It has been nearly nine years since the Fukushima Daiichi nuclear power plant nuclear disaster, and while people still remain evacuated from the areas most contaminated by radioactivity, many wonder: What happened to the wildlife left behind?

A newly released study by a team of scientists from the University of Georgia and Fukushima University found that years after the disaster at Fukushima, populations of mid-to-large-sized mammals and birds are thriving in the absence of human pressure.

The March 11, 2011, nuclear disaster in Japans Fukushima Prefecture caused by the tsunami that resulted from a massive magnitude-9 earthquake was one of the worst nuclear plant disasters in human history, second only to the 1986 Chernobyl incident in Ukraine.

A wild boar. Courtesy of the University of Georgia.

Through remotely operated, motion-activated cameras placed at 106 sites, researchers saw that some species like raccoons and wild boar were more abundant in the humans excluded zone the most contaminated area people are not allowed to live in when compared to the humans restricted zone where people have returned and the humans inhabited zone that was never evacuated.

The fact that animals seem to be doing well at a population level is counterintuitive. I mean, these are very contaminated landscapes, says James Beasley, the wildlife ecology professor at the University of Georgia who led this project. He says the popular movie or video game perception of abandoned nuclear wastelands is not exactly real life at Fukushima or Chernobyl.

Beasley and the team went to the Fukushima exclusion zone in 2016 to begin this camera study. They set up the cameras across the landscape, including the zone in which people can no longer live because the radiation dose rates are still above the recommended safety threshold.

Even in the most contaminated zones of the field site, Beasley says, it is still safe to set up the cameras if one doesnt linger too long. They wear heavy rubber boots and an alarm that sounds if a certain radiation dose rate is exceeded.

It's okay to put a camera up for a few minutes and then move on. But, you know, that's not the sort of place you want to stop and have your lunch, for example, he adds.

Macaque monkeys. Courtesy of the University of Georgia

Caught on Camera

The observation period lasted for 120 days from 2016 to 2017, and in that time, more than 267,000 photos were captured on the motion-activated cameras. In total, 20 species of mammal and birds were spotted roaming across the three zones surveyed.

Out of all the animals spotted on the cameras, wild boar showed up in the human-excluded zone the most in more than 26,000 of the images to be precise. This is not exactly surprising, Beasley says, because wild boar are opportunistic and reproduce at a high rate. In comparison, wild boar were caught on camera more than 7,200 times in the human-inhabited region during the observation period.

Red foxes, masked palm civets, green pheasant, Japanese macaques, Japanese hares and raccoon dogs were all captured on the cameras. The one lucky camera snap of a baby macaque riding on its mothers back is not just adorable, it is evidence reproduction is happening in this area despite the contamination.

A Japanese serow. Courtesy of the University of Georgia

Timothy Mousseau, a biology professor at the University of South Carolina, was not involved in this study, but also does similar research in Fukushima and Chernobyl. He says the findings in this study reflect what he has seen in his own work in Fukushima: that population-wise, human presence can impact animal abundance more than the radiation effects.

He says the massive clean-up effort of the area was likely a large disturbance for animals in the region. All of this noise and dust and human activity seems to be a much bigger factor shaping the abundance and distribution of the mammals than the radiation effects, says Mousseau.

A hare. Courtesy of the University of Georgia

This study examines the population-level impacts of the disaster and not the molecular-level impacts of radiation. Beasley says while there may not be enough of an impact on physiology or reproduction from the radiation to suppress the population, they will conduct more research on animal health at Fukushima in the future to learn more.

Mousseau did a study on barn swallows in Fukushima shortly after the disaster in 2011 and found they did have genetic damage, but it was minimal. Another study on genetic damage in earthworms and wild boars shows there are molecular impacts of radiation exposure, but these studies need to be continued over time to see if this DNA damage manifests at the population level.

In this case at Fukushima, the inverse correlation of human presence and animal abundance indicates people leaving the area has a positive impact on the rewilding of the landscape, which is similar to findings from longterm wildlife abundance studies in Chernobyl.

Many of the organisms like the birds and insects were pretty dramatically impacted in the first year or two after the accident, Mousseau says. But now, the main message can be optimism.

It's clear that many of these organisms have come back...these areas can self-remediate just by being left alone for a little while.

A badger. Courtesy of the University of Georgia

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In the wake of the Fukushima nuclear disaster, some animals are thriving - The Hill