Of intrinsic traits and extrinsic threats

Once numbering tens of millions, American bison (Bison bison) were almost hunted to extinction during the 1800s for their meat and pelts. Yellowstone National Park was the only refuge in North America that did not see total extirpation of wild, free-ranging bison. Like many species, the bison’s risk of extinction has been shaped by its intrinsic traits as well as extrinsic threats – its body size, behaviour and abundance made it an easy and valuable target for human exploitation. Protecting the species from over-hunting and enacting active management has been responsible for its partial recovery. More recently, culling to manage risk of brucellosis transmission to domestic cattle has hurt breeding herds, altered breeding structure, reduced female cohorts and suppressed productivity. It is now listed as Near Threatened by the IUCN because viable populations are very limited and it is a conservation dependent species.

(Photo by Chris Murray)

(Photo by Chris Murray)

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