Roads present a growing threat to the wildlife of the U.S. Northern Rocky Mountains, a region spanning the Greater Yellowstone, Salmon-Selway, and Crown of the Continent Ecosystems that is unique in continuing to support a full suite of native ungulates and carnivores. The continued viability of wildlife populations are dependent on their continued ability to move, including daily movements among local resources, migrations between seasonal ranges, long-range dispersal supporting gene flow, and species range shifts over time in response to changing conditions.
As wildlife movements across landscapes intersect with human movements via roads, both human safety and the health of wildlife populations are impacted. Several mitigation measures aimed at reducing wildlife-vehicle collisions and other road impacts on wildlife connectivity have been proven as effective means of both protecting human safety and preventing wildlife mortality. In this study, we seek to provide decision support in answering the crucial question of where to mitigate roads to yield the greatest positive impact for wildlife and people.
We create an index of road risk to wildlife based on roadside carcass data, then overlay corridors modeled by the Western Governors’ Association Wildlife Corridors and Crucial Habitat Initiative to understand how risk and connectivity values align. We show that high risk road segments tend to have low connectivity value, though carnivores tend to be killed closer to road intersections with corridors than other species. Based on these, findings we identify four alternative sets of potential priority sites for mitigating road impacts on wildlife that together capture the unique perspectives of diverse stakeholder groups, including departments of transportation, land and wildlife managers, citizen groups, and conservation practitioners.
We also detail specific roles that diverse stakeholders can play in the mitigation process, and highlight opportunities for each to engage in that process by working in partnership with transportation agencies. Examples of these roles and opportunities are described through case studies that together illustrate the four alternative perspectives on mitigation priorities that we identify.
