Temporal and spatial influences on road mortality in otters: Conservation implications

Roadkills are the major cause of mortality in some predator species, including endangered species, and are considered one of the causes for the marked decline of otter populations around the world during the last century. We collected all available records of otter (Lutra lutra) roadkills in Israel, and analyzed them in order to assess the role of roadkills in the decline of the otter population in Israel and to find ways in which otter road mortality might be reduced. We found a significant increase in otter road casualty over the last 3 decades. Based on general estimates of population size, we suggest that at least 5% of the otter population in Israel is killed on the roads each year. A seasonal pattern was found: 64% of otter roadkills occurred in winter and spring. There was a slight male bias ratio in fatalities (1.27:1). A majority of casualty records (57.1%, n = 63) were within 100 m of fresh water. Our findings suggest that roadkill has a significant impact on the otter population in Israel. Suitable bridge design, underpasses at favored crossing points, ledges in culverts and bridges to allow otters to walk through even at high flows, fencing to divert otters to a safe underpass, and reflectors and warning signs for motorists can all be used to reduce roadkills.