design: DNA from soil samples was extracted via the Qiagen DNeasy PowerSoil Kit (Germantown, MD), following manufacturers instructions. Sequencing was performed in the Ge- netics Core at the University of Arizona, and polymerase chain re- action (PCR) parameters included denaturation at 98 C for 5 min, 34 cycles of denaturation at 50 C for 30 sec, annealing at 72 C for 1 min, and an extension at 72 C for 5 min. For fungi, the ITS2 gene region was amplified using primers fITS7 and ITS4 ( Ihrmark et al. 2012 )