Effectiveness of a highway overpass to promote landscape connectivity and movement of moose and roe deer in Sweden

Ungulate-vehicle accidents accounted for approximately 60% of the total police reported traffic accidents in Sweden during the 1990s. While exclusion fences are effective at reducing such collisions, they create a new threat to wildlife by limiting individual movements and access to resources. To promote movements across fenced highways, wildlife crossing structures have been constructed in many countries. We used infrared remote cameras, track count surveys, and GPS telemetry to monitor the use of a highway overpass by moose (Alces alces) and roe deer (Capreolus capreolus) in southwestern Sweden. Moose and roe deer used the overpass mostly during nocturnal hours (84 and 76%, respectively). Overpass use declined with increased traffic volume on the highway, indicating that highway traffic affected the frequency in which ungulates used the overpass. We calculated that 5–7 individual moose used the overpass annually which is enough to maintain gene flow between otherwise disjunct subpopulations.