47 to 72 inches or deeper and available water holding capacity is low (4 to 5 inches). Most of this ecological site is used for farmland; areas not farmed are vegetated by mostly introduced grass, forb, and tree species. White leadtree or tangantangan (Leucaena leucocephala) is abundant in places. Soils of QX191X01X005 (The Very Poorly Drained Muck Ecological Site) occurs in depressions near sea level. Soils are very deep (greater than 72 inches) organic soils with fresh to saline groundwater that is at the soil surface. Flooding is frequent; ponding is rare. Most of the area is vegetated by marsh grasses and, in a few locations, small stands of hibiscus (Hibiscus tiliaceus) or mangrove (Rhizophora spp.) forest.

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 high (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. White leadtree or tangantangan (Leucaena leucocephala) is abundant in places. Soils of QX191X01X005 (The Very Poorly Drained Muck Ecological Site) occurs in depressions near sea level. Soils are very deep (greater than 72 inches) organic soils with fresh to saline groundwater that is at the soil surface. Flooding is frequent; ponding is rare. Most of the area is vegetated by marsh grasses and, in a few locations, small stands of hibiscus (Hibiscus tiliaceus) or mangrove (Rhizophora spp.) forest.

QX191X01X501

Excessively and Somewhat Excessively Drained Coastal Strand

Soils of QX191X01X501 (The Excessively Drained Coastal Strand Ecological Site) formed in coral sand near the sea and fine materials over limestone where it borders inland limestone plateaus and escarpments. Effective rooting depth is 6 to greater than 72 inches; available water holding capacity is very low to low (0 to 3 inches). Windborne salt spray and rare flooding by seawater affect the entire area. Vegetation is mostly native forest. Soils of QX191X01X005 (The Very Poorly Drained Muck Ecological Site) occurs in depressions near sea level. Soils are very deep (greater than 72 inches) organic soils with fresh to saline groundwater that is at the soil surface. Flooding is frequent; ponding is rare. Most of the area is vegetated by marsh grasses and, in a few locations, small stands of hibiscus (Hibiscus tiliaceus) or mangrove (Rhizophora spp.) forest.

QX191X01X502

Deep and Very Deep Soils on Limestone Plateaus

Soils of F191XY502MP (Deep and Very Deep Soils on Limestone Plateaus) formed in fine materials over porous coralline or argillaceous limestone. Effective rooting depth is 47 to 72 inches or deeper and available water holding capacity is low (4 to 5 inches). Most of this ecological site is used for farmland; areas not farmed are vegetated by mostly introduced grass, forb, and tree species. White leadtree or tangantangan (Leucaena leucocephala) is abundant in places. Soils of QX191X01X005 (The Very Poorly Drained Muck Ecological Site) occurs in depressions near sea level. Soils are very deep (greater than 72 inches) organic soils with fresh to saline groundwater that is at the soil surface. Flooding is frequent; ponding is rare. Most of the area is vegetated by marsh grasses and, in a few locations, small stands of hibiscus (Hibiscus tiliaceus) or mangrove (Rhizophora spp.) forest.

Similar sites

QX191X01X507	Very Poorly Drained Mucky Clay Soils of QX191X01X507 (The Very Poorly Drained Mucky Clay Ecological Site) occur on coastal valley bottoms and plains. Soils formed in alluvium from mixed sources. The surface soil (2 inches deep) is mucky clay; beneath this is clay. Soils have water tables that fluctuate between 0 to 18 inches, 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 (Rhizophora spp.) forest. Soils of QX191X01X005 (The Very Poorly Drained Muck Ecological Site) occurs in depressions near sea level. Soils are very deep (greater than 72 inches) organic soils with fresh to saline groundwater that is at the soil surface. Flooding is frequent; ponding is rare. Most of the area is vegetated by marsh grasses and, in a few locations, small stands of hibiscus (Hibiscus tiliaceus) or mangrove (Rhizophora spp.) forest.

