A Keystone Species Comes Home

“These prairies now seem bare of life, but it was not always so. Not very long ago, they were trodden by multitudinous herds of buffalo and antelope; then, along the wooded river valleys and on the pine-clad slopes of the mountains, elk, deer, and wild sheep fed in great numbers. They are all gone now. The winter’s wind still whistles over Montana prairies, but nature’s shaggy-headed wild cattle no longer feel its biting blasts.”

– George Bird Grinnell, Blackfoot Lodge Tales, 1892

On June 26, 2023, a small herd of around 40 bison were released back into a homeland that had not seen them in over a hundred years. The triumphant return of bison, called iinnii in the Blackfoot language, was a moment of celebration for the Blackfeet Nation and the wider Blackfoot Confederacy, who organized the reintroduction initiative. Tribal leaders released the bison onto a large (~25,000 acre) tract of Blackfeet land in the Chief Mountain area. There is hope that they will eventually expand their range to include the grasslands and woods of the northeast area of Glacier National Park.

Bison are an essential, and long absent, touchstone for Blackfeet culture and practices, “Our Blackfeet stories about who we are, about the buffalo and other land and water animals, plants, the stars, and about our songs, dances, and other sacred knowledge need to be safeguarded and carried on,” says Tyson Running Wolf, a Blackfeet member and state representative from Browning in a statement for the Iinnii Buffalo Spirit Center.

The significance of bison reintroduction lies at the intersection of cultural and ecological values. It affects people, plants, animals, soil, and water – bison are at the core of what makes this area special. Having iinnii back in their home makes this place more complete.

Chief Mountain

“[Bison] are a keystone species culturally as well as ecologically,” Lauren Monroe Jr., vice chairman of the Blackfeet Tribal Business Council told the Flathead Beacon. “We felt it was important to release this herd and manage this program according to our cultural and ecological principles while also respecting those of our partners.”

The reintroduction creates an important and valuable laboratory to observe the ecological impact of bison. Bison reintroductions are few to begin with, and none have ever been done in the exact type of grassland ecosystem (fescue dominated) present in this region of Glacier National Park and the Blackfeet reservation – nor in an area quite this large.

With your support, the Glacier Conservancy funds grassland ecology research, to understand and document the effects of bison on the ecosystem. The work is done collaboratively between Glacier National Park staff and Blackfeet researchers, and study areas lie on both sides of the boundary – within the park and the reservation.

The research is, in part, a repeat of a study done from 1999-2001, but with a twist. The original researchers did not know that bison would eventually be reintroduced, and there were no survey plots on the Blackfeet Reservation. The current work involved resurveying the 155 sites visited in the original study to observe any trends from the last 20 years, plus the surveying of new sites on the Blackfeet Reservation with students from Browning High School and Blackfeet Community College. The plots cover all of the major east side drainages and range in elevation from around 4,500 feet up to nearly 7,000. This study will establish a baseline for what conditions were like right when bison were reintroduced that future scientists can inspect for trends.

A huge amount of plant diversity is found in Glacier’s grasslands. About 400 different species will be identified by the grassland research team during the course of the survey work. A full third of the around 1,100 vascular plant species known to exist in Glacier are found in these meadows.

“It’s not unheard of to find 30 different species in a single microplot, which is only 0.25 square meters” said Nico Matallana, the grassland botanist leading the survey efforts, “There is an incredible amount of plant diversity here.”

Matallana (left) and team identify grasses. The white frame marks one microplot, which is a quarter of a square meter.

Matallana, and other scientists, are optimistic that bison reintroduction could further improve species richness in the area.

“Bison and fire were always here together,” Matallana explains, “After a fire, when the aspens shoot up new growth the bison graze it. That keeps trees from encroaching onto the meadows. Bison can’t graze back mature trees in the same way.”

Tree encroachment is one of the biggest threats to grasslands Matallana’s team has observed. Compared with the data from the original study, they are seeing more aspen and cottonwood trees moving into the grasslands.

Inspecting a grass blade to determine the species.

Research from other parts of the country has repeatedly shown the powerful restorative impact bison can have on grassland ecosystems. A recent study from South Dakota found that bison grazing increased the proportion of native plants in the grassland, increased plant biomass, and improved soil quality. Another study from the Flint Hills of Kansas found that bison reintroduction more than doubled the native plant species richness. (Species richness is a measure of the diversity of organisms in a given area).

A large body of scientific research shows that the same effects cannot be achieved with domestic cattle. Bison are often considered “keystone herbivores” because they graze preferentially on species that tend to dominate grasslands and crowd out diversity, making space for a wider variety of plants. Unlike domestic cattle, bison have evolved adaptations to the defenses of prairie plants, and bison spend more time moving and less time grazing, which can reduce their impact on particular meadows.

Although these studies generally focus on tallgrass prairie, a very different type of ecosystem than the fescue grasslands of the Crown of the Continent, scientists are cautiously optimistic that the same results may be observed here. Thanks to these grassland studies, made possible with your support, we will know the answer sooner rather than later.

Matallana and GNPC Hispanic Outreach Intern Lucia Quintanar practice identifying grasses.

Throughout the discussion of grass ecology and potential impacts of bison, Matallana bubbled with excitement. His passion for this project was evident and contagious. Still, he became most visibly excited speaking, not about grasses, but about the partnership this project involves with the Blackfeet Nation. 

“Working with the tribal interns and working closely with Buzz Cobell, (Director of Blackfeet Nation Fish and Wildlife) is so powerful”, Matallana said, “It’s a wonderful thing when the park can support and take a backseat while the original inhabitants of this land lead the way.”