7. Application to basic landscape genetics
Finally, to verify that eDNA can address basic landscape genetics questions, we examined whether two patterns previously shown in the targeted system (Nakajima et al. 2021) were also detected by analysis using eDNA. These patterns were: (i) genetic differentiation is significantly correlated with waterway geographic distance (isolation-by-distance) and (ii) genetic differentiation is not correlated with differences in summer water temperature between populations. From the 19 populations except Pop 20 and Pop 21 where water temperature data are unavailable and 13 populations in the upstream dataset (assuming local scale studies), correlations ofD PS with waterway geographic distance and water temperature differences were calculated by Mantel tests with 9999 permutations.