The aims of this UK government-funded project were to develop standardised cost-effective survey methods to assess the effects of linear transport infrastructure on bats and the effectiveness of crossing structures as mitigation. The methods developed (which include broadband acoustic surveys along transects and static observational surveys) are suitable for robust, objective statistical analysis when appropriate, and can be used for pre, during and post-construction monitoring. They can also be used to gather baseline data for Environmental Statements. To assist practitioners detailed protocols for fieldwork and subsequent data analysis and presentation have been published. The effectiveness of many currently used mitigation measures for bats (including underpasses, overpasses, wire bat bridges and a green landscape bridge) was assessed during the development and testing of the methods and many were shown to be failing. We will outline the rationale behind our methods and describe the main findings.
bats; road; railways; mitigation; survey methods; mortality; barrier effect; crossing structures