Mitigating the Impact of Bats in Historic Churches: The Response of Natterer’s Bats Myotis nattereri to Artificial Roosts and Deterrence

Abstract

Bats frequently roost in historic churches, and these colonies are of considerable conservation value. Inside churches, bat droppings and urine can cause damage to the historic fabric of the building and to items of cultural significance. In extreme cases, large quantities of droppings can restrict the use of a church for worship and/or other community functions. In the United Kingdom, bats and their roosts are protected by law, and striking a balance between conserving the natural and cultural heritage can be a significant challenge. We investigated mitigation strategies that could be employed in churches and other historic buildings to alleviate problems caused by bats without adversely affecting their welfare or conservation status. We used a combination of artificial roost provision and deterrence at churches in Norfolk, England, where significant maternity colonies of Natterer’s bats Myotis nattereri damage church features. Radio-tracking data and population modelling showed that excluding M. nattereri from churches is likely to have a negative impact on their welfare and conservation status, but that judicious use of deterrents, especially high intensity ultrasound, can mitigate problems caused by bats. We show that deterrence can be used to move bats humanely from specific roosting sites within a church and limit the spread of droppings and urine so that problems to congregations and damage to cultural heritage can be much reduced. In addition, construction of bespoke roost spaces within churches can allow bats to continue to roost within the fabric of the building without flying in the church interior. We highlight that deterrence has the potential to cause serious harm to M. nattereri populations if not used judiciously, and so the effects of deterrents will need careful monitoring, and their use needs strict regulation.

Effects of artificial illumination on drinking bats: a field test in forest and desert habitats

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No evidence for memory retention of a learned association between a cue and roost quality after hibernation in free‐ranging bats

“…From an applied conservation perspective, getting insights into species’ behavioral responses in their habitat is essential for planning adequate conservation measures (Berger‐Tal et al., 2011). In the particular case of bats, how species react to new roosting options (i.e., exploration and use) determines, in the long term, the success of species management measures (Rueegger, Goldingay, Law, & Gonsalves, 2019; Zeale et al., 2016).…”

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