- The 2011 Fukushima nuclear disaster is considered the second-worst nuclear accident in history.
- According to a new study, animal populations are thriving in the Fukushima Exclusion Zone, which was abandoned after the accident.
- The animals are multiplying in the absence of humans, despite the lingering presence of radiation.
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The villages outside the Fukushima Daiichi Nuclear Power Plant in Japan are relatively quiet. In the town of Ōkuma, elderly men walk the streets searching for trash or fallen branches to pick up. Residents buy newspapers and snacks at the local convenience store.
But in some nearby communities, humans still aren’t allowed back.
Almost nine years ago, on March 11, 2011, the Tōhoku earthquake and tsunami caused three nuclear meltdowns and multiple hydrogen explosions at the Fukushima power plant. The incident forced 150,000 people to evacuate across a 440-square-mile area.
Although many neighbourhoods remain empty today, wild animals like boar, snow monkeys, and red foxes seem to be thriving, even in the presence of lingering radiation.
For a new study published in the journal Frontiers in Ecology and the Environment, researchers observed more than 20 species on camera over the course of 120 days from May 2016 to February 2017.
“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,” James Beasley, a wildlife biologist who co-authored the study, said in a press release.
Here’s what the researchers saw.
The Fukushima disaster is considered the world’s second-worst nuclear accident, behind Chernobyl.
Only two disasters have ever been designated “level 7” nuclear accidents – the classification used by the International Atomic Energy Agency for major events with widespread health and environmental effects. The 1986 nuclear disaster at the Chernobyl Nuclear Power Plant in Ukraine was one; Fukushima was the other.
The latter released plumes of radioactive material into the air, putting residents at risk of developing some forms of cancer if they stayed in the area.
Some of the evacuation orders have been lifted, but only about 5% of the original population has chosen to return.
In early 2019, Japanese authorities determined that radiation levels in parts of Ōkuma (a town that had about 10,000 residents at the time of the Fukushima disaster) were low enough for people to return.
The government has also partially lifted the evacuation orders in Namie, allowing around 21,000 former residents to reoccupy certain areas of the town if they want to. But only about 1,000 people have moved back.
Some former residents remain sceptical about safety, while others find it too painful to live among the demolished homes and empty school buildings.
A team of researchers from Fukushima University and the University of Georgia divided the current evacuation zone into three parts.
On the map above, beige represents areas that were not evacuated and are currently occupied. Radiation there never surpassed normal background levels.
Green represents areas in which people were evacuated but allowed to return starting in 2016, after remediation efforts were complete.
Red indicates zones the Japanese government has labelled as “difficult-to-return.” Radiation levels measured there have been high enough to cause skin cancer, so humans are unlikely to be allowed back for several more years.
The researchers used that information to study how wild animals are faring in Fukushima.
They snapped more than 267,000 photos of wildlife there, using cameras stationed at 106 locations.
For the most part, the animals stuck to their normal behaviours.
Nocturnal raccoons were active at night, for example, while diurnal pheasants were active during the day.
The analysis showed that wild boars were three to four times more likely to be found in the deserted zone than in the areas occupied by humans.
The boars were spotted more than 46,000 times, making them the most abundant species observed in the disaster region. More than half of the sightings took place in the “difficult-to-return” zone where humans aren’t allowed.
In Fukushima’s abandoned towns, wile boars roam the streets, forage for food, and tear apart dilapidated homes. They seem to have multiplied fast since humans left, the researchers wrote. (Wild boars have one of the highest reproductive rates of all large mammals.)
Some residents of the occupied zones hunt the boars to restrict their population growth. They have also reported that the boars no longer seem scared of humans.
“They stare squarely at us as if saying, ‘What in the world are you doing?'” Shoichiro Sakamoto, a resident of the town Tomioka, told Reuters. “It’s like our town has fallen under wild boars’ control.”
Japanese serow — goat-like mammals with long legs like antelope — seem to prefer the inhabited zone.
The animals typically avoid areas with lots of humans, but the researchers suspect that the serow are steering clear of the wild boar.
Another possible explanation is that the serow had trouble surviving in the abandoned zones, where radiation is higher.
Japanese macaques (snow monkeys) preferred the restricted zones.
Red foxes, by contrast, were somewhat evenly distributed across all three zones.
The researchers didn’t test the animals for radiation, but they think many received significant doses based on where they were spotted.
Research has shown that radiation from the Fukushima disaster contributed to DNA damage in earthworms, barn swallows, mice, and wild boar. Scientists also think radioactive contaminants may be interfering with the reproduction of goshawks, a type of raptor.
But in general, animal populations appear to be growing.
A similar situation has arisen in Chernobyl, where scientists believe a lack of humans has given rise to a diverse wildlife community.
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