Fig 1.
Map of survey sites and eDNA concentration of water on the surface of headwater streams.
At the sites on the expanded map (A1-A7, O1-O3), we directly captured the species using the hand-capture method (Table 1). N. D. means eDNA was not-detected.
Table 1.
The results of hand-capture surveys and eDNA detection (September and October) for O. japonicus.
Fig 2.
Illustration water sampling under stones.
Fig 3.
The designed PCR primer/probe set (Ony-j_12S_F (A), _R (B), and _Probe (C)) for O. japonicus in 12S rRNA and sequence information of O. japonicus, other Onychodactylus species found outside Japan (*), and Hynobius species found in Japan. Note the sequence of Ony-j_12S_R was a reverse complement.
Fig 4.
The eDNA concentrations (in PCR reactions) from water samples collected from the surface and under stones at sites in the Akazai River.
The bold line in the box indicates the median value. The upper and lower limits of the box and the whisker plots indicate the first and third quartiles and ± 1.5 × interquartile ranges, respectively. The red dots represent each data point.
Fig 5.
Comparison of mean eDNA concentration of the water samples collected from the surface and under stones at sites in the Akazai River.
The line shows 1:1 correlation for the log10 concentrations.
Fig 6.
The mean ΔCt value from internal positive controls by the PCR inhibition test for the samples collected from the surface and under stones at sites in the Akazai River.
The bold line in the box indicates the median value. The upper and lower limits of the box and the whisker plots indicate the first and third quartiles and ± 1.5 × interquartile ranges, respectively. The red dots represent each data point.