The number of shared DNA species amongst extraction methods illustrated using Venn diagrams (a–c; g–i) and pairwise beta diversity values within extraction methods at each site measured as Sørensen dissimilarity (βsor, which is partitioned to nestedness, βsne and species turnover, βsim) (d–f; j–l), lines denote group means and 95% confidence intervals for βsor and βsne. The small letters denote significantly different extraction methods at each sampling site based on non-overlapping 95% confidence intervals for βsor and βsne.