How should we mitigate road effects on animal populations?

 Dr. Lenore Fahrig (Carleton University)

Roads can have large, negative effects on animal populations, particularly on populations of amphibians, reptiles and larger mammals. These effects may be cause by various mechanisms, including direct road mortality, obstruction of animal movements, and disturbances such as traffic noise. Designing effective mitigation of road effects depends on knowing which mechanism is the main driver. I present evidence suggesting that road mortality effects are generally more important than movement barrier and noise effects. This implies that the first priority for road mitigation should be to reduce road kill. Increasing movement connections and reducing traffic disturbance are secondary. Population-level tests of mitigation effectiveness are lacking and urgently needed.