Upgrading a 144-km section of highway in prime moose habitat: where, why, and how to reduce moose-vehicle collisions
- Author(s): Leblanc, Yves;
- Bolduc, François;
- Martel, Donald
- et al.
In Quebec, as throughout North America, the number of vehicles on roads and the daily distances travelled increase continuously. At the same time, populations of moose (Alces alces) and white-tailed deer (Odocoileus virginianus) have reached unprecedented levels in this province. For example, the moose population increased from 60,000 to 100,000 animals in Quebec between 1990 and 2002. Hence, moose-vehicle collisions have increased and caused numerous human injuries and fatalities in recent years in Quebec. The main objective of our study was to identify roadway, habitat, and moose population features that correlated with the reported number of moose-vehicle collisions (MVCs) and propose measures to reduce risks to motorists. Our study was implemented in the context of a planned project to upgrade a two-lane primary artery to a four-lane divided highway, located north of Québec City that bisects a wide forested area, the Laurentides Wildlife Reserve (LWR). Moose population and habitat variables were obtained from harvest, aerial inventory data, and aerial photos. Other variables were also measured from digital data layers using the ArcView GIS. Habitat suitability was computed using digital layers from ecoforestry maps and ArcView Spatial Analysis. Roadway variables were collected in the field or extracted and computed from digital layers with AutoCad and InRoads software packages. Moose-track surveys were also conducted monthly from June to September 2004 along the major conflict zone. Moose densities varied between 1.0 moose/10 km2 in the center of the 144-km Highway 175 to 8 individuals/10 km2 in its southern and northern portions. We estimated that between 573 and 860 moose were roaming within 5 km on each side of the highway in 2004. A controlled hunt and high quality habitats following forest exploitation and natural perturbations occurring within the LWR are likely to be major contributors to this growing population. Our data analysis using AIC showed that four variables explained most variations in the number of MVCs among 1-km sections. These variables were (1) the slope complexity of the adjacent landscape, (2) the total length of rivers, streams, and brooks located within a 250-m buffer zone on each side, (3) the habitat suitability for forage within a buffer zone of 1 km on both sides, and (4) the proportion of steep (> 3-m high) road cuts. During fall and early winter habitat features were strongly related to the number and location of MVCs, whereas the influence of slope complexity was greater during summer. However, annual and seasonal models explained a limited amount of the variance in the number of MVCs (R2 < 0.288) and could not be used efficiently to identify conflicting sections and set management priority. The longest and the most hazardous section tallied 25 km, which was surrounded by high-quality moose habitat. Track surveys in the summer of 2004 showed frequent movements across the highway, but little clustering. Because we could not find strong relationships between MVCs and road and habitats features, we used the numbers of recorded MVCs to delineate 5-km sections and establish actions to be taken to reduce risks. The top priority hazardous zone, which encompasses 25 km, will be fenced during the upgrading project and combined with two major underpasses.