In February of 2022, Russia’s invasion of Ukraine set off not just the largest armed conflict in Europe since the Second World War. It also triggered an unprecedented experiment in how wars spill into the natural world.

As Russian armored vehicles poured into Ukraine, the contaminated land surrounding the defunct Chornobyl nuclear reactor turned from a massive de facto wildlife sanctuary into a battleground. By coincidence, the reaction of wildlife to this incursion was captured on more than two dozen motion-detection cameras set up the previous year to study lynx.

The resulting trove of images, which reached scientists after the Ukrainian military retook the territory in April 2022, offer a previously unseen look at how animals change behavior when their habitat becomes a war zone. The results, published in June in Science, show that the war did in fact alter the animals, sometimes in unexpected ways.

The findings point “to a broader transformation of the Chornobyl Exclusion Zone — away from an ecosystem that, in the absence of human disturbance, had recovered from the reactor disaster, toward a militarized landscape in which wildlife habitat use and behavior changed,” said University of Freiburg ecologist Marco Heurich, who took part in the research.

The results underscore yet another way that wars can take a toll on wildlife. This at a time when conflicts rage on many continents, including civil conflicts in places like Sudan and Myanmar, and attacks by one country on another in Ukraine, Lebanon, and Iran. While the human tragedy of such conflicts is most shocking, nature is also a casualty.

The Chornobyl region had already witnessed more than its share of destruction at the hands of humans. The 1986 explosion of a nuclear reactor there had left the surrounding land tainted with radiation. But the accident also led to the creation of a 4,200 square kilometer zone largely off-limits to people, giving birth to an unexpected haven for wildlife. Wild boars, roe and red deer, wolves and moose flourished. Brown bears and lynx, once extinct from the region, returned.

In early 2021, scientists set out a network of camera traps aimed at studying the revived lynx population. A year later, Russian troops turned up, then were forced out by Ukrainian fighters. The timing meant the scientists had an unusual opportunity to compare how wildlife in 2021 behaved compared to the same time in 2022 when the war had begun.

The arrival of war fits within a broader body of research studying what is commonly called the “landscape of fear.” Scientists have delved into the ways animal behavior is altered when their habitat is perceived as being more perilous, often because a predator turns up. It could be guard dogs scaring off foxes, fish restricting where they graze on algae, or the smell of predators shifting antelope feeding habits.

It’s commonly thought that animals in a war zone will shift their movements more toward the nighttime. Darkness can off be quieter and makes it easier to move undetected.

In some animals, the researchers saw just that. Brown hares, for example, showed up more often in night camera shots. But just the opposite occurred for both red deer and red fox. “The decline in nighttime detections suggests that these species have shifted their activity to daytime hours in response to increased conflict intensity,” said Svitlana Kudrenko a former Freiburg Ph.D. student who led the research.

The cameras turned up other surprises. While bombs and gunfire might be expected to trigger animals to flee spots occupied by people, both lynx and red fox turned up close to human settlements more often during the occupation.

The researchers don’t offer explanations for this divergence in how different species responded to the war. And the occupation of Chornobyl was brief enough that it was impossible to see how these immediate behavioral changes might translate into broader ecological effects.

But with the war dragging, and some parts of the country reduced to front lines of devastation and violence, there are plenty of landscapes of fear where ecosystems are have been affected by the war for years, even if there are no cameras to capture it.

Kudrenko, et. al. “Changes in wildlife activity patterns in response to war in Ukraine.” Science. June 18, 2026.

Photo: Black storks and a grey heron resting on metal structures at the former cooling pond of the Chornobyl Nuclear Power Plant (June 2020) ©Kateryna Korepanova

Note on spelling: Many people are used to the “Chernobyl” spelling. But this paper spells it “Chornobyl.” The older spelling was Russian, and the new spelling is the internationally accepted one preferred by Ukraine.