Christmas Island
| Topics: |
Geology (main)
|
Christmas Island. Source: Masatomo Fujiwara
Countries and Regions of the World Collection 
Christmas Island is a Territory of Australia located along major sea lanes of Indian Ocean, south of Indonesia (360 kilometers (km) south of Jakarta).
It includes 1,400 people.
Contents
Background
Discovered on Christmas Day in 1643, the island was annexed and settlement began by the UK in 1888.
Phosphate mining began in the 1890s. Phosphate mining had been the only significant economic activity, but in December 1987 the Australian government closed the mine. In 1991, the mine was reopened. With the support of the government, a $34 million casino opened in 1993, but closed in 1998.
The UK transferred sovereignty to Australia in 1958. It is a non-self governing territory of Australia; administered from Canberra by the Department of Regional Australia, Regional Development and Local Government.
Almost two-thirds of the island has been declared a national park.
Its major environmental issues include: loss of rainforest and the impact of phosphate mining.
Location: Southeastern Asia, island in the Indian Ocean, south of Indonesia
Geographic Coordinates: 10 30 S, 105 40 E
Area: 135 sq km - mainly tropical rainforest; 63% of the island is a national park) (2005)
Coastline: 138.9 km
Maritime Claims:
territorial sea: 12 nm
contiguous zone: 12 nm
exclusive fishing zone: 200 nm
Terrain: steep cliffs along coast rise abruptly to central plateau. The highest point is Murray Hill (361 m)
Climate: tropical with a wet season (December to April) and dry season; heat and humidity moderated by trade winds
Capital: The Settlement
Legal System: legal system is under the authority of the governor general of Australia and Australian law
Population: 1,402 (July 2010 est.)
Ethnic groups: Chinese 70%, European 20%, Malay 10% Note: There is no indigenous population (2001)
Languages: English (official), Chinese, Malay
Topography
Ecology
Christmas Island forests are dominated by Indo-Malaysian and Melanesian tree species that form a dense evergreen canopy supporting a diverse epiphyte community, but with little understory vegetation. During the dry season some deciduous species drop their foliage exposing the understory to more light. In areas with deep soil, the canopy reaches 30-40 m with emergents growing to 50 m. The most common tree canopy species are: Planchonella nitida, Syzygium nervosum, Tristiropsis acutangula, Inocarpus fagifer, and Hernandia ovigera. The understory is dominated by two endemic species: the palm Arenga listeri and the tree-like Pandanus elatus. The forest floor is almost bare of leaf litter, seeds, or seedlings because they are quickly consumed by the approximately 100 million red crabs (Gecarcoidea natalis) found in the forest. In total there are 237 native and 174 introduced plant species on the island, and most of the introduced species are restricted to disturbed sites.
With individual weights up to 500 grams (1 lb.), densities of 1.2 – 2.6 crabs/m2, and biomass up to 1454 kilograms (kg) per hectare, red crabs (Gecarcoidea natalis) are the most striking feature of Christmas Island forests. The crabs live in the understory of rainforest where humidity is high enough to prevent desiccation. They excavate burrows 40-100 centimeters (cm) long and live a solitary existence feeding on leaf litter, fruit, and seeds. Their densities are so high that most fruit and seeds are removed and consumed within 12 hours of falling to the ground and the forest floor is often completely clear of plant matter. At the beginning of the wet season, usually in November or December, all adult crabs leave their burrows and spend 9-18 days migrating to coastal locations. They mate near the sea, in burrows excavated by males, lay eggs in the ocean, and then return to the forest.
What Christmas Island is known for - its red crabs, Gecarcoidea natalis. They are literally everywhere on the island, and have very funny expressions on their faces. Margaret Knoll, Christmas Island, Australia, April 2011. Image source: John Tann/Encyclopedia of Life
For such a small island, Christmas Island supports a large number of endemic species and subspecies of animal and plant including:
- one of the rarest owls in the world, the Christmas Island hawk owl (Ninox natalis),
- Christmas Island frigatebird (Fregata andrewsi),
- the endangered Abbott’s booby (Papasula abbotti),
- Christmas Island imperial pigeon (Ducula whartoni), and
- the Christmas Island white-eye (Zosterops natalis).
All but three endemic species are still present. The extinction of the endemic rat, Rattus maclari, around 1900 was caused by hybridization with introduced Rattus rattus and disease. Two of 16 endemic plant species have also disappeared. There are also another 16 species of land crab present in low densities, including a large population of coconut crabs (Birgus latro).
Phosphate mining of extensive bird guano deposits has resulted in the destruction of some of the island’s native habitat; however, the inclusion of 63% of the island in a national park should ensure the protection of this unique forest.
See:Christmas and Cocos Islands tropical forests
Lava flows at the coastal zone of Christmas Island
