Fauna of New Caledonia - Location and Description

Location and Description

New Caledonia lies on the southernmost edge of the tropical zone, near the Tropic of Capricorn. It is part of the Melanesia subregion. It includes the main island of Grande Terre, the Loyalty Islands, the Belep archipelago, the Isle of Pines, the Chesterfield Islands in the Coral Sea, and a few remote islets.

The archipelago is about 1,300 kilometres (810 mi) east of Australia and 1500 km, 1800 km and 1200 km from New Zealand, Papua New Guinea and Fiji respectively. A few lesser islands are closer, but now provide no convenient island-hopping path by which animal species could pass either to or from major mainlands. Some plants, invertebrates, sea mammals, and many flying species as aquatic birds, parrots, and bats have spread to new locations, either under their own power or due to freak events such as storms, or have been transported by human actions. Some plant species have colonized new areas by means of seed carried by ocean currents.

Some animal and plant species have reached New Caledonia from surrounding regions and in turn, some New Caledonian species have successfully extended their ranges into the Pacific Ocean area. Other New Caledonian species or their close relatives are found in regions remote from the archipelago. For example, the New Caledonian Parakeet is known to be the basal species in the genus Cyanoramphus, which has spread to many Pacific islands. Many bats and birds that rely heavily on fruit for their diet, including members of the families Cotingidae, Columbidae, Trogonidae, Turdidae, and Rhamphastidae, swallow seeds, then regurgitate them or pass them in their faeces. Such seed dispersal (ornithochory) has been a major mechanism of seed dispersal across ocean barriers. Seeds of grasses, spores of algae, and the eggs of molluscs and other invertebrates may stick to the feet or feathers of birds, particularly migratory or aquatic birds, and in this way may travel long distances.

The main island, Grande Terre hosts multiple habitats under the influence of varied precipitation, geology, edaphic factors and altitude. New Caledonia has several biotopes, including dense evergreen forests, maquis shrubland, sclerophyllous forest (dry forest), wetlands, savannas, and halophytic vegetation. The island has two main ecoregions: the greater area is occupied by the eastern New Caledonia rainforest while the now-fragmentary New Caledonia dry forest runs along the west coast.

The most conspicuous aspects of the New Caledonian marine environment are associated with the surrounding coral reef.

Such circumstances may be expected in general to promote biodiversity, but in the case of New Caledonia, a striking feature is the sheer intensity of concentration of biodiversity in such a small land area. Presumably this is partly because the edaphic and topographic features define a number of discrete regions and ecological gradients. However, the local species do not always occupy all the potential niches, leaving the territory vulnerable to certain forms of invasion.

The larger flora include Nothofagus, Beilschmiedia, Adenodaphne, Winteraceae, Myrtaceae, Southern Sassafras (Atherospermataceae), conifers of Araucariaceae, Podocarpaceae, and Cupressaceae, and tree ferns.