The use of wildlife overpasses by mammals: Results from infrared video surveys in Switzerland, Germany, France, and the Netherlands

  • Published source details Keller V. (1999) The use of wildlife overpasses by mammals: Results from infrared video surveys in Switzerland, Germany, France, and the Netherlands. Fifth Infra EcoNetwork Europe (IENE) Meeting report.


This study is summarised as evidence for the following.

Action Category

Install overpasses over roads/railways

Action Link
Terrestrial Mammal Conservation
  1. Install overpasses over roads/railways

    A replicated study in 1996 of roads in Germany, Switzerland, France and the Netherlands (Keller 1999) found that mammals used flyovers as bridges/overpasses across roads, and frequency of their use tended to increase with overpass width. For all mammal species, frequency of use of the seven narrow overpasses (<15 m wide) was very low. Roe deer Capreolus capreolus used the nine medium-sized (15–50 m wide) and five wide overpasses (>50 m wide) significantly more frequently than they used narrow overpasses. Twenty-one wildlife flyovers/overpasses, in Germany (eight), Switzerland (six), France (four) and the Netherlands (three), were monitored using infra-red video equipment. Flyover widths were 3.4–186 m. Video surveys were carried out during a total of 223 nights.

    (Summarised by: Rebecca K. Smith)

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