"Nature abhors a vacuum."
- Aristotle, ancient Greek philosopher
The world's worst nuclear accident happened on April 26, 1986, when the Chernobyl nuclear power plant in the former Soviet Union exploded, releasing a cloud of highly toxic radioactive particles that spread in the air, water, and soil across swaths of Europe. Thirty-one people died in the explosion but many more deaths followed, as well as illnesses due to the lethal exposure.
The horrific event gave no warning. Residents and power plant workers were exposed to dangerous levels of nuclear radiation. The radiation emitted was more than 400 times that released by the atomic bomb blast at Hiroshima, Japan, to end World War II in 1945.
Some 350,000 people were evacuated from the area around the power plant, called the exclusion zone. They never returned and authorities limit the people living there permanently.
The areas surrounding the Chernobyl nuclear power plant immediately became highly polluted due to the radioactive fallout. In 1986, the exclusion zone measured about 19 miles from the Chernobyl power plant in all directions. Later, the zone was expanded to encompass additional affected areas.
Technically, the Chernobyl nuclear power plant is located nearer to the city of Pripyat, now empty of people, than it is to the city of Chernobyl.
The Chernobyl Exclusion Zone is now the officially designated exclusion zone in Ukraine. It adjoins the Palieski State Radioecological Reserve, which is the exclusion zone in neighboring nation Belarus. Winds blew radiation from Chernobyl across parts of Belarus, contaminating them, too.
Scientists warn that the exclusion zone around Chernobyl is still far too poisonous to support human life.
A pine forest near the plant - dubbed the "Red Forest" - received the highest doses of radiation. The pine trees died instantly and all their green needles turned red. Very few animals survived the highest radiation levels so close to Ground Zero.
The outlook for any animal habitation in the Chernobyl exclusion zone was gloomy. The region was presumed to have become a modern-day wasteland testifying to the long-lasting destructive nature of good nuclear energy gone horribly wrong.
Incredibly, 34 years after most humans left the polluted Soviet lands, many species of wildlife are thriving. Plants and animals are returning to occupy the Red Forest and other blighted places.
One study showed that, contrary to the expected radiation die-off of all forms of animals, large and small, the forest creatures seemed unaffected by the toxic exposure.
Scientists predicted that very few large mammals would be able to survive in the radioactive wasteland around Chernobyl. Thankfully, this has not proven to be true.
In fact, the opposite seems to be happening. Big mammals and other forms of wildlife seem to be resistant to radiation or perhaps have inborn coping mechanisms to stave off the harmful effects of a high-powered radiation bombardment.
Could the absence of human occupation account for the abundant forest animal populations?
Aerial survey counts of wild boar (1987–1996), elk and roe deer (1988–1996) rose significantly over time after the initial explosion. From 1987–2006, increases in large non-predatory mammals were accompanied by a large increase in wolves, a likely cause of the decline in wild boar, a primary prey of wolves.
Wolves, elk, boar, bear, lynxes, deer, Przewalski horses, more than 200 bird species, and dozens of other species have made their homes inside the irradiated zone after the humans departed.
The elusive European lynx and the European brown bear, which haven't been seen in the region for almost 100 years, are making a come-back. The number of wolves is seven times higher than in comparable reserves uncontaminated by nuclear fallout.
Environmental scientist Jim Smith, who authored the 2015 study, observed:
"It's much like the landscape of the rest of that area of Ukraine and Belarus, but without the people. Ten years ago, it was like a town overgrown by the forest. Today it's like a forest that has swallowed some buildings."
Smith teaches earth and environmental sciences at the University of Portsmouth in the United Kingdom. The professor added:
"Nature flourishes when humans are removed from the equation, even after the world's worst nuclear accident."
Humans are at the heart of the problem, according to Smith:
"We're not saying the radiation levels are good for the animals; we know it damages their DNA, but human habitation and development of the land are worse for wildlife."
The polluted region surrounding Chernobyl has been transformed into a nature preserve, attracting the interest of international biodiversity conservationists.