New York Natural Heritage Program
Northern Long-eared Bat
Myotis septentrionalis (Trovessart, 1897)

Conservation Overview [-]
The northern myotis is primarily associated with uplands and mature interior forests. Populations in New York and the eastern U.S. are threatened by white-nose syndrome. Due to the potential for continued rangewide declines from white-nose syndrome, the northern myotis has been proposed for listing as an endangered species under the Endangered Species Act (U.S. Fish and Wildlife Service 2013). Other threats to this species include incompatible forest management practices, development, habitat fragmentation, and environmental toxins.

Threats [-]
By far the largest threat to northern myotis in New York is white-nose syndrome (WNS) which was first discovered among bats in a cave in Schoharie County, New York in 2006. White-nose syndrome is caused by a fungus Pseudogymnoascus destructans (previously Geomyces destructans) that is often visible on the bats' muzzle and wings (Blehert et al. 2009). The fungus may invade hair follicles and cause lesions under the skin (Blehert et al. 2009). Bats wake from hibernation to groom and consequently burn fat reserves that are needed to survive the winter and they become emaciated (Blehert et al. 2009). Extensive damage to their wing membranes and dehydration may also be contributing factors to mortality (U.S. Fish and Wildlife Service 2013).
Some forest management practices may not be compatible with this species. Since northern myotis are adapted to exploit mature interior forest, harvests that remove significant canopy cover can reduce habitat for this species. The 90-day finding on the petition to list the northern myotis under the Endangered Species Act cited direct and indirect effects of logging as a threat to this species (U.S. Fish and Wildlife Service 2011). Direct mortality could occur when felled live trees contain colonies or roosting individuals and timber management may reduce or fragment the mature interior forest habitat required by this species. Similarly, development can also fragment forests making them unsuitable for this species.
Bats may be particularly sensitive to environmental toxins including those found in herbicides and pesticides. Although no studies have targeted northern myotis directly, elevated levels of persistent organic pollutants including especially PCBs, DDT, Chlordanes, and PBDEs have been found in a similar species, the little brown bat, in the Hudson River Valley in New York (Kannan et al. 2010). The levels found in the bats were only 1 to 3 times less than lethal concentrations reported from previous studies (Kannan et al. 2010). Lesser toxin levels may be expected in northern myotis since little brown bats typically consume a greater percentage of prey with an aquatic life stage. Bats are highly susceptible to DDT residue and this chemical was widely used as a pesticide to control bat infestations in houses in the 1940s (USGS 2013). It was widely used as an agricultural pesticide in the 1950s and 60s until its agricultural use was banned in 1972. Since DDT is highly persistent (soil half-life is 2-15 years, aquatic half-life is about 150 years) (NPIC 1999), it can pose a threat to bats when there is exposure to trace residues in the environment (USGS 2013). Extensive applications of insecticides and some bio control methods, such as Btk, could also pose an indirect risk to northern myotis by reducing availability of prey.
If proper precautions are not used, cavers and researchers entering hibernacula may cause disturbance that rouses bat colonies or transport the fungus that causes WNS on their clothing (NatureServe 2013). Other potential threats may include climate change, commercial cave development, flooding and hibernacula collapse; habitat loss and fragmentation from development, hydraulic fracturing, and construction of new wind facilities; and direct mortality from wind facilities (U.S. Fish and Wildlife Service 2013).

Conservation Strategies and Management Practices [-]
Gating mines and caves can prevent human entry while allowing the bats unobstructed access. Following proper specifications and monitoring bat populations before and after gate installation are important, however, as gating can affect the airflow and temperature in the cave, making areas of the cave uninhabitable for certain species (U.S. Fish and Wildlife Service 2013). Buildup of debris at cave entrance gates may have the same effect (U.S. Fish and Wildlife Service 2013). Retaining large trees and unfragmented blocks of late-seral stage forests of mixed age classes may be important for this species. Harvests that substantially reduce the forest canopy may not be compatible with habitat management for this species.

Development and Mitigation Considerations [-]
Retaining snags and dying trees can provide summer roosting habitat for northern myotis. Retaining overhead canopy, mature trees, and minimizing fragmentation of mature patches may also be important.

Research Needs [-]
Research is needed to document summer roost locations in New York and to determine the extent of local populations. Ongoing winter hibernacula surveys are needed to monitor trends of the remaining populations.

Regional Conservation Needs [-]
Conservation needs have not yet been assessed for this species in New York. The current distribution of northern myotis in the state, as well as identification of summer locations with the highest local abundances are needed prior to determining specific management and conservation needs.