Divert bats to safe crossing points over or under roads/railways with plantings or fencing
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
Background information and definitions
Linear features such as hedgerows and treelines provide important commuting routes for bats (e.g. Limpens & Kapteyn 1991, Verboom & Huitema 1997, Downs & Racey 2006). Roads or railways can fragment these commuting routes cutting off important habitat. Attempts may be made to divert bats from their original commuting routes to crossing structures or safe crossing places along roads/railways, by planting tree lines or hedgerows, or installing fences. Berthinussen & Altringham (2012) found that although diverted bats were not recorded directly, very few bats used two underpasses below roads where attempts had been made to divert bats to them with plantings. Conversely, high numbers of bats were found using an underpass constructed on an original flight path.
For general interventions that involve creating or retaining bat commuting routes, see ‘Create new unlit bat commuting routes using planting’ and ‘Retain existing bat commuting routes’.
Berthinussen A. & Altringham J. (2012) Do bat gantries and underpasses help bats cross roads safely? PLoS ONE, 7,e38775.
Downs N.C. & Racey P.A. (2006) The use by bats of habitat features in mixed farmland in Scotland. Acta Chiropterologica, 8, 169–185.
Limpens H.J. & Kapteyn K. (1991) Bats, their behaviour and linear landscape elements. Myotis, 29, 39–48.
Verboom B. & Huitema H. (1997) The importance of linear landscape elements for the pipistrelle Pipistrellus pipistrellus and the serotine bat Eptesicus serotinus. Landscape Ecology, 12, 117–125.
Supporting evidence from individual studies
A controlled, before-and-after study in 2003 of a bat roost in an agricultural area of Giswil, Switzerland (Britschgi et al. 2004) found that more lesser horseshoe bats Rhinolophus hipposideros exiting from the roost from one side flew in a particular direction after an artificial hedgerow was installed. The number of bats flying in a particular direction increased after an artificial hedgerow had been installed for over two weeks (before: average 3% of bats; after: 10% of bats). Bats flying along the artificial hedgerow were found to emerge earlier from the roost and return later than bats using other flight routes and were out of the roost for longer (up to 4 minutes more). The artificial hedgerow (1 m wide x 1.5–2 m high x 200 m long) consisted of native hedgerow plants in containers. It was placed through open farmland to connect the bat roost with a foraging habitat within forest. The experiment was split into phases of 4–5 nights, with one phase each for before and after control periods, and 6 experimental phases with the artificial hedgerow in place. Bat activity was monitored with bat detectors and infrared video cameras for >50 minutes at sunset and sunrise for 39 nights in July–September 2003.Study and other actions tested
Referenced paperBritschgi A., Theiler A. & Bontadina F. (2004) Wirkungskontrolle von Verbindungsstrukturen. Teilbericht innerhalb der Sonderuntersuchung zur Wochenstube der Kleinen Hufeisennase in Friedrichswalde-Ottendorf / Sachsen. BMS GbR, Erfurt & SWILD, Zurich report, Unpublished report on behalf of DEGES, 23pp.