Determinants of the performance of bat gantries installed to carry bat commuting routes over the S3 expressway in Poland

Abstract

In road construction, environmental protection issues often become a challenge, both in the case of new routes and the existing network expansion projects. A number of specific issues are involved in severing of bat commuting routes and the relevant mitigation measures are still in the experimental stage. One of the measures are bat gantries installed on the established bat flyways aligned with the linear features of the landscape used by bats for echolocation calls, which is an example of the structures installed near Szczecin in Poland. The bat activity surveys revealed different levels of acceptance of the respective structures. The available studies identify the following factors as being relevant to relocated or modified commuting routes: road traffic volume, traffic noise, and light pollution. The article discusses which factors are the most likely to have a significant bearing on accepting specific structures by bats. The analyses show that a gantry structure can turn out to be acceptable to bats even on a completely new route if the landscape features are symmetrical and friendly to bats on both sides of the road and on both sides of their flyway as well. Conversely, without such a symmetry along the approach section, the structure may fail to perform.