Limited dispersion and quick degradation of environmental DNA in fish ponds inferred by metabarcoding

Environmental DNA (eDNA) metabarcoding is a promising tool for rapid, non-invasive biodiversity monitoring. In this study, eDNA metabarcoding is applied to explore the spatial and temporal distribution of eDNA in two ponds following the introduction and removal of two rare fish species. When two rare species were introduced and kept at a fixed location in the ponds, eDNA concentration (i.e., proportional read counts abundance) of the introduced species typically peaked after two days. Thereafter, it gradually declined and stabilised after six days. These findings are supported by the highest community dissimilarity of different sampling positions being observed on the second day after introduction, which then gradually decreased over time. On the sixth day, there was no longer a significant difference in community dissimilarity between sampling days. The introduced species were no longer detected at any sampling positions 48 hrs after removal from the ponds. The eDNA signal and detection probability of the introduced species were strongest near the keepnets, resulting in the highest community variance of different sampling events at this position. Thereafter, the eDNA signal significantly decreased with increasing distance, alt...Continue Reading