[noselasd]

Most of it is habitat loss.

I.e. look at e.g. https://www.google.com/maps/@43.9922189,-97.664741,145755m/d... , and it's just patches of fields no matter which way you go for hundreds of miles. Areas that once was wild forrest (or praerie), and housing numerous of of species having enough space to live and reproduce.

Give it some more years, perhaps a few hundred, and e.g. this https://www.google.com/maps/@43.9922189,-97.664741,145755m/d... , will look much like the above map, with fields for hundreds of miles in all direction. With it goes the home of many, many species.