The promise and reality of using genetic techniques to quantify the impacts of linear infrastructure and evaluate the effectiveness of mitigation

Roads, railways and other linear infrastructure can affect the movement and survival of wildlife, with negative consequences for gene flow and genetic diversity.  Several reviews highlight the importance of these issues, yet genetic approaches are relatively underutilised in road ecology. Further, many researchers seem unaware of the power of genetic techniques to address ‘non-genetic’ road ecology questions. Here, we revisit the importance of conservation genetic approaches in road ecology research, discuss the latest advances in ‘molecular road ecology’, and introduce studies that apply these techniques to common road ecology questions. Individual-based approaches, simulation modelling, next generation sequencing and non-invasive genetic sampling have the potential to provide great insights to genetic and ecological road effects. For example, genetic approaches can be used to quantify barrier effect, identify ‘unidentifiable’ roadkill carcasses and estimate demographic parameters. Genetic approaches are particularly valuable when investigating the impacts of roads and wildlife crossing structures on animal movement and functional connectivity. We also discuss some of the perceived hurdles to using genetic approaches (e.g. cost, expertise, time constraints, scale) and suggest ways that they can be overcome. Finally, it is important to remember that while genetic techniques are powerful, they are not a cure-all. They are most informative when applied in the context of question-driven science, a robust study design (e.g. BACI) and sufficient replication. Further, combining genetic and non-genetic approaches will provide a more comprehensive understanding of the effects of linear infrastructure and mitigation on population viability. Our goal is to provide a realistic overview of the opportunities, challenges and requirements of genetic approaches in the hope that people will feel better prepared to include them in road ecology research.

genetic techniques; population genetics; evaluating mitigation; barrier effect; wildlife crossing structures; study design