This BioProvince (as defined by Armen Takhtajan) includes Vanuatu (formerly New Hebrides) which forms a Y shaped archipelago of more than 80 islands, the largest of which is Espiritu Santo (3900 square metres). These tropical islands have a climate that comprises two seasons. The cool trade wind season between May and October, and the warmer hurricane season between November and April when the sun is more or less above the archipeligo. During the trade wind season the northern, leeward side of islands experience a dry period but during the hurricane season levels of precipitation is more erratic. On average up to six tropical cyclones of hurricane strength can be expected during this period. The islands are largely composed of volcanic rocks but terraces of coral reef limestone are also present on some islands. They were created as a result of sea level changes combined with subsequent uplifting and now reach elevations above 600 m on Malakula. These comparatively young volcanic islands only became fully developed during the post Pleistocene period and so their flora has had very little time to develop. Nevertheless, the extinct volcanic cones on Erromango are said to be up to 5 million years old but because the archipelago in general is relatively young it is comparatively poor floristically with just 534 genera and about 1120 species. This is also reflected in the level of endemism with just three endemic genera (Carpoxylon, Kajewskia and Trichochilus) and about 150 endemic species. Most of the flora appears to have been derived from Malesian sources but they lack the rare, ancient Gondwanic floristic elements, such as members of the Winteraceae, which can be found, for example, on Fiji and New Caledonia.
The following accounts for this BioProvince have been written or will be written with particular reference to endemic and locally important species. Accounts available are displayed in green or yellow. Those displayed in red are either in the pipeline or awaiting expert contributions.
|Endemic Vascular Plant Flora|