07/30/2024 | Ren Lashley, Museum Day Camp Educator at The Museum of the Grand Prairie
The bison, despite its depleted numbers, served a vital role in the ecology of the Great Plains. Bison are roaming creatures, moving from place to place depending on the season and weather. Unlike their bovine cousins (with whom they share a whopping 99% of their DNA!), they rarely graze at the same place twice in one year, which allows fresh vegetation to grow back much more rapidly.
They also almost exclusively eat grasses, which typically grow much faster than other plants, and thinning them out can help promote the growth of these slower plants. On pastures grazed by bison, plant diversity doubled purely due to the amount of grass they eat – 30 pounds per day! Without these dominate grasses in the way, wildflowers like blue violets, Dutchman’s Breeches, and black-eyed Susans can flourish, bringing color back to the prairies and giving pollinators a smorgasbord of delicacies that they wouldn’t get otherwise.
Bison also partake in wallowing, where they roll on the ground repeatedly to avoid biting insects and shed loose fur. This creates deep impressions in the earth that can fill with water when it rains, creating temporary ponds for animals and insects as well as encouraging the growth of prairie vegetation that require more moisture. This increases biological diversity and creates a mosaic of mini ecosystems for thirsty animals across the plains.
Besides wallows, bison have left considerable physical changes to the landscape. Buffalo Trace, just across from the Museum of the Grand Prairie, got its name due to the path millions of migrating bison used to take each year, following the same paths for centuries. Their hooves wore down the soil, creating trails initially used by Indigenous Americans and, later, European settlers. Interstate 74 follows approximately the same path as an old bison migration route!
But these benefits extend beyond just the prairie. Scientists at the Yale School of the Environment created a model that calculates the additional amount of atmospheric CO2 that wildlife species help to capture and store in soils through their interactions within the ecosystems. Using this model, they found that a single herd of 170 European bison can store 54,000 metric tons of CO2, the carbon emissions 43,000 U.S. cars produce in one year! This is due to their hooves pounding down the soil and preventing the release of carbon into the atmosphere. While it is still unknown how this would apply to the American Bison, this research highlights the important role that keystone species like the bison play in their ecosystems.
Image Source: Library of Congress.