Article first published online: 21 JAN 2014
© 2014 The Authors. New Phytologist © 2014 New Phytologist Trust
Volume 202, Issue 2, pages 521–530, April 2014
How to Cite
Pillon, Y., Hopkins, H. C. F., Rigault, F., Jaffré, T. and Stacy, E. A. (2014), Cryptic adaptive radiation in tropical forest trees in New Caledonia. New Phytologist, 202: 521–530. doi: 10.1111/nph.12677
- Issue published online: 20 MAR 2014
- Article first published online: 21 JAN 2014
- Manuscript Accepted: 9 DEC 2013
- Manuscript Received: 21 OCT 2013
- NSF. Grant Number: DEB 0954274
- adaptive radiation;
- aluminium (Al) hyperaccumulator;
- New Caledonia;
- nickel (Ni) hyperaccumulator;
- rainforest trees;
- The causes of the species richness of tropical trees are poorly understood, in particular the roles of ecological factors such as soil composition. The nickel(Ni)-hyperaccumulating tree genus Geissois (Cunoniaceae) from the South-west Pacific was chosen as a model of diversification on different substrates.
- Here, we investigated the leaf element compositions, spatial distributions and phylogeny of all species of Geissois occurring on New Caledonia.
- We found that New Caledonian Geissois descended from a single colonist and diversified relatively quickly into 13 species. Species on ultramafic and nonultramafic substrates showed contrasting patterns of leaf element composition and range overlap. Those on nonultramafic substrates were largely sympatric but had distinct leaf element compositions. By contrast, species on ultramafic substrates showed similar leaf element composition, but occurred in many cases exclusively in allopatry. Further, earlier work showed that at least three out of these seven species use different molecules to bind Ni.
- Geissois qualifies as a cryptic adaptive radiation, and may be the first such example in a lineage of tropical forest trees. Variation in biochemical strategies for coping with both typical and adverse soil conditions may help to explain the diversification and coexistence of tropical forest trees on similar soil types.