The transportation infrastructure is rapidly expanding and are being upgraded to move goods and people in and out of populated areas. The impacts of roads and traffic are globally recognized as threats to the functioning of healthy ecosystems, and mitigation strategies are increasingly being adopted around the world. However, not all impacts can be fully mitigated, and not all mitigation measures are equally effective. Wildlife crossing structures encompass a broad range of natural (e.g. tunnel roofs) or artificial (e.g. grey and green bridges, culverts, underpasses) structures designed to provide habitat connectivity and reducing animal-vehicle collisions (AVCs). The objective of our study was to contribute with knowledge that can be used to develop best practice guides for designing and placement of wildlife crossing structures under Scandinavian conditions. More specifically we first aimed to analyze if increasing intensity of human use of crossing structures affected the use by our target species, moose (Alces alces) and roe deer (Capreolus capreolus). Secondly, our aim was to identify which crossing structures that were important during moose migration and small-scale daily movements. Our analysis was based on 20 crossing structures monitored by motion triggered wildlife cameras located on fenced roads and railways in a study area surrounding Oslo Airport Gardermoen, in Norway. During the monitoring period March 2012 – June 2013 (15 months) we got pictures of 2354 moose, 4628 roe deer and 33508 humans (walking, skiing or bicycling). We examined the temporal (daily and monthly) patterns between moose and roe deer crossing frequency, and related this to the intensity of human use. We used data from GPS-marked moose (n = 55) to support our discussion regarding the frequency and direction moose used different passages during migration periods. We discuss how our results can inform management about best practice guides for planning and building of crossing structures to counteract the barrier effect of wildlife fences.
use of wildlife crossing structures, moose, roe deer, barrier, wildlife cameras, crossing frequency, wildlife fences, human use, functionality.