Prey responses to predation risk under chronic road noise

Anthropogenic noise has dramatically increased over the past decades with potentially significant impacts on wildlife and their community interactions. Using giving-up densities (GUDs) paired with camera traps, we examined the concurrent influence of chronic road noise and predation risk on free-living small mammals. Specifically, we looked for differences in foraging and vigilance behavior during various noise treatments. We found that small mammals significantly reduced food intake when exposed to predation risk; however, concurrent exposure to road noise eliminated this effect; small mammals increased food intake when exposed to road noise and risk compared to risk alone. Furthermore, road noise reduced the number of visits and time spent at foraging trays while it increased vigilance behavior of small mammals in risky situations, meaning they were able to increase their foraging efficiency. Mice also ate less when moon illumination was greater; however, this had no effect on our overall results. This is one of the first studies to concurrently examine the effects of road noise and predation risk on free-living prey. It shows the complex responses of prey exposed to chronic noise conditions as they attempt to gain reliable information about predation risk and respond appropriately. We highlight the potential consequences road noise may have on the survival of prey as it interferes with their appropriate risk responses.

Automated summary

Anthropogenic noise and predation risk have concurrent influences on free-living small mammals, affecting their foraging behavior and vigilance. Road noise can increase foraging efficiency but reduce food intake.