Bats and Roads

Habitat fragmentation is one of the reasons that many species are endangered. Roads and railroads can present barriers for bats, i.e. if roosts are separated from hunting areas. The barrier effect exists when bats fatally collide with traffic as they attempt to cross roads. Also bats may opt to avoid passing the road, or venture a much greater distance to reach their destination.

Wildlife crossing aids serve to mitigate or eliminate the disturbances caused by man-made fragmentation in the landscape. The optimal designing of crossing aids for bats on future roads requires the assessment of how the local bat species use the area. Detailed surveys involving radio-tagging as well as the development of habitat and flight path models serve to find the exact crossing points. We employ these instruments regularly and successfully in various projects.

Crossing aids over motorways:

BAB5 near Offenburg

By constructing or remodeling existing crossing aids at major crossing points, the barrier effect can be greatly lessened. These could be underpasses or suitable overpasses (e.g. rural road bridges planted with shrubs and greenery, wildlife crossings). Taking into consideration the individual species, foliage can be implemented structurally and spatially to actually guide the bats to safety using the crossing aids.

For over 15 years we have been studying the effects of roads and transportation routes on bat populations. In 2003 Dr. Robert Brinkmann founded the task force Wildlife Crossings. His goal was to summarize the current state of knowledge and publish it in a position paper. Our expert knowledge was also incorporated into the "Planung und Gestaltung von Querungshilfen für Fledermäuse in Sachsen ‚ ein Leitfaden für Straßenbauvorhaben im Freistaat Sachsen" (Planning and designing wildlife crossings for bats in Saxony, a guideline for road building projects in Saxony).

Through our current monitoring and planning projects we continuously gain new insights on how to design crossing aids so that bats are most likely to use them.

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Please contact us with your questions.

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