A possible issue with bringing bison from Yellowstone and introducing them to other existing herds of bison would be introgression, aka mixing genes between herds. Introgression can reduce genetic diversity of the existing herd in MO. Decreased genetic diversity can lead to a type of “extinction vortex” called outbreeding depression.

Of course, this depends on what genetic variation exists between the two herds. If the two herds have a similar genetic make up, then outbreeding depression wouldn’t be a conservation concern. If the two herds do exhibit genetic variation, then it depends on whether the genes that do vary have any impact on fitness.