Evaluation of the use of wildlife crossings by large mammals: İzmir-Çeşme highway ecological bridge

Transportation networks fragmentize the landscape and cause adverse effects on wildlife. Wildlife overpasses, on the other hand, are structures that allow safe passage of wild animals by combining divided landscapes. In order to reduce wildlife vehicle accidents on İzmir Çeşme Highway, the first ecological bridge was put into service in Zeytinler District in 2020. In order to reduce the collision of wild boars and vehicles on İzmir Çeşme Highway, it was decided to build a wildlife overpass at three different points, and the first one was put into service in Zeytinler Locality in 2020. In this study, it was aimed to evaluate the use of Zeytinler Ecological Bridge by medium-large mammals. For this purpose, wildlife crossing were monitored and analyzed and modeled with Bayesian networks. During the study, 686 passing belonging to six medium-large mammalian wildlife species were observed. Wild boars accounted for approximately 87.5% of wildlife crossings and foxes 10%. Wildlife crossed the overpass the most during the crescent and bulge phases of the moon between 22:00 and 02:00 in autumn. The model results showed that in the fall, when the pond is full, wild boar passes reach one and a half times the herd wild boar passes. This study not only analyzed the usability of the overpass by wildlife, but also provided important clues in understanding the timing of wildlife vehicle collisions and revealing how elements in the design of the overpass affect crossings. Along with the results and conclusions of the study, an improvable guide has been created for the overpasses to be built in the future on the target species and design issues, especially on the ecological bridge location selection.