Yellowstone National Park has a rich history — one scientists are still digging up.
In fact, this October, researchers from Oklahoma State University published new findings that examine ancient fecal records to better understand the past — and future — of the hallowed grounds.
That’s right — ancient poop holds invaluable clues to one of America’s most beloved national parks.
By analyzing steroids from animal dung in lake sediments dating from about 238 B.C. to the present time, John Wendt and his research team were able to confirm that large herbivores like bison and elk have continuously lived in the Yellowstone region for about 2,300 years.
The layers of sediment studied by the researchers showed history in action.
The top layer, which contains mud closest to the water found in the area, reflects a recent rise in bison use of the area. In the samples, researchers could also see the historic fires of the 1980s, which burned thousands of acres.
And 2,000 years ago, they noted a period of ecological stability, in which samples reflected very few changes in vegetation or the animals who existed in that time.
But why does this record matter?
“We developed a 2,300-year record of wild herbivore activity in northern Yellowstone National Park with fossil biomarkers found in lake sediments,” the researchers said in a statement.
“This information is critical for understanding long-term dynamics of ecologically and culturally important herbivores such as bison and elk.”
Wendt told Wyofile that this record provides a baseline for a small system within the region and fills in knowledge gaps of the park’s history.
“If park managers are interested in understanding the baseline of large herbivore use, they could now compare modern levels to the long-term average and variability,” Wendt said. “As in, is what we’re doing now outside of some historic range of variability?”
A more expansive and scientific account of history also corroborates human accounts from Indigenous peoples, while also pointing to the plants and animals that thrived in various climate scenarios.
This could, in theory, provide more insights about how plants and animals in Yellowstone may react as our climate continues to change.
It all started five years ago, when Wendt and his colleagues gathered samples from the deepest part of Yellowstone River (referred to as Buffalo Ford Lake), digging about five feet down, and pulling up layers of history.
The researchers had previously analyzed steroids found in bison, elk, pronghorn, mule deer, and moose feces, isolating unique compounds in each. Using the new sediment samples, they compared what they found to the existing samples.
“Because Yellowstone has such a well-documented history, we were able to compare the management practices and some of what is known about where animals were distributed at different points over the past 150 years to our observations,” Wendt explained. “That gave us a lot more confidence in interpreting the record further down.”
The fecal samples gathered from Buffalo Ford Lake likely came from the animals congregating on the frozen lake during the winter, or from the shore, where snowmelt would wash their waste into the lake, eventually settling to the bottom.
Their findings — that bison and elk were in healthy supply in the region for thousands of years — tell a story of colonization. It’s a story that is well known, Rick Wallen, a former bison manager at Yellowstone (who was not involved in the study), told Wyofile.
But it’s one that must be studied.
“Everyone acknowledges there were a lot more animals in the lower country and as the colonization of the West occurred, they retreated back up into wherever they could get away from development and conflicts,” Wallen said. “But bottom line, this shows bison and elk had been in that area of the high country for at least 2,300 years.”
This study plays a significant role in setting the historic record straight. But ongoing studies of various samples in the region could also inform the future.
A lone study will not likely change current wildlife management strategies. But as more information becomes available, Cathy Whitlock, a co-author of the study and Montana State University professor, believes more decisions about how the region should be utilized can be made, based on how it best thrived in the past.
“Our lake studies are not like finding a bone in a cave,” Whitlock told Wyofile. “Sure, you can get a radiocarbon date and show how old the bone is, but that doesn’t indicate sustained presence, it’s a one off.”
These lake studies hold a greater depth of understanding — literally and figuratively.
As the researchers write in the conclusion of their study: “Continued development of fecal steroid records can address critical questions about the historic role of bison, elk, and other ungulates in Yellowstone National Park and other grazed ecosystems.”
Header image courtesy of NPS
