On a typical June day in Yellowstone, it’s not unusual to see hundreds of bison grazing in the Lamar Valley.
On a typical June day in Yellowstone, it’s not unusual to see hundreds of bison grazing in the Lamar Valley. The herds appear to aimlessly move back and forth through meadows threaded by a winding river, just passive figures in an idyllic scene. But, as it turns out, that’s far from the full picture.
In fact, with every blade of grass that bison bite off and swallow, they are fundamentally manipulating the landscape to maintain the best forage for themselves. They even change the way spring green-up occurs in Yellowstone’s vast grasslands.
Without bison moving freely on the landscape, the springtime season of plant growth in Yellowstone would be shorter, the habitat would not be as green, and the grasses would not be as nutritious.
Remarkably, that allows bison to migrate differently from other species.
When bison move to higher elevation by mid to late summer, the herd’s small army of hooves and hungry mouths causes the grasslands to revert to earlier stages of plant growth. In effect, the bison graze with such intensity that they turn back the clock on forage green-up, hitting reset on springtime.
Read more at University of Wyoming
Photo: Bison graze on a patch of green grass in late summer in this August 2016 photo from Yellowstone National Park’s Lamar Valley. Researchers have found that intensive grazing and fertilization by bison allow them to reset the clock on springtime plant growth, so they can migrate on their own terms, unlike mule deer and other ungulates. (Neal Herbert/National Park Service Photo)
