The Chernobyl nuclear disaster zone, sealed off to humans for four decades, now supports more wildlife than any formally protected nature area in northern Ukraine, according to a new study.
Wildlife abundance in the exclusion zone
The radioactive landscape, too dangerous for human life, boasts some of the world's wildest populations of Przewalski's horses, wolves and Eurasian lynx. Researchers deployed 174 camera traps across 60,000 square kilometres of northern Ukraine between 2020 and 2021, capturing nearly 31,000 animal sightings of 13 mammal species. The exclusion zone alone accounted for 19,832 sightings—more than 63 per cent of the total—and was the only site where all 13 species appeared. In contrast, the Cheremskyi Nature Reserve, a formally designated wildlife protected area, recorded only one sighting.
Why the exclusion zone thrives
Researchers believe the size of the area and strictly enforced restrictions on human access are the main reasons it is more conducive to wildlife than formal conservation status. “Protected areas are most effective when they are large and contiguous, and human access restrictions are actively enforced,” the study, published in Proceedings of the Royal Society B, notes.
The exclusion zone was created after a reactor at the Chernobyl nuclear power plant exploded on 26 April 1986, scattering radioactive contamination across Europe and forcing the evacuation of nearby towns including Pripyat. Ukraine designated the area as the Chernobyl Radiation and Ecological Biosphere Reserve in 2016, covering roughly 2,600 square kilometres.
Return of rare species
The near-total absence of human activity allowed species locally extinct before the disaster to return. Brown bears, absent from the region for more than a century, recolonised the zone, while wolves and lynx re-established populations across both the Ukrainian and Belarusian parts of the exclusion zone. Przewalski's horses, native to Mongolia and genetically distinct from domestic breeds, were introduced to the Ukrainian zone in 1998 and 1999 with an initial population of 23 animals. By 2021 their numbers had reached 120, and they have since dispersed beyond the zone into Belarus and across the Prypiat river.
Comparison with protected areas
The wildlife gap between the exclusion zone and the protected areas was stark. Eurasian lynx were nearly four times more likely to be present in the exclusion zone than in the Rivne and Cheremskyi reserves. Wolves and red foxes followed a similar pattern, with both far more prevalent in the exclusion zone than anywhere else in the study area. Unprotected land in northern Ukraine fared no better than many of the designated reserves nearby. “Non-protected areas had species composition and occupancy values similar to small-sized PAs,” the study points out, adding that smaller reserves “may merely be too small to sustain permanent abundant populations of species with extensive home ranges”.
Radiation not a deterrent
The study did not assess the effects of radiation on wildlife populations, citing prior research from the Belarusian part of the exclusion zone that mammal distribution was unaffected by caesium-137 levels. However, conditions in the region have changed sharply since the research was conducted. Russia's invasion of Ukraine in 2022 brought military activity through the exclusion zone and the protected areas along the Belarus border. Fires linked to military operations have swept through the zone's forests, risking radioactive particles getting back into the air. Civilian monitoring and research have been severely restricted across the border zone since the war began.
