Characterizing the winter bat population, microclimate, and mycobiota of hibernating bats in New Brunswick caves

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University of New Brunswick


Little is known regarding the overwintering population and hibernaculum conditions of bats in New Brunswick. The predicted arrival of white-nose syndrome (WNS), an invasive pathogen associated with the fungus Geomyces destructans, emphasized the need to establish population estimates and the fungal community on overwintering bats before WNS arrival. Known hibernacula were surveyed in autumn-spring 2009-2011 and the mycology of a sample of bats from each site was determined. The majority of hibernating bats in New Brunswick caves and mines are Myotis lucifugus and M septentrionalis, with low numbers of Perimyotis subflavus. The New Brunswick hibernacula that appear to be preferred by these species have little temperature variation and average winter dark zone temperatures of 4-5°C. A total of 118 fungal species were recorded from the fur and skin of apparently healthy hibernating bats. The fungi include a core group of nine commonly-isolated taxa, and a larger secondary group, often with rare species occurring in a single sample. Less than 25 taxa had been recorded in the two previous studies on bat mycology worldwide and my work suggests that the fungal community associated with wintering bats is more diverse and complex than believed. Geomyces destructans was not recorded, but the isolation of G. pannorum sensu lato from 70% of hibernating bats sampled may complicate diagnostics for G. destructans in other studies. WNS was first documented in New Brunswick in March 2011, and resulted in catastrophic declines in overwintering bats in the province.