The wildlife of Christmas Island is composed of the flora and fauna of this isolated island in the tropical Indian Ocean. Christmas Island is the summit plateau of an underwater volcano. It is mostly clad in tropical rainforest and has karst, cliffs, wetlands, coasts and sea. It is a small island with a land area of 135 km2 (52 sq mi), 63% of which has been declared a National park. [1] Most of the rainforest remains intact and supports a large range of endemic species of animals and plants.
The island is about 19 kilometres (12 mi) long and 14.5 km (9.0 mi) wide. The total land area is 135 square kilometres (52 sq mi), with 138.9 km (86.3 mi) of coastline. The island is the flat summit of an underwater volcano more than 4,500 m (14,800 ft) high, [2] with about 4,200 m (13,800 ft) being submerged and only about 300 m (1,000 ft) above the surface. [3] Some basalt is exposed in places but most of the surface rock is limestone accumulated from coral growth. The karst terrain supports numerous anchialine pools. [4] Steep cliffs along much of the coast rise abruptly to a central plateau. The island is mainly covered by tropical rainforest, much of which remains intact. Two thirds of the island is included in the Christmas Island National Park which includes rainforests, wetlands, cliffs, shore and coral reefs. [5]
The climate is tropical and temperatures vary little throughout the year. The highest temperature of around 29 °C (84 °F) usually occurs in March and April, while the lowest temperature is around 23 °C (73 °F) in August. There is a dry season from July to October with only occasional showers. The wet season is between November and June, and includes monsoons and occasional tropical cyclones. [6]
About 213 species of vascular plant are native to the island, with sixteen of them endemic. The rainforest on the upper slopes and central plateau consists of large evergreen trees with a canopy at 30 to 40 m (100 to 130 ft) and a scattering of emergent trees some 50 m (160 ft) high. The dominant trees are Planchonella duclitan , Syzygium nervosum , Tristiropsis acutangula , Inocarpus fagifer and Hernandia ovigera . Mid-storey species include two endemic trees, the Christmas Island palm, Arenga listeri and the screw pine Pandanus elatus . There are few shrubs, but the trunks and branches of the trees are swathed in a tangle of vines, orchids and ferns. [7]
On terraces lower down the cliffs the trees are shorter, reaching 20 to 30 m (70 to 100 ft). Here the dominant species are Pisonia grandis , Gyrocarpus americanus , Gyrocarpus americanus , Terminalia catappa and Erythrina variegata . Various shrubs grow at the foot of the cliffs and on the coastal flats, sometimes in dense thickets. These include the endemic Pandanus christmatensis and Abutilon listeri , as well as certain shrubs and trees whose buoyant seeds are dispersed across the sea such as Scaevola taccada , Cordia subcordata , Morinda citrifolia , Hibiscus tiliaceus and Guettarda speciosa . [7]
Christmas Island was uninhabited until the end of the nineteenth century. The island possesses no large native, terrestrial mammals and the endemic mammal fauna of the island has been largely destroyed by the introduction of exotic species such as cats, dogs and black rats (Rattus rattus). [7] The diurnal bulldog rat (Rattus nativitatis) and the nocturnal Maclear's rat (Rattus macleari) both became extinct after the accidental introduction of the black rat. The Christmas Island shrew (Crocidura trichura) may also be extinct, [8] and the Christmas Island pipistrelle (Pipistrellus murrayi) has not been seen since 2009. [9] The Christmas Island flying fox (Pteropus melanotus natalis), the only other endemic mammal, is declining in numbers and is considered threatened. [8]
Rather than mammals, it is crabs that dominate the fauna. [10] There are at least 50 species on the island, some of them endemic, 30 of them terrestrial species whose only link with the ocean is the necessity to travel to the sea to breed. Several are small and inconspicuous, but others such as the coconut crab and Christmas Island red crab are large and present in enormous numbers. In the late twentieth century there were estimated to be about 120 million red crabs on the island, and the mass migration made by the mature individuals to the coast was spectacular. [10] The red crabs are a keystone species, feeding on the forest floor on leaves, fallen fruits, flowers, seedlings and carrion and maintaining a lawn-like turf. In the twenty-first century the number of red crabs has reduced considerably because of the accidental introduction of the yellow crazy ant to the island; this invasive species has formed supercolonies, killed crabs and had a profound impact on the biodiversity of the island. [10] [11]
