American bison have been restored from near-extinction and now face new welfare challenges from habitat confinement and management in smaller ranges than they evolved for.
Bison welfare in managed reserves involves tradeoffs between population viability and natural behavioral expression. Historic migrations covered hundreds of kilometers seasonally; managed herds cannot replicate this. Culling operations cause acute stress and death for removed animals. Brucellosis management creates intense political conflict between conservation and livestock interests, with bison sometimes killed or hazed to prevent livestock exposure. The Yellowstone bison population faces constant pressure at park boundaries. Expanding bison range through tribal land restoration is both a conservation and welfare improvement.