1. P. Taberlet is in the Laboratoire de Biologie des Populations d'Altitude, CNRS UMR 5553, Université Joseph Fourier, BP 53, F-38041 Grenoble Cedex 9, France.
2. R. Cheddadi is with the European Pollen Database, CNRS UMR 6116, Centre Universitaire d'Arles, F-13200 Arles, France.