Movement ecology of a large ungulate following human abandonment of areas contaminated by the Fukushima Dai-ichi nuclear accident

The Fukushima Dai-ichi nuclear power plant disaster in the Tōhoku region of Japan resulted in the release of a large quantity of radionuclides into the environment; while humans were quickly evacuated from the contaminated area, wildlife remained. Changes in human activity and presence can impact habitat use and movement patterns of wild animals across demographic levels, including shifts in resource selection such as incursions into human-abandoned areas. Thus, understanding changes in spatiotemporal patterns of wildlife within human-abandoned landscapes can help mitigate human-wildlife conflict in preparation for anthropogenic resettlement. In this study, we investigated spatial utilization and temporal behaviors of Japanese wild boar (Sus scrofa leucomystax) in and around the Fukushima Exclusion Zone (FEZ). We used GPS data from 34 wild boar within the FEZ to conduct second- and third-order resource selection and movement path analyses. We also included GPS data from seven additional wild boar collared surrounding the FEZ to generate hidden Markov models to compare the temporal trends of wild boar inside the FEZ to wild boar outside the FEZ across three behavioral states (e.g., resting, foraging, traveling). We found that wild boar within the FEZ shifted their activity patterns to be more diurnal than those outside the zone where humans continue to reside. Additionally, while wild boar within the FEZ used natural spaces like forests, individuals also selected for human-abandoned areas such as rice paddy fields and urban areas. Our results provide insights into the adaptability of wildlife following human abandonment following large-scale human displacement events.