Another view on Chernobyl radiation’s effects on wildlife:
Radiation exposure has caused genetic damage and increased mutation rates in many organisms in the Chernobyl region. So far, we have found little convincing evidence that many organisms there are evolving to become more resistant to radiation.
Organisms’ evolutionary history may play a large role in determining how vulnerable they are to radiation. In our studies, species that have historically shown high mutation rates, such as the barn swallow (Hirundo rustica), the icterine warbler (Hippolais icterina) and the Eurasian blackcap (Sylvia atricapilla), are among the most likely to show population declines in Chernobyl. Our hypothesis is that species differ in their ability to repair DNA, and this affects both DNA substitution rates and susceptibility to radiation from Chernobyl.
Much like human survivors of the Hiroshima and Nagasaki atomic bombs, birds and mammals at Chernobyl have cataracts in their eyes and smaller brains. These are direct consequences of exposure to ionizing radiation in air, water and food. Like some cancer patients undergoing radiation therapy, many of the birds have malformed sperm. In the most radioactive areas, up to 40 percent of male birds are completely sterile, with no sperm or just a few dead sperm in their reproductive tracts during the breeding season.
Not every species shows the same pattern of decline. Many species, including wolves, show no effects of radiation on their population density. A few species of birds appear to be more abundant in more radioactive areas. In both cases, higher numbers may reflect the fact that there are fewer competitors or predators for these species in highly radioactive areas.
Moreover, vast areas of the Chernobyl Exclusion Zone are not presently heavily contaminated, and appear to provide a refuge for many species. One report published in 2015 described game animals such as wild boar and elk as thriving in the Chernobyl ecosystem. But nearly all documented consequences of radiation in Chernobyl and Fukushima have found that individual organisms exposed to radiation suffer serious harm.
photo: Tim Mousseau