"Those studies found mammal diversity and abundance equal to 
  that of a protected nature reserve, with rare species 
  including bears, lynx, river otter, and badger as well as 
  introduced herds of European bison and Przewalski’s horses. 
  Bird diversity is even richer and includes 61 rare species.
  Whooper swans—never before reported in the region—now appear 
  regularly."

I love how the best conclusion you can get from this research is that even nuclear fallout is better for the environment than the presence of humans in the area.