The comparison was made considering the presence/absence (qualitative) and the abundance (quantitative) of taxonomic unities. All P-values have been corrected for multiple comparisons by multiplying the calculated P-value by the number of comparisons made (Bonferroni correction). For each pairwise comparison, if the p-value is less than or equal to 0.001 the result indicates a highly significant difference in the composition of the communities sampled by each library. P-values from 0.001 to 0.01 indicate a significant difference, from 0.01 to 0.05 indicate a marginally significant difference, from 0.05 to 0.1 indicate a suggestive difference and if the p-values are greater than 0.1 the result indicate that the difference is not significant.