AUTHOR CONTRIBUTIONS
GFF, JP, WT, PT, GAD, DF, RA and MC designed the experiment. SM, GFF,
RA, MC, FG, MG, conducted the field work. AG, AB and LG conducted
molecular analyses. AG and AB performed the bioinformatic treatment of
sequence data. CC, AZ, JP performed edaphic analyses. AG, AC, IC ran
statistical analyses. AG, AC and GFF drafted the manuscript. All the
authors contributed substantially to the revision process, and accepted
the final version.