The anthropocene is often considered as the tale of human journey towards supremacy in the world. This one-sided glory results into destruction of ecosystem as well as extinction of the species. However, to control the damage we often opt for the option like restoration which means return the damaged ecosystem or reviving the animal population to their pre-mayhem level. To date, restoration work is mostly intervened by the human who determine management and processes both for ecosystem and species. What happens when we allow the natural processes to go as per their will? Whether animals other than human can handle the post damage situation by themselves? What could be the possible scenario in extreme cases like nuclear accidents? The findings are really intriguing, let’s see.
On March 11, 2011 Japan faced one of its biggest disasters in the 
centuries. An earthquake of 9.0 magnitude, a violent tsunami with 15 mt. high sea wave and consequently nuclear meltdown and hydrogen explosions at the Fukusima Daichi Nuclear Power plant near the city of Okuma. The accident at the nuclear reactor results into leakage of radioactive materials and hydrogen into the atmosphere, terrestrial system and Pacific Ocean. An estimated 20-40 trillion becquerels of radioactive tritium leaked only into the Pacific ocean since the disaster. In response to the disaster, Japanese government evacuated humans from an area of 1150 km2 as a precautionary measure against radioactive contamination. The exclusion zone was divided into three categories – innermost one where humans cannot return in foreseeable future, in middle and outer ones based on contamination levels restricted activities and rehabitation are allowed.
Interestingly, this devastation proves to be an opportunity for the wildlife in that region. The deserted landscape acts as a ground for “rewilding”, a term often used for positive response of the species to the restoration efforts. Here the rewilding process is natural unlike in other cases where anthropogenic intervention is often evident. It is only comparable to places like Korean Demilitarized Zone (DMZ) and Chernobyl Exclusion Zone in northern Ukraine where nature takes its’ own accord to reshape the damaged ecosystem. The scientific study on vertebrate wildlife in Fukushima reveals that an abundant and diverse wildlife community exists in the region, providing an evidence of natural rewilding, despite having beyond the permissible limit of radioactive contaminants. There is notable increase in wild boar, raccoon, civet, hare, macaque population along with other mid to large sized animals. What could be the probable reason for this population boom? Researchers tested multiple factors like radiation intensity, human habitation, elevation, vegetation type and interactive ones to find out the most relevant ones. Surprisingly they found that human is the major factor rather than radiation intensity and majority of the animals are crowding more in the innermost exclusion zone where human entry is completely banned.
What about radiation sickness among the animals? Are they resistant
or bearing the effect of radiation exposure? Earlier studies on individual animals from the region documented the biological effect of the exposure like DNA damage, physiological damage, hematopoiesis etc. But this study pointed out that whatever damages occurred at the individual level (physiological or molecular level) that is not manifested (or yet manifested) at the population level attributes like abundance or occupancy patterns. Perhaps regular monitoring at the larger time period may provide the answer whether radioactive stressors ultimately doom the entire population. This finding has similarity with the studies conducted at the Chernobyl region. There too, despite having high radiation, there is dramatic increment in the number of wild life (grey wolf, raccoon dog, red fox, Eurasian boar) in the deserted region. Interestingly, even endangered species found their way in the nuclear landscape. Przewalski’s horse, the last remaining sub-species of wild horse, became extinct in the wild, was available only in captivity. As an experimental basis, 36 horses were released in the Chernobyl exclusion zone from 1998 to 2004. Their population got doubled within 10 years up to 65.
The lesson is worthy to learn. Wild life can manage themselves pretty well if we allow them required space and time. It seems that human intervention in nature is worse than even radioactive contamination. These vivid examples of natural rewilding tell us about the resilience power of the animals even under extreme conditions provided we allow them to do so.
Source: Lyons et al. (2020) Front Ecol Environ 2020; doi:10.1002/fee.2149
Ania Tsoukanova (2021) . Wild horses flourish in Chernobyl 35 years after explosion. https://phys.org/news/2021-04-wild-horses-flourish-chernobyl-years.html
Image courtesy: James Beasley, Phillip Lyons, and Tatyana Deryabina
Collector- Rajasri Ray
