Format: ORAL

Olivier J. Hardy1

1 Université Libre de Bruxelles, Brussels, Belgium

Although tropical Africa is home to the second largest tropical rainforest, the origin and evolution of its rich biodiversity remain poorly studied. However, the accumulation of phylogeographic and population genetic studies on tree species makes it possible to look for general patterns. 1. We found that about a quarter of African tree species studied, as delineated by current taxonomy, contain multiple species following the biological species concept, which might double the tree species richness in Tropical Africa and indicate a trend toward taxonomic overlumping. 2. Genome skimming makes it possible to sequence hundreds of plastomes at a reasonable cost, shedding light on the colonization dynamics of species or genera using time-calibrated phylodynamic models. Major distribution range shifts seemed to have occurred c. 200,000 years ago in several unrelated taxa. 3. The comparison of maternally inherited plastomes and nuclear markers provides information on the respective role of seed and pollen dispersal, and highlights situations of extensive plastid capture, suggesting that certain taxa (e.g. several genera of the Berlinia clade, Detarioidea , Fabaceae) could evolve as a syngameon. Finally, phylogeographic data on exploited tree species provide key information to conserve their natural populations or design breeding program for plantation of native species.