I am still working on the research, folks, and I have found some interesting information concerning bison (or buffalo) in Arkansas. In 1541, when Hernando De Soto came through Arkansas, there were no bison. His men noted that they met tribes on the western edge of Arkansas who had buffalo hides and had informed them that buffalo were one to two days away.
By the 1700s, buffalo were all over Arkansas and some of the Southeast. Buffalo hunters came to Arkansas to hunt the herding animals, and Native Americans hunted them for food and their hides. By the 1840s, no buffalo remained in Arkansas because of overhunting.
Why were there no buffalo in 1540, and Arkansas had plenty 150 years later? According to scientists, historians, and archaeologists, Arkansas contained so many Native Americans that buffalo could not migrate into the area without being killed. Furthermore, Native American agricultural practices (slash and burn) had cleared large sections of ground for crops and removed habitable areas for buffalo. These practices removed cover and food sources for the large beasts.
However, after European contact, so many Native Americans died from disease (as high as 90% in some areas) that there were fewer hunters to kill the buffalo and fewer people to clear the tracts of ground for farming. Therefore, places like the Arkansas, White, and St. Francis River bottoms grew in canebrakes, providing cover and food sources for the buffalo. So, the animals moved into Arkansas and the American southeast during the 17th and 18th centuries. In Arkansas, the last buffalo were hunted out by the 1840s.
Arkansas Wildlife History 