I used to live in MN and there was a while there when the insect population had dropped critically low. Certain species like the native ladybirds appeared to disappear completely, replaced by the Eurasian invasive ones. And the monarch butterflies almost disappeared as well, but the practice of leaving prairie buffers on the edges of farms in the western part of the state seems to have helped their numbers recover. By the time I left, you would see monarchs in the summertime again. I still have grave concerns about biota in America though, as I suspect there will be major abuse of wild habitat as energy descent takes hold.