Yellowstone Bison Are Iconic And Special

Copyright:   Pete Bengeyfield

Copyright:   Pete Bengeyfield

Yellowstone’s bison are truly special and unique because they represent the last remaining TRULY wild, ecologically viable, genetically pure, and wide-ranging population of plains bison in existence. They are descended from the last wild herd in North America, and are still wild, still predated by wolves and grizzly bears, still competing for resources and mates, exposed to harsh environmental conditions, and still roaming across a vast and varied landscape. As a result, they have likely retained many of the adaptations that have been lost in other bison herds through domestication.

managing bison once they leave yellowstone

Yellowstone Bison are a migratory species and much of their natural winter habitat exists outside of the park in lower elevation areas such as the Madison and Paradise Valleys in Montana. However, unlike all other Yellowstone wildlife that are allowed to roam freely in and out of the park, Yellowstone bison are artificially confined to the high elevation reaches of Yellowstone National Park (the grey in the map below represents their current distribution).

Bison hazing.jpg

This is due to fears that bison will transmit the disease brucellosis to livestock on the landscape in Montana. Brucellosis is a European livestock disease that was brought here in the early 1900s and was thought to have been introduced in to the Yellowstone Ecosystem by dairy cows being held at the Buffalo ranch in the Lamar valley.  While brucellosis has been largely eradicated in livestock throughout the country, there still exists this reservoir in Greater Yellowstone wildlife. Today the fear is that brucellosis could be transmitted from Yellowstone bison back to livestock on the landscape, which could have significant economic implications for MT’s livestock industry. Brucellosis is a bacterial disease that causes abortion and can be transmitted between elk, bison, and cattle through contact with fetal tissue in the environment during specific transmission periods.

YNP Historic Distribution.jpg

Thus, bison management today revolves around the perceived risk of brucellosis transmission. Due to these fears, bison are subjected to intense testing, hazing, and slaughter operations, and essentially managed as livestock as soon as they leave the park following the current Interagency Bison Management Plan. The IBMP was implemented in 2000 to drastically limit Yellowstone bison numbers (to between 3,000 and 3,500) as well as their access to lands outside the Park in order to maintain spatial separation with cattle to protect Montana’s livestock industry.

Today, there is new information and science and a changing landscape that makes the current bison management regime outdated and unacceptable. For example, we know now the risk of brucellosis transmission from wild bison to cattle on the landscape is much lower than we once thought. In fact, there has never been a documented case of bison transmitting brucellosis to cattle on the landscape. Furthermore, many Greater Yellowstone elk carry brucellosis, however they are allowed to roam freely and rightfully so, without such intrusive management. There’s a lot more tolerance for bison on the landscape now and very few cattle left in areas adjacent to the park. This is due in large part to grazing allotment buyouts and land leases over the last decade that GYC has been very much involved with, in addition to our ongoing conflict reduction and coexistence work.