Raw data of qPCR swab results in Nova Scotia hibernacula.docx

White-nose syndrome is a skin disease of bats caused by the fungus <i>Pseudogymnoascus destructans</i> (<i>Pd</i>). <i>Pd </i>has devastated populations of some bat species in North America, where environmental reservoirs of the fungus are considered a threat to the persistence of bat populations. However, long-term patterns of <i>Pd</i> environmental persistence in North American hibernacula are unknown. We swabbed hibernacula walls eleven years after the invasion of <i>Pd</i> into Maritime Canada in 2011. This is the first study to examine persistence of <i>Pd</i> in North American hibernacula &gt; 7 years after the first documentation of <i>Pd </i>at a site. The proportion of hibernacula wall swabs with viable <i>Pd</i> decreased over time, with 40.6% of wall swabs positive (n=32) in 2012, 35.0% (n=40) in 2015, and 1.7% (n=120) in 2022. In early winter 2022, 41.18% (n=17) of bats (<i>Myotis lucifugus</i>, <i>M. septentrionalis</i>, and <i>Perimyotis subflavus</i>) were <i>Pd</i>-positive compared to 6.67% (n=15) in late winter, a low prevalence and the opposite pattern compared to the first 4 years after <i>Pd</i>-invasion to sites. Our results suggest that <i>Pd</i> loads in the environment naturally decrease to low or undetectable levels over time in our study region. Since attempts to reduce environmental reservoirs have a high likelihood of negative non-target effects on hibernacula ecosystems, and a low likelihood of completely eradicating <i>Pd</i>, actions to reduce environmental reservoirs in hibernacula should consider deprioritizing sites where <i>Pd</i> has been present &gt; 10 years. We urge the collection of further data across hibernacula sites with varied geochemistry, microclimates, organic matter availability, timing of <i>Pd</i> arrival, and surviving bat colony sizes. This will allow a more comprehensive assessment of this strategy.