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Age of enlightenment : Long-term effects of outdoor aesthetic lights on bats in churches

Rydell, Jens LU ; Eklöf, Johan and Sánchez-Navarro, Sonia (2017) In Royal Society Open Science 4(8).
Abstract

We surveyed 110 country churches in south-western Sweden for presence of brown long-eared bats Plecotus auritus in summer 2016 by visual inspection and/or evening emergence counts. Each church was also classified according to the presence and amount of aesthetic directional lights (flood-lights) aimed on its walls and tower from the outside. Sixty-one of the churches had previously been surveyed by one of us (J.R.) between 1980 and 1990, before lights were installed on Swedish churches, using the same methods. Churches with bat colonies had decreased significantly in frequency from 61% in 1980s to 38% by 2016. All abandoned churches had been fitted with flood-lights in the period between the two surveys. The loss of bat colonies from... (More)

We surveyed 110 country churches in south-western Sweden for presence of brown long-eared bats Plecotus auritus in summer 2016 by visual inspection and/or evening emergence counts. Each church was also classified according to the presence and amount of aesthetic directional lights (flood-lights) aimed on its walls and tower from the outside. Sixty-one of the churches had previously been surveyed by one of us (J.R.) between 1980 and 1990, before lights were installed on Swedish churches, using the same methods. Churches with bat colonies had decreased significantly in frequency from 61% in 1980s to 38% by 2016. All abandoned churches had been fitted with flood-lights in the period between the two surveys. The loss of bat colonies from lit churches was highly significant and most obvious when lights were applied from all directions, leaving no dark corridor for the bats to leave and return to the roost. In contrast, in churches that were not lit, all of 13 bat colonies remained after 25+ years between the surveys. Lighting of churches and other historical buildings is a serious threat to the long-term survival and reproduction of light-averse bats such as Plecotus spp. and other slow-flying species. Bat roosts are strictly protected according to the EU Habitats Directive and the EUROBATS agreement. Lighting of buildings for aesthetic purposes is becoming a serious environmental issue, because important bat roosts are destroyed in large numbers, and the problem should be handled accordingly. As a start, installation of flood-lights on historical buildings should at least require an environmental impact assessment (EIA).

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Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Biodiversity, Cultural heritage, Energy, Global change, Historic buildings, Light pollution
in
Royal Society Open Science
volume
4
issue
8
publisher
Royal Society
external identifiers
  • scopus:85026997787
ISSN
2054-5703
DOI
10.1098/rsos.161077
language
English
LU publication?
yes
id
6cf53581-4fe8-402e-b94e-cebecaa14b01
date added to LUP
2017-08-29 13:26:00
date last changed
2017-08-29 13:26:00
@article{6cf53581-4fe8-402e-b94e-cebecaa14b01,
  abstract     = {<p>We surveyed 110 country churches in south-western Sweden for presence of brown long-eared bats Plecotus auritus in summer 2016 by visual inspection and/or evening emergence counts. Each church was also classified according to the presence and amount of aesthetic directional lights (flood-lights) aimed on its walls and tower from the outside. Sixty-one of the churches had previously been surveyed by one of us (J.R.) between 1980 and 1990, before lights were installed on Swedish churches, using the same methods. Churches with bat colonies had decreased significantly in frequency from 61% in 1980s to 38% by 2016. All abandoned churches had been fitted with flood-lights in the period between the two surveys. The loss of bat colonies from lit churches was highly significant and most obvious when lights were applied from all directions, leaving no dark corridor for the bats to leave and return to the roost. In contrast, in churches that were not lit, all of 13 bat colonies remained after 25+ years between the surveys. Lighting of churches and other historical buildings is a serious threat to the long-term survival and reproduction of light-averse bats such as Plecotus spp. and other slow-flying species. Bat roosts are strictly protected according to the EU Habitats Directive and the EUROBATS agreement. Lighting of buildings for aesthetic purposes is becoming a serious environmental issue, because important bat roosts are destroyed in large numbers, and the problem should be handled accordingly. As a start, installation of flood-lights on historical buildings should at least require an environmental impact assessment (EIA).</p>},
  articleno    = {161077},
  author       = {Rydell, Jens and Eklöf, Johan and Sánchez-Navarro, Sonia},
  issn         = {2054-5703},
  keyword      = {Biodiversity,Cultural heritage,Energy,Global change,Historic buildings,Light pollution},
  language     = {eng},
  month        = {08},
  number       = {8},
  publisher    = {Royal Society},
  series       = {Royal Society Open Science},
  title        = {Age of enlightenment : Long-term effects of outdoor aesthetic lights on bats in churches},
  url          = {http://dx.doi.org/10.1098/rsos.161077},
  volume       = {4},
  year         = {2017},
}