The karst limestone areas are riddled with caves and sink-holes, some of the underground water-filled cavities being saline. These underground habitats have been imperfectly sampled, but at least twelve endemic subterranean invertebrates are known including some such as ostracods, the cave shrimp Procaris noelensis and a blind cave scorpion Hormurus polisorum , that may be relicts from the Mesozoic fauna of the Tethys Ocean. The island is fringed by coral reefs and nearly seven hundred species of marine fish have been recorded in the surrounding waters as well as three species of marine turtle and about a dozen species of whales and dolphins. [7]
Christmas Island is recognised by BirdLife International as being an Important Bird Area, mostly because of the breeding populations of seabirds. These include the red-footed booby, which nests in colonies in bushes and trees, the brown booby, which nests on cliffs, and the endemic Abbott's booby which nests on tall, emergent trees. Another endemic bird, the Christmas frigatebird, nests on the shore terraces, and the great frigatebird nests in semi-deciduous trees nearby. The brown noddy and two species of tropicbird also nest on the island. Land birds include four endemic species, the Christmas thrush, the Christmas imperial pigeon, the Christmas white-eye and the Christmas Island hawk-owl, and several endemic sub-species. Over a hundred migrants and vagrant species of bird have been recorded on the island. [7]
The Territory of Christmas Island is an Australian external territory in Southeast Asia comprising the island of the same name. It is located in the Indian Ocean around 350 kilometres south of Java and Sumatra and about 1,550 km (840 nmi) northwest of the closest point on the Australian mainland. It has an area of 135 square kilometres (52 sq mi).
Frigatebirds are a family of seabirds called Fregatidae which are found across all tropical and subtropical oceans. The five extant species are classified in a single genus, Fregata. All have predominantly black plumage, long, deeply forked tails and long hooked bills. Females have white underbellies and males have a distinctive red gular pouch, which they inflate during the breeding season to attract females. Their wings are long and pointed and can span up to 2.3 metres (7.5 ft), the largest wing area to body weight ratio of any bird.
The great frigatebird is a large seabird in the frigatebird family. There are major nesting populations in the tropical Pacific Ocean, such as Hawaii and the Galápagos Islands; in the Indian Ocean, colonies can be found in the Seychelles and Mauritius, and there is a tiny population in the South Atlantic, mostly on and around St. Helena and Boatswain Bird Island.
The lesser frigatebird is a seabird of the frigatebird family Fregatidae. At around 75 cm (30 in) in length, it is the smallest species of frigatebird. It occurs over tropical and subtropical waters across the Indian and Pacific Oceans as well as off the Atlantic coast of Brazil.
Gorgona is a Colombian island in the Pacific Ocean situated about 28 km (17 mi) off the Colombian Pacific coast. The island is 9 km (5.6 mi) long and 2.5 km (1.6 mi) wide, with a maximum height of 338 m (1,109 ft) and a total area of 26 km2 (10 sq mi). Gorgona is separated from the continent by a 270 m (890 ft) deep underwater depression.
The terrestrial fauna of the Cocos (Keeling) Islands is unsurprisingly depauperate, because of the small land area of the islands, their lack of diverse habitats, and their isolation from large land-masses. However, the fauna dependent on marine resources is much richer.
The wildlife of Cape Verde is found across its archipelago of ten islands and three islets, albeit in smaller numbers of species than mainland Africa. Each volcanic island within the archipelago is unique, and each of them have parks under their jurisdiction, by decree promulgated by the Cape Verde government. Located just off the west coast of Africa, the total land area of the island nation is 4,564 square kilometres (1,762 sq mi).
With the exception of bats, there are no truly endemic species of mammal on Cabo Verde; historically, the archipelago was only accessible to creatures with the ability to fly or swim, or to be brought by humans. The islands were first explored in 1456, but not actually settled until 1462; humans brought their livestock with them, including donkeys, pigs, cattle and goats—many of the latter are now so wild, they resemble mainland ibex, and are considered endemic “by default”.
