White nose Syndrome (WNS) Fact Sheet

Recently a disease of unknown origin has been affecting hibernating bats in the northern and mid-Atlantic portion of the United States. Termed White-nose Syndrome (WNS) because of the noticeable white fungus growing on the muzzle and wings membranes of affected bats, mortality rates at a hibernation site after 2 years of infection range from 90-100%. First detected in bat hibernacula in the late winter 2007 in upper New York, it has spread to include caves in 9 states occurring as far south as Virginia. Although the causative agent is unknown, most evidence points to a newly described cold-adapted fungus Geomyces destructicans. To date, WNS is estimated to have killed over 1 million hibernating bats. The syndrome results in bats prematurely emerging from hibernation, and dying due to a lack of food resources or from exposure to freezing temperatures. Species experiencing mortality have included the federally endangered Indiana bat (Myotis sodalis) the little brown bat (Myotis lucifugus), the northern long-eared bat (Myotis septentrionalis), the small-footed bat (Myotis leibii), the eastern pipistrelle (Perimyotis subflavus), and the big brown bat (Eptesicus fuscus). The extreme declines in population levels of these two species are exacerbated by the very slow reproduction rates of bats (1-2 pups/year). There is no indication that the spread of WNS slowing and new affected hibernacula have been identified this year.

Biologists are actively discussing WNS and bat management issues, research findings, and proactive planning to devise strategies that might decrease the likelihood that many bat populations, and possibly species, are extirpated due to this disease. Due to the speed of movement and the mortality rates, there is extreme urgency in conservation needs for these species. As DoD lands play a significant role in providing roosting, maternity, and hibernacula habitat for many species of bats currently or likely to be affected by WNS, there are currently two potentially major impacts of WNS to DoD:

1. Listed species – At present, the Indiana bat is being severely affected by WNS and the advancing WNS front is now in close proximity to the range of the endangered gray bat. Once WNS appears at these hibernacula, evidence suggests bats in each affected site will be decimated. Additionally, installations are already being indirectly impacted since those bats that spend the summer on installations are experiencing mortality during the winter and are thus not returning. Declining populations of listed species will likely result in tighter restrictions on training and management activities in and around bat habitat. These increase restrictions may also eventually extend to installations that provide only maternity habitat for these species.

2. New candidates for listing – In addition to impacts to presently listed species, the declines of two formerly abundant species, the little brown bat and the northern bat have been so dramatic that discussions about their status has started. Because these two species are ubiquitous throughout the East, listing of either or both of would likely result in considerable impacts to a whole host of stewardship and management activities.

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