Proof of the indigenous nature of Populus alba L. in the western Mediterranean Basin

Around the western Mediterranean Basin, the ecological status of Populus alba, whether indigenous or introduced, is controversial. This note presents new palaeobotanical data based on analyses of leaf imprints from a travertine formation located in southern France. This travertine presents two levels with Populus alba imprints. The oldest level is dated back by 14C to the Early Holocene, i.e., 8890 +/- 70 BP. This demonstrates that Populus alba is an autochthonous species of the southern-France vegetation, removing speculations reporting that its distribution area was greatly influenced by Roman civilization. Finally, we discuss this new data in regard to other Pleistocene and Holocene deposits circum the Mediterranean Basin and in Europe, where this species was identified.