Marcel P Huijser

Cost–Benefit Analyses of Mitigation Measures Aimed at Reducing Collisions with Large Ungulates in the United States and Canada: a Decision Support Tool

Wildlife–vehicle collisions, especially with deer (Odocoileus spp.), elk (Cervus elaphus), and moose (Alces alces) are numerous and have shown an increasing trend over the last several decades in the United States and Canada. We calculated the costs associated with the average deer–, elk–, and moose–vehicle collision, including vehicle repair costs, human injuries and fatalities, towing, accident attendance and investigation, monetary value to hunters of the animal killed in the collision, and cost of disposal of the animal carcass. In addition, we reviewed the effectiveness and costs of 13 mitigation measures considered effective in reducing collisions with large ungulates. We conducted cost–benefit analyses over a 75-year period using discount rates of 1%, 3%, and 7% to identify the threshold values (in 2007 U.S. dollars) above which individual mitigation measures start generating benefits in excess of costs. These threshold values were translated into the number of deer–, elk–, or moose–vehicle collisions that need to occur per kilometer per year for a mitigation measure to start generating economic benefits in excess of costs. In addition, we calculated the costs associated with large ungulate–vehicle collisions on 10 road sections throughout the United States and Canada and compared these to the threshold values. Finally, we conducted a more detailed cost analysis for one of these road sections to illustrate that even though the average costs for large ungulate–vehicle collisions per kilometer per year may not meet the thresholds of many of the mitigation measures, specific locations on a road section can still exceed thresholds. We believe the cost–benefit model presented in this paper can be a valuable decision support tool for determining mitigation measures to reduce ungulate–vehicle collisions. Key words: animal–vehicle collisions; cost–benefit analysis; deer; economic; effectiveness; elk; human injuries and fatalities; mitigation measures; moose; roadkill; ungulate; vehicle repair cost; wildlife–vehicle collision

The effect of roads and traffic on hedgehog (Erinaceus europaeus) populations

We studied the effect of roads and traffic on hedgehog population density by comparing relative densities in 15 paired road and control plots matched for landscape parameters. Relative hedgehog density was determined by means of footprints in specially designed tunnels. The relative density was closely correlated with the total number of individual hedgehogs that were caught in traps in five of the plots immediately after the tunnels were removed. A power analysis indicated that, with the resources available, we could only detect an effect greater than 35%. We were unable to demonstrate a significant effect, i.e. hedgehog density in areas adjacent to roads is not reduced by more than 35%. However, we did find about 30% fewer tracks in road plots when compared to control plots and the P-values were marginally insignificant at the P⩽0.05 significance level. These results suggest that roads and traffic are likely to reduce hedgehog density by about 30%, which may affect the survival probability of local populations.

Habitat and corridor function of rights-of-way

This chapter describes the habitat and corridor function of right-of-way habit and includes factors that influence the quality of these functions. Some of the potential problems are also discussed. Species with large home ranges that are not tied to one particular habitat are more likely to use rights-of-way as only part of their home range than species that are sedentary and that have small home ranges than the species that are tied to a specific habitat. Therefore most examples of species that use right-of-way habitat but do not restrict their movements to these relatively narrow strips are birds and larger mammals. While the functions of right-of-way are generally well documented and understood, the corridor function is not. Dispersal, movements over relatively long distances, has rarely been documented. Even though right-of-way habitat and corridors are continuously exposed to disturbance from the roads and traffic, and even though they may be of lesser quality than habitat and corridors away from infrastructure, they can be important to the survival of some species, especially in developed landscapes.

Planning and prioritization strategies for phased highway mitigation using wildlife-vehicle collision data

Abstract Mitigation measures to reduce wildlife-vehicle collisions (WVCs) on highways are becoming an established practice in many jurisdictions. Most highway mitigation projects occur while roads are being upgraded, enlarged or repaired. Many smaller highways may not be subject to these types of upgrades in the near future but are nonetheless problematic for causing WVCs. Thus, it is important to find cost effective ways to locate and prioritize stretches of highway for mitigation. We present several criteria that can be used to assist in prioritizing the location of wildlife-proof fencing along a 94-km stretch of road in one of Canadas National Parks. We considered temporal consistency of WVC occurrences, conservation value (i.e. reduction in WVC rates), economic benefits (i.e. cost of mitigation vs benefits in WVC reduction), and a combined approach to prioritize management actions. We compared the efficacy of four different lengths of fencing (i.e. phase lengths) at meeting these criteria: 2 km, 5 km, 10 km and 25 km. We used 1,244 WVC records from a long-tem monitoring program (1981-2005) as data to assess mitigation effectiveness. We found that longer fences best address conservation concerns, but all fencing sections, irrespective of length, rarely captured > 50% of WVC locations by species. We found that shorter fences were more economically efficient, but also more variable in performance, than longer fences. Lastly, we found that longer fence lengths tend to produce the best results for the combined metric criteria. Clearly defined management goals will determine the extent to which a phased approach to highway mitigation is viable.

Preliminary Evaluation of Drivers’ Responses to a Roadside Animal Warning System

The problem of vehicle-animal crashes is one of the few areas in which the number of incidents has been climbing steadily in recent years. Many strategies and technologies have been investigated over the years to try to reduce the number of vehicle-animal crashes, and each have had their own strengths and shortcomings. Thus far, no single strategy or technology has proven to be an effective solution. In this project, a 0.6 mi (1 km) site in Northern California, along State Route 3, near the city of Fort Jones, was selected based on a high frequency of vehicle-deer collisions to test a new animal detection and driver warning system. An animal detection system used microwave break-a-beam technology to detect objects along side or crossing the roadway, and warnings were provided to drivers using dynamic, LED, warning signs. These signs were typically blank in the off position and were only illuminated when the animal detection system detected a beam break. Coupled with the animal detection and driver warning system was a traffic monitoring system and data collection system, and a total of 10 months of data were collected between August 2011 and April of 2012. An analysis of the data showed that when illuminated, the warning signs reduced the traffic speeds by an average of 3.1 mph (5 km/h) to 5.1 mph (8.2 km/h), depending on the analysis method.

Performance of Arch-Style Road Crossing Structures from Relative Movement Rates of Large Mammals

In recent decades, an increasing number of highway construction and reconstruction projects have included mitigation measures aimed at reducing wildlife-vehicle collisions and maintaining habitat connectivity for wildlife. The most effective and robust measures include wildlife fences combined with wildlife underpasses and overpasses. The 39 wildlife crossing structures included along a 90 km stretch of US Highway 93 on the Flathead Indian Reservation in western Montana represent one of the most extensive of such projects. We measured movements of large mammal species at 15 elliptical arch-style wildlife underpasses and adjacent habitat between April and November 2015. We investigated if the movements of large mammals through the underpasses were similar to large mammal movements in the adjacent habitat. Across all structures, large mammals (all species combined) were more likely to move through the structures than pass at a random location in the surrounding habitat. At the species level, white-tailed deer (Odocoileus virginianus) and mule deer (O. hemionus) used the underpasses significantly more than could be expected based on their movement through the surrounding habitat. However, carnivorous species such as bear (Ursus americanus) and coyote (Canis latrans) moved through the underpasses in similar numbers compared to the surrounding habitat.