This area was designated a UNESCO World Heritage Site in 1983 for the biological diversity of the Peace-Athabasca Delta , one of the world 's largest freshwater deltas , as well as the population of wild bison .
It was named as a UNESCO World Heritage Site in 1983 because of it 's biological diversity of the Peace-Athabasca Delta , which is one of the world 's largest freshwater deltas , as well as the population of wild bison .