Bison function as a keystone species whose presence dramatically shapes prairie ecosystems, with cascading welfare benefits for thousands of species beyond bison themselves.
The welfare case for bison reintroduction extends beyond individual bison welfare to encompass the entire prairie ecosystem whose wellbeing depends on bison ecological function. The keystone role of bison in creating habitat heterogeneity, supporting invertebrate communities, and enabling grassland bird reproduction makes bison conservation a multi-species welfare intervention. Supporting large-scale bison rewilding therefore maximises animal welfare benefit per conservation dollar invested.