Environment

Can We Make Green Roofs More Biodiverse?

A study of decades-old German green roofs found that they don’t support a wide range of animal and plant life. But researchers and designers are trying to change that.
A man puts a pallet of live plants on the roof of the Illinois Department of Agriculture building in Springfield, Ill.Seth Perlman/AP

Every time Kelly Ksiazek-Mikenas scrambled onto a new green roof, it was hard to tell exactly where she was. The city below was definitely Berlin or Neubrandenburg, but the expanse of scraggly greens ahead of her looked a lot like the green roofs in Chicago, her home.

The only difference was that the German green roofs were much older than anything found in the United States: three to nine times older. Which is why the Northwestern University Ph.D. student in plant biology spent her summer there a few years ago.