Abstract

Roads and traffic negatively impact many wildlife populations because they increase wildlife mortality, are barriers to animal movement and reduce the amount and quality of available habitat. There is increasing concern about the reduction in connectivity for wildlife across roads.
During the widening of Highway 175 between Québec City and Saguenay from two to four lanes (in 2006 - 2011), 33 wildlife underpasses for medium-sized and small mammals were constructed along the highway between km 60 and km 144. They are among the first designated wildlife passages for medium-sized and small mammals in the province of Québec.
Our research project had three main objectives:
To characterize the locations and rates of vehicle collisions with medium-sized and small mammals and to evaluate the changes in the frequency of highway-related mortality due to the mitigation measures.
To determine the performance of the four types of wildlife passages for medium-sized and small mammals.
To assess how well the mitigation measures provide for the permeability of the highway for individuals and for gene flow across the road, with a focus on the American marten.
Based on the results, we provide 16 recommendations, 9 of which relate to possible improvements of road mitigation measures and 7 relate to monitoring and research.
Making good use of the large research potential of HW 175 can make an important contribution to improved knowledge about the effectiveness of road mitigation. The HWY 175 is particularly suitable for such research for several reasons, e.g., our study provides 4 years of baseline data about small and medium-sized mammals, which is a rare opportunity, and because the high numbers of animals being killed on HWS 175 result in larger sample sizes and in faster detection of the wildlife responses to modifications to the mitigation measures than in areas with lower wildlife mortality.
The implementation of 33 wildlife passages for small and medium-sized fauna along HW 175 represents an important step in the right direction. The results of this study demonstrate a major success for the existing wildlife passages along HW 175.
Driver safety is also an important consideration for small and medium-sized mammals.
Road mitigation is also a matter of halting biodiversity decline (as required by the internationally defined Aichi biodiversity targets set by the Convention on Biological Diversity, CBD) and of ensuring long-term maintenance of ecosystem services. Measures for road mitigation can be implemented effectively only if there is an awareness of the issue. Decision-makers and the general public alike should, therefore, be made more aware of the short-term and long-term ecological effects of roads and need to be informed about suitable mitigation measures. Many road agencies have “environmental sustainability” as one of their goals and the only way to achieve such goal is to establish collaborative links between transportation agencies and ecologists and to support long-term and credible scientific research (van der Ree et al. 2011).