Microclimate and roost selection in four New Hampshire bat hibernacula

Durham, Heather C.
Jon Atwood, PhD
Department of Environmental Studies
Hibernating bats have evolved some of the most physiologically demanding adaptations of any temperate taxa. I examined the microclimates of four New Hampshire bat hibernacula in abandoned mines during winter population surveys. Bat species distributions in the mineshafts were noted, and an attempt was made to determine roots selection patterns based on microclimate variables. Microclimate characteristics were similar among the four mines surveyed. Our data showed three factors that influence relative location of bat species within each mine - relative humidity, temperature, and distance from the entrance. Relative humidity was adequate for the needs of most hibernating bats throughout all four mines. Although it was difficult to identify specific temperature preferences of these hibernating baths, species did show strong preferences for the 6-9 degree C range across all mines surveyed. Distance from entrance likely affected each species differently, although more research is needed in this area. Each mine was evaluated based on its importance as a hibernaculum, and suggestions made for protection from disturbance. Due to their limited availability, vulnerability, and importance to bat survival, bat hibernacula should continue to be studied and protected.

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