Mark Brigham

Permanent URI for this collectionhttps://hdl.handle.net/10294/8900

Professor

Office: LB 242
E-mail: Mark.Brigham@uregina.ca
Phone: 306-585-4255 or 306-585-4562
Fax: 306-337-2410

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Browsing Mark Brigham by Author "Brigham, R. Mark."

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    Home is where you hang your bat: winter roost selection by prairie-living big brown bats
    (American Society of Mammalogists, 2017) Klug-Baerwald, Brandon J.; Lausen, Cori L.; Willis, Craig K.R.; Brigham, R. Mark.
    Information on the roost requirements of small, temperate-zone hibernating bats, which can spend up to 8 months in hibernation, is crucial to their conservation. We studied male big brown bats (Eptesicus fuscus) in southeastern Alberta, Canada, to investigate the physical and microclimate characteristics of hibernacula used by this species in a prairie river valley (Dinosaur Provincial Park, DPP). We monitored roosting behavior and movement, and also compared microclimate conditions (temperature and humidity) within these crevice hibernacula to those of random crevices within the study area, and to conditions inside 4 known cave hibernacula in central and northern Canada. Our results show that male E. fuscus in DPP use rock-crevice hibernacula with less variable temperatures than ambient and random crevice temperatures, with evidence of winter roost fidelity within and between years. Bats used only 3 hibernacula and, although mid-winter flight is common in our study area, there was little movement by bats between hibernacula. Rock-crevice hibernacula were warmer and more thermally stable than other available crevices in DPP, and drier but not necessarily colder than known cave hibernacula elsewhere. Our study is the first to examine crevice roost selection by bats during winter, and suggests that specific hibernacula are important for individual bats, despite the fact that numerous crevices are available.
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    Hung out to dry? Intraspecific variation in water loss in a hibernating bat
    (Springer, 2017) Klug-Baerwald, Brandon J.; Brigham, R. Mark.
    Hibernation is a period of water deficit for some small mammals, and humidity strongly influences hibernation patterns. Dry conditions reduce length of torpor bouts, stimulate arousals, and decrease overwinter survival. To mitigate these effects, many small mammals hibernate in near saturated (100% RH) conditions. However, big brown bats (Eptesicus fuscus) hibernate in a wider variety of conditions and tolerate lower humidity than most other bats. To assess arid tolerance in this species, we compared torpid metabolic rates (TMR) and rates of total evaporative water loss (TEWL) between two populations of E. fuscus with differing winter ecologies: one that hibernates in humid karst caves and one that hibernates in relatively dry rock crevices. We used flow-through respirometry to measure TMR and TEWL of bats in humid and dry conditions. Torpid metabolic rates did not differ between populations or with humidity treatments. Rates of TEWL were similar between populations in humid conditions, but higher for cave-hibernating bats than crevice-hibernating bats in dry conditions. Our results suggest that E. fuscus hibernating in arid environments have mechanisms to decrease evaporative water loss that are not evident at more humid sites. Drought tolerance may facilitate the sedentary nature of the species, allowing them to tolerate more variable microclimates during hibernation and thus increasing the availability of overwintering habitat. The ability to survive arid conditions may also lessen the susceptibility of E. fuscus to diseases that affect water balance.