Guam was ceded to the United States by Spain in 1898. It is now an organized, unincorporated territory of the US with policy relations between Guam and the US under the jurisdiction of the Office of Insular Affairs, US Department of the Interior.
Captured by the Japanese in 1941, it was retaken by the US three years later. The military installation on the island is one of the most strategically important US bases in the Pacific.
Guam is part of the volcanic island arc of the Mariana Islands which extend about 900 kilometers (km) north-south along the edge of the Mariana Trench in western Micronesia. Guam is the largest and southernmost island in the Mariana Islands archipelago.
The islands can be divided into two distinct groups: the northern, geologically young islands still have some active volcanism; the older southern islands, including Guam, are composed of elevated coral limestone and older weathered volcanic sequences.
Its major environmental issues include the extirpation of the native bird population by the rapid proliferation of the brown tree snake, an exotic, invasive species.
Guam is susceptiblle to frequent squalls during rainy season; relatively rare but potentially destructive typhoons (June - December).
Guam strategic location in western North Pacific Ocean.
Location: Oceania, island in the North Pacific Ocean, about three-quarters of the way from Hawaii to the Philippines
Geographic Coordinates: 13 28 N, 144 47 E
Area: 544 sq km
Coastline: 125.5 km
territorial sea: 12 nm
exclusive economic zone: 200 nm
Natural Hazards: frequent squalls during rainy season; relatively rare but potentially destructive typhoons (June - December)
Terrain: volcanic origin, surrounded by coral reefs; relatively flat coralline limestone plateau (source of most fresh water), with steep coastal cliffs and narrow coastal plains in north, low hills in center, mountains in south. The highest point is Mount Lamlam (406 m).
Climate: tropical marine; generally warm and humid, moderated by northeast trade winds; dry season (January to June), rainy season (July to December); little seasonal temperature variation
Ecology and Biodiversity
Ecologically, Guam is part of the Marianas tropical dry forests ecoregion which includes all the Mariana Islands
There has been no volcanic activity since the Miocene, and some of the land on Guam may have been exposed for the past 25 to 30 million years. The volcanic portions of Guam are characterized by many streams and complex drainage patterns. The soils are either highly weathered lateritic clays (oxisols or ultisols) or very young inceptisols.
|Cetti Bay, on the southern coast of Guam. Source: David Burdick/NOAA|
|Tumon Bay resort area on the Guam coastline. Source: David Burdick/NOAA|
|Mangroves growing in the coral rocks of the Guam coastline. Source: David Burdick/NOAA|
|Inajaran Falls in the interior of Guam. Source: David Burdick/NOAA|
Most of Guam, the largest and southernmost island of the Mariana chain, is covered by secondary growth forest. However, scattered patches of possibly original forest still exist on the northern plateau and in less accessible areas. .
A number endemic plants occur in the Marianas, including the critically endangered Serianthes nelsonii (endemic to Guam and Rota), the endangered Succinea piratarum and Succinea quadrasi, and the vulnerable Aglaia mariannensis, Heritiera longipetiolata (only in crevices of rough limestone, often on cliffs, in Saipan, Tinian, Rota, and Guam). Only 4 individual H. longipetiolata trees remained on Guam in the mid-1980s.
In 1993, a National Wildlife Refuge was established on Guam to protect the remaining forest and the habitat of the Mariana crow (Corvus kubaryi) whose status is considered critical. Four of the northern islands—Farallon de Pájaros, Maug, Asuncion, and Guguan—are also wildlife sanctuaries.
Types and Severity of Threats
A major threat to birds is the potential spread of the introduced brown tree snake (Boiga irregularis), an Australasian native, from Guam to the other Marianas islands. Two bird species extinctions have already occurred on Guam in the 1980s, and the endemic Guam rail (Gallirallus owstoni) is extinct in the wild. The snake numbers on Guam have declined with the bird population, but the snakes are now feeding on an introduced skink, which allows them to maintain their population. Also, the introduction of the black drongo (Dicrurus macrocercus), a passerine bird native to Africa, Asia, and Australia, has been implicated in the rapid decline of the Rota bridled white-eye (Zosterops rotensis). Cattle, pigs, and goats represent a threat to native vegetation, and there is little available information about the introduced Philippine deer in the Marianas.
People and Society
Population: 185,674 (July 2012 est.)
Ethnic Groups: Chamorro 37.1%, Filipino 26.3%, other Pacific islander 11.3%, white 6.9%, other Asian 6.3%, other ethnic origin or race 2.3%, mixed 9.8% (2000 census)
0-14 years: 27% (male 25,577/female 23,836)
15-64 years: 65.5% (male 61,237/female 58,891)
65 years and over: 7.5% (male 6,287/female 7,458) (2011 est.)
Population Growth Rate: 1.276% (2012 est.)
Birthrate: 17.55 births/1,000 population (2012 est.)
Death Rate: 4.78 deaths/1,000 population (July 2012 est.)
Net Migration Rate: 0 migrant(s)/1,000 population (2012 est.)
Life Expectancy at Birth: 78.5 years
male: 75.46 years
female: 81.73 years (2012 est.)
Total Fertility Rate: 2.45 children born/woman (2012 est.)
Languages: English 38.3%, Chamorro 22.2%, Philippine languages 22.2%, other Pacific island languages 6.8%, Asian languages 7%, other languages 3.5% (2000 census)
Literacy (age 15 and over can read and write): 99% (1990 est.)
Urbanization: 93% of total population (2010) growing at an annual rate of change of 1.2% (2010-15 est.)
Dependency status: organized, unincorporated territory of the US with policy relations between Guam and the US under the jurisdiction of the Office of Insular Affairs, US Department of the Interior
Capital: Hagatna 153,000 (2009)
Legal System: common law modeled on US system; US federal laws apply.
Total Renewable Water Resources:
Freshwater Withdrawal: (domestic, industrial, agricultural)
Per Capita Freshwater Withdrawal:
Agricultural products: fruits, copra, vegetables; eggs, pork, poultry, beef
Irrigated Land: 2 sq km (2008)
Natural Resources: aquatic wildlife (supporting tourism), fishing (largely undeveloped)
arable land: 3.64%
permanent crops: 18.18%
other: 78.18% (2005)
The economy depends largely on US military spending and tourism.
Total US grants, wage payments, and procurement outlays amounted to $1.3 billion in 2004.
Over the past 30 years, the tourist industry has grown to become the largest income source following national defense. The Guam economy continues to experience expansion in both its tourism and military sectors.
GDP: (Purchasing Power Parity): $2.5 billion (2005 est.)
GDP: (Official Exchange Rate): $2.773 billion (2001)
GDP- per capita (PPP): $15,000 (2005 est.)
Industries: US military, tourism, construction, transshipment services, concrete products, printing and publishing, food processing, textiles
Currency: US dollar
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