Diversity, Endemism, and Extinction in the Flora and Vegetation of New Caledonia
|Map of New Caledonia (source: Atlas de la Nouvelle-Calédonie. ORSTOM, Paris).|
The Territory of New Caledonia can be divided into the following geographically distinct entities:
The principal island, Grande Terre, is approximately 390 km long and about 50 km wide on average, covering an area of 16,890 km². Grande Terre is continental in origin, and is oriented along a NNW- SSE axis, with extensions in both directions to several smaller, geologically related islands to the NNW (Iles Bélep, Ile Baaba, Ile Balabio) and the SSE (Ile Ouen, Ile des Pins).
The Loyalty Islands (Ouvéa, Lifou, Tiga, and Maré), situated approximately 200 km to the NE of Grande Terre, and covering about 1,970 km², are geologically distinct, being of much more recent oceanic origin (Dubois et al., 1973).
A number of small, isolated islands (the Chesterfields, Beautemps-Beaupré, Walpole, Hunter, and Matthew), which are geologically young.
Several reefs (Bellone, d'Entrecasteaux, Astrolabe),which are also administered as part of the Territory of New Caledonia (Dubois et al., 1981).
Essentially all of New Caledonia's botanical diversity is concentrated on Grande Terre. The smaller islands have depauperate, relatively species-poor floras; even the Loyalty Islands have less than 400 species (Jaffré, 1993), representing only a minor sub-set of the diversity occurring on the main island, having been established relatively recently through long-distance dispersal from Grande Terre, and to a much lesser degree from other areas such as Vanuatu (formerly the New Hebrides). Only a few locally endemic species occur on the smaller islands, such as the palmCyphophoenix nucele, which is restricted to a single population on Lifou (cf. MacKee et al., 1985; Jaffré and Veillon, 1989), and no unique vegetation types occur in these areas. Because the younger surrounding islands are of limited interest botanically, only Grande Terre will be taken into consideration below.
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