<P> It is unknown whether fallout contamination will have any long - term adverse effect on the flora and fauna of the region, as plants and animals have significantly different and varying radiologic tolerance compared with humans . Some birds are reported with stunted tail feathers (which interferes with breeding). There are reports of mutations in plants in the area . The Chernobyl area has not received very much biological study, although studies that have been done suggest that apparently healthy populations may be sink instead of source populations; in other words, that the apparently healthy populations are not contributing to the survival of species . </P> <P> Using robots, researchers have retrieved samples of highly melanized black fungus from the walls of the reactor core itself . It has been shown that certain species of fungus, such as Cryptococcus neoformans and Cladosporium, can actually thrive in a radioactive environment, growing better than non-melanized variants, implying that they use melanin to harness the energy of ionizing radiation from the reactor . </P> <P> The Exclusion Zone around the Chernobyl nuclear power station is reportedly a haven for wildlife . As humans were evacuated from the area 25 years ago, existing animal populations multiplied and rare species not seen for centuries have returned or have been reintroduced, for example Eurasian lynx, wild boar, Eurasian wolf, Eurasian brown bear, European bison, Przewalski's horse, and Eurasian eagle owls . Birds even nest inside the cracked concrete sarcophagus shielding the shattered remains of Reactor 4 . In 2007 the Ukrainian government designated the Exclusion Zone as a wildlife sanctuary, and at 488.7 km it is one of the largest wildlife sanctuaries in Europe . </P> <P> According to a 2005 U.N. report, wildlife has returned despite radiation levels that are presently 10 to 100 times higher than normal background radiation . Although radiation levels were significantly higher soon after the accident, they have fallen because of radioactive decay . </P>

What were the environmental effects of the chernobyl disaster