Prioritizing road sections for wildlife fencing to reduce road mortality.

Collisions between wildlife and vehicles can be extremely hazardous and have deadly consequences for both people and animals. The presence of animal along the road represents a significant risk-factor to road safety since their behavior is unpredictable and drivers cannot anticipate which direction the animal will move, and result in injuries and fatalities to drivers and passengers and millions of dollars of property damage losses for owners and insurers. Road mortality has also detrimental negative effects on the abundance, persistence probability, and genetic diversity of wildlife populations. Techniques designed to lessen the number of wildlife-vehicle collisions have been used for decades and are a necessary component of a sustainable transportation strategy. Available evidence indicates that one of the most effective mitigation measure to date is the combined use of sections of fence in high-risk areas and wildlife crossing structures. Their combination not only allows to decrease road mortality, preventing the animals from accessing the road, but funnel these to safe crossing passages, increasing connectivity among the regions that have been disjointed by the road. Fencing certain road sections may be more efficient than fencing other sections, which can be identified through a hotspot analysis of the spatial configuration of roadkill patterns. However, varying the scale at which the spatial pattern is analyzed may affect the locations identified for mitigation measures and their predicted effectiveness, and even with the knowledge of the spatial pattern of the wildlife-vehicle collision the identification where fences should start and end, how long the sections should be prolonged is often a challenge for road planners and ecologists. While a very fine scale results in many sections of fence that may be inefficient due to a high probability of a fence-end effect to occur, a very coarse-scale would result in the implementation of fences parts of which would not be needed. To help managers to select the most efficient scale and prioritize locations for mitigation solutions we created several configurations of fencing analyzing the roadkill data of small and medium-sized mammals along Highway 175 with a Hotpot Identification Analysis, and we predict their effectiveness in reducing roadkill using a model that estimate the probability of success of each sections of fence as a function of the length of the section and the home range size of the species in analysis. We believe that the model for estimating the probability of success of the stretches of fence and the method of optimization identified could help researchers and practitioners formulate new approaches to road safety, wildlife management, and road design.