Original sentence: As humans were evacuated from the area about 25 years ago, animals moved in.Baker of Texas Tech University was one of the first to report that Chernobyl had become a wildlife haven and that many rodents he has studied at Chernobyl since the early 1990s have shown remarkable tolerance for elevated radiation levels.Biologist Robert J.Birds even nest inside the cracked concrete sarcophagus shielding the shattered remains of the reactor.Existing populations multiplied and species not seen for decades, such as the lynx and eagle owl, began to return.More research is needed into the long-term health effects on Chernobyl's wildlife species.Some researchers claim that by halting the destruction of habitat, the Chernobyl disaster helped wildlife flourish.Some scientists have suggested that soy plants in the area have also mutated in order to adapt to  the high radiation levels and toxic metals present in the zone.The Exclusion Zone around the Chernobyl nuclear power station is reportedly a haven for wildlife.The Exclusion Zone is so flush with wildlife and greenery that the Ukrainian government designated it a wildlife sanctuary in 2000.Wildlife has returned despite radiation levels that have been reported to be 10 to 100 times higher than background levels - according to a 2005 U.report - though they have fallen significantly since the accident, due to radioactive decay