The Fukushima and Chernobyl disasters have had massive consequences on local biodiversity.

Evidence suggests rewilding within the Fukushima and Chernobyl evacuation zones, with human presence creating greater pressure on animal populations than radioactivity levels. Some species appear to be more affected than others by the effects of radiation.

While both disasters led to the release of radioactive products into the environment, the area and level of contamination were greater at Chernobyl. Two phenomena took place simultaneously: the increase in exposure to radioactivity of local species and the departure of human populations from these areas.

At Chernobyl, during the acute phase of the accident, significant damage to biodiversity was observed. In particular, in an area of 6 km² around the plant, 90% of the pine trees died [1].

However, researchers agree that a wide-ranging biodiversity has returned to the Chernobyl area [2][3]. The TREE program, which studies the effects of radiation on biodiversity, detected the new presence of brown bears and European bison in the area. Wolves and wild horses also thrive there [3].

At Fukushima, the accident was not followed by visible short-term effects on fauna and flora. In the long term, we can also observe a rewilding of the evacuated area, especially by mammals and landfowl [2].

Different effects depending on the species

The effects of radioactivity on local biodiversity are differentiated by species, which are more or less sensitive to radioactivity and adapt to local exposure levels to varying degrees [3].

At Chernobyl, wildlife in the exclusion zone show several genetic changes associated with decades of radiation exposure; some clearly harmful, but others that reflect adaptation and selection [4].

At Fukushima, bird population size appears to have decreased [5]. Individual anomalies have also been observed, which do not threaten the viability of the populations. Finally, a number of species have adapted to the level of local radioactivity, such as frogs which tend to become darker in heavily contaminated areas [3].

For a large number of species, contamination from a nuclear accident appears to be less harmful than the presence of humans. The 2022 Russian military occupation of the Chernobyl zone, which disrupted the earth and caused radioactive particles to recirculate, has added a layer of uncertainty regarding the recovery of the zone's ecosystem.