External temperature and distance from nearest entrance influence microclimates of cave and culvert‐roosting tri‐colored bats (Perimyotis subflavus)

• Published in: Ecology and evolution Vol. 9; no. 24; pp. 14042 - 14052
• Main Authors: Leivers, Samantha J., Meierhofer, Melissa B., Pierce, Brian L., Evans, Jonah W., Morrison, Michael L.
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.12.2019; John Wiley and Sons Inc; Wiley
• Subjects: actual water vapor pressure; Air temperature; Animal care; Bats; cave; Cavernicolous species; Caves; Chiroptera; culvert; Culverts; Data collection; Endangered & extinct species; hibernation; Humidity; Microclimate; Original Research; Overwintering; Perimyotis subflavus; Roosts; temperature; tri‐colored bat; Vapor pressure; Variation; Water vapor; Wildlife conservation; United States > US; North America; Texas; culvert; cave; microclimate; actual water vapor pressure; Perimyotis subflavus; temperature; hibernation; tri‐colored bat
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.5841

Many North American bat species hibernate in both natural and artificial roosts. Although hibernacula can have high internal climate stability, they still retain spatial variability in their thermal regimes, resulting in various “microclimates” throughout the roost that differ in their characteristics (e.g., temperature and air moisture). These microclimate components can be influenced by factors such as the number of entrances, the depth of the roost, and distance to the nearest entrance of the roost. Tri‐colored bats are commonly found roosting in caves in winter, but they can also be found roosting in large numbers in culverts, providing the unique opportunity to investigate factors influencing microclimates of bats in both natural and artificial roost sites. As tri‐colored bats are currently under consideration for federal listing, information of this type could be useful in aiding in the conservation and management of this species through a better understanding of what factors affect the microclimate near roosting bats. We collected data on microclimate temperature and microclimate actual water vapor pressure (AWVP) from a total of 760 overwintering tri‐colored bats at 18 caves and 44 culverts. Using linear mixed models analysis, we found that variation in bat microclimate temperatures was best explained by external temperature and distance from nearest entrance in both caves and culverts. External temperature had a greater influence on microclimate temperatures in culverts than caves. We found that variation in microclimate AWVP was best explained by external temperature, distance from nearest entrance, and proportion from entrance (proportion of the total length of the roost from the nearest entrance) in culvert‐roosting bats. Variation in microclimate AWVP was best explained by external temperature and proportion from entrance in cave‐roosting bats. Our results suggest that bat microclimate temperature and AWVP are influenced by similar factors in both artificial and natural roosts, although the relative contribution of these factors differs between roost types. Tri‐colored bats are commonly found winter roosting in caves, but they can also be found roosting in culverts, providing the unique opportunity to investigate factors influencing bat microclimate temperatures in both natural and artificial roost sites. We collected data on microclimate temperatures and actual water vapor pressure near roosting bats in 18 caves and 44 culverts. Our results suggest that bat microclimate components are influenced by the same factors in both artificial and natural roosts, although the relative contribution of these factors differs between roost types.