3.2. Sediment analysis
The results of the PCA showed that the first three axes explain 90% of the total variance (Axis 1 = 52.1%; Axis 2 = 26.4%; Axis 3 = 11.5%; Axis 4 = 0.08%; Axis 5 = 0.02%). The variable loadings to each axis demonstrate that total Nitrogen concentration, %Clay, pH and %Sand equally contribute to the variance of the first axis (Tab. 1). While the contribution of total Nitrogen concentration and %Clay is positive, the contribution of pH and %Sand is negative. Regarding the second axis, most of the variance is explained by the %Sand and %Silt, with positive and negative contribution, respectively (Tab. 1). The variance of the third axis is mostly explained by the concentration of organic carbon, which shows a negative contribution (Tab. 1). Results of the PERMANOVA performed on the physical and chemical parameters of collected sediments (Fig. 2) revealed significant differences among caves (F3,31 = 55.4, P = 0.001), but not among transects (F3,31 = 1.81, P = 0.165) and sectors (F2,31 = 0.856, P = 0.485).