QX191X01X507

Very Poorly Drained Mucky Clay

Soils of QX191X01X507 (The Very Poorly Drained Mucky Clay Ecological Site) occur on coastal valley bottoms and plains. Soils formed in alluvium from mixed sources. The surface soil (2 inches deep) is mucky clay; beneath this is clay. Soils have water tables that fluctuate between 0 to 18 inches, 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 (Rhizophora spp.) forest. Soils of QX191X01X005 (The Very Poorly Drained Muck Ecological Site) occurs in depressions near sea level. Soils are very deep (greater than 72 inches) organic soils with fresh to saline groundwater that is at the soil surface. Flooding is frequent; ponding is rare. Most of the area is vegetated by marsh grasses and, in a few locations, small stands of hibiscus (Hibiscus tiliaceus) or mangrove (Rhizophora spp.) forest.

Table 1. Dominant plant species

Tree	(1) Hibiscus tiliaceus
Shrub	Not specified
Herbaceous	(1) Phragmites karka (2) Acrostichum aureum

Legacy ID

R191XY005MP

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Physiographic features

This ecological site consists of marshes occurring in depressions or on coastal plains and valleys (USDA-SCS, 1989).

Table 2. Representative physiographic features

Landforms	(1) Coastal plain > Marsh (2) Coastal plain > Depression (3) Coastal plain > Valley
Runoff class	Very low
Flooding frequency	Frequent
Ponding frequency	Rare
Elevation	0 – 16 ft
Slope	0 – 2 %
Ponding depth	0 – 12 in
Water table depth	0 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 74 to 75 inches (1,880 to 1,905 millimeters) while actual (10th and 90th percentiles) values for mean annual precipitation range from 70 to 76 inches (1,790 to 1,930 millimeters). Extreme values range from 69 to 76 inches (1,750 to 1,930 millimeters). The mean annual precipitation is 74 inches (1,880 millimeters) and the median annual average precipitation is also 75 inches (1,905 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 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 a climate station in Saipan. I used the data from this station because it is representative of the spatial distribution of this ecological site. However, the climate station value for mean annual precipitation (100 inches or 2,540 millimeters) is much higher than the PRISM data value for mean annual precipitation (74 inches or 1,880 millimeters).

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)	370 days
Freeze-free period (characteristic range)	370 days
Precipitation total (characteristic range)	70-80 in
Frost-free period (actual range)	370 days
Freeze-free period (actual range)	370 days
Precipitation total (actual range)	70-80 in
Frost-free period (average)	370 days
Freeze-free period (average)	370 days
Precipitation total (average)	70 in

Characteristic range

Actual range

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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) CAPITOL HILL 1 [CQC00914080], MP

Influencing water features

Number of National Wetland Inventory (NWI) features overlapping ecological site: Freshwater emergent wetland (49), freshwater forest/shrub wetland (39), freshwater pond (26), estuarine and marine wetland (4), riverine (4), and lake (1) (USFWS, 2023).

Soil features

Soils associated with this ecological site are all Mesei Variant which is in the Histisol soil order. They are very deep (greater than 72 inches), very poorly drained Terric Haplosaprists that formed in deposits of organic material overlying alluvial sediment. Soil temperature regimes are isohypothermic (very warm); soil moisture regimes are aquic. They exhibit a wide range of salinity as indicated by their electrical conductivity (8 to 16 dS/m). Because only one delineation occurs right at the coast and the Soil Survey indicates that tall reed (Phragmites karka), a fresh to brackish water species, is the dominant vegetation in most locations, it is likely that most of this ecological site has salinity levels at the low range of the indicated electrical conductivity. Another indicator is that much of this site was cultivated for rice, swamp taro, and coco yam (USDA-SCS, 1989).

