Wildlife Crossing Hotspot Analyses for Major Highways in Wisconsin, USA

Abstract

In this report we explore where and how to enhance road safety in Wisconsin through reducing collisions with large wild mammals on state-maintained routes, while also ensuring safe crossing opportunities for wildlife. We identified and prioritized road sections in Wisconsin along state-maintained routes that have a relatively high concentration of collisions involving large wild mammals, mostly with white-tailed deer. We used the large wild mammal crash and carcass data to conduct cost-benefit analyses to identify road sections where the implementation of mitigation measures may be less expensive than doing nothing and letting these types of collisions continue to occur. We also identified 36 species of conservation concern in Wisconsin. The species of conservation concern, as defined for this report, included 4 amphibian species (3 frog species, 1 salamander species), 20 reptile species (3 lizard species, 13 snake species, 4 turtle species), and 12 mammal species (1 insectivore species, 5 rodent species, 1 mustelid species, 1 canid species, 2 felid species, 2 ungulate species). We identified road sections, or counties, where species of conservation concern have been observed. Road sections that would need to be prioritized for reducing collisions with common large mammals (i.e., mostly white-tailed deer) are mostly in the eastern and southeastern parts of Wisconsin. Areas where a relatively high number of species occur that are of conservation concern are predominantly in the southwestern parts of Wisconsin. This illustrates that there would be benefits to having a two-track system of policy, funding mechanisms and implementation programs; one that is rooted in human safety through reducing collisions with large wild mammals that are common, and another that is rooted in biological conservation. We also identified measures for both large wild mammals and small animal species that are aimed at reducing wildlife-vehicle collisions and associated direct road mortality of the animals, and at reducing the barrier effects of roads and traffic to wildlife.