Infections by the fungal pathogen Batrachochytrium dendrobatidis (Bd) and members of the genus Ranavirus (Rv) are increasingly reported as significant determinants of amphibian population die-offs. The complexity associated with their transmission and spatial distribution leads to an increase in demand for comprehensive reporting systems and global mapping of their distribution. Here, we document the distribution of these 2 pathogens in a remote northern temperate lowland where environmental sensitivity is high, providing important insight into the pathogens' natural history and infection patterns. Wood frog Lithobates sylvaticus tissues were collected from the James Bay area in northeastern Canada and were screened for the presence of Bd and Rv using conventional and real-time PCR. Both pathogens were present in the study area, which is the northernmost record in eastern North America. Interestingly, different patterns of distribution were observed between the eastern and western coasts of James Bay, suggesting differences in the spatial and transmission dynamics for each pathogen. Anthropogenic introduction may still influence the distribution patterns observed, even at these latitudes. The presence of infections in this remote area also raises further questions on the risk these pathogens pose to northern amphibian communities. We encourage further research in remote locations for a better understanding of these pathogens, their transmission dynamics, and especially their respective impacts on amphibian populations worldwide.

Aim Where post‐glacial colonization and founder events are numerous, peripheral populations tend to have reduced genetic diversity as compared to their centrally located counterparts. Such decrease in genetic variability can limit their potential to adapt to changes in their environment. At northern latitudes for instance, populations are often living in conditions close to their physiological limits. Thus, identifying the levels of genetic diversity in peripheral populations is key to estimating the potential for adaptation to ongoing environmental change. In this context, we investigated the distribution of genetic diversity at the northern edge of the wood frog's (Lithobates sylvaticus) range by reconstructing its post‐glacial history in an area where phylogeographical data were lacking. Location James Bay area (north‐central Canada). Methods DNA was extracted from 463 wood frog tissue samples from 17 localities. Seven microsatellite loci were used to quantify genetic diversity and evaluate genetic structure through estimates of the fixation index, isolation‐by‐distance analyses and Bayesian clustering algorithms (tess and structure). Phylogeographical relationships were investigated using single nucleotide polymorphisms in the ND2/tRNATRP mitochondrial genes. Phylogenetic trees were built using the neighbour‐joining and the maximum likelihood inference methods implemented in mega5. Results Our analyses identified a contact zone between two colonizing lineages originating from one glacial refugium. Populations in this contact zone present sympatrically distributed haplotypes from both lineages and higher genetic variation than the surrounding populations. Population structure analyses revealed the differentiation of three genetic clusters, each covering large areas around the coast of James Bay. Main conclusions Our study suggests that higher than expected genetic diversity and gene flow may be present in peripheral populations. Such adaptive potential is critical in areas of upcoming development and environmental changes. Thus, our study emphasizes the importance of understanding species post‐glacial history for the prediction of future evolutionary trends and species distributions.