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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: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: 02/03/98