No evidence of wildlife-vehicle collision displacement to unfenced roads after fencing the Czech D10 motorway: A baci study
摘要
Wildlife-vehicle collisions (WVC) are a major concern for both wildlife conservation and traffic safety, as transportation infrastructure fragments habitats and increases wildlife mortality and the risk of injury for road users. Motorway fencing is widely implemented to reduce these impacts, often in combination with wildlife crossing structures; however, uncertainty persists regarding whether fencing may displace WVC to nearby unfenced roads. This study investigates both the effectiveness of fencing in reducing WVC on motorways and the potential displacement effect to adjacent roads. We analysed four continuously fenced sections of the Czech D10 motorway, using police-reported WVC data collected between 2007 and 2023. A total of 11,654 WVC records from the study area, comprising six surrounding districts and the motorway itself, formed the basis of the analysis. Using a Before–After Control–Impact (BACI) design and applying Fisher’s exact test across multiple distance thresholds (0.5 km, 1 km, 2 km, 3 km and 5 km) from the motorway study sections, we evaluated changes in collision patterns following fence installation. The WVC occurring farther than 5 km from the study section served as the Control. Across all study sections, motorway fencing resulted in a statistically significant reduction in WVC compared to the period before fence installation, with decreases ranging from 66% to 84%. We found no evidence of WVC displacement to neighbouring roads within the analysed distance thresholds, suggesting that any displacement effects were not detectable at these spatial scales. In one study section, a significant decline on adjacent roads was observed, likely influenced by concurrent landscape modifications. Further subdivision of WVC by motorway direction also revealed no displacement effects. Overall, continuous fencing substantially reduced motorway WVC, and we found no evidence that collisions were shifted to nearby unfenced roads at the spatial scales analysed.