Radiation: The Ecological Fallout in Wildlife
Three and a half decades after the nuclear disaster, wildlife is thriving in the Chernobyl area. However, this does not mean that the radiation is harmless for living creatures — we might just fail to notice its profound effect.
Radiation is harmful for all living creatures — it is a well-known fact. Or, maybe, it is a stereotype — because wildlife has been thriving in the Chernobyl area ever since the nuclear disaster broke out. Once people left the 30 km exclusion zone, animals rapidly took over their abandoned houses. Today, hidden cameras placed by scientists would often show a cat’s family that lives in a room that once used to be a human bedroom or wolves that roam the streets being absolutely not afraid of hunters. Yet it would be premature to say that radiation poses no threat to wildlife. Probably, we just fail to detect meaningful transformations that will be revealed later.
What Happened After the Explosion at the Chernobyl Nuclear Power Plant
Unfortunately, little objective research was done in the middle of the 20th century on the impact that radiation could have on wildlife. Most papers of that period were too focused on propaganda. After the disaster took place in 1986, independent foreign scientists were not allowed to explore the Chernobyl area. Now, three and a half decades after, the scientific community still does not have complete and exhaustive information on how harmful the radiation was to the local wildlife.
Almost immediately after the explosion, the coniferous forest on an area of 5 sq. km. turned rusty red. Many trees and soil invertebrates died. The small mammal population plummeted. It seemed that the local wildlife was doomed. However, in a few months, the radiation levels dropped drastically in large areas of the exclusion zone — and the revival began.
What Happened in Chernobyl in the Late 1980s and the 1990s
Scientists started an aerial survey program to count the population of wild boar, roe deer and elk. Even though observations made from a helicopter were not too precise and were carried out just once per year, the researchers were surprised to see that all three species were plentiful in the area.
In mid-1990-s, Ukrainian and US ecologists set up traps in the exclusion zone to measure the population of small mammals. It turned out that the abundance of shrews, mice and voles in Chernobyl did not differ too much from the regions that never suffered from the radiation.
By the 2010s, the density of animal trackways in the exclusion zone was comparable to those in four Belarusian nature reserves that were never exposed to the radiation. The scientists surveyed hundreds of kilometers of tracks used by foxes, roe deer, wild boar, wolf and elk and were impressed by their population size. Wolves were especially abundant in the area: their population was 7 times larger if compared to other reserves. Bison, lynx, badgers, beavers and even a brown bear were spotted in the area too.
Relying on this data, you might think that wildlife has fully recovered in less than a decade after the nuclear disaster. Alas, this would have been a false assumption.
The Proven Negative Impact of the Radiation
The above-mentioned observations regarding the track density turned out to be relevant only for the areas with low radiation levels. In 2013, the animal tracks were still not too dense in those parts of the forest that were initially exposed to the greatest radiation risks.
In the areas with high radiation levels, the population of spiders and insects declined dramatically. In 2009, it was still much lower than three decades ago. Moreover, even in the areas with less radiation the population was not as numerous as it used to be before the disaster.
Researchers found out that low-dose radiation affected the DNA of living creatures. They either became prone to quicker mutations or their chromosomes were damaged. Scientists came to the same conclusion when scrutinizing the population of the pale grass blue butterfly in the area of the 2011 Fukushima nuclear accident. Even though the radiation doses were not too high, the butterfly suffered from genetic damage.
Under laboratory conditions, these DNA changes did not seem too hazardous. Yet in the real world, animals are exposed to a vast variety of ecological pressures and thus might be more vulnerable to the potential risks caused by radiation.
The authors of the papers that accentuate the harm of radiation to living creatures have been severely criticized. They were accused of committing numerous mistakes and being not too accurate in their research. Nevertheless, it seems that radiation is highly likely to cause profound changes in the organisms of wildlife creatures, even though the impact of the shift might be not too striking at first sight.
Some studies suggest that low radiation doses might be beneficial for living things. If an animal receives a small dose and then a larger one within 24 hours, it will better endure the latter. This happens thanks to the hormetic effect that provides an overcompensation for mild environmental stress.
Judging by the relatively recent disasters of Chernobyl and Fukushima, even high doses of radiation do not cause an immediate extinction of wildlife species. Yet it might provoke mutations that can tell on health, life expectancy and other vital parameters of the next generations of living creatures. So far, scientists lack enough evidence and background to precisely estimate the impact of radiation on animals, plants, birds and insects. However, it can be said for sure that the areas that were exposed to lower levels of radiation recover quicker than those that were heavily affected.