The National Geographic article, the author links to, states that

  The effects of the Chernobyl catastrophe are still being felt today—whole towns
  lie abandoned, and cancer rates in people living close to the affected areas
  are abnormally high
  

then goes on to say that

  But it turns out that the radioactive cloud may have a silver lining. Recent
  studies suggest that the 19-mile (30-kilometer) "exclusion zone" set up around
  the reactor has turned into a wildlife haven.
  

So basically, the accident at Chernobyl turned the area into a wildlife haven, because it was left to wild animals. If this were to mean that Chernobyl had a net positive effect, it would still contradict the author’s claim that there hasn’t been “much impact on the area around Chernobyl”.