Turnover in taxonomic functional and phylogenetic composition from eDNA
We computed taxonomic beta diversity between samples in the two areas using the Jaccard index. To document the functional dissimilarity between the two coastal areas, we computed the functional βdiversity index and its classical decomposition into two additive components: the functional turnover and the functional nestedness resultant (Villéger et al. 2013, Baselga 2010, 2012). To document the dissimilarity in phylogenetic diversity between the two areas, we computed the UniFrac index (Lozupone and Knight 2005) and its classical decomposition in two additive components: the UniFrac Turnover (UniFracTurn) and the UniFrac Phylogenetic Diversity (UniFracPD, Leprieur et al. 2012 ). We computed the mean and the standard deviation of all the previous indices. All the β -diversity indices were computed using the “Betapart” R package. To visually represent the differences in eDNA composition between the sampling stations in Willemstad and Valentijnsbaai, we used a PCoA on the Jaccard distance matrix. We reported the explained deviance of each axis and mapped the ordination values in the geographic space of the PCoA. We further performed a PCoA on the UVC samples which we compared with the eDNA ordination.