Argument: Road-grooming for snowmobiling causes harmful bison migrations
Daniel Dustin. "Ban snowmobiles in Yellowstone National Park". Parks & Recreation. June, 2003 - "Exacerbating the situation is what some scientists believe to be a direct link between the grooming of Yellowstone's roadways for snow traffic and the increased ease with which bison move in and out of the park. In recent years, many of the bison have been infected with brucellosis, a highly contagious disease that threatens domesticated livestock outside the park. Fear of contamination has resulted in the killing of large numbers of bison when wandering beyond the protective boundary of Yellowstone into Montana."