Pipestone National Monument, when it was established in 1937, inherited a tallgrass prairie ecosystem that had changed little from prehistoric times. While some areas have been restored, a significant portion of the tallgrass prairie within Pipestone National Monument is native prairie - prairie that has never been plowed.
Because the climate in which tallgrass prairie occurs naturally is also favorable to agriculture, much of the tallgrass prairie today has been converted to farm fields of one kind or another. Only a tiny sliver of the tallgrass prairie remains, less than 1 or 2% of the former range. Some of that prairie is within Pipestone National Monument.