Characterizing the diversity of coral reef habitats and fish communities found in a UNESCO World Heritage Site: the strategy developed for Lagoons of New Caledonia.

Since 1972, the UNESCO "World Heritage Convention" offers an international canvas for conservation and management that targets areas of high cultural and environmental significance. To support the designation of areas within the 36.000 km(2) of New Caledonia coral reefs and lagoons as a World Heritage Site, the natural value and diversity of the proposed zones needed to be demonstrated. To exhaustively identify each configuration of shallow habitats, high resolution remote sensing images were used to select the sampling sites. This optimal scheme resulted in the selection of nearly 1300 sampling sites, and was then simplified to render its application realistic. In the final sampling plan, only the most common or the most remarkable coral zones were selected. Following this selection, in situ habitat and fish surveys were conducted in 2006-2008 in five large areas spanning a 600 km-long latitudinal gradient. Habitats were described using line-intercept transects in parallel with underwater visual census of indicator and commercial coral reef fish species. We report here on the results achieved in terms of: (i) the actual diversity of coral habitats captured by the remote sensing based sampling strategy, (ii) the different reef fish communities captured from the different sites, and (iii) how well they represent New Caledonia diversity. We discuss the possible generalization of this scheme to other sites, in the context of World Heritage Site selection and for other large-scale conservation planning activities.