Fig. 6

Redundancy analysis (RDA) of microbial indices (blue lines) and environmental variables (red lines) with the ordination scores of seven biomarker classes. Seven biomarker classes were used to construct statistical matrix. The angle and length of the blue (and/or red) arrows (vectors) indicate the direction and strength of the relationship of microbial indices with the ordination scores in litter substrate quality (carbon (C), nitrogen (N) and phosphorous (P) stoichiometric ratio and dissolved organic carbon (DOC), dissolved nitrogen (DN), dissolved phosphorous (DP)) and enzyme activities (β-glucosidase (BG), acid phosphatase (AP), cellobiohydrolase (CBH), leucine aminopeptidase (LAP), β-N-acetylglucosaminidase (NAG) and POD (peroxidase)). Gram-positive bacteria (G+), gram-negative bacteria (G−), fungi: bacteria ratio (F/B), gram-negative:gram-positive (G−/G+) (blue lines). Trilateral: spruce; square: fir; rhombus: birch; circle: rhododendron. Yellow: fresh litter layer; white: fermentative layer; green: humus layer