Wildlife is thriving in the human-free nuclear accident area in Fukushima, Japan.

A new study from the University of Georgia reports that populations of wild animals in the nuclear exclusion zone in Fukushima, Japan are blooming. According to the findings, more than 20 species, including wild boar, Japanese hare, macaques, pheasant, fox, and the raccoon dog, make their home in various areas of the landscape.

No humans, more animals

“Our results represent the first evidence that numerous species of wildlife are now abundant throughout the Fukushima Evacuation Zone, despite the presence of radiological contamination,” said UGA associate professor James Beasley.

It’s been nearly a full decade since the nuclear accident at Fukushima. As in other nuclear accidents (such as that at Chernobyl), authorities established a no-go zone around the site of the accident to safeguard public health.

Animals, however, are free to come and go as they please, and both the public and scientific community are curious to see how life gets by in such areas — the answer seems to be ‘better than expected’.

In addition to the team’s past research at Chernobyl, the current paper suggests that quarantined areas can act as safe havens for wild animals, especially species that tend to come into conflict with humans, such as wild boars. These animals were predominantly seen in human-evacuated areas or zones, according to Beasley.

“This suggests these species have increased in abundance following the evacuation of people,” he says.

For the study, the team worked with three zones of interest (established by the government in the Fukushima region after the 2011 accident) and gathered wildlife population figures by using 106 camera sites in these zones. Among the zones, one was completely off-limits for humans due to high levels of radiation contamination, one saw restricted access due to intermediate levels of contamination, and the last one was still open to human access and habitation due to low background levels of radiation.

The uninhabited zone served as the control zone for the research. There is no previous data on wildlife populations in the evacuated areas from which to establish a baseline, but the three areas are in close proximity and have a similar landscape. Thus, the team explains, the human-inhabited area can act as a reliable control.

The cameras captured over 46,000 images of wild boar over 120 days. Around 26,000 were taken in the uninhabited area, approximately 13,000 in the restricted one, and only 7,000 in the inhabited zones. Other species seen in high numbers included raccoons, Japanese marten, and Japanese macaque or monkeys, according to the team.

“This research makes an important contribution because it examines radiological impacts to populations of wildlife, whereas most previous studies have looked for effects to individual animals,” said Hinton.

The team looked at the impact of variables such as distance to road, time of activity (as captured by the cameras’ date-time stamps), vegetation type, and elevation on the wildlife population. They report that the behavioral patterns of most species align with their historically-recorded patterns. Raccoons, for example, a nocturnal species, were more active during the night; pheasants, which are diurnal, were more active during the day. In the meantime, wild boar in the uninhabited area were more active during the day, while boar in human-inhabited areas were more active during the night. The team says this suggests that the species is modifying their behavior in response to humans.

However, the team underscores that these findings refer to whole populations, and doesn’t make any assessments as to the health of individual animals.

“The terrain varies from mountainous to coastal habitats, and we know these habitats support different types of species. To account for these factors, we incorporated habitat and landscape attributes such as elevation into our analysis,” Beasley said.

“Based on these analyses, our results show that level of human activity, elevation and habitat type were the primary factors influencing the abundance of the species evaluated, rather than radiation levels.”

One exception to the general pattern was the Japanese serow, a goat-like mammal, which was most-seen in rural, human-inhabited upland areas. The team believes this comes as a behavioral adjustment to avoid the growing numbers of boar in the evacuated areas.

The paper “Rewilding of Fukushima’s human evacuation zone” has been published in the journal Frontiers in Ecology and the Environment.