[1] Univ Lausanne, Dept Ecol & Evolut, CH-1015 Lausanne, Switzerland
[2] Swiss Inst Bioinformat, CH-1015 Lausanne, Switzerland
[3] Swiss Fed Res Inst WSL, CH-8903 Birmensdorf, Switzerland
[4] Univ Zurich, Inst Systemat Bot, CH-8008 Zurich, Switzerland
[5] Univ Grenoble 1, CNRS, Lab Ecol Alpine, UMR 5553, F-38041 Grenoble 9, France