Fig 1.
Conceptual diagram of the experimental design.
The impact of different environmental processes (retention, transport, binding and resuspension) on eDNA analysis as a function of time and fish density (2, 4 and 8 fish): A: Treatment with sediment and flowing water, B: Treatment with flowing water without sediment, C: Treatment with still water and sediment, and D: Treatment with still water without sediment. Samples were taken after fish were removed (24 h after start of the experiment). In addition, the bins were sampled three times within 144 hours. A control without fish was included for every treatment.
Fig 2.
Positive eDNA detection rates over the 144 h experimental time course.
Grey area: Duration of fish exposure. Fish were removed at time point 24 h. Sample size n = 27 per time point. A) Treatments without sediment (NS-NF: no sediment, no flow; NS-F: no sediment, flow) B) treatments with sediment (S-F: sediment, flow; S-NF; sediment, no flow).
Table 1.
Full model results for binary logistic regression.
Likelihood estimation for positive eDNA detection for different experimental conditions and variable interactions for sediment presence (0/1), flow condition (0/1), fish density (n = 2,4,8) and time point (t = 0,24,48,144h).
Fig 3.
3D surface plots of significant 2-way interactions responsible for changes in positive eDNA detection likelihood.
Table 2.
Binary logistic regression analysis during the 144 h experimental time course.
Likelihood estimation for positive eDNA detection for different experimental conditions sediment (0/1), flow (0/1) and fish density (n = 2,4,8). Significant P—values are indicated in bold.
Table 3.
Binary logistic regression analysis for different inhibitor effects (algae (ALG), humus (HUM), siliceous (SEDA) and calcareous (SEDB) fine sediment) on positive eDNA detection.
Significant P–values are indicated in bold.
Fig 4.
DNA quantification with different inhibitors.
Cycle thresholds of goby DNA quantification with different inhibitors at 10, 100, and 1000 mg L-1. Cq values are fitted to a logarithmic trend. Higher Cq values represent a lower amount of DNA. A) algae, B) humus, C) a sediment, D) b sediment. Dotted lines indicate 95% confidence limits.