Table 4. Representative soil features

Parent material	(1) Organic material (2) Alluvium
Surface texture	(1) Mucky
Family particle size	(1) Loamy-skeletal
Drainage class	Very poorly drained
Permeability class	Moderate
Depth to restrictive layer	72 in
Soil depth	72 in
Surface fragment cover <=3"	8 %
Surface fragment cover >3"	Not specified
Available water capacity (0-40in)	5.7 – 7.6 in
Calcium carbonate equivalent (0-40in)	Not specified
Electrical conductivity (0-40in)	8 – 16 mmhos/cm
Sodium adsorption ratio (0-40in)	Not specified
Soil reaction (1:1 water) (0-40in)	4.5 – 6.2
Subsurface fragment volume <=3" (0-40in)	37 %
Subsurface fragment volume >3" (0-40in)	5 %

Ecological dynamics

These coastal marshes occur on low areas dominated by herbaceous hydrophytic vegetation and saturated with fresh or brackish water. They appear to be separated from the sea by low ridges or littoral or alluvium deposits except for one site on Saipan that adjoins the sea (Amidon et al., 2017; CNMI SWARS Council, 2010; Donnegan et al., 2011; Falanruw et al., 1989; Fosberg, 1960; Kuo and Berry, 2018; Liske-Clark, 2015; Marshall et al., 2020; Plentovich et al., 2020; Wagner and Grether, 1948; Willsey et al., 2019).

The main natural disturbance is strong storms that can damage vegetation and possibly bring seawater into the marsh. The effects of seawater incursion will gradually diminish. The main human disturbances are filling to claim areas for building construction, replacement of native vegetation by crops, and weed invasion after abandonment of agriculture (Amidon et al., 2017; CNMI SWARS Council, 2010; Donnegan et al., 2011; Falanruw et al., 1989; Fosberg, 1960; Kuo and Berry, 2018; Liske-Clark, 2015; Marshall et al., 2020; Plentovich et al., 2020; Wagner and Grether, 1948; Willsey et al., 2019).

State and transition model

Custom diagram

Standard diagram

Figure 7. State-and-Transition Model for R191XY005MP (The Very Poorly Drained Muck Ecological Site)

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Click on state and transition labels to scroll to the respective text

Ecosystem states

T1A	-	The Reference State (1) transitions to the Cultivated State (2) through the removal of native vegetation and planting rice (Oryza sativa), swamp taro (Cyrtosperma chamissonia), or coco yam (Colocasia esculenta).
T1B	-	The Reference State (1) transitions to the Landfilled State (4) by intentional filling of a marsh to create construction sites.
T2A	-	The Cultivated State (2) transitions to the Abandoned State (3) with the abandonment of agricultural fields, which are quickly invaded by native or introduced species.
T2B	-	The Cultivated State (2) transitions to the Landfilled State (4) by intentional filling of cropland to create construction sites.
R3A	-	The Abandoned State (3) can be restored the Cultivated State (2) by weed removal and resumption of crop cultivation.
T3A	-	The Abandoned State (3) transitions to the Landfilled State (4) by intentional filling to create construction sites.

State 1 submodel, plant communities

1.1. Sea Hibiscus/Tall Reed/Golden Leatherfern

1.2. Tall Reed/Knotgrass

1.1A	-	Community phase 1.1 changes to phase 1.2 due to damage to native vegetation stands by storms.
1.2A	-	Community phase 1.2 may revert to phase 1.1 with gradual regrowth of dominant native species when given adequate time to recover after disturbance. However, it is likely that some introduced species will remain.

State 1
Reference State

The Reference State (1) consists of two community phases dominated by wetland vegetation.

Storms that disturb or kill native vegetation can bring a rapid phase change from 1.1, which has all native species, to 1.2, which has a mix of native and introduced species.

Community 1.1
Sea Hibiscus/Tall Reed/Golden Leatherfern

The dominant species in this community are thicket-forming sea hibiscus (Hibiscus tiliaceus), dense stands of tall reed (Phragmites karka), and golden leatherfern (Acrostichum aureum). One small area currently supports Oriental mangrove (Bruguiera gymnorhiza). Also present are the native shrub embrert (Clerodendrum inerme) and the bulrush (Schoenoplectus subulatus). Eleocharis melanostachys and shoreline sea purslane (Sesuvium portulacastrum) occur in areas of higher salinity.

