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![]() Like specks on a world map, the islands of the South Pacific might appear as insignificant entities, but many of these island ecosystems support some of the highest levels of marine diversity in the world, with up to 3,000 species found on a single reef. Today, however, coral reefs and marine ecosystems of this region are increasingly threatened by land-based development and over-exploitation of natural resources. The South Pacific is a region of great contrasts: the smallest island of this group, Tuvalu, has a land area of just 26 square kilometres, compared with New Caledonia which has an area of more than 19,000 square kilometres. Some of the islands are low-lying atolls with a human population of just a few thousand people, while others are towering mountain areas with populations of 100,000 or more. While terrestrial ecosystems may vary from one country to another, depending on topography, soil conditions and levels of human intervention, the marine ecosystem is also quite varied in composition and species representation. Mangroves, seagrass beds, estuarine lagoons, and barrier and fringing reefs are all represented on Fiji, New Caledonia, Samoa, Tonga, Tuvalu and Vanuatu, but the extent of these habitats varies from one country to another. Combined, they provide an unrivalled haven for thousands of different species, hundreds of which are found nowhere else in the world. These same ecosystems provide important resources for local people, as well as sport and tourism amenities to large numbers of foreign visitors each year. The structure of these islands varies considerably, a feature which not only determines the nature and extent of their biological resources, but also their productivity and vulnerability to disruption and over-exploitation. Countries such as Tuvalu are atolls of coralline reef limestone which surround a lagoon; such islands are generally more easily affected by natural disasters than are volcanic or continental islands. Vanuatu and Western Samoa, in contrast, are volcanic peaks of undersea volcanoes, which are frequently surrounded by fringing reefs. |