On April 26, 1986 the world's worst nuclear accident took place at the Chernobyl Nuclear Power Plant located in modern day Ukraine. This tragic event has altered and claimed the lives of thousands of plants and animals. For obvious reasons, humans have abandoned Chernobyl's radioactive dead zone, however, the animal kingdom has no such policy in place. As a result, scientists from all over the world have and continue to investigate the impact this disaster has had on the surrounding wildlife. Despite all of the complexities involved in this analysis, scientists have uncovered a variety of ecological anomalies in the weeks, months, and years following the disaster.
Assessing Chernobyl's ecological impact is an incredibly complex problem for a variety of reasons. Perhaps the most intuitive of these complexities is that the radioactive material spewed out of the reactor did not uniformly coat the surrounding areas. As a result, the amount of radiation any one creature was exposed to depends on the distribution of radioactive particles, the mobility of the creature, and where it lives (i.e. in trees, underground, underwater etc.). In addition, each and every species responds differently to a given dosage of radiation. The acute lethal dosage of radiation for mammals, reptiles, and insects span three orders of magnitude. Humans are among the most sensitive and can only withstand a few grays of radiation. To make matters worse, the distribution of radioactive particles within the Chernobyl dead zone is constantly changing in time as radioactive species decay and as the landscape changes due to weather and seasonal changes (i.e. erosion, forest turnover etc.).  While I have mentioned only a few of the many complexities associated with assessing Chernobyl's ecological impact, scientists have managed to bring some method to this madness.
While the Chernobyl dead zone is neither desolate nor cluttered with freakishly mutated animals, its reality over the past 25 years has tasted bits of these extremes. For example, in the Exclusion Zone that received 10-20 Gy, 90% of the trees died by 1997.  This 10 km2 region was coined "the red forest" due to the overwhelming presence of orange colored pine tree needles. Krivolutsky et al. found that diversity of invertebrate species in heavily contaminated areas did not return to normal levels until 1996.  And while you'll be hard pressed to find two headed rabbits frolicking near ground zero, numerous morphological changes in trees have been documented ranging from growth of secondary shoots and intense needle growth to feature specific gigantism (i.e. needles) and dwarfism (i.e. trunks). Studies conduced by Shevchenko et al. (1992) and Pomerantseva et al. (1997) showed that embryo fatality rates were elevated when mating captured mice that were exposed to chronic radiation with laboratory female mice. [3,4] These rates decreased after a period of two weeks. In addition 2 of 122 captured mice were found to be sterile.
What is perhaps most exciting, yet also most depressing, about this madness is that the Chernobyl nuclear disaster appears to have been a blessing for the local wildlife by forcing the evacuation of human life. There may be radioactive particles, but there are no humans, no road building, no dam building, no deforestation, no farming, no hunting, no planes, trains or automobiles. And as a result, Chernobyl is quickly transforming into a wildlife refuge. Numbers of wild boar, deer, elk, wolf, fox, hare, and beavers have all increased significantly since the Chernobyl accident.  Hundreds of species of vertebrate animals inhabit Pripyat and its surrounding area, 50 of which are protected species. The Exclusion Zone has become a breeding area for rare species such as the white-tailed and spotted eagles.  So while the negative health consequences of acute and chronic radiation are undeniable, evidently they are less disruptive than the presence of human life.
The Chernobyl disaster has undoubtedly left its footprint upon the landscape where it once laid. While assessing Chernobyl's ecological impact involves addressing a plethora of complexities, it is certain that mass execution and increased numbers of mutated of species followed the accident. Twenty-five years after the disaster, wildlife has reclaimed the land and are thriving in this once-deemed nuclear wasteland. Chernobyl now serves as a humbling example of the intrusive nature of human life.
© Chris Goldenstein. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 T. J. Hinton et al., "Radiation-Induced Effects on Plants and Animals: Findings of the United Nations Chernobyl Forum," Health Phys. 93, 427 (2007).
 D. Krivolutsky and A. Pokarzhevsky, "Effect of Radioactive Fallout on Soil Animal Populations in the 30-km Zone of the Chernobyl Atomic Power Station," Sci. Total Environ. 112, 69 (1992).
 V. A. Shevchenko et al., "Genetic Disorders in Mice Exposed to Radiation in the Vicinity of the Chernobyl Nuclear Power Station," Sci. Total Environ. 112, 45 (1992).
 M. D. Pomerantseva, L. K. Ramaiya, and A. V. Chekhovich, "Genetic Disorders in House Mouse Germ Cells After the Chernobyl Catastrophe," Mutat. Res. 381, 97 (1997).