By Alyssa Nyberg
My drive to work involves one-stop sign and a herd of bison. It hasn’t always been that way…
My commute used to involve one stop sign and several agricultural fields. That all started to change in 1996, when The Nature Conservancy began planting 8,000 newly-acquired acres with native prairie grasses and flowers.
In two decades, we made huge changes to the landscape and have seen extraordinary responses from plants and animals in this newly created habitat. Then in 2016, we brought bison to Kankakee Sands, and my drive to work got really interesting!
The bison have been a game changer for our Kankakee Sands prairies. Since the bison have set hoof on Kankakee Sands ground, we have seen positive changes in the height of the prairie and the different types of plants that are growing on the prairie. In the years to come we hope to see increases in the number of grassland birds and the diversity of grassland birds that utilize Kankakee Sands.
Our bison herd is changing, too! As the herd grows in number and the animals age, we are finding that the dynamics of our bison are changing to mimic natural bison behavior, which is very exciting!
Our bison are exhibiting something called “seasonal aggregation’ in which the herd comes together during “rut” or mating season in the late summer, and ‘seasonal segregation’ in which the herd breaks out into different groups when not in mating season. When you visit Kankakee Sands this winter and spring, you will see that herd has broken out into three main groups.
The matriarchal family group is comprised mainly of females and young bison. These family groups usually stick close together and form the main herd of bison that we see out on the Kankakee Sands prairie.
A ‘bachelor pod’ of five to eight male bison has also formed. These males move out of the matriarchal family groups at about age three and are often seen grazing together away from the main herd. It is theorized that these males, being much larger in size than the females and young bison, require more forage and therefore move through the prairie at a different rate than the matriarchal group.
And then there is the lone bull. He is our oldest bull and prefers his personal space. He is almost always seen grazing alone, far from the other bison. As bison bulls age, they typically become less and less social and remove themselves from the other bison. But when mating season comes around, as you might imagine, he can be seen grazing within the main herd of females.
These three groups move differently across the prairie. The main herd, comprised mainly of females and young males, is very mobile – often moving to graze several different areas over the course of the day. The bachelor pods are much more stationary – they will often stay in the same general area for days at a time. And the lone male, well, there’s no telling where he will be.
With these differences in movement come different grazing patterns, and that results in greater plant diversity. This is good news to us, because we want our bison making similar grazing decisions about what to eat and not eat as they would have done historically on the Indiana prairie. This helps make our Kankakee Sands prairies as authentic as can be.
Visit Kankakee Sands. Enjoy the beauty and be a part of the change that is happening here.
The Nature Conservancy’s Kankakee Sands is an 8,400-acre prairie and savanna habitat in Northwest Indiana, open every day of the year for public enjoyment. For more information about Kankakee Sands, visit www.nature.org/KankakeeSands or call the office at 219-285-2184.