Abstract Detail

From High Islands to the Ocean Floor: Pacific Island Plants at the Extreme

Meyer, Jean-Yves Hiro [1].

Atoll floras and forests as « harbingers » of local and global changes in the Pacific Ocean.

Although they have a far poorer terrestrial flora both in terms of species number and endemism, as well as lower forest diversity compared to high volcanic tropical islands, atolls are excellent models to study the natural and anthropogenic changes that occur at both at a local and global scales, including phenomena related to global warming (e.g. sea-level rise, strong swells, cyclones). All atolls share the same geological and geomorphological characteristics, « harsh » ecological conditions for plant colonization and survival (e.g. calcareous substrate with a low pH and high salinity, strong insolation and air temperature, low rainfall and moisture), and they display strong floristic similarities across the Pacific Ocean. Their native floras have a large set of common plant taxa, allowing biogeographical and ecological comparisons. Atolls and their numerous sandy islets can thus be considered « natural replicates ». Forest structure and composition of some atolls that we have recently studied among the ca. 80 of French Polynesia (of the 400-600 worldwide) with different human impacts, ranging from uninhabited and almost pristine islands (e.g. Maria in the Austral archipelago, Morane in the Gambier) to highly populated or degraded islands (e.g. Raroia, or the « nuclear » atoll of Moruroa in the Tuamotu) where native forests have often been converted to introduced coconut plantations, are presented. Preliminary results obtained from an on-going restoration project in Tetiaroa (Society archipelago) illustrate the importance of considering biotic interactions between native plants and seabirds, and alien invasive rats, to better understand vegetation dynamics and ecosystem functioning. Atolls can be considered as unique harbingers ('ārere or kārere in Polynesian languages) to study resilience and vulnerability of small oceanic islands in a fast changing world.

1 - Government of French Polynesia, Délégation à la Recherche, B.P. 20981, Papeete, Tahiti, 98713, French Polynesia

Keywords:
atoll
climate change
human impacts
Pacific islands
restoration.

Presentation Type: Symposium Presentation
Number: S6006
Abstract ID:185
Candidate for Awards:None