Pillon Y., Hopkins H.C.F., Rigault Frédéric, Jaffré Tanguy, Stacy E.E. (2014). Cryptic adaptive radiation in tropical forest trees in New Caledonia. New Phytologist, 202 (2), p. 521-530. ISSN 0028-646X.
Titre du document
Cryptic adaptive radiation in tropical forest trees in New Caledonia
Pillon Y., Hopkins H.C.F., Rigault Frédéric, Jaffré Tanguy, Stacy E.E.
Source
New Phytologist, 2014,
202 (2), p. 521-530 ISSN 0028-646X
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.
Plan de classement
Constituants et propriétés des sols [068PROSOL]
;
Ecologie végétale [076BOTA05]
Descripteurs
ARBRE FORESTIER ; ESPECE TROPICALE ; FORET DENSE ; DISTRIBUTION SPATIALE ; DIVERSITE SPECIFIQUE ; PHYLOGENIE ; ADAPTATION ; RELATION SOL PLANTE ; ACCUMULATION ; ALUMINIUM ; NICKEL ; MILIEU INSULAIRE ; COMPOSITION FOLIAIRE ; SOL ULTRAMAFIQUE
