Humans Are Worse for Wildlife Than Nuclear Radiation
In the wake of the Fukushima-Daiichi nuclear disaster in March 2011, at least 164,865 people were evacuated from their homes as far as thirty kilometers away. Most have now returned, but some 40,000 people are still unable to do so, as the government prohibits lodging in areas where the annual radiation dose exceeds 50 millisieverts, roughly equivalent to three full-body CT scans.
But where humans are absent, wildlife has flourished.
University of Georgia wildlife biologist James Beasley and a team of colleagues recently set up 106 cameras in Fukushima's evacuation zone and captured more than 267,000 images of animals over 120 days. Wild boar, hares, macaques, pheasants, foxes, raccoon dogs, martens, bears, and civets were a few of the many creatures spotted. Beasley and his co-authors found no evidence that radiation exposure had harmed animal populations.
“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,” he said in a statement.
What Beasley noticed around Fukushima echoes what scientists have already discovered around Chernobyl, the site of the world's worst nuclear disaster: where humans are absent, wildlife thrive.
"Relative abundances of elk, roe deer, red deer and wild boar within the Chernobyl exclusion zone are similar to those in four (uncontaminated) nature reserves in the region and wolf abundance is more than 7 times higher. Additionally, our earlier helicopter survey data show rising trends in elk, roe deer and wild boar abundances from one to ten years post-accident," scientists reported in 2015 in the journal Current Biology.
The breathtaking re-wilding in regions contaminated with radiation initially surprised a great many researchers. Given radiation's ominous reputation, many initially predicted that the area around Chernobyl would become a desert of life. After more than thirty years, it's growing apparent that the opposite is true. On the whole, animal populations have multiplied within the 1,000-square-mile Chernobyl Exclusion Zone in both diversity and number.
That's not to say that radiation hasn't done damage – it has. Many birds and mammals in the most contaminated areas have cataracts in their eyes, smaller brains, tumors, deformed sperm, and other abnormalities. This is a direct result of ionizing radiation scrambling their DNA. Farther away, where contamination is only ten times natural levels, these deleterious effects are less pronounced.
Yet despite these handicaps, animals of all shapes and sizes are maintaining viable, growing populations. Threatened animals like the European bison and Przewalski's horse have found a safe haven in the exclusion zone. Birds even nest near the decrepit nuclear plant.
"First, wildlife could be much more resistant to radiation than previously thought. Another alternative possibility is that some organisms could be starting to show adaptive responses that would allow them to cope with radiation and live inside the exclusion zone without harm. In addition, the absence of humans inside the exclusion zone could be favouring many species – big mammals in particular."
He placed particular emphasis on the latter explanation.
“That final option would suggest that the pressures generated by human activities would be more negative for wildlife in the medium-term than a nuclear accident – a quite revealing vision of the human impact on the natural environment.”
Fukushima and Chernobyl have now provided us with two tragic data points inexorably leading to a blunt conclusion: humans are far worse for wildlife than nuclear radiation. Animals can adapt and even prosper in contaminated habitats, but they can't survive in those polluted and often completely destroyed by humans.