The European bison or wisent (Bison bonasus) was extinct in the wild by 1927. Captive breeding programs have enabled reintroduction across Poland, Romania, Germany, and the Netherlands, creating the world's largest land animal reintroduction success story — with ongoing welfare management challenges.
Reintroduced European bison carry the genetic legacy of a severe bottleneck, increasing susceptibility to inbreeding depression and disease. Supplemental feeding in winter — while preventing starvation — creates aggregations that facilitate disease transmission and alter natural movement patterns. Road collisions kill dozens of bison annually as herds expand into new territories. Management culling is used in some areas to control population growth and prevent habitat degradation, raising welfare concerns about the methods used. Long-term welfare depends on maintaining genetic diversity through managed breeding, providing wildlife crossing infrastructure, and developing coexistence protocols with farming and forestry operations.