For the first time in more than 15 years, Montana bison will roam new grazing grounds on public land. After 4 years of review, the Bureau of Land Management (BLM) on 28 July granted a request by the nonprofit American Prairie to release its bison herd onto more than 24,000 hectares in central Montana. This is the largest land approval BLM has given American Prairie. Many ecologists are celebrating the expansion, part of American Prairie’s effort to restore Montana’s prairie ecosystems and return the U.S. national mammal to its former glory.
“We get a lot of bad news about declines of biodiversity,” says ecologist Liesbeth Bakker of the Netherlands Institute of Ecology, who has worked with bison in Nebraska. “But then to see these things really gives you hope; it makes you think it is possible to restore these ecosystems and give these majestic animals the room they deserve.” She notes that the benefits go beyond bison to a host of prairie plants and other native animals. Ranching groups and state officials are less enthusiastic, fearing the bison will compete with cattle.
American Prairie aims to create the largest nature preserve in the lower 48 states using purchased and leased land in central Montana. Bison are instrumental to its goal of restoring the prairies. The organization already manages about 180,000 hectares of public and private land, much of it former ranchland, on which they now graze about 800 bison. It hopes to expand that number to 1000 now that it has the extra space.
Grasslands, especially tallgrass prairies, are some of the most endangered and least protected ecosystems in the world, and they have received relatively little restoration. Some former prairie is difficult or impossible to restore, such as that converted to cropland or urban development. But there’s hope for land used for cattle grazing, notes American Prairie spokesperson Beth Saboe. “The biodiversity that can exist there is astonishing.”
Just a few bison can aid the rebirth. Although all grazing animals can improve grassland diversity if carefully managed in small numbers, no species does it quite like bison, says University of Minnesota, Twin Cities, ecologist Joseph Bump. Bison are less reliant on water sources than are cattle, which means they can travel farther from rivers to graze. As a result, they are less likely to trample riparian plants, allowing fish and amphibian diversity to recover.
Studies have also shown that compared with cattle, bison graze in a way that makes them more effective at trimming dominant grasses, allowing sunlight to reach the smaller flowering plants known as forbs. This stimulates their growth, attracting more native insects and birds. Bison also famously create wallows, depressions that fill with rainwater and draw microcommunities of diverse organisms. BLM cited this research, arguing that the reintroduction of bison to the proposed sites in Montana grasslands will not only increase plant and animal diversity, but improve water quality and overall habitat conditions.
“I don’t see any ecological downside to this development,” Bump says. “And I don’t really see a long-term downside in any way.”
Several organizations disagree. The United Property Owners of Montana, the Montana Stockgrowers Association, and Montana Public Lands Council (MPLC) have fought the nonprofit’s efforts in recent years. They are concerned the BLM decision signifies a shift in range management that will favor restoration and harm ranching communities and cattle production, which is the primary industry in central Montana.
“The final decision issued by the BLM is a failure to our public lands system,” MPLC Chair Vicki Olson said in a statement issued on 29 July. “The rangeland will be the ultimate victim.”
Montana legislators have already vowed to get the decision reversed. “As we review BLM’s bison grazing decision, we share Montanans’ frustration with the agency’s woeful and repeated failures to properly engage Montanans and act within the bounds of its authority on this issue,” Montana Governor Greg Gianforte tweeted.
BLM addressed many of the concerns in a letter issued on 29 July. The bureau’s 2021 environmental analysis of American Prairie’s request concluded the change would not harm the land or the local ranching economy. Bump agrees. “The tension lies in thinking that it’s an either or,” he says. “It’s a false dichotomy that we can’t have ranching and bison, we can certainly have both. Even in these areas that are human dominated, there can still be room for these large animals as well.”
Source: Science Mag