Nine miles from the heart of downtown Lincoln lies an ecological rarity.
Surrounded by farm fields and a retired Cold War-era bomb storage depot, a 230-acre plot of native prairie remains untouched.
Named for its distance from Lincoln’s urban core, Nine-Mile Prairie is one of the last tallgrass remnants that once dominated eastern Nebraska. Home to species such as big blue stem, Indiangrass and goldenrod, the prairie plants can reach peaks of 8 feet in the fall, when gold and red hues begin to replace the summer green.
But among the sea of grass and flowering plants is a now-common sight that alarms grassland experts, including David Wedin, who formerly oversaw the Nine-Mile Prairie: shrubs and trees.
“One of the things prairie conservation’s coming to grips with in the Midwest is ‘How much shrubs and trees (and) which shrubs and trees are acceptable?’” Wedin said. “Because we can never go back to no trees at all.
“The game has changed.”
Nebraska used to be 98% prairie. Agriculture, urban development and heavy grazing changed that, and much of the state’s native ecosystem has disappeared over time.
Although advocates continue to manage and restore the state’s remaining prairies, experts say that factors such as rising CO2 and increased atmospheric nitrate levels have created new conditions that favor woody and invasive species.
The Nine-Mile Prairie is owned by the University of Nebraska Foundation and managed by the University of Nebraska-Lincoln’s Center for Grassland Studies. The top priority: keeping the land a prairie.
But that is becoming harder to do.
At least once every three years, the Nine-Mile Prairie’s managers and student workers remove unwanted species and dead plant material by mowing, haying and conducting prescribed burns. They sometimes carefully use herbicides to keep woody species like dogwood and eastern red cedar trees at bay.
While these are typical prairie management practices, Wedin said they’re no longer enough. Shrubs and trees are growing faster than they can manage them.
One reason for the change, Wedin said, is the increase of CO2 in the atmosphere. While CO2 itself is essential for plants, extra CO2, he said, “tilts the balance away” from Nebraska’s dominant warm-season grasses that don’t benefit from it as much as shrubs, trees and cool-season grasses.
The shifting climate has also caused warmer winters, Wedin said, and cool-season grasses, shrubs and trees can establish themselves long before warm-season grasses and flowering plants start growing in mid- to late spring.
The changes, combined with extra nitrogen in the atmosphere primarily from farming, he said, mean conditions are stacked against tallgrass prairies. Land managers can’t get “too hung up on what was ‘natural’ in 1850,” Wedin said.
“I’m willing to let it go,” he said. “… As long as we’re removing biomass every three years, I can live with the dogwood and the sumac and the little red cedar seedlings.”
Prairies in North America formed around 10,000 years ago, when the climate warmed and the last major ice age ended. Indigenous tribes, such as the Ponca Tribe of Nebraska, have long been intertwined with them.
Stacy Laravie, a Ponca member and 3x great-granddaughter of Chief Standing Bear, said the prairie was and is “a way of life.”
Living in earth lodges along the Niobrara and Missouri rivers in Nebraska, the Ponca farmed and hunted bison. They would also set fire to the prairie, a practice of many Great Plains tribes.
The fresh, nutritious growth after a burn would attract bison, Laravie said. It also created habitat for different plants and animals during regrowth phases and helped keep the shrubs and trees away.
“(Burning) was our guide to what happens within the season and next,” Laravie said. “The land spoke to us in that way.”
Without burning by indigenous tribes, areas of the state would have had more woodlands and less prairie, said Gerry Steinauer, Nebraska Game and Parks plant ecologist and botanist. Before the ice age ended, he said, Nebraska was predominantly spruce forest, not prairie.
Now, Nebraska is made up of four prairie ecoregions from east to west: tallgrass prairie, mixed-grass prairie, Sandhills prairie and shortgrass prairie.
Steinauer said only about 1% of the state’s tallgrass prairie remains in restored and preserved patches, and much of it is degraded. Most of it was plowed under by 1880 because eastern Nebraska’s fertile soil and higher precipitation rates made it ideal for homesteading farmers.
Urban sprawl in the 20th century has reduced it to even smaller fragments.
Nebraska’s mixed-grass and shortgrass prairies are about 50% intact, and the Sandhills prairie remains about 90% intact, Steinauer said. Although they face similar threats to the tallgrass prairie, less precipitation and sandier soils have kept them from undergoing the same rapid decline.
While conservation groups are working to protect the state’s prairies, Steinauer said Nebraska is still “behind the eight ball” in prairie conservation.
The Prairie Plains Resource Institute is a nonprofit that preserves and restores tallgrass and mixed-grass prairies in the state. Founded in 1980 by Bill Whitney and his wife, the institute manages eight prairies totaling 6,512 acres, mostly in central and eastern Nebraska.
Whitney, who retired in 2019, said prairies are dependent on people. A large part of prairie conservation, he said, is educating a community to care for them.
“Restoration as a process is a great human thing to do,” Whitney said. “People that do it love it, and it’s going to catch on.”
To Chris Helzer, science and stewardship director for The Nature Conservancy, prairie management standards need to change, especially for tallgrass prairies.
Helzer, echoing Wedin at the Nine-Mile Prairie, said prairies are being “swamped out” by woody plants in the eastern part of the state because of increasing CO2. He also said the absence of large-range grazers such as pronghorn and bison is adding to the problem.
And those conditions are pushing west, Helzer said.
“We need to learn how to manage today’s grasslands as shrubbier grasslands than what we’ve been used to,” Helzer said, “and we need to figure out how to do that in a way that’s going to allow pollinators and a lot of wildlife species to thrive.”
A decade ago, Sarah Bailey of the Prairie Plains Resource Institute said she would see some woody species among the prairie grasses and flowers. Now, she notices a lot more of them in “much denser areas,” mostly in the state’s eastern tallgrass prairies.
Once woody species start taking over a prairie, they start to “choke out” the prairie understory, said Bailey, the institute’s conservation and education director. And without access to consistent sunlight, most native plants wither and die.
“We never want to lose prairie ecosystems,” Bailey said. “That’s where we see the most biodiversity in this region.”
Helzer said grasslands are “one of the most diverse communities in the world.” Much of his work as a scientist, he said, is solving how to optimize grassland use while conserving its biodiversity.
A good example of that, he said, is happening in the Sandhills.
For 33 years, the Sandhills Task Force, a nonprofit based in Broken Bow, has promoted conservation and private, profitable ranching.
Shelly Kelly, the task force’s executive director, said they typically complete 50-100 projects a year, with assistance from conservation partners.
In 2024, the task force helped private landowners improve over 77,000 acres of Sandhills prairie through practices such as prescribed burns, woody species control and modified grazing plans that allow for regrowth.
“Every piece of land that we touch, we’ve impacted for the better,” Kelly said, “and probably increased the chances of it either staying prairie or improved the productivity of it.”
The Sandhills remains one of the largest intact temperate grasslands on Earth, spanning about 12 million acres in north-central Nebraska. But it has also undergone cropland conversion and faces threats from woody encroachment, Kelly said.
Most landowners are open to conservation switches that will help their ranching operations, Kelly said. And the task force, she said, helps move things along.
To Helzer, the story of Nebraska’s prairies isn’t depressing. Instead, he said, it’s a story of survival and resilience.
“We have a lot of work to do, but I still think there’s a ton of reasons to be optimistic about the future of prairies in Nebraska,” he said. “… I think the biggest challenge we have is getting people to care.”
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