Movement Behavior and Habitat Selection of Rat Snakes (Elaphe spp.) in the Fukushima Exclusion Zone

The 2011 nuclear accident in Fukushima, Japan was one of the largest anthropogenic releases of radioactive contamination in history, and many questions remain regarding its ecological impacts. As part of a larger study estimating animal movements and radiation exposure within the impacted area, we used a combination of VHF and GPS transmitters to estimate home range size and habitat use of nine Japanese rat snakes (Elaphe climacophora and E. quadrivirgata) over three months within the Fukushima Exclusion Zone. Short-term a-LoCoH ranges varied from 0.15–6.80 ha, and daily movements ranged from 30–116 m. Short-term home ranges included more areas close to streams, buildings, and roads, as well as more grassland and less evergreen forest than expected given the availability of these habitat components on the landscape. Within their home ranges, snakes selected areas close to streams and avoided evergreen broadleaf forests. They also frequently used habitat features such as trees and buildings, although use of buildings was highly variable among individuals. The limited distance snakes moved compared to more mobile species suggests snakes could be useful bioindicators of local contamination. However, radionuclide exposure will still vary considerably among individual snakes within localized areas due to differences in habitat use.