Where do snakes cross roads? Habitat associated road crossings and mortalities in a fragmented landscape in western France

Reptiles are commonly impacted by roads. Mortalities from road traffic are best documented in snakes, but information on roadside habitat features where snakes cross or attempt to cross roads are less frequently reported. If roadside habitat is important, then snakes should be selective of where they make a crossing. To test this hypothesis, roadside habitats where snakes crossed or attempted to cross roads were compared with roadside habitat availability in a study site in western France. Vipera aspis, Hierophis viridiflavus, Natrix natrix and N. maura crossed roads more often than expected next to woodland and low density urban areas. Road crossing locations were also compared with snake abundance in roadside habitat. Frequencies of crossings were higher than expected in woodland and high-density urban areas in relation to their abundance in these habitats. However, abundance related road crossings were less frequent than expected near hedgerows. This suggests that snakes were reluctant to emerge from a habitat pathway that connects prime habitat patches in a fragmented landscape.