Dominant plant species

sea hibiscus (Hibiscus tiliaceus), tree
tall reed (Phragmites karka), grass
golden leatherfern (Acrostichum aureum), other herbaceous

Community 1.2
Tall Reed/Knotgrass

The dominant species in this community are tall reed (Phragmites karka) and knotgrass (Paspalum distichum), an introduced species. Sea hibiscus (Hibiscus tiliaceus) and golden leatherfern (Acrostichum aureum) may be present also (Amidon et al., 2017; CNMI SWARS Council, 2010; Donnegan et al., 2011; Falanruw et al., 1989; Fosberg, 1960; Kuo and Berry, 2018; Liske-Clark, 2015; Marshall et al., 2020; Plentovich et al., 2020; Wagner and Grether, 1948; Willsey et al., 2019).

Dominant plant species

tall reed (Phragmites karka), grass
knotgrass (Paspalum distichum), grass

Pathway 1.1A
Community 1.1 to 1.2

Community phase 1.1 changes to phase 1.2 due to damage to native vegetation stands by storms.

Pathway 1.2A
Community 1.2 to 1.1

Community phase 1.2 may revert to phase 1.1 with gradual regrowth of dominant native species when given adequate time to recover after disturbance. However, it is likely that some introduced species will remain.

State 2
Cultivated State

The Cultivated State (2) consists of one community phase that has been cleared of vegetation and cultivated.

Community 2.1
Rice/Swamp Taro – Coco Yam

This community phase consists of cultivated rice (Oryza spp.), swamp taro (Cyrtosperma chamissonis), or coco yam (Colocasia esculenta) (Amidon et al., 2017; CNMI SWARS Council, 2010; Donnegan et al., 2011; Falanruw et al., 1989; Fosberg, 1960; Kuo and Berry, 2018; Liske-Clark, 2015; Marshall et al., 2020; Plentovich et al., 2020; Wagner and Grether, 1948; Willsey et al., 2019).

Dominant plant species

rice (Oryza), grass
swamp taro (Cyrtosperma chamissonis), other herbaceous
coco yam (Colocasia esculenta), other herbaceous

State 3
Abandoned State

The Abandoned State (3) consists of one community phase dominated by native or introduced plant species.

Dominant plant species

sea hibiscus (Hibiscus tiliaceus), tree
tall reed (Phragmites karka), grass
para grass (Urochloa mutica), grass

Community 3.1
Sea Hibiscus/Tall Reed - Para Grass

This community phase typically is dominated by native sea hibiscus (Hibiscus tiliaceus) and tall reed (Phragmites karka) along with introduced para grass (Urochloa mutica) (Amidon et al., 2017; CNMI SWARS Council, 2010; Donnegan et al., 2011; Falanruw et al., 1989; Fosberg, 1960; Kuo and Berry, 2018; Liske-Clark, 2015; Marshall et al., 2020; Plentovich et al., 2020; Wagner and Grether, 1948; Willsey et al., 2019).

Dominant plant species

sea hibiscus (Hibiscus tiliaceus), tree
tall reed (Phragmites karka), grass
para grass (Urochloa mutica), grass

State 4
Landfilled State

The Landfilled State (4) consists of filled land occupied by buildings.

Community 4.1
Urban Use

The hydrologic conditions of the marsh have been obliterated. Vegetation consists of weedy and intentionally planted species.

Transition T1A
State 1 to 2

The Reference State (1) transitions to the Cultivated State (2) through the removal of native vegetation and planting rice (<a class="species-link" href="https://plants.usda.gov/core/profile?symbol=ORSA" target="_blank" title="Open in plants.usda.gov">Oryza sativa</a>), swamp taro (<a class="species-link" href="https://plants.usda.gov/core/profile?symbol=CYCH7" target="_blank" title="Open in plants.usda.gov">Cyrtosperma chamissonis</a>), or coco yam (<a class="species-link" href="https://plants.usda.gov/core/profile?symbol=COES" target="_blank" title="Open in plants.usda.gov">Colocasia esculenta</a>).

Transition T1B
State 1 to 4

The Reference State (1) transitions to the Landfilled State (4) by intentional filling of a marsh to create construction sites.

Transition T2A
State 2 to 3

The Cultivated State (2) transitions to the Abandoned State (3) with the abandonment of agricultural fields, which are quickly invaded by native or introduced species.

Transition T2B
State 2 to 4

The Cultivated State (2) transitions to the Landfilled State (4) by intentional filling of cropland to create construction sites.

Restoration pathway R3A
State 3 to 2

The Abandoned State (3) can be restored the Cultivated State (2) by weed removal and resuming crop cultivation.

Transition T3A
State 3 to 4

The Abandoned State (3) transitions to the Landfilled State (4) by intentional filling to create construction sites.

Additional community tables

Table 5. Community 1.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Table 6. Community 1.2 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Table 7. Community 2.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Table 8. Community 3.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Table 9. Community 4.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)

Supporting information

Other references

References for R191XY005MP (The Very Poorly Drained Muck Ecological Site):

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

Amidon, F., Metevier, M., and Miller, S. E.. (2017). Vegetation Mapping of the Mariana Islands: Commonwealth of the Northern Mariana Islands and Territory of Guam. US Fish and Wildlife Service and Pacific Islands Climate Change Cooperative. Final Report November 2017.

CNMI SWARS Council. (2010). Commonwealth of the Northern Mariana Islands (CNMI) Statewide Assessment and Resource Strategy 2010-2015+. CNMI Forestry.

Donnegan, J. A., Butler, S. L., Kuegler, O., and Hiserote, B. A. (2011). Commonwealth of the Northern Mariana Islands’ Forest resources, 2004. Resour. Bull. PNW-RB-261. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 40 p.

Falanruw, M. C., Cole, T. G., and Ambacher, A. H. (1989). Vegetation survey of Rota, Tinian, and Saipan, Commonwealth of the Northern Mariana Islands. Resour. Bull. PSW-27. Berkeley, CA: Pacific Southwest Forest and Range Experiment Station, Forest Service, U.S. Department of Agriculture.

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.

Kuo, H. and Berry, L. (2018). Commonwealth of the Northern Mariana Islands Wetland Plants Identification Guide. Prepared for Division of Coastal Resources Management, CNMI Bureau of Environmental and Coastal Quality, Commonwealth of the Northern Mariana Islands.

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.

Liu, Z. and Fischer, L. (2008). Commonwealth of the Northern Mariana Islands Vegetation Mapping Using Very High Spatial Resolution Imagery. USDA Forest Service Pacific Southwest Region, Forest Health Protection, McClellan, CA.

Marshall, A. P., Willsey, T., Reeves, M., Amidon, F., and 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., and 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.

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

USDA-Soil Conservation Service. (1988). Soil Survey of Territory of Guam.

USDA-Soil Conservation Service. (1989). Soil Survey of the Islands of Aguijan, Rota, Saipan, and Tinian, Commonwealth of the Northern Mariana Islands.

USDI-Fish and Wildlife Service. (1979). Classification of Wetlands and Deepwater Habitats of the United States. Cowardin LM, V Carter, FC Golet, and ET LaRoe. Office of Biological Services. Washington, DC.

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

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

Contributors

David Clausnitzer PhD
John Proctor
Ann Tan
Daniel Bowman
Amy Koch
Kendra Moseley
Daniel Block
Jill Ficke-Beaton
Sarah Quistberg

Approval

Curtis Talbot, 8/19/2025

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	08/19/2025
Approved by
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

Natural ResourcesConservation Service

Ecological site QX191X01X005

Very Poorly Drained Muck

Last updated: 8/19/2025 Accessed: 09/14/2026

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General information

MLRA notes

Classification relationships

Ecological site concept

Associated sites

Similar sites

Table 1. Dominant plant species

Legacy ID

Natural Resources
Conservation Service

Last updated: 8/19/2025
Accessed: 09/14/2026