In the centuries since settlement began, more mainland species would make their way with waves of settlers. There are no snakes present on the archipelago, which has allowed for the proliferation of many other species of other herpetiles, such as geckos, frogs and lizards. The main predators of these reptiles and amphibians would be the various birds of prey and raptors present, including the Egyptian vulture, Eurasian buzzard, kestrel, osprey, peregrine falcon, and the rare Cape Verde kite. This kite species is currently threatened by extinction but may yet be observed on Boa Vista and Maio.
The wildlife of Mauritius consists of its flora and fauna. Mauritius is located in the Indian Ocean to the east of Madagascar. Due to its isolation, it has a relatively low diversity of wildlife; however, a high proportion of these are endemic species occurring nowhere else in the world. Many of these are now threatened with extinction because of human activities including habitat destruction and the introduction of non-native species. Some have already become extinct, most famously the dodo which disappeared in the 17th century.
The Christmas boobook, also known more specifically as the Christmas Island hawk-owl, is a species of owl in the family Strigidae.
The Christmas white-eye is a species of bird in the family Zosteropidae. It is endemic to Christmas Island. Its natural habitats are tropical and subtropical moist broadleaf forests and subtropical or tropical moist shrubland. It is threatened by habitat destruction.
The Christmas Island shrew, also known as the Christmas Island musk-shrew is an extremely rare or possibly extinct shrew from Christmas Island. It was variously placed as subspecies of the Asian gray shrew or the Southeast Asian shrew, but morphological differences and the large distance between the species indicate that it is an entirely distinct species.
The Socotra Island xeric shrublands is a terrestrial ecoregion that covers the large island of Socotra and several smaller islands that constitute the Socotra Archipelago. The archipelago is in the western Indian Ocean, east of the Horn of Africa and south of the Arabian Peninsula. Politically the archipelago is part of Yemen, and lies south of the Yemeni mainland.
Los Haitises National Park is a national park located on the remote northeast coast of the Dominican Republic that was established in 1976. It consists of a limestone karst plateau with conical hills, sinkholes and caverns, and there is a large area of mangrove forest on the coast. Other parts of the park are clad in subtropical humid forest and the area has an annual precipitation of about 2,000 mm (79 in). The park contains a number of different habitats and consequently has a great diversity of mammals and birds, including some rare species endemic to the island. Some of the caverns contain pictograms and petroglyphs. The park has become a popular ecotourism destination but the number of tourists allowed to visit is limited.
Christmas Island National Park is a national park occupying most of Christmas Island, an Australian territory in the Indian Ocean southwest of Indonesia. The park is home to many species of animal and plant life, including the eponymous red crab, whose annual migration sees around 100 million crabs move to the sea to spawn. Christmas Island is the only nesting place for the endangered Abbott's booby and critically endangered Christmas Island frigatebird, and the wide range of other endemic species makes the island of significant interest to the scientific community.
The Christmas goshawk or Christmas Island goshawk, is a bird of prey in the goshawk and sparrowhawk family Accipitridae. It is a threatened endemic of Christmas Island, an Australian territory in the eastern Indian Ocean.
The Ascension scrub and grasslands ecoregion covers the dormant volcano, Ascension Island in the Atlantic Ocean. As well as shrubs and grasses wildlife on the island includes a range of unique flora and fauna. In particular the surrounding islets are important havens for many seabirds. However the seabird populations on Ascension Island itself have been severely affected by introduced species, especially cats, which were the subject of an eradication campaign between 2002 and 2006.
Grand-Îlet is an island in the Îles des Saintes archipelago, in the Lesser Antilles. It belongs to the commune (municipality) of Terre-de-Haut into the French department of Guadeloupe.
The Christmas and Cocos Islands tropical forests ecoregion covers forested areas of Christmas Island and North Keeling Island, two small seamount islands south of the Indonesian island of Java. The forests of these two islands share tree species of the Indo-Pacific and Melanesian types on nearby islands, the forests of Christmas Island and North Keeling Island are unique in how they reflect the effects of large populations of terrestrial red crabs. Because of the remoteness of the islands, there are many endemic species.
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