design: For total DNA extraction, we used the PowerMax Soil DNA Isolation Kit (MO BIO Laboratories, USA) according to the manufacturers instructions. We used 10 g (dry weight) from all soil samples and 15 ml of the litter samples (corresponding to 310 g of dry weight litter, depending on texture and composition). We checked DNA extraction quality and concentration in a Qubit 30 fluorimeter (Invitrogen, Sweden). The soil and litter samples from which DNA was successfully extracted were sent to Aimethods (Germany) for amplification and sequencing. We targeted prokaryotes with the V3-V4 region (~460 bases) of the 16S rDNA gene using the forward primer (5-CCTACGGGN GGCWGCAG-3) and the reverse primer (5-GACTACH VGGGTATCTAATCC-3) from Klindworth et al. (2013).