Modifications of the shore line in the Society islands (French Polynesia)

The people living on the mountainous islands of the Society archipelago have the good luck to benefit from peaceful lagoon waters. The narrow littoral plain is protected from the assaults of the sea by a barrier-reef and the temptation to live by the sea-side is strong. It is all the more stronger as the mountains, although splendid, are not easy places to settle. As an interface between the terrestrial and lagoon environments, the shore line of the mountainous islands is mainly occupied by high vegetation in its natural configuration. Rocks, sandy beaches and muddy areas can be accounted for by geomorphologic factors directly linked to the transformation process of each mountainous island becoming an atoll. While the shore line in the mountainous islands of the Society archipelago is mostly natural, more than 40% has been directly modified by man. But nevertheless this anthropogenization does not correlate with population density or economic development. It results from the complex interactions between human and natural factors. Embankment works and excavating coral materials from the fringing reef are particularly destructive activities for the environment. Current concerns related to rising sea levels emphasized the quality of the shore line for human activities and development of the littoral in the future. Only joint management encompassing the lagoon and terrestrial environments will maintain the natural and human balances, and thus, the harmonious development of the islands’ populations.