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ISLAND DIRECTORY
Islands of Guam (United States)
Guam - including Cocos [4]
Group: Archipelago: Mariana Islands
Country: United States - Guam Region: Oceania 12
Lat: 13.42º N Long : 144.78º E
Area: 541.0 sq. km Altitude: 393 m
Shoreline: 152.5 km (scale 1: 1000000) Coastal Index: 0.2819
Depth to nearest land: 2000 m
Nearest island: 80 km group: 500 km
Nearest continent: Asia Distance: 3000 km Isolation Index: 86
ISLAND TYPE: raised coral; old volcanic Natural Protection Indicator: 0
GEOLOGY/SOILS:
Raised coral in north, old weathered volcanic in south; fringing reefs,
barrier reef system (CRD); reefs affected by Acanthaster in 1960's
causing
shift from stony to soft corals
CLIMATE: tropical
CATASTROPHIC THREATS: cyclones
Threat Indicator: 1
ECOSYSTEMS: Number of Ecosystems - Terrestrial: 2 Marine: 10
Lowland rain forest on limestone with considerable endemism (remaining
fragment on extreme northern rim), some ravine and beach forests,
possible
cloud forest on Mt. Lamlam, scrub, savanna and grasslands; poor
mangroves;
marsh, reed swamp and other aquatic habitats; fringing reef, lagoons and
barrier reef (CRD). Forest Coral reefs, Mangroves
| SPECIES NUMBERS: |
Total |
Endemic |
Threatened (EVRI) |
| Plants |
330 |
20 |
2 |
| Butterflies |
15 |
1 |
0 |
| Land snails |
9 |
0 |
0 |
| Rept/Amphib |
10 |
1 |
4 |
| Land birds |
12 |
2 |
3 |
| Mammals |
4 |
1 |
3 |
SPECIES OF CONSERVATION INTEREST:
Plants
931 (or 530) species of flowering plants and ferns, of which at least
330 are
native, 69 are endemic to the Mariana Islands; 20 endemics and more
than 30
non-endemics threatened on Guam, including:
Serianthes nelsonii (Leguminosae) endemic to Guam and Rota (4
remaining
trees on Guam), Endangered (RDB)
Heritiera longipetiolata (Sterculiaceae) group endemic, Endangered
(RDB)
Tabernaemontana rotensis (Apocynaceae) one remaining tree on Guam
Hernandia ovigera (Hernandiaceae)
Merrilliodendron megacarpum (Icacinaceae) known from two areas
Xylosoma nelsonii (Flacourtaceae)
Fagraea galilai (Loganiaceae) two sites including Mt. Lamlam
Solanum guamense, few plants known
Ceratopteris gaudichaudii, from freshwater areas
Potamogeton mariannensis, from freshwater, Cotal area
Insects
15 species of butterfly, 1 only on Guam
Neptis guamensis, endemic, not seen since type collection in 1916
Other invertebrates
9 native land snails, including 4 Partulidae (tree snails):
Partula gibba
Partula salifana
Partula radiolata
Samoana fragilis
Reptiles-amphibians
Ramphotyphlops (?) pseudosaurus (Typhlopidae) endemic?
Birds
95 species, 17 resident, 7 introduced
12 indigenous terrestrial bird species, 2 endemic
Rallus owstoni (Guam Rail) endemic, Vulnerable (RDB), fewer than 100
(1984),
declining.
Ptilinopus roseicapilla (Marianas Fruit Dove) group endemic, northwest
forest, Vulnerable (RDB), estimate of 241 on Guam (1981).
Myiagra freycineti (Guam Flycatcher or Broadbill) endemic, endangered,
fewer
than 100 (1983).
Gallinula chloropus guami (Marianas Gallinule or Common Moorhen) group
endemic subspecies, Rare (RDB), 100-200 (1983)
Gallicolumba xanthonura xanthonura (White-throated Ground Dove),
150-200
(1983).
Aerodramus vanikorensis bartshi (Vanikoro Swiftlet), less than 50
(1983).
Halcyon cinnamomina cinnamomina (Guam Micronesian Kingfisher) endemic
subspecies, Endangered (RDB) or vulnerable, conflicting reports of
3000
or 250-300 remaining (1982-83).
Rhipodura rufifrons uraniae (Rufous-fronted Fantail), less than 200
(1983).
Zosterops conspicillata conspicillata (Bridled White-eye), vulnerable,
less
than 50 (1984).
Myzomela cardinalis saffordi (Cardinal Honeyeater), estimated 250-300
(1983).
Aplonis opaca guami (Micronesian Starling), 1000 birds (1983).
Corvus kubaryi (Mariana Crow) Endangered (RDB), 150-200 birds (1983).
at least 4 bird species or subspecies are now extinct on Guam
Mammals
Pteropus marianus marianus (Mariana Fruit Bat) endangered by poaching.
Pteropus tokudae (Little Marianas Fruit Bat) only in northern mature
forest,
may be extinct
Emballonura semicaudata (Sheath-tailed Bat) may be extinct
Dugong dugon (Dugong), Vulnerable (RDB), very rare locally
SPECIES RICHNESS:
Species Richness Indicator - Terrestrial: 1 Marine: 0
moderate
ENDEMISM: Terrestrial: Terrestrial Endemism Indicator - Island: 2 Group: 3
moderately high
Marine endemic species: 0
Marine Endemism Indicator - Island: 0 Group: 1
SPECIAL FEATURES : Special Features Indicator - Terrestrial: 3 Marine: 0
some seabird rookeries, former turtle nesting
Lake Fena; caves in south with endangered swiftlet
INVASIVE SPECIES: Invasive Species Indicator: 4
serious effects on native flora and fauna
Feral pigs and other domestic animals
Elk
Boiga irregularis (Philippine Rat Snake) introduced 1947, densities up
to
2000 per sq. km, believed responsible for disappearance of many
native
birds
Achatina fulica (Giant African Snail)
Varanus indicus (Monitor Lizard)
HUMAN OCCUPATION: Inhabited, occupied since prehistoric times
Population: 107000 (1981) Density: 197.8 persons/sq. km
Growth Rate: 2.0%/yr Increasing
Major Human Activities: military, tourism,, agriculture
HUMAN IMPACTS:
Heavy damage during World War II; extensive urban development around
Agana
and elsewhere; major military bases; some agriculture; considerable
tourism
development
Habitat: Urban Pop: 0 Urban Indicator: 1
Accessibility: port, airport
Percent population in agr/mining/fishing: 1% Human Threat Indicator: 0
Gross Domestic Product: $ 4744 per capita Economic Pressure Indicator: 2
Conservation support: environmental legislation
PROTECTED AREAS: Protected Area Coverage Indicators - Terrestrial: 2 Marine: 0
Number: 7 Area: Terrestrial: 45.0 sq. km Marine: 29 sq. km
Anao Conservation Reserve (263 ha)
Pati Point Natural Area (112 ha)
Haputo Ecological Reserve Area (73 ha land; 29 ha marine)
Orote Peninsula Ecological Reserve Area (12 ha land; 44 ha marine)
Masso River Reservoir Area (67 ha)
Guam Territorial Seashore Park (3,645 ha land; 2430 ha marine)
War in the Pacific National Historical Park (374 ha land; 405 ha
marine)
DATA RELIABILITY: good recent data Data Rel. Indicator: 3
HUMAN IMPACT INDEX HI: 15
CONSERVATION IMPORTANCE INDEX CI-Terrestrial: 16 High
CI-Marine: 11 Moderate
REFERENCES:
Last updated: 05/07/88
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Page last updated: 09/05/10