Horse Butte is the only last wild bison calving grounds outside the park!

Horse Butte is a wildlife-rich peninsula, mainly on the Gallatin National Forest, extending over 10,000 acres from the border of Yellowstone National Park to Hebgen Lake, just outside West Yellowstone, Montana. It is a traditional calving ground for the park's Buffalo herds where they return annually for spring green up.

Yellowstone Buffalo are central to the long-term conservation of the species as they are one of the last herds of American bison. The vast majority of buffalo in North America are hybrids, with some cow genes. The Yellowstone population of Buffalo is the only continuously wild and free-roaming population in the U.S.

Buffalo play a central role in maintaining the health of the Greater Yellowstone Ecosystem. Their movements are essential for maintaining proper soil conditions in the prairie grasslands and they provide important food for imperiled species in the area such as wolves and bears. Yellowstone is one of the last remaining intact ecosystems in the lower 48 states, replete with the full complement of species. To maintain the long-term health of the ecosystem, including wide ranging species such as Buffalo, we must conserve lands beyond the boundaries of the national park.

Water is the Driving Force of Nature
Connecting Buffalo through Perspective

by Lily Brock
Wild Bison 2024-25 Field Season Internship 

The Buffalo have a long standing history of maintaining the health of the plains ecosystem. As a keystone species, habits and actions taken by the bison positively affect the biodiversity of organisms in the plains.

Bison roll or wallow in patches of dry ground, creating an impression that is as visible as a geyser across the landscape and as effective as a bath. These wallows result in more soil compaction, increased seed distribution, and a higher potential for water retention. It’s been found that “the altered structure caused by past bison activity creates a microhabitat with modified physical resources and a subsequent distinctive biological community” (Polley and Wallace 1986, Hartnett et al. 1997). These areas can hold water, acting as a place for amphibians to spring to life or can lead to higher arthropod numbers leading to better foraging for birds and native small animals.

The way Bison graze also has a big impact on plant ecohydrology, or the interactions between water and the environment. One study finds that “The presence of grazers, not fire history, altered water uptake patterns in these common grassland species…. reducing niche overlap with other co-occurring species.” (Nippert and O’Keefe, 2016).

Buffalo have a greater ability to increase biodiversity in an ecosystem than many other biotic and abiotic factors, and work as a keystone species in the way they shape their environment. “Bison are strong allogeneic ecosystem engineers (i.e., they behaviorally modify their environment)” and should the population increase in areas where the species once roamed, the environment would be positively benefited (Moran, Nickell, Plemmons, and Varriano, 2018).

Buffalo Photos:  Megan Langlois, BFC Volunteer, shares her time with the Buffalo via photos while BFC Intern Lily Brock shares her time via words. 

Join us in the field and find your story of and with the Buffalo!