Journal Article

Disease‐related population declines in bats demonstrate non‐exchangeability in generalist predators

Jusino, Michelle A., Peery, M. Zachariah, Wang, Jing Jamie, Banik, Mark T., Gratton, Claudio, Lindner, Daniel L., Wray, Amy K., Kochanski, Jade M., Palmer, Jonathan M.

2022

Overview

The extent to which persisting species may fill the functional role of extirpated or declining species has profound implications for the structure of biological communities and ecosystem functioning. In North America, arthropodivorous bats are threatened on a continent‐wide scale by the spread of white‐nose syndrome (WNS), a disease caused by the fungus Pseudogymnoascus destructans. We tested whether bat species that display lower mortality from this disease can partially fill the functional role of other bat species experiencing population declines. Specifically, we performed high‐throughput amplicon sequencing of guano from two generalist predators: the little brown bat (Myotis lucifugus) and big brown bat (Eptesicus fuscus). We then compared changes in prey consumption before versus after population declines related to WNS. Dietary niches contracted for both species after large and abrupt declines in little brown bats and smaller declines in big brown bats, but interspecific dietary overlap did not change. Furthermore, the incidence and taxonomic richness of agricultural pest taxa detected in diet samples decreased following bat population declines. Our results suggest that persisting generalist predators do not necessarily expand their dietary niches following population declines in other predators, providing further evidence that the functional roles of different generalist predators are ecologically distinct. While many bat species are known to function as suppressors of arthropod abundance, including several economically important agricultural pest taxa, the broader ecological consequences of disease‐related bat declines have not been fully assessed in many regions. In our study, we tested whether big brown bats (Eptesicus fuscus), which demonstrate lower mortality from white‐nose syndrome, could potentially fill the ecological role formerly occupied by the more severely affected little brown bat (Myotis lucifugus). Overall, we found that big brown bats did not adopt more of the prey formerly consumed by little brown bats and that the dietary niche overlap between the two bat species did not change over time.

• Publisher: John Wiley & Sons, Inc,John Wiley and Sons Inc,Wiley
• Subject: bat diet / Bats / Chelonoidis abingdonii / community science / Dung / Ecological function / Eptesicus fuscus / Flexibility / Foraging behavior / Guano / high‐throughput sequencing / metabarcoding / Myotis lucifugus / Niches / Physiology / Population / Population decline / Predators / Prey / Species / Trophic Interactions / White-nose syndrome / white‐nose syndrome (WNS)