Can Bison Help Blanding's Turtle Populations?

In 2014, we reintroduced bison to our Nachusa Grassland preserve — one of the most diverse and species-rich sites in northern Illinois. This herd was the first to roam east of the Mississippi in almost 200 years. Nachusa also happens to be one of the few places where Blanding’s turtles have managed to persist. 

“Blanding’s turtles used to be common and pretty widespread, but habitat loss is causing their decline,” said Jeff Walk, director of science for the Illinois chapter. “Blanding’s are the ‘home town turtle’ here in the Midwest - it’s the core of their range. Illinois has a responsibility for this species because we’re right in the heart of their habitat.”  

Unfortunately, the prairies that Blanding’s turtles call home are considered the world’s most imperiled habitat type; in Illinois just one tenth of one percent of native grasslands remain

Bison Make Way for Turtles  

Very little is known about the gentle, wary Blanding’s turtles of Nachusa. The shy reptiles spend most of their time dwelling in, or moving between, quiet bogs and marshes. 

But the decline in grassland habitat has meant a decline in these pools of water – and a decline in turtles. 

Conservancy scientists know quite a bit about bison, however, as many herds have been introduced across North America in the last decade. The mammals – endemic to grassland habitats – are incredibly good for the health of their native lands. Their grazing habits can replenish grasslands, encouraging other wildlife to thrive as well – including, as it turns out, Blanding's Turtles. 


Bison create natural depressions in the ground when they lay down, which can fill with water and create natural pools  perfect turtle habitat. © 2014 Morgan Heim for The Nature Conservancy

In the summer of 2016, researchers conducted a first-of-its-kind radio telemetry study to track the turtles’ movements. 

“We believe the turtles may follow the herd because bison can create new aquatic habitat when they wallow on low-lying spots of the prairie. Their heavy bodies carve out deep depressions which fill with rain water,” explained Tom Anton, a Northern Illinois University researcher.

The bison create the bogs and marshes that the turtles need, and so the turtles follow the bison – and grow their numbers in the process. 

Additionally, our scientists hope to learn how far individual turtles move during the course of an active season -- approximately April to October – so that they can know which ponds, corridors, and lands to focus on protecting.  

The results of their study were beyond what many hoped for. The team successfully tracked two female turtles as they laid their eggs, and were able to protect the nests from predators with chicken wire. Recently, 11 turtles hatched from these two nests. The hatchlings will be monitored to aid future conservation efforts. 

How Can You Help?

If you live near an area that Blanding’s turtles are known to inhabit (if you’re not sure, considering asking local environmental agencies and organizations), be cognizant of how the activities on your property may be affecting the water quality of adjacent marshes. Avoid attracting nest-predators (skunks, raccoons, opossums) by removing any pet food that may be around your property. Most importantly, support agencies and organizations that are working toward protecting the turtles, their habitat, and water quality.


Stay Updated

Learn about the places you love and find out how you can help by signing up for Nature eNews.

I'm already on the list Read our privacy policy

Thank you for joining our online community!

We'll be in touch soon with more Nature Conservancy news, updates, and exciting stories.