The boreal chorus frog (Pseudacris maculata) is at risk of extinction in parts of its range in Canada. Our objectives were to quantify the influence of local and landscape characteristics on the occurrence of the species in wetlands in southern Québec. We hypothesized that site occupancy depends on local characteristics and landscape characteristics contributing to site connectivity. We developed an environmental DNA (eDNA) method to detect the species and compared the detection probability of this method to traditional call surveys. We collected water samples at a total of 180 sites (90 in 2017, 110 in 2018), whereas we surveyed a subset of 63 sites using both eDNA and call surveys in 2018. Site occupancy varied across years, but was higher in sites where the species had been previously detected during the last 12 years by other studies. Site occupancy did not vary with other local and landscape characteristics, in part due to an apparent decrease in the number of sites occupied by the species since the last 12 years. Detection probability via eDNA (0.81; 95% CI: [0.31; 0.98]) did not differ from that of call surveys (0.62; 95% CI: [0.25; 0.89]). To identify the optimal sampling period for the boreal chorus frog, future studies should estimate the detection probability of eDNA during the breeding season and the larval development period of the species.

The data presented in the files include the detection data of the boreal chorus frog (Pseudacris maculata) using environmental DNA (eDNA) and call surveys in southeastern Québec, Canada. A total of 180 ponds were sampled during the breeding season in 2017 and 2018 with eDNA, whereas a subset of these ponds were also sampled with call surveys.

The values presented in the data set are the original variables. Note that numeric explanatory variables (except PCA scores) were standardized to mean 0 and unit variance before being entered in the analyses.