Differences in the environmental variables (salinity, mean grain size, sorting, total organic content, sand, silt and clay percentages) were also tested using PERMANOVA using the same design as for the fauna. The relationships between environmental variables and nematode assemblages were explored using distance-based redundancy analysis (dbRDA) that enabled us visualize the percentage of variability in the original data explained by the axis and the relative contributions of each of the predictor variables on the assemblage structure .