Exploring 15 years of brown bear (Ursus arctos)-vehicle collisions in northwestern Greece

Abstract

Road networks provide several benefits to human societies; however, they are also one of the major drivers of fragmentation and habitat degradation. Their negative effects include wildlife-vehicle collisions which are associated with increased barrier effects, restricted gene flow, and increased local extinction risk. Large carnivores, such as the brown bear (Ursus arctos), are vulnerable to road mortality while they also put human safety at risk in every collision. We recorded approximately 100 bear-vehicle collisions during the last 15 years (2005–2020) in northwestern Greece and identified common aspects for collisions, i.e., spatial, or temporal segregation of collision events, road features, and age or sex of the involved animals. We recorded collisions in both the core distribution area of brown bears, as well as at the periphery, where few individuals, mostly males, disperse. According to our findings, there are four collision hotspots which include ca. 60% of total collisions. Bear-vehicle collisions occurred mostly in periods of increased animal mobility, under poor light conditions and low visibility. In most cases, we deem that a collision was unavoidable at the time of animal detection, because the driver could not have reacted in time to avoid it. Appropriate fencing, in combination with the retention of safe passages for the animals, can minimize collisions. Therefore, such mitigation measures, wildlife warning signs and other collision prevention systems, such as animal detection systems, should be adopted to decrease the number of bear-vehicle collisions and improve road safety.

The influence of road networks on brown bear spatial distribution and habitat suitability in a human‐modified landscape

“…Finally, visibility of the nearest road had a very small effect on the models. To our knowledge, this parameter has not been taken into account in other studies to determine avoidance from a bear's point of view, although it has been considered from a human perspective in the analysis of traffic mortality sites (Huber et al., 1998; Psaralexi et al., 2022). Also, visibility of the nearest road is related to the type of habitat in which the road is located.…”

“…Yet, as roads increase mortality rates (Bourbonnais et al., 2014; McLellan, 2015), vehicle networks represent sink‐like areas (Braid & Nielsen, 2015; Falcucci et al., 2009) or ecological/evolutionary traps (Ciarniello et al., 2007; Penteriani et al., 2018). This is particularly relevant since collision mortality is greater in near‐road habitats with low visibility, such as those with high vegetation cover, or in areas with greater animal mobility and poor light (Psaralexi et al., 2022).…”

Rapid expansion of the golden jackal in Greece: research, management and conservation priorities

“…Road mortality has been a conservation concern for other large carnivores in Greece (e.g. brown bear, Psaralexi et al 2022), prompting close monitoring of the effects of linear transportation infrastructure on wildlife to identify and establish effective mitigation measures (e.g. Karamanlidis et al 2012).…”

Ecological Solutions for Linear Infrastructure Networks: The key to green infrastructure development

“…From India, Sur et al (2022) present the first patterns of vertebrate roadkill assessed in a National Park, demonstrating that roadkill rates were highest during the monsoon season, particularly for amphibians. The analysis of long-term mortality of the brown bear (Ursus arctos) in Greece revealed 60% of roadkills were concentrated in four hotspots, occurring most often in periods of increased animal mobility, under poor light conditions and reduced visibility (Psaralexi et al 2022). All of these results are crucial for identifying the risk to different taxonomic groups, and defining proper mitigation measures specific to each region and communities.…”