McHenry County Conservation’s bison reintroduction project considered a success

Over the past year and a half, the McHenry County Conservation District has successfully reintroduced bison to prairies in the county, a project that has been long-awaited by district officials.

Brenna Ness, an agricultural ecologist with the McHenry County Conservation District, said officials were interested in integrating bison into its grassland management strategy for decades. It wasn’t until 2021, however, that everything aligned to have the opportunity to implement the project.

Bison play an important role in the ecology of prairies and grasslands, and are an excellent management tool for these ecosystems, Ness said.

“In prairies, when you don’t have any disturbance to the ecosystem from grazing or fire, grasses will tend to outcompete flowering plants and dominate the landscape,” Ness said. “So, by grazing primarily grasses, bison encourage more flowering plants which promotes a diverse plant community and a better balanced ecosystem.”

The McHenry County Conservation District signed a 15-year lease in 2021 on 180 acres of pasture land at Pleasant Valley Conservation Area in Woodstock. The herd is not open to the public, and will be kept at a low stocking rate while being rotated through the pasture to manage the habitat.

Bison have been reintroduced elsewhere in Illinois in recent years.

For example, there is a herd at Fermilab in Batavia that has been there since 1969 and has its own web cam. There’s also a herd at the Nachusa Grasslands in Franklin Grove that was introduced in October 2014, according to the Friends of Nachusa Grasslands’ website.

Midewin National Tallgrass Prairie in Wilmington also has a herd, with its own webcam, that was introduced in October 2015. There also are bison at Buffalo Rock State Park in Ottawa. And, earlier this year, the Kane County Forest Preserve approved bringing bison to Burlington Prairie Forest Preserve.

Bison help their environment through their grazing patterns and preferences, which create microhabitats for pollinators and wildlife. This, in turn, benefits breeding birds, a crucial aspect of the project in McHenry County.

The vegetation structure created by grazing bison is particularly attractive to various grassland birds. The population of declining bird species, especially bobolinks, have been monitored within the bison’s pasture over the past two years.

Adam Rex, restoration ecologist with the McHenry County Conservation District, said that they’ve seen the number of bobolinks skyrocket in the bison’s pasture through the bird surveys that the district has conducted.

“The benefits have been great,” Rex said. “Right outside the pasture, the numbers were almost nonexistent. Inside the pasture, the number of bobolinks just went through the roof.”

Other declining bird species also have experienced a notable population boost over the past two years.

Ness and Rex are excited to see all of the various benefits that bison can bring to prairies in McHenry County over the next 13 years.

Of the many expected benefits, bison are considered a keystone species of the prairie ecosystem and their grazing patterns also play an important role in prairie restoration.

“Anything they do affects the ground and without having them, you can never really do a complete restoration of a landscape.”

—  Adam Rex, restoration ecologist with McHenry County Conservation District

Rex said that since the bison were reintroduced in 2021, officials have considered the project a huge success in restoring McHenry County’s prairies.

“Take an old cornfield, we’ll try and turn it back into a prairie as close as possible to what it was during pre-settlement times,” Rex said. “To do that completely, you need the bison.”

Rex said that the landscape is directly affected by everything that the bison do.

“Anything they do affects the ground and without having them, you can never really do a complete restoration of a landscape,” Rex said of the bison. “They’re a key to getting full circle and balancing things out.”