Thermoregulatory ecology and roost selection of imperiled bat species

Bats represent a diverse order of mammals with almost 1,500 species. Over one-third of bats are threatened with extinction due to a novel disease, wind energy development, human persecution, and unsustainable land conversion. In North America, the introduced fungal pathogen known as white-nose syndrome has killed millions of hibernating bats and resulted in the regional extirpation of some species. To mitigate these threats, managers are focused on providing bats with safe hibernacula and creating energetically beneficial summer roosting habitat through strategic forest management practices and the deployment of novel artificial roost designs. For my doctoral research, I used temperature-sensitive radio telemetry, bioenergetic models, and acoustic lure technology to investigate roost selection, torpor expression, and energy expenditures of bats using novel artificial roost designs and roost trees generated through forest management. I further used remote temperature-sensing dataloggers and experimental fungal growth trials to assess the suitability of silica mine hibernacula as refugia from white-nose syndrome for bats. My summer roost-focused work demonstrated that strategically girdling trees creates viable roosts for the endangered Indiana bat (Myotis sodalis), subtle modifications to artificial roost design that impact the supported internal temperatures do not alter the torpor expression of Indiana bats, and that broadcasting an acoustic lure at clusters of artificial roosts did not speed colonization by the endangered Florida bonneted bat (Eumops floridanus). In my hibernacula-focused work, I demonstrated that the fungus Pseudogymnoascus destructans, responsible for white-nose syndrome in bats, does not grow as well on silica mine hibernacula substrates compared to cave substrates. Key takeaways from this work are: 1) strategic tree girdling can generate roosts for bats where dead trees are lacking, 2) it is possible to modify artificial roosts to reduce instances of overheating without affecting bats’ thermoregulatory behaviors, 3) we need further study of the context behind bat vocalizations to improve acoustic lure technology, and 4) silica mines are significant hibernacula for bats, as they may represent disease refugia for hibernating bats. Taken together, my dissertation work will influence the future use and deployment of artificial roosts globally, adds scientific backing to an emerging conservation tool intended to generate roosts on managed forests, and highlights the importance of investigating unique and novel overwintering sites for bats.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Ecol, Evol, Conservation Biol

Grantor

University of Illinois Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Crawford, Reed David

Contributors dc:contributor

• O'Keefe, Joy M
• Doty, Anna C
• Fuller, Rebecca C
• Suski, Cory D
• Ward, Michael P

• Artificial roosts
• Bats
• Bat boxes
• Conservation
• Ecology
• White-nose syndrome

Statement dc:rights

• Copyright 2025 Reed Crawford

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/129244

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F129244