Systematics/Phytogeography / Taxonomie/ Section
Pillon, Yohan , Munzinger, Jérôme , Amir, Hamid , Hopkins, Helen H.C.F. , Chase, Mark W. .
Reticulate evolution on a mosaÃ¯c of soils: diversification of Cunoniaceae in New Caledonia.
New Caledonia is an archipelago in the South West Pacific well known for its rich and original flora. The peculiarity of its vegetation has generally been explained by the large surface of ultramafic soils that cover the main island. Ultramafic soils, also commonly named “serpentine” represent a challenge to the development of most plants, because of their low fertility and high concentration of heavy metals. To get a better understanding of the diversification of the New Caledonian flora, molecular phylogenies are the ideal tool to reconstruct the history of a given plant lineage. We investigated the evolution of two genera, Codia and Spiraeanthemum in the Cunoniaceae family, using three nuclear single-copy genes. Our results show that reticulate evolution has played a major role in the evolution of both genera and that the adaptation to ultramafic soils may be transmitted through collective evolution. We also found that the species produced through hybridisation can present some morphological novelties. A biogeography of the genus Codia within New Caledonia suggests extensive range movement as several daughter species do not co-occur anymore with any of their putative parental species. Because of the flora of New Caledonia is also threatened by fires, nickel mining, invasive species and climate change, conservation implications of this work are also discussed.
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1 - Institut de Recherche pour le Developpement, Laboratoire de Botanique, bp A5, Noumea, 98848, New Caledonia
2 - University of New Caledonia, Laboratoire Insulaire du Vivant et de l Environnement, bp R4, Noumea, 98851, New Caledonia
3 - Royal Botanic Gardens, Kew, The Herbarium, Richmond, Surrey, TW9 3AB, United Kingdom
4 - Royal Botanic Gardens, Kew, Jodrell Laboratory, Richmond, Surrey, TW9 3AB, United Kingdom
Presentation Type: Oral Paper:Papers for Sections
Location: Room 5/Woodward
Date: Tuesday, July 29th, 2008
Time: 2:15 PM