only marginally significantP = 0.074
PERMANOVA indicated differences among site groups ( F = 2.226, P < 0.001, R 2 = 0.12) and years ( F = 4.6196, P = 0.004, R 2 = 0.24), while interaction between time and site group was only marginally significant ( F = 1.143, P = 0.074, R 2 = 0.12).