How did early humans contribute to the growth of the prairie in Kansas

Around 10,000 years ago, early human established themselves as the primary hunter within that region, since there is an abundance amount of birds to hunt in that region (such as duck or geese)

Over the time, they keep creating more population and more technologies for their survival mechanism (such as hunting tools, watering system, plantation method, etc) which lead to the growth of praire in